M. Z. Kashim, A. Giwelli, B. Clennell, L. Esteban, R. Noble, S. Vialle, Mohsen Ghasemiziarani, Alieh Saedi, Sahriza Salwani Md Shah, J. Ibrahim
In line with PETRONAS commitment to monetize high CO2 content gas field in Malaysia, C Field which is a carbonate gas field located in East Malaysia's waters with approximately 70% of CO2 becomes main target for development because of its technical and economic feasibility. Injectivity has been determined as one of the key parameters that determine the success of CO2 storage in field operations. In order to characterize the CO2 injecitivity behavior in C Field, long duration coreflooding experiments has been conducted on two representative core samples under reservoir conditions. The first set of coreflooding test has been conducted on gas zone sample and another one is on aquifer sample. Two important approach has been applied in the experiment in which the first one is where the base rate is established after each incremental stage and the second one is the pre-equilibration of carbonated brine with standard minerals based on the percentage of core mineralogy before saturating the core with aquifer brine to mimic the insitu geochemical conditions of the reservoir. Pre- and post-flooding characterization was conducted using Routine Core Analysis (RCA), X-Ray CT-scan, Nuclear Magnetic Resonance (NMR) and Inductive Coupled Plasma (ICP) to examine the porosity-permeability changes, pore size alterations and the geochemical processes that might take place during CO2 flooding. Based on the differential pressure data, it showed no clear indication of formation damage even after injection of large CO2 pore volume. Pre and post-flooding characterization supported the findings where minor dissolution/precipitation is observed. Overall intrepretation indicates that the critical flowrate is not yet reached for both samples within the maximum rates applied.
{"title":"Determining Critical Flowrate in High CO2 Content Carbonate Field, Sarawak Basin, Offshore East Malaysia","authors":"M. Z. Kashim, A. Giwelli, B. Clennell, L. Esteban, R. Noble, S. Vialle, Mohsen Ghasemiziarani, Alieh Saedi, Sahriza Salwani Md Shah, J. Ibrahim","doi":"10.2523/IPTC-19422-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19422-MS","url":null,"abstract":"\u0000 In line with PETRONAS commitment to monetize high CO2 content gas field in Malaysia, C Field which is a carbonate gas field located in East Malaysia's waters with approximately 70% of CO2 becomes main target for development because of its technical and economic feasibility. Injectivity has been determined as one of the key parameters that determine the success of CO2 storage in field operations. In order to characterize the CO2 injecitivity behavior in C Field, long duration coreflooding experiments has been conducted on two representative core samples under reservoir conditions. The first set of coreflooding test has been conducted on gas zone sample and another one is on aquifer sample. Two important approach has been applied in the experiment in which the first one is where the base rate is established after each incremental stage and the second one is the pre-equilibration of carbonated brine with standard minerals based on the percentage of core mineralogy before saturating the core with aquifer brine to mimic the insitu geochemical conditions of the reservoir. Pre- and post-flooding characterization was conducted using Routine Core Analysis (RCA), X-Ray CT-scan, Nuclear Magnetic Resonance (NMR) and Inductive Coupled Plasma (ICP) to examine the porosity-permeability changes, pore size alterations and the geochemical processes that might take place during CO2 flooding. Based on the differential pressure data, it showed no clear indication of formation damage even after injection of large CO2 pore volume. Pre and post-flooding characterization supported the findings where minor dissolution/precipitation is observed. Overall intrepretation indicates that the critical flowrate is not yet reached for both samples within the maximum rates applied.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":" 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91410671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Weisheng He, Yan Wang, Huifeng Wang, Yongjun Wang, Tingting Pan, Z. Deng
A heavy oil field is developed with the Steam Assisted Gravity Drainage (SAGD). Since the start of oil production, the oil production amount of the studied reservoir has been lower than that of the surrounding oil fields. The development of the steam chambers are relatively poor, and the spatial distribution of the steam chambers is not clear. In order to describe the shape of the steam chambers accurately, a novel method of monitoring the steam chambers is proposed by using broadband, high-density seismic data and dynamic production data. Broadband, high-density seismic data are acquired. Firstly, seismic horizons are well interpreted, and multiple seismic attributes are analyzed in combination with well data to understand the seismic response of the steam chambers. Then, several seismic inversion methods are tried to obtain high-resolution impedance, and they are compared with each other to find optimal inversion result for steam chamber prediction. Finally, the shape of the steam chambers are delineated with seismic attributes, inverted impedance, production data, and temperature logs of observation wells. The predicted steam chamber has good agreement with the temperature logs of observation wells. The result shows that the appearance of steam chambers has an obvious impact on seismic signals, and broadband, high-density seismic data make great contributions to the description of the steam chambers. The proposed method reduces the uncertainty in steam chamber prediction with single data source, and is applicable to other oilfields using steam injection.
{"title":"Steam Chamber Description Using Seismic and Production Data","authors":"Weisheng He, Yan Wang, Huifeng Wang, Yongjun Wang, Tingting Pan, Z. Deng","doi":"10.2523/IPTC-19105-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19105-MS","url":null,"abstract":"\u0000 A heavy oil field is developed with the Steam Assisted Gravity Drainage (SAGD). Since the start of oil production, the oil production amount of the studied reservoir has been lower than that of the surrounding oil fields. The development of the steam chambers are relatively poor, and the spatial distribution of the steam chambers is not clear. In order to describe the shape of the steam chambers accurately, a novel method of monitoring the steam chambers is proposed by using broadband, high-density seismic data and dynamic production data. Broadband, high-density seismic data are acquired. Firstly, seismic horizons are well interpreted, and multiple seismic attributes are analyzed in combination with well data to understand the seismic response of the steam chambers. Then, several seismic inversion methods are tried to obtain high-resolution impedance, and they are compared with each other to find optimal inversion result for steam chamber prediction. Finally, the shape of the steam chambers are delineated with seismic attributes, inverted impedance, production data, and temperature logs of observation wells. The predicted steam chamber has good agreement with the temperature logs of observation wells. The result shows that the appearance of steam chambers has an obvious impact on seismic signals, and broadband, high-density seismic data make great contributions to the description of the steam chambers. The proposed method reduces the uncertainty in steam chamber prediction with single data source, and is applicable to other oilfields using steam injection.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78271383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qifan Gu, Amirhossein Fallah, A. Ambrus, Dongmei Chen, P. Ashok, E. Oort
For a robust and efficient automated Managed Pressure Drilling (MPD) operation, the choke controller requires an accurate hydraulics model that can be run at minimum computational expense. Integration of a suitable thermal model would improve the accuracy of the hydraulics model used by the choke controller. The use of existing thermal models, however, comes with additional computational costs that are a hurdle when aiming to achieve real-time control at sufficiently fast time-scales. In this paper, a quasi-steady thermal model is integrated with an automated MPD control approach that uses a reduced Drift-Flux Model (RDFM) to describe the hydraulics of multiphase flow in real-time. This integrated modeling approach provides the dynamic temperature profile along a well without increasing the computational expense. The energy equation is solved using the finite-difference method (FDM) in an explicit scheme, with all the temperature-dependent parameters updated in accordance with the calculated temperature profile in each computation step. The RDFM is also reformulated to account for the heat transfer between the gas and the surroundings. This modified model is then incorporated into an automated observer algorithm to estimate parameters, e.g. volume of gas expansion (dependent on temperature), which are used by the controller for choke opening manipulation. Validations are first conducted in a simulation environment for the scenario with a dynamic temperature profile along the well. The results indicate that the proposed modeling approach offers significant improvement compared to approaches which do not consider thermodynamics. A good agreement of the temperature results is observed between the proposed approach and existing models as well as commercial software. Case studies are also conducted for two scenarios to demonstrate the utility of the proposed integrated thermal and hydraulics model. Simulation results indicate that the proposed modeling approach can generate more accurate estimations of unmeasurable variables, which leads to a better performance of the choke manipulation. It should be noted that when employing the modified RDFM with a finite difference scheme, the computational cost is minimized. On a standard laptop computer, the computational time to simulate an entire well is of the order of 70ms for 1s sensor data sampling. Therefore, the proposed thermal and hydraulics model provides an enabling tool for a faster and more precise control of MPD systems.
{"title":"Higher Precision Automated Managed Pressure Drilling Control Achieved Through the Addition of a Thermal Model","authors":"Qifan Gu, Amirhossein Fallah, A. Ambrus, Dongmei Chen, P. Ashok, E. Oort","doi":"10.2523/IPTC-19326-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19326-MS","url":null,"abstract":"\u0000 For a robust and efficient automated Managed Pressure Drilling (MPD) operation, the choke controller requires an accurate hydraulics model that can be run at minimum computational expense. Integration of a suitable thermal model would improve the accuracy of the hydraulics model used by the choke controller. The use of existing thermal models, however, comes with additional computational costs that are a hurdle when aiming to achieve real-time control at sufficiently fast time-scales.\u0000 In this paper, a quasi-steady thermal model is integrated with an automated MPD control approach that uses a reduced Drift-Flux Model (RDFM) to describe the hydraulics of multiphase flow in real-time. This integrated modeling approach provides the dynamic temperature profile along a well without increasing the computational expense. The energy equation is solved using the finite-difference method (FDM) in an explicit scheme, with all the temperature-dependent parameters updated in accordance with the calculated temperature profile in each computation step. The RDFM is also reformulated to account for the heat transfer between the gas and the surroundings. This modified model is then incorporated into an automated observer algorithm to estimate parameters, e.g. volume of gas expansion (dependent on temperature), which are used by the controller for choke opening manipulation.\u0000 Validations are first conducted in a simulation environment for the scenario with a dynamic temperature profile along the well. The results indicate that the proposed modeling approach offers significant improvement compared to approaches which do not consider thermodynamics. A good agreement of the temperature results is observed between the proposed approach and existing models as well as commercial software. Case studies are also conducted for two scenarios to demonstrate the utility of the proposed integrated thermal and hydraulics model. Simulation results indicate that the proposed modeling approach can generate more accurate estimations of unmeasurable variables, which leads to a better performance of the choke manipulation. It should be noted that when employing the modified RDFM with a finite difference scheme, the computational cost is minimized. On a standard laptop computer, the computational time to simulate an entire well is of the order of 70ms for 1s sensor data sampling. Therefore, the proposed thermal and hydraulics model provides an enabling tool for a faster and more precise control of MPD systems.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75731182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Unconventional shale reservoirs have become a key player in the oil and gas industry to cover the world's energy demands. Traditionally, oil-based drilling fluids (OBM) are preferred to drill shale plays due to negligible chemical interactions. Nevertheless, strict environmental regulations have motived the industry to design water-based drilling fluids (WBM) capable to control the shale-water interactions, improving their performance. Still, conventional additives are too large to plug shales’ micro-fractures and nanopores. Thus, nanoparticles due to their unique size, shape, and properties can provide a solution for the WBM. This study focus on the design and evaluation of a customized nanoparticle water-based drilling fluid (NP-WBM) using silica nanoparticles (SiO2-NPs) and graphene nanoplatelets (GNPs). The main objective is to identify the optimal NP concentration to improve the rheological and filtration properties of the NP-WBM and evaluated its inhibition benefit. The NP selection was based on the characteristics of the Woodford shale obtained through x-ray diffraction (XRD), cation exchange capacity (CEC), and scanning electron microscopy (SEM). NPs’ colloidal stability was analyzed in an alkaline environment with zeta-potential measurements. The concentration of NPs was evaluated below 1 wt.%. Laboratory measurements for the NP-WBM included API filtrate test (LTLP) and high-temperature/high-pressure (HTHP) test using a static filter press and rheological analysis with a rotational viscometer. To evaluated the inhibition benefit, the NP-WBM was tested against the Woodford shale by performing immersion and cutting dispersion tests. The results showed zeta-potential values below −30 mV for both nanomaterials, indicating good dispersibility of the NPs within the WBM. Also, significant improvements in the filtration properties were observed when adding 0.5 wt.% of SiO2-NPs with 0.25 wt.% of GNPs to the base fluid with no spurt-loss and minor effects on the rheological parameters. Higher concentrations did not show further improvements; thus the previous combination was selected as the optimal. Chemical interactions tests indicated that the Woodford shale might develop micro-fractures when exposed to water for long periods of time. However, no micro-fractures were observed when the rock was exposed to NPs. Furthermore, the NP-WBM reduced the cutting dispersion by 35.61% compared to the base fluid, showing superior inhibition properties even in high illitic shales that are prone to experience cuttings disintegration. NPs’ stability and benefits at low concentrations, indicates their potential to improve the design of WBM for unconventional shales, reducing the environmental impacts linked to the drilling operations.
{"title":"Design and Evaluation of a Water-Based Drilling Fluid Formulation Using SiO and Graphene Oxide Nanoparticles for Unconventional Shales","authors":"Jose Aramendiz, Abdulmohsin Imqam, Sherif Fakher","doi":"10.2523/IPTC-19342-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19342-MS","url":null,"abstract":"\u0000 Unconventional shale reservoirs have become a key player in the oil and gas industry to cover the world's energy demands. Traditionally, oil-based drilling fluids (OBM) are preferred to drill shale plays due to negligible chemical interactions. Nevertheless, strict environmental regulations have motived the industry to design water-based drilling fluids (WBM) capable to control the shale-water interactions, improving their performance. Still, conventional additives are too large to plug shales’ micro-fractures and nanopores. Thus, nanoparticles due to their unique size, shape, and properties can provide a solution for the WBM. This study focus on the design and evaluation of a customized nanoparticle water-based drilling fluid (NP-WBM) using silica nanoparticles (SiO2-NPs) and graphene nanoplatelets (GNPs). The main objective is to identify the optimal NP concentration to improve the rheological and filtration properties of the NP-WBM and evaluated its inhibition benefit. The NP selection was based on the characteristics of the Woodford shale obtained through x-ray diffraction (XRD), cation exchange capacity (CEC), and scanning electron microscopy (SEM). NPs’ colloidal stability was analyzed in an alkaline environment with zeta-potential measurements. The concentration of NPs was evaluated below 1 wt.%. Laboratory measurements for the NP-WBM included API filtrate test (LTLP) and high-temperature/high-pressure (HTHP) test using a static filter press and rheological analysis with a rotational viscometer. To evaluated the inhibition benefit, the NP-WBM was tested against the Woodford shale by performing immersion and cutting dispersion tests. The results showed zeta-potential values below −30 mV for both nanomaterials, indicating good dispersibility of the NPs within the WBM. Also, significant improvements in the filtration properties were observed when adding 0.5 wt.% of SiO2-NPs with 0.25 wt.% of GNPs to the base fluid with no spurt-loss and minor effects on the rheological parameters. Higher concentrations did not show further improvements; thus the previous combination was selected as the optimal. Chemical interactions tests indicated that the Woodford shale might develop micro-fractures when exposed to water for long periods of time. However, no micro-fractures were observed when the rock was exposed to NPs. Furthermore, the NP-WBM reduced the cutting dispersion by 35.61% compared to the base fluid, showing superior inhibition properties even in high illitic shales that are prone to experience cuttings disintegration. NPs’ stability and benefits at low concentrations, indicates their potential to improve the design of WBM for unconventional shales, reducing the environmental impacts linked to the drilling operations.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83292290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zuobin Lv, Hongli Gao, Qi Cheng, D. Cheng, Zhiqiang Meng
JZS is an offshore metamorphic rock buried hill oilfield. Both horizontal and vertical velocities of the oil field change very fast. The interval velocity of the buried hill stratum is twice that of the overlying strata, and the top surface of the buried hill fluctuates greatly with a maximum height difference of 300m. In the complex buried hill reservoir, since the current professional seismic software can not realize variable time-depth relationship in horizontal direction, which leads to the error of the trajectory form and position of the horizontal well in time domain, therefore the well trajectory in time domain is not matched with that in depth. In this paper, a new practical trajectories matching method for buried hill horizontal wells in time domain and in depth is presented. First of all, we carried on the research on the theoretical form of horizontal well trajectory in buried hill in time domain. The research shows that the theoretical trajectory form of a horizontal well in buried hill is consistent with trend of the buried hill top surface morphology. On the basis of theoretical research, by establishing the pseudo time-depth relationship of horizontal well based on measure depth (MD) and seismic reflection two way time (TWT), we realized the accurate characterization of the trajectory form and position of a horizontal well in buried hill in time domain: (1)For normal horizontal well with no more than 90 degrees inclination angle, we can respectively establish the pseudo time-depth relationship of the horizontal well in buried hill segment and in upper segment, and then merge both time-depth relationship data into a whole; (2)For the complex horizontal well with well segment whose inclination angle is more than 90 degrees, we need firstly split the well trajectory into normal well segment and complex segment according to inclination angle, then establish the pseudo time-depth relationship in normal and complex well segments respectively. More specifically, we can split the trajectory into normal trajectory segment with the inclination angle no more than 90 degrees and complex trajectory segment with the inclination angle more than 90 degrees, for normal segment, we can establish pseudo time-depth relationship like the normal horizontal well described earlier, for complex trajectory segment, we need creatively invert the top and bottom of the complex segment to convert inclination angle of the segment to within 90 degrees, and then establish pseudo time-depth relationship of the inverted segment. Through this method, we can obtain the accurate trajectory form and position of the horizontal well in time domain and it provides a basis for accurate geological modeling based on 3D seismic attributes constrains. The real reservoir performance of JZS buried oilfield in Bohai Bay in China has proved that the 3D geological model based on the new time-depth relationship (MD&TWT) of the horizontal wells is closer to the actual reservoir.
{"title":"A Practical Method to Match Trajectories of a Horizontal Well in Time Domain and in Depth in Ancient Buried Hill","authors":"Zuobin Lv, Hongli Gao, Qi Cheng, D. Cheng, Zhiqiang Meng","doi":"10.2523/IPTC-19504-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19504-MS","url":null,"abstract":"\u0000 JZS is an offshore metamorphic rock buried hill oilfield. Both horizontal and vertical velocities of the oil field change very fast. The interval velocity of the buried hill stratum is twice that of the overlying strata, and the top surface of the buried hill fluctuates greatly with a maximum height difference of 300m. In the complex buried hill reservoir, since the current professional seismic software can not realize variable time-depth relationship in horizontal direction, which leads to the error of the trajectory form and position of the horizontal well in time domain, therefore the well trajectory in time domain is not matched with that in depth.\u0000 In this paper, a new practical trajectories matching method for buried hill horizontal wells in time domain and in depth is presented. First of all, we carried on the research on the theoretical form of horizontal well trajectory in buried hill in time domain. The research shows that the theoretical trajectory form of a horizontal well in buried hill is consistent with trend of the buried hill top surface morphology. On the basis of theoretical research, by establishing the pseudo time-depth relationship of horizontal well based on measure depth (MD) and seismic reflection two way time (TWT), we realized the accurate characterization of the trajectory form and position of a horizontal well in buried hill in time domain: (1)For normal horizontal well with no more than 90 degrees inclination angle, we can respectively establish the pseudo time-depth relationship of the horizontal well in buried hill segment and in upper segment, and then merge both time-depth relationship data into a whole; (2)For the complex horizontal well with well segment whose inclination angle is more than 90 degrees, we need firstly split the well trajectory into normal well segment and complex segment according to inclination angle, then establish the pseudo time-depth relationship in normal and complex well segments respectively. More specifically, we can split the trajectory into normal trajectory segment with the inclination angle no more than 90 degrees and complex trajectory segment with the inclination angle more than 90 degrees, for normal segment, we can establish pseudo time-depth relationship like the normal horizontal well described earlier, for complex trajectory segment, we need creatively invert the top and bottom of the complex segment to convert inclination angle of the segment to within 90 degrees, and then establish pseudo time-depth relationship of the inverted segment.\u0000 Through this method, we can obtain the accurate trajectory form and position of the horizontal well in time domain and it provides a basis for accurate geological modeling based on 3D seismic attributes constrains. The real reservoir performance of JZS buried oilfield in Bohai Bay in China has proved that the 3D geological model based on the new time-depth relationship (MD&TWT) of the horizontal wells is closer to the actual reservoir.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"118 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73419537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jianguo Xu, Chenxu Zhao, Jiangang Zheng, G. Xuan, Ruquan Zhang, Chong Peng, Hongxia Liu
In recent years, the investment of new area productivity construction in Jilin oil field is high, stabilized production becomes more and more difficulty, so the strategic center of oil field transfers to the refracturing of old well, however, the comprehensive water cut and recovery of old oil field is high, and the remaining oil dispersed, increasing production and increasing efficiency by refracturing becomes more and more difficulty. In order to deal with these challenges and realize the benefits of tapping in old area, the new idea of "group fracturing" was proposed basing on the concept of volumetric fracturing, starting from the reconsideration of reservoir geology, injection production unit for the smallest study unit, and integrating multiple fracturing method, we conduct a series of technical studies and field experiment in the old area of Jilin oilfield. The group fracturing technology series mainly includes the following: (1) The high strength positioning and plugging technique for re-orientation fracturing; (2) Energy develop before fracturing and fast energy storage technique in fracturing; (3) Synchronous fracturing technique of multi wells; (4) Synchronous fracturing technique of oil and water well, re-orientation fracturing technique of water well; (5) Fracturing combining with rapid profile control and water plugging technique; (6) "Factory-oriented construction".Since 2016, the group fracturing has carried out a total of 143 wells in 14 blocks in the old area, which has achieved good results. Compared with the conventional fracturing in the same area, the economic efficiency is increased by 10.2%, the oil increase of the single well is increased by 1 times, and the effective period of the measure is raised by 50%. The practice shows that the group fracturing technique is an effective measure to exploit the benefits of the old area in the low permeability oilfield.
{"title":"Application of Group Fracturing Technology in the Old Area of Low Permeable Oilfield: A Case from Jilin Oilfield, Songliao Basin","authors":"Jianguo Xu, Chenxu Zhao, Jiangang Zheng, G. Xuan, Ruquan Zhang, Chong Peng, Hongxia Liu","doi":"10.2523/IPTC-19563-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19563-MS","url":null,"abstract":"\u0000 In recent years, the investment of new area productivity construction in Jilin oil field is high, stabilized production becomes more and more difficulty, so the strategic center of oil field transfers to the refracturing of old well, however, the comprehensive water cut and recovery of old oil field is high, and the remaining oil dispersed, increasing production and increasing efficiency by refracturing becomes more and more difficulty. In order to deal with these challenges and realize the benefits of tapping in old area, the new idea of \"group fracturing\" was proposed basing on the concept of volumetric fracturing, starting from the reconsideration of reservoir geology, injection production unit for the smallest study unit, and integrating multiple fracturing method, we conduct a series of technical studies and field experiment in the old area of Jilin oilfield. The group fracturing technology series mainly includes the following: (1) The high strength positioning and plugging technique for re-orientation fracturing; (2) Energy develop before fracturing and fast energy storage technique in fracturing; (3) Synchronous fracturing technique of multi wells; (4) Synchronous fracturing technique of oil and water well, re-orientation fracturing technique of water well; (5) Fracturing combining with rapid profile control and water plugging technique; (6) \"Factory-oriented construction\".Since 2016, the group fracturing has carried out a total of 143 wells in 14 blocks in the old area, which has achieved good results. Compared with the conventional fracturing in the same area, the economic efficiency is increased by 10.2%, the oil increase of the single well is increased by 1 times, and the effective period of the measure is raised by 50%. The practice shows that the group fracturing technique is an effective measure to exploit the benefits of the old area in the low permeability oilfield.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78782876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y WangJason, M. Sami, A. Troshko, Federico Gallo, Christian S. J. Mayer, Matthew J. Tenny
When producing hydrocarbons from an oil well, managing erosion of both surface and subsurface components caused by solids in the flow stream is critical to maintaining operations integrity in both land and offshore assets. Although component lifetime prediction has advanced in the past few decades, the prediction's accuracy remains a major oil and gas industry challenge. Current computational models only provide an initial erosion rate which is usually assumed constant until equipment failure. However, observed erosional rates vary as a function of time due to the geometrical changes caused by equipment material loss, which result in variations in solid particle impingement velocity [1] thereby either accelerating or slowing the erosional process. The constant rate simplified erosion model often produces inaccurate results that can lead to unexpected equipment failures or unnecessary equipment upgrades depending on whether the rate accelerates or decelerates. Therefore, developing a transient erosion model to capture the variations of erosional rate is needed for an accurate prediction of equipment lifetime. This paper presents an implementation of an erosion dynamics model in ANSYS FLUENT, a commercial computational fluid dynamics (CFD) software, to capture the progression of transient erosion. The model has the capability to capture the effects of surfaces receding from erosion at each time interval. By dynamically adjusting these surfaces and recalculating the local flow conditions in the area, this method can predict new erosion rates for each time interval and achieve fully coupled geometry-flow-erosion interactions. This new erosion dynamics model was validated against experimental data from both literature and physical testing, and was determined to have accurately captured the observed erosion trends over time in terms of location and magnitude. The model was then employed to study two real world applications: 1) in evaluating the erosion risk for a high-rate water injector, it predicted the evolution of damage to a coupler designed to connect different diameter pipes, and 2) in analyzing facility piping systems connected to an unconventional well, it predicted the transient erosion trend from proppant flowback, which allowed for pipe geometry optimization to increase in erosional life expectancy.
{"title":"Development of an Erosion Dynamics Model and its Application to Wells and Facilities","authors":"Y WangJason, M. Sami, A. Troshko, Federico Gallo, Christian S. J. Mayer, Matthew J. Tenny","doi":"10.2523/IPTC-19136-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19136-MS","url":null,"abstract":"\u0000 When producing hydrocarbons from an oil well, managing erosion of both surface and subsurface components caused by solids in the flow stream is critical to maintaining operations integrity in both land and offshore assets. Although component lifetime prediction has advanced in the past few decades, the prediction's accuracy remains a major oil and gas industry challenge. Current computational models only provide an initial erosion rate which is usually assumed constant until equipment failure. However, observed erosional rates vary as a function of time due to the geometrical changes caused by equipment material loss, which result in variations in solid particle impingement velocity [1] thereby either accelerating or slowing the erosional process. The constant rate simplified erosion model often produces inaccurate results that can lead to unexpected equipment failures or unnecessary equipment upgrades depending on whether the rate accelerates or decelerates. Therefore, developing a transient erosion model to capture the variations of erosional rate is needed for an accurate prediction of equipment lifetime.\u0000 This paper presents an implementation of an erosion dynamics model in ANSYS FLUENT, a commercial computational fluid dynamics (CFD) software, to capture the progression of transient erosion. The model has the capability to capture the effects of surfaces receding from erosion at each time interval. By dynamically adjusting these surfaces and recalculating the local flow conditions in the area, this method can predict new erosion rates for each time interval and achieve fully coupled geometry-flow-erosion interactions.\u0000 This new erosion dynamics model was validated against experimental data from both literature and physical testing, and was determined to have accurately captured the observed erosion trends over time in terms of location and magnitude. The model was then employed to study two real world applications: 1) in evaluating the erosion risk for a high-rate water injector, it predicted the evolution of damage to a coupler designed to connect different diameter pipes, and 2) in analyzing facility piping systems connected to an unconventional well, it predicted the transient erosion trend from proppant flowback, which allowed for pipe geometry optimization to increase in erosional life expectancy.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"108 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80817212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fangchao Tong, M. Tang, Gang Chen, Ningbo Wang, Peng Liu, Gongrui Yan, Wei Lin
Drilling horizontal wells in YB gas field in Ordos Basin presents significant challenges due to severe wellbore instabilities problems in drilling through Permian Lower Shihezi and Upper Shanxi formations, where laminated shales overlies with sand and coal seam. In first phase of horizontal wells drilling, most wells encountered severe wellbore instabilities including pack-off, stuck-pipe, over-pull, drilling pipe lost in hole and even side track. Post-well analysis showed that these horizontal wells instabilities mainly occurred in Permian Lower Shihezi and Upper Shanxi formation where most cavings and drilling events (stuck-pipe, over-pull) were observed. In contrast, vertical exploration wells have no such instability issues in same interval. To analyze and understand the mechanism of wellbore instability issue and provide optimal mud weight and better drilling practice to reduce the risk of wellbore instabilities, an anisotropic wellbore stability modeling using Plane-of-Weakness (PoW) failure criterion was carried out in this study. The PoW failure criterion is adopted to compute the onset of rock shear sliding and/or fracture along a weak plane (bedding or fracture) and identify the potential wellbore instability risk in drilling through anisotropic rock formations. The influence of bedding orientation, rock anisotropic elastic and strength properties, and wellbore trajectory on the wellbore stability are all included in the model. This paper describes the process and workflow of conducting PoW wellbore stability modeling for YB field wellbore drilling. The proposed drilling parameters (stable mud weight) from the modeling and its application and improvement for next wells drilling, are also included. The analysis showed that the laminated shale and coal intervals were very prone to fail when well drilled with deviation between 600 to 850. The stable mud weight computed from PoW for drilling through these intervals is 1.40-1.45 g/cc, where as it is 1.20-1.25 g/cc from conventional isotropy wellbore stability model, which was not enough to keep wellbore stable. Based on results from PoW modeling, drilling mud weight scheme was updated and applied to another 3 horizontal wells planned at nearby location. All these three wells were drilled and completed safely without severe wellbore instability issue. In these wells’ 216mm (8.5 in) section, wellbore instability related non-productive time (NPT) was reduced about 11.5 days per well and section time was reduced about 26 days per well. This PoW modeling was first time applied in wellbore stability analysis for horizontal well drilling at Ordos Basin and the results are satisfied and encouraged. The insights provided in this paper suggests that, for drilling in other locations with similar instability challenges, PoW modeling will be a better choice to provide solution and recommendation to ensure drilling safely, improve drilling efficiency and reduce drilling costs.
{"title":"New Modified Plane of Weakness Method Enables Drilling Horizontal Wells Successfully in Ordos Basin, China","authors":"Fangchao Tong, M. Tang, Gang Chen, Ningbo Wang, Peng Liu, Gongrui Yan, Wei Lin","doi":"10.2523/IPTC-19381-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19381-MS","url":null,"abstract":"\u0000 Drilling horizontal wells in YB gas field in Ordos Basin presents significant challenges due to severe wellbore instabilities problems in drilling through Permian Lower Shihezi and Upper Shanxi formations, where laminated shales overlies with sand and coal seam. In first phase of horizontal wells drilling, most wells encountered severe wellbore instabilities including pack-off, stuck-pipe, over-pull, drilling pipe lost in hole and even side track. Post-well analysis showed that these horizontal wells instabilities mainly occurred in Permian Lower Shihezi and Upper Shanxi formation where most cavings and drilling events (stuck-pipe, over-pull) were observed. In contrast, vertical exploration wells have no such instability issues in same interval. To analyze and understand the mechanism of wellbore instability issue and provide optimal mud weight and better drilling practice to reduce the risk of wellbore instabilities, an anisotropic wellbore stability modeling using Plane-of-Weakness (PoW) failure criterion was carried out in this study. The PoW failure criterion is adopted to compute the onset of rock shear sliding and/or fracture along a weak plane (bedding or fracture) and identify the potential wellbore instability risk in drilling through anisotropic rock formations. The influence of bedding orientation, rock anisotropic elastic and strength properties, and wellbore trajectory on the wellbore stability are all included in the model.\u0000 This paper describes the process and workflow of conducting PoW wellbore stability modeling for YB field wellbore drilling. The proposed drilling parameters (stable mud weight) from the modeling and its application and improvement for next wells drilling, are also included. The analysis showed that the laminated shale and coal intervals were very prone to fail when well drilled with deviation between 600 to 850. The stable mud weight computed from PoW for drilling through these intervals is 1.40-1.45 g/cc, where as it is 1.20-1.25 g/cc from conventional isotropy wellbore stability model, which was not enough to keep wellbore stable. Based on results from PoW modeling, drilling mud weight scheme was updated and applied to another 3 horizontal wells planned at nearby location. All these three wells were drilled and completed safely without severe wellbore instability issue. In these wells’ 216mm (8.5 in) section, wellbore instability related non-productive time (NPT) was reduced about 11.5 days per well and section time was reduced about 26 days per well.\u0000 This PoW modeling was first time applied in wellbore stability analysis for horizontal well drilling at Ordos Basin and the results are satisfied and encouraged. The insights provided in this paper suggests that, for drilling in other locations with similar instability challenges, PoW modeling will be a better choice to provide solution and recommendation to ensure drilling safely, improve drilling efficiency and reduce drilling costs.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73211010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Razak, M. N. K. Zaman, Affira Ali, J. Shah, M. Z. Sakdillah, Zarin Zainuri
Brownfield in Balingian and Baram Delta have handful of idle wells and well to be abandoned in their inventories. The project aims to reduce the idle well inventories and support production gain through monetizing behind casing opportunities. The target is to appraise and develop LRLC potentials with lower cost of appraisals. This will maximize full field potentials before abandonment and leads to future development of LRLC opportunities as conventional reservoir becomes more difficult to develop. The idle well inventory has grew up due to problem in production (increase water cut, HGOR) and well problems (sand, fish). An order has been introduced to reduce the idle well list up to 50%. Additionally, in the past, the LRLC intervals were often ignored and considered as water-wet sands due to high water saturation or as tight sands. These intervals, that contain significant reserves, are recognized in many technical papers explaining its identification and evaluation techniques from well-data (logs and samples/cores). The scope of the project is to rejuvenate the idle wells by add-perf LRLC reservoirs. It is impossible to achieve the target without the presence of proper and improved LRLC BCO evaluation process, thus an integrated workflow approach (between Petrophysicist, Reservoir Engineer, Production Technologist, Asset manager & Well Intervention group) has been developed and applied in the project. A new evaluation tools had also been developed called REM (Resolution Enhanced Modelling) in order to improve the log properties of LRLC reservoirs so that the data obtained from old conventional tools can still be used to evaluate LRLC reservoir. Although LRLC is termed UNSEEN, the risk is reduced by proper understanding of hydrocarbon column and sand development. To date, 7 fields are already benefitted from this approach. Field A LRLC reservoir for example has tripled the hydrocarbon saturation, and net to gross has improved to 20% using REM compare to 5% without REM. The other 6 fields are also gaining the same increase in the properties. This has resulted in a cumulative potential of 4.4 MMstb of reserves addition and ~11 KBopd potential gain. As a result, a better and attractive BCO proposals can be generated from LRLC opportunities. The exercise will provide the company with cheaper options of appraising and developing LRLC reservoir while reducing the idle wells. There is no better way of understanding LRLC reservoir; as no tools can identify & quantify it yet, rather from the actual production.
{"title":"Reviving Idle Wells and Unlocking Potential Production Gain in Offshore Sarawak Through Exposing BCO-LRLC Opportunities","authors":"M. Razak, M. N. K. Zaman, Affira Ali, J. Shah, M. Z. Sakdillah, Zarin Zainuri","doi":"10.2523/IPTC-19218-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19218-MS","url":null,"abstract":"\u0000 Brownfield in Balingian and Baram Delta have handful of idle wells and well to be abandoned in their inventories. The project aims to reduce the idle well inventories and support production gain through monetizing behind casing opportunities. The target is to appraise and develop LRLC potentials with lower cost of appraisals. This will maximize full field potentials before abandonment and leads to future development of LRLC opportunities as conventional reservoir becomes more difficult to develop.\u0000 The idle well inventory has grew up due to problem in production (increase water cut, HGOR) and well problems (sand, fish). An order has been introduced to reduce the idle well list up to 50%. Additionally, in the past, the LRLC intervals were often ignored and considered as water-wet sands due to high water saturation or as tight sands. These intervals, that contain significant reserves, are recognized in many technical papers explaining its identification and evaluation techniques from well-data (logs and samples/cores). The scope of the project is to rejuvenate the idle wells by add-perf LRLC reservoirs.\u0000 It is impossible to achieve the target without the presence of proper and improved LRLC BCO evaluation process, thus an integrated workflow approach (between Petrophysicist, Reservoir Engineer, Production Technologist, Asset manager & Well Intervention group) has been developed and applied in the project. A new evaluation tools had also been developed called REM (Resolution Enhanced Modelling) in order to improve the log properties of LRLC reservoirs so that the data obtained from old conventional tools can still be used to evaluate LRLC reservoir. Although LRLC is termed UNSEEN, the risk is reduced by proper understanding of hydrocarbon column and sand development.\u0000 To date, 7 fields are already benefitted from this approach. Field A LRLC reservoir for example has tripled the hydrocarbon saturation, and net to gross has improved to 20% using REM compare to 5% without REM. The other 6 fields are also gaining the same increase in the properties. This has resulted in a cumulative potential of 4.4 MMstb of reserves addition and ~11 KBopd potential gain. As a result, a better and attractive BCO proposals can be generated from LRLC opportunities. The exercise will provide the company with cheaper options of appraising and developing LRLC reservoir while reducing the idle wells. There is no better way of understanding LRLC reservoir; as no tools can identify & quantify it yet, rather from the actual production.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"231 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76435090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Gorgi, J. Joya, A. Al-Ebrahim, Mohamad Rashed Al-Othman, M. Al-Dousari, Abdulsamad Mohamad Ahmed, Mohamad Omar Hassan, Jassim Mohammad Al-Mansour, Abdou Elsayed, A. Alboueshi, A. Allam, Fernando Robles
This paper presents a case history application of real-time fiber-optic technology in the Bahrah oil field, onshore Kuwait. A primary challenge during openhole swellable packer completion operations with multistage fracturing is understanding the number of fractures induced in the formation, particularly in heterogeneous formations where the fracture pressure energy will be distributed along the openhole section. Therefore, fiber-optic technology was selected for the Bahrah project. The application consists in diagnosing a tight carbonate reservoir after multistage acid fracturing and milling the baffles of a production sleeve completion to obtain a well production profile. This technology consists of a fiber-optic cable and a modular sensing bottomhole assembly (BHA). The fiber-optic cable provides distributed temperature sensing (DTS), whereas the BHA is used to monitor pressure, temperature, and the casing collar locator (CCL) in real time. The usual procedure when using conventional coiled tubing (CT) to stimulate a carbonate openhole section is to treat all pay zones with acid and diverter, which increases both operation time and operational costs. In addition, inadequate control of the treatment placement will often result in ineffective stimulation. When using the fiber-optic technology, monitoring is performed by analyzing the distributed temperature profiles both before and after stimulation; the BHA helps ensure that the optimum pressure is maintained and that the fluid is placed accurately through depth correlation sensors. All components of this intervention are performed in a single trip, which reduces both costs and operation time. This paper presents an application that uses the modular sensing BHA to improve the performance of milling balls and baffles in the horizontal production sleeve completion. Afterward, DTS is used to diagnose the reservoir performance after multistage acid fracturing to identify fracture initiation points (FIPs). This assists in design optimization, provides better understanding of formation properties, and helps determine the flow rate distribution of each stage across the entire lateral. Another application uses DTS to obtain the production profile of a 3,286-ft horizontal section while flowing back the well through an electrical submersible pump (ESP). The paper presents the methodology and results of these applications. Using this technology in the petroleum industry helps reduce operation time by up to 50% as a result of performing various CT activities in a single run. This eliminates the need for additional logging or slickline runs using the same BHA, after performing the milling operation to collect DTS data for FIPs and flow rate distribution analysis in the same run. It also reduces costs by enabling real-time decision-making capabilities and effective stimulation.
{"title":"Case History: Real-Time Fiber-Optic Technology Maximizes Tight Carbonate Formation Returns in Kuwait, Multistage Acid Fracturing Diagnostics, Post-Treatment Flowback Allocation, and Production Profiling","authors":"S. Gorgi, J. Joya, A. Al-Ebrahim, Mohamad Rashed Al-Othman, M. Al-Dousari, Abdulsamad Mohamad Ahmed, Mohamad Omar Hassan, Jassim Mohammad Al-Mansour, Abdou Elsayed, A. Alboueshi, A. Allam, Fernando Robles","doi":"10.2523/IPTC-19178-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19178-MS","url":null,"abstract":"\u0000 This paper presents a case history application of real-time fiber-optic technology in the Bahrah oil field, onshore Kuwait. A primary challenge during openhole swellable packer completion operations with multistage fracturing is understanding the number of fractures induced in the formation, particularly in heterogeneous formations where the fracture pressure energy will be distributed along the openhole section. Therefore, fiber-optic technology was selected for the Bahrah project. The application consists in diagnosing a tight carbonate reservoir after multistage acid fracturing and milling the baffles of a production sleeve completion to obtain a well production profile. This technology consists of a fiber-optic cable and a modular sensing bottomhole assembly (BHA). The fiber-optic cable provides distributed temperature sensing (DTS), whereas the BHA is used to monitor pressure, temperature, and the casing collar locator (CCL) in real time.\u0000 The usual procedure when using conventional coiled tubing (CT) to stimulate a carbonate openhole section is to treat all pay zones with acid and diverter, which increases both operation time and operational costs. In addition, inadequate control of the treatment placement will often result in ineffective stimulation. When using the fiber-optic technology, monitoring is performed by analyzing the distributed temperature profiles both before and after stimulation; the BHA helps ensure that the optimum pressure is maintained and that the fluid is placed accurately through depth correlation sensors. All components of this intervention are performed in a single trip, which reduces both costs and operation time.\u0000 This paper presents an application that uses the modular sensing BHA to improve the performance of milling balls and baffles in the horizontal production sleeve completion. Afterward, DTS is used to diagnose the reservoir performance after multistage acid fracturing to identify fracture initiation points (FIPs). This assists in design optimization, provides better understanding of formation properties, and helps determine the flow rate distribution of each stage across the entire lateral. Another application uses DTS to obtain the production profile of a 3,286-ft horizontal section while flowing back the well through an electrical submersible pump (ESP). The paper presents the methodology and results of these applications.\u0000 Using this technology in the petroleum industry helps reduce operation time by up to 50% as a result of performing various CT activities in a single run. This eliminates the need for additional logging or slickline runs using the same BHA, after performing the milling operation to collect DTS data for FIPs and flow rate distribution analysis in the same run. It also reduces costs by enabling real-time decision-making capabilities and effective stimulation.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82007476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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