How to effectively identify the oil and water layer has been a difficult problem in the hydrocarbon indicator (HCI). It is generally believed that the oil layer has the characteristics of low frequency enhancement and high frequency attenuation on the frequency spectrum. But in the actual application, the amplitude and frequency characteristics of the thicker water layer are very similar to that of the oil layer, which makes it hard to distinguish one from the other. In this paper, in order to identify the oil and water layer, a new method basis on matching pursuit decomposition (MPD) is proposed. Firstly, the time-frequency analysis of seismic data is carried out though high precision MPD method. Through analyzing the instantaneous amplitude at different frequencies, we consider that the main difference of the oil and water layer in the frequency spectrum is at the high frequency band where the oil layer shows relatively strong amplitude characteristics. Secondly, base on the high frequency resonance (HFR), the high frequency bright spot attribute is calculated from the frequency division data in the high frequency range. In this new attribute, the water layer is suppressed by the strong amplitude of the oil layer. Finally, the results of the HCI are obtained by multiplying the new attribute with the −90 degree phase shift of the seismic data. The forward modeling test and actual application in Bohai oilfield show that the high frequency bright spot method is more effective in suppressing the water layer and identifying thinner oil layers compared with the conventional low frequency and high frequency attenuation methods of HCI.
{"title":"The Application of High Frequency Resonance Based on MPD in the Identification of Oil and Water Layer","authors":"Pingping Zhang, D. Hou, Xugang Ma, Yichuan Wang","doi":"10.2523/IPTC-19329-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19329-MS","url":null,"abstract":"\u0000 How to effectively identify the oil and water layer has been a difficult problem in the hydrocarbon indicator (HCI). It is generally believed that the oil layer has the characteristics of low frequency enhancement and high frequency attenuation on the frequency spectrum. But in the actual application, the amplitude and frequency characteristics of the thicker water layer are very similar to that of the oil layer, which makes it hard to distinguish one from the other. In this paper, in order to identify the oil and water layer, a new method basis on matching pursuit decomposition (MPD) is proposed. Firstly, the time-frequency analysis of seismic data is carried out though high precision MPD method. Through analyzing the instantaneous amplitude at different frequencies, we consider that the main difference of the oil and water layer in the frequency spectrum is at the high frequency band where the oil layer shows relatively strong amplitude characteristics. Secondly, base on the high frequency resonance (HFR), the high frequency bright spot attribute is calculated from the frequency division data in the high frequency range. In this new attribute, the water layer is suppressed by the strong amplitude of the oil layer. Finally, the results of the HCI are obtained by multiplying the new attribute with the −90 degree phase shift of the seismic data. The forward modeling test and actual application in Bohai oilfield show that the high frequency bright spot method is more effective in suppressing the water layer and identifying thinner oil layers compared with the conventional low frequency and high frequency attenuation methods of HCI.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82601043","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}
Yeen Voon Tan, N. Amiruddin, Hui Ming Li, C. Sim, Shahrizal Abdul Aziz, N. Adnan, M. Mansor, M. A. Anuar, S. Jacobs, Aizuddin Khalid, Ashok Kumar
This paper discusses an alternative study approach with multiple lessons learned from a recent successful infill drilling campaign in a medium-sized brownfield. The team conducted a practical and an optimized subsurface study, including the no-frills classical reservoir engineering and a simple sector model to justify the infill wells. From idea generation to monetization of the barrels, it was fast and cost effective without compromising technical assurance. Results of the infill drilling campaign and lessons learned are discussed in this paper. This is a case study on how a comprehensive understanding of reservoir complexity using creative data integration can be an adequate tool for field development. The results of the campaign demonstrated that an optimized study helps the operator and partners make an efficient investment decision in materializing development opportunities.
{"title":"Unlocking and Materializing Development Opportunities with an Optimized Subsurface Study Approach and Adaptive Execution in a Brownfield","authors":"Yeen Voon Tan, N. Amiruddin, Hui Ming Li, C. Sim, Shahrizal Abdul Aziz, N. Adnan, M. Mansor, M. A. Anuar, S. Jacobs, Aizuddin Khalid, Ashok Kumar","doi":"10.2523/IPTC-19494-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19494-MS","url":null,"abstract":"\u0000 This paper discusses an alternative study approach with multiple lessons learned from a recent successful infill drilling campaign in a medium-sized brownfield. The team conducted a practical and an optimized subsurface study, including the no-frills classical reservoir engineering and a simple sector model to justify the infill wells. From idea generation to monetization of the barrels, it was fast and cost effective without compromising technical assurance.\u0000 Results of the infill drilling campaign and lessons learned are discussed in this paper. This is a case study on how a comprehensive understanding of reservoir complexity using creative data integration can be an adequate tool for field development. The results of the campaign demonstrated that an optimized study helps the operator and partners make an efficient investment decision in materializing development opportunities.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77228387","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}
There is abundant natural gas in Kuqa foreland area of Tarim basin, the reservoir has characteristics of ultra depth(6500m-8000m), high pressure(115MPa-140MPa), high temperature(170°C-190°C) and complex corrosive medium, which bring well integrity high challenge. There are 52 production wells in the Kuqa foreland basin in 2012. The 16 wells of these production wells exist sustained casing pressure(SCP). The SCP wells caused by the tubing string failure is 61%. Since 2012, in order to build safe well barrier and achieve scientific production management, consider all important periods of drilling, well testing, well completion and production in well full life cycle. the design methods of the four main well barrier components(casing string, cement, tubing string, well head) are optimized. A set of technology for well barrier quality control, well maintenance and well production management is formed. Finally, the key technology of full life cycle well integrity for ultra depth, HPHT gas well is formed. In view of the large angle of bedding, well deviation controlled difficultly, and coexistence of high pressure saline aquifer and week bed in one open hole section which lead to serious casing wear and poor cement stone, the vertical well drilling technology, the collapse resistance casing design methods, the casing wear preventing measures, negative pressure test method and high temperature, high density cementing technology are completed. These technologies improve the safety of casing string and the quality of cement. Considering the extreme working conditions(the partial pressure of CO2 is beyond 2MPa, The content of chlorine is about 80000mg/L, acid job, 136MPa pump pressure in well head)of tubing string, material selection method, triaxial stress analysis method, quality control technology for tubing string is optimized. The failure ratio of tubing string reduced from 50% in 2013 to zero in 2017. Referencing API RP 90-2 and IOS16530-2, a special calculation method for annulus pressure management is formed, which include minimum operation pressure and maximum allowable pressure for different annulus. Then a risk assessment system is established. The SCP wells is controlled less than 22% in the condition of increasing number of high pressure gas wells. Based on the research introduced above, China's first set of well integrity specification series is completed. The integrity specification series include the well integrity guide, the well integrity design and the well integrity management for high temperature high pressure and high sulfur gas. These results effectively support safty in production for high pressure gas field in Tarim basin, and will promote the well integrity level in the same kind of oilfield.
塔里木盆地库车前陆地区天然气储量丰富，储层具有超深(6500m ~ 8000m)、高压(115mpa ~ 140mpa)、高温(170℃~ 190℃)、复杂腐蚀介质等特点，对井的完整性提出了很高的挑战。库车前陆盆地2012年生产井52口。这些生产井中有16口井存在持续套管压力(SCP)。由管柱失效引起的SCP井占61%。从2012年开始，为了建立安全井障，实现科学的生产管理，在井全生命周期中考虑钻井、试井、完井和生产的所有重要时期。优化了4个主要井障部件(套管柱、水泥、管柱、井口)的设计方法。形成了一套井眼质量控制、井眼维护和井眼生产管理的技术体系。最后，形成了超深高温气井全生命周期井完整性的关键技术。针对层理角度大、井斜控制困难、同一裸眼段高压盐水层与周层共存导致套管磨损严重、固井效果差的问题，完成了直井钻井技术、抗塌套管设计方法、防套管磨损措施、负压试验方法和高温高密度固井技术。这些技术提高了套管柱的安全性和固井质量。针对管柱的极端工况(CO2分压大于2MPa、氯含量80000mg/L左右、酸作业、井口泵压136MPa)，对管柱的选材方法、三轴应力分析方法、质量控制工艺进行了优化。管柱的故障率从2013年的50%降至2017年的零。参考API RP 90-2和IOS16530-2，形成了环空压力管理的专用计算方法，包括不同环空的最小操作压力和最大允许压力。然后建立了风险评估体系。在高压气井数量不断增加的情况下，SCP井控制在22%以下。在此基础上，完成了国内第一套井完整性规范系列。完整性规范系列包括高温高压高硫气体井完整性指南、井完整性设计和井完整性管理。这些成果有效地支撑了塔里木盆地高压气田的安全生产，提高了同类型油田的井完整性水平。
{"title":"Research and Practice of Full Life Cycle Well Integrity in HTHP Well, Tarim Oilfield","authors":"Hongtao Liu, Lihu Cao, Jun-feng Xie, Xiangtong Yang, Nu Zeng, Xuesong Zhang, Fei Chen","doi":"10.2523/IPTC-19403-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19403-MS","url":null,"abstract":"\u0000 There is abundant natural gas in Kuqa foreland area of Tarim basin, the reservoir has characteristics of ultra depth(6500m-8000m), high pressure(115MPa-140MPa), high temperature(170°C-190°C) and complex corrosive medium, which bring well integrity high challenge. There are 52 production wells in the Kuqa foreland basin in 2012. The 16 wells of these production wells exist sustained casing pressure(SCP). The SCP wells caused by the tubing string failure is 61%.\u0000 Since 2012, in order to build safe well barrier and achieve scientific production management, consider all important periods of drilling, well testing, well completion and production in well full life cycle. the design methods of the four main well barrier components(casing string, cement, tubing string, well head) are optimized. A set of technology for well barrier quality control, well maintenance and well production management is formed. Finally, the key technology of full life cycle well integrity for ultra depth, HPHT gas well is formed.\u0000 In view of the large angle of bedding, well deviation controlled difficultly, and coexistence of high pressure saline aquifer and week bed in one open hole section which lead to serious casing wear and poor cement stone, the vertical well drilling technology, the collapse resistance casing design methods, the casing wear preventing measures, negative pressure test method and high temperature, high density cementing technology are completed. These technologies improve the safety of casing string and the quality of cement. Considering the extreme working conditions(the partial pressure of CO2 is beyond 2MPa, The content of chlorine is about 80000mg/L, acid job, 136MPa pump pressure in well head)of tubing string, material selection method, triaxial stress analysis method, quality control technology for tubing string is optimized. The failure ratio of tubing string reduced from 50% in 2013 to zero in 2017. Referencing API RP 90-2 and IOS16530-2, a special calculation method for annulus pressure management is formed, which include minimum operation pressure and maximum allowable pressure for different annulus. Then a risk assessment system is established. The SCP wells is controlled less than 22% in the condition of increasing number of high pressure gas wells.\u0000 Based on the research introduced above, China's first set of well integrity specification series is completed. The integrity specification series include the well integrity guide, the well integrity design and the well integrity management for high temperature high pressure and high sulfur gas. These results effectively support safty in production for high pressure gas field in Tarim basin, and will promote the well integrity level in the same kind of oilfield.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"365 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80331664","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}
Waterflood (WF) is the main drive mechanism of North Kuwait reservoirs. Different development strategies has been adopted to develop a giant carbonate reservoir in the asset. Irregular scheme of WF has been implemented in the last 5 years which made it challenging to properly evaluate the WF performance. This paper presents both numerical and analytical approaches to assess the current performance of the waterflood in this reservoir. The first method uses actual production and injection data to generate traditional waterflood plots such WOR vs. Np, injection throughput, VRR and other diagnostics. The second approach uses the numerical model to understand the fluid movements in terms of production and water injection. A high resolution model is used to know about the horizontal producers and injectors WF scheme. Streamline model tool is used to understand how the injectors impact their surrounding producers. Injector's efficiency, allocation factors and reservoir sweep efficiency are calculated using the simulation model. Both approaches are compared to have a better evaluation of the waterflood. When the waterflood started, a regular i-9 spot patterns was the way to develop the reservoir. The heterogeneity of the reservoir was observed clearly in the different performance of each pattern. Also, high permeability layer (thief zone) has adversely affected the reservoir performance during WF. The sharp increase of water cut with very low corresponding recovery factor triggered a paradigm shift in developing this waterflooded reservoir. Injecting in lower layers and producing in upper layers (horizontal wells) was the next stage. This brought a great challenge to assess the performance of this WF scheme. Evaluating such a development strategy remains a achallenge.
{"title":"Numerical and Analytical Waterflood Evaluation of North Kuwait Giant Carbonate Reservoir","authors":"B. Al-Otaibi, Sadok Lamine","doi":"10.2523/IPTC-19480-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19480-MS","url":null,"abstract":"\u0000 Waterflood (WF) is the main drive mechanism of North Kuwait reservoirs. Different development strategies has been adopted to develop a giant carbonate reservoir in the asset. Irregular scheme of WF has been implemented in the last 5 years which made it challenging to properly evaluate the WF performance. This paper presents both numerical and analytical approaches to assess the current performance of the waterflood in this reservoir.\u0000 The first method uses actual production and injection data to generate traditional waterflood plots such WOR vs. Np, injection throughput, VRR and other diagnostics.\u0000 The second approach uses the numerical model to understand the fluid movements in terms of production and water injection. A high resolution model is used to know about the horizontal producers and injectors WF scheme. Streamline model tool is used to understand how the injectors impact their surrounding producers. Injector's efficiency, allocation factors and reservoir sweep efficiency are calculated using the simulation model.\u0000 Both approaches are compared to have a better evaluation of the waterflood.\u0000 When the waterflood started, a regular i-9 spot patterns was the way to develop the reservoir. The heterogeneity of the reservoir was observed clearly in the different performance of each pattern. Also, high permeability layer (thief zone) has adversely affected the reservoir performance during WF.\u0000 The sharp increase of water cut with very low corresponding recovery factor triggered a paradigm shift in developing this waterflooded reservoir. Injecting in lower layers and producing in upper layers (horizontal wells) was the next stage. This brought a great challenge to assess the performance of this WF scheme. Evaluating such a development strategy remains a achallenge.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87446329","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}
Shusheng Guo, Yongde Gao, F. Gui, Shanshan Wang, S. Bordoloi, S. Ong, Chao Du, Shiyue Wang
The drilling in Wushi Sag of the Beibu Gulf appears to be problematic with frequent pack-off, tight-hole and stuck-pipe events as well as kicks and losses occurring in different wells. It is of great importance to find out the main cause or causes of these problems so that proper methods and techniques can be utilized to mitigate the problems and reduce the drilling non-productive time (NPT). A series of drilled wells were reviewed to identify the key wells to be used for the geomechanical modelling and to help with understanding the drilling problems. One of the outcomes of the detailed geomechanical analysis was the realization that the stresses and rock behaviors are mainly affected and controlled by the structures. Wushi Sag can be divided into four structural areas: subsag-steep slope in the south, central inverted structure area, north slope and strike-slip faulting belt in the west. As a consequence of the complex structures, the formation depth varies greatly while some formations are absent or incomplete in some wells due to the well-developed high-angled faults. An outcome of the study was the understanding that formation pressures are different in every structural area and are controlled by structural location and burial depth. The main overpressure generating mechanism was found to be type-II fluid expansion caused by either hydrocarbon generation or thermal effects, which can be well correlated to the oil window threshold in the area. Under-compaction may also play a role in some cases, but the overpressure caused by this mechanism is usually low in magnitude. Rock properties vary across the Sag while wells are hard to correlate with each other in different structural areas. The stress conditions appear to be different in each area although the main stress regime is strike-slip with the strike-slip faulting belt in the west having the highest stress ratio. Due to the complexity of the pressure distribution, lateral formation changes and different stress conditions, improper mud weights and casing designs were used in some earlier wells, which likely led to the types of drilling problems listed above. Wells with severe instability problems were generally drilled with lower mud weights compared to the wells with lesser problems. Wells with both pack-off/tight holes and fluid losses usually have surface or intermittent casing shoes set too shallow while not preparing for the steep pressure ramp in deeper formations. Based on the problem diagnostics and geomechanical analyses, recommendations were made to help with the drilling of future wells by mitigating drilling-related instability problems. A series of wells were drilled successfully following the recommendations with all the possible risks properly understood and mitigated.
{"title":"Full Scale Geomechanics Review Assisting Drilling Risk Mitigation in Wushi Sag, Beibu Gulf, China","authors":"Shusheng Guo, Yongde Gao, F. Gui, Shanshan Wang, S. Bordoloi, S. Ong, Chao Du, Shiyue Wang","doi":"10.2523/IPTC-19274-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19274-MS","url":null,"abstract":"\u0000 The drilling in Wushi Sag of the Beibu Gulf appears to be problematic with frequent pack-off, tight-hole and stuck-pipe events as well as kicks and losses occurring in different wells. It is of great importance to find out the main cause or causes of these problems so that proper methods and techniques can be utilized to mitigate the problems and reduce the drilling non-productive time (NPT).\u0000 A series of drilled wells were reviewed to identify the key wells to be used for the geomechanical modelling and to help with understanding the drilling problems. One of the outcomes of the detailed geomechanical analysis was the realization that the stresses and rock behaviors are mainly affected and controlled by the structures. Wushi Sag can be divided into four structural areas: subsag-steep slope in the south, central inverted structure area, north slope and strike-slip faulting belt in the west. As a consequence of the complex structures, the formation depth varies greatly while some formations are absent or incomplete in some wells due to the well-developed high-angled faults.\u0000 An outcome of the study was the understanding that formation pressures are different in every structural area and are controlled by structural location and burial depth. The main overpressure generating mechanism was found to be type-II fluid expansion caused by either hydrocarbon generation or thermal effects, which can be well correlated to the oil window threshold in the area. Under-compaction may also play a role in some cases, but the overpressure caused by this mechanism is usually low in magnitude. Rock properties vary across the Sag while wells are hard to correlate with each other in different structural areas. The stress conditions appear to be different in each area although the main stress regime is strike-slip with the strike-slip faulting belt in the west having the highest stress ratio.\u0000 Due to the complexity of the pressure distribution, lateral formation changes and different stress conditions, improper mud weights and casing designs were used in some earlier wells, which likely led to the types of drilling problems listed above. Wells with severe instability problems were generally drilled with lower mud weights compared to the wells with lesser problems. Wells with both pack-off/tight holes and fluid losses usually have surface or intermittent casing shoes set too shallow while not preparing for the steep pressure ramp in deeper formations. Based on the problem diagnostics and geomechanical analyses, recommendations were made to help with the drilling of future wells by mitigating drilling-related instability problems. A series of wells were drilled successfully following the recommendations with all the possible risks properly understood and mitigated.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"80 2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87978036","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}
The igneous reservoir of Shahejie formation in eastern sag of Liaohe depression is characterized by complex geological environment, variable lithology and high heterogeneity. Reservoir evaluation is difficult only based on conventional logs due to complex lithology and pore structures. Effective igneous reservoirs were identified and reservoir controlling factors were analyzed based on effective porosity calculation, pore structure analysis, lithology identification, lithofacies analysis, fracture evaluation and heterogeneity analysis by combing nuclear magnetic resonance data, micro-resistivity image data, conventional logs as well as mud logging data. Based on our study, the igneous reservoirs in the study area are more related with effective porosity and pore connectivity, and less related with fractures. Good reservoirs are mainly distributed on the top part of explosive facies and effusive facies, where lithologies are mainly Trachyte, volcanic breccia and breccia-bearing tuff. The weathering leaching process is quite important for igneous reservoirs, but the reservoir qulity would not be good if the weathering process is too strong as it will lead to low effective porosity. The accuracy of igneous reservoir evaluation gets improved a lot by this integrated approach and the conclusion from this study will help to optimize igneous reservoire exploration plan.
{"title":"Effective Igneous Reservoir Identification and Controlling Factor Analysis in Eastern Sag of Liaohe Depression, China","authors":"Zhenhua Hu, Shenqin Zhang, Fangfang Wu, Xunqi Liu, Jinlong Wu, Shenzhuan Li, Yuxi Wang, Xianran Zhao, Haipeng Zhao","doi":"10.2523/IPTC-19442-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19442-MS","url":null,"abstract":"\u0000 The igneous reservoir of Shahejie formation in eastern sag of Liaohe depression is characterized by complex geological environment, variable lithology and high heterogeneity. Reservoir evaluation is difficult only based on conventional logs due to complex lithology and pore structures. Effective igneous reservoirs were identified and reservoir controlling factors were analyzed based on effective porosity calculation, pore structure analysis, lithology identification, lithofacies analysis, fracture evaluation and heterogeneity analysis by combing nuclear magnetic resonance data, micro-resistivity image data, conventional logs as well as mud logging data.\u0000 Based on our study, the igneous reservoirs in the study area are more related with effective porosity and pore connectivity, and less related with fractures. Good reservoirs are mainly distributed on the top part of explosive facies and effusive facies, where lithologies are mainly Trachyte, volcanic breccia and breccia-bearing tuff. The weathering leaching process is quite important for igneous reservoirs, but the reservoir qulity would not be good if the weathering process is too strong as it will lead to low effective porosity.\u0000 The accuracy of igneous reservoir evaluation gets improved a lot by this integrated approach and the conclusion from this study will help to optimize igneous reservoire exploration plan.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84906245","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}
Yijin Zeng, Yuan Gao, Shiming Zhou, Q. Tao, Sang Laiyu, Guangguo Yang, Peiqing Lu
Many challenges exist in ultra-deep high-temperature and high-pressure gas well cementing, such as, high-temperature, active gas layer, narrow density window, and seal integrity failure of cement sheath, which brings huge difficulties in anti-gas channeling cementing. By selecting the nano-liquid silicon and latex anti-gas channeling agents, and synergistically enhancing the anti-gas channeling performance of cement slurry, the mechanical properties of cement set is improved; by optimizing the compounding and dosage of silicon powder with different particle sizes, the high-temperature stability of cement set is enhanced. Via the selection of inorganic fiber cracking-prevention and plugging system, the crack propagation is inhibited, and the leakage resistance of cement slurry and the impact resistance of cement set are improved. Hence, a high-temperature resistant latex anti-gas channeling cement slurry system was developed. The cement slurry system has the following properties: API water loss of <50 mL at 180 °C, SPN value of <1, cement set compressive strength of 39.3 MPa under 200 °C×21 MPa×60 d, Young's modulus of 6.9 GPa, gas layer permeability of 0.004×10-3 μm2, and its comprehensive mechanical properties are better than that on the 30th day. The cement sheath seal integrity evaluation shows that the 26.7 mm sheath can achieve an effective seal effect under the cyclic loading process (peak pressure is 90 MPa). Combined with the staged gas layer stability prediction, the pressure management cementing technology under unsteady conditions was proposed, which solves the problems of gas channeling and leakage prevention in ultra-deep high-temperature and high-pressure reservoirs with enriched fracture-cavity. The anti-gas channeling cementing technology has been used in the Shunnan and Shunbei plays of Sinopec Northwest Oilfield Company, and it can provide references for the cementing of similar gas wells.
{"title":"Anti-Gas Channeling Cementing Technology for Ultra-Deep High Temperature and High Pressure Gas Wells","authors":"Yijin Zeng, Yuan Gao, Shiming Zhou, Q. Tao, Sang Laiyu, Guangguo Yang, Peiqing Lu","doi":"10.2523/IPTC-19109-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19109-MS","url":null,"abstract":"\u0000 Many challenges exist in ultra-deep high-temperature and high-pressure gas well cementing, such as, high-temperature, active gas layer, narrow density window, and seal integrity failure of cement sheath, which brings huge difficulties in anti-gas channeling cementing. By selecting the nano-liquid silicon and latex anti-gas channeling agents, and synergistically enhancing the anti-gas channeling performance of cement slurry, the mechanical properties of cement set is improved; by optimizing the compounding and dosage of silicon powder with different particle sizes, the high-temperature stability of cement set is enhanced. Via the selection of inorganic fiber cracking-prevention and plugging system, the crack propagation is inhibited, and the leakage resistance of cement slurry and the impact resistance of cement set are improved. Hence, a high-temperature resistant latex anti-gas channeling cement slurry system was developed. The cement slurry system has the following properties: API water loss of <50 mL at 180 °C, SPN value of <1, cement set compressive strength of 39.3 MPa under 200 °C×21 MPa×60 d, Young's modulus of 6.9 GPa, gas layer permeability of 0.004×10-3 μm2, and its comprehensive mechanical properties are better than that on the 30th day. The cement sheath seal integrity evaluation shows that the 26.7 mm sheath can achieve an effective seal effect under the cyclic loading process (peak pressure is 90 MPa). Combined with the staged gas layer stability prediction, the pressure management cementing technology under unsteady conditions was proposed, which solves the problems of gas channeling and leakage prevention in ultra-deep high-temperature and high-pressure reservoirs with enriched fracture-cavity. The anti-gas channeling cementing technology has been used in the Shunnan and Shunbei plays of Sinopec Northwest Oilfield Company, and it can provide references for the cementing of similar gas wells.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87775949","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. Harris, Samita Santoshini, Stewart Smith, A. Levannier, O. H. Khan
The vast majority of grids for reservoir modeling and simulation workflows are based on pillar gridding or stairstep grid technologies. The grids are part of a feature-rich and well-established modeling workflow provided by many commercial software packages. Undesirable and significant simplifications to the gridding often arise when employing such approaches in structurally complex areas, and this will clearly lead to poor predictions from the downstream modeling. In the classical gridding and modeling workflow, the grid is built in geological space from input horizon and fault interpretations, and the property modeling occurs in an approximated ‘depositional’ space generated from the geological space grid cells. The unstructured grids that we consider here are based on a very different workflow: a volume-based structural model is first constructed from the fault/horizon input data; a flattening (‘depositional’) mapping deforms the mesh of the structural model under mechanical and geometric constraints; the property modeling occurs in this depositional space on a regular cuboidal grid; after ‘cutting’ this grid by the geological discontinuities, the inverse depositional mapping recovers the final unstructured grid in geological space. A critical part of the depositional transformation is the improved preservation of geodetic distances and the layer-orthogonality of the grid cells. The final grid is an accurate representation of the input structural model, and therefore the quality checking of the modeling workflow must be focused on the input data and structural model creation. We describe a variety of basic quality checking and structurally-focused tools that should be applied at this stage; these tools aim to ensure the accuracy of the depositional transformation, and consequently ensure both the quality of the generated grid and the consistent representation of the property models. A variety of quality assurance metrics applied to the depositional/geological grid geometries provide spatial measures of the ‘quality’ of the gridding and modeling workflow, and the ultimate validation of the structural quality of the input data. Two case studies will be used to demonstrate this novel workflow for creating high-quality unstructured grids in structurally complex areas. The improved quality is validated by monitoring downstream impacts on property prediction and reservoir simulation; these improved prediction scenarios are a more accurate basis for history matching approaches.
{"title":"Complex Geological Modeling Using Unstructured Grids: Quality Assurance Approaches and Improved Prediction","authors":"S. Harris, Samita Santoshini, Stewart Smith, A. Levannier, O. H. Khan","doi":"10.2523/IPTC-19303-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19303-MS","url":null,"abstract":"\u0000 The vast majority of grids for reservoir modeling and simulation workflows are based on pillar gridding or stairstep grid technologies. The grids are part of a feature-rich and well-established modeling workflow provided by many commercial software packages. Undesirable and significant simplifications to the gridding often arise when employing such approaches in structurally complex areas, and this will clearly lead to poor predictions from the downstream modeling.\u0000 In the classical gridding and modeling workflow, the grid is built in geological space from input horizon and fault interpretations, and the property modeling occurs in an approximated ‘depositional’ space generated from the geological space grid cells. The unstructured grids that we consider here are based on a very different workflow: a volume-based structural model is first constructed from the fault/horizon input data; a flattening (‘depositional’) mapping deforms the mesh of the structural model under mechanical and geometric constraints; the property modeling occurs in this depositional space on a regular cuboidal grid; after ‘cutting’ this grid by the geological discontinuities, the inverse depositional mapping recovers the final unstructured grid in geological space. A critical part of the depositional transformation is the improved preservation of geodetic distances and the layer-orthogonality of the grid cells.\u0000 The final grid is an accurate representation of the input structural model, and therefore the quality checking of the modeling workflow must be focused on the input data and structural model creation. We describe a variety of basic quality checking and structurally-focused tools that should be applied at this stage; these tools aim to ensure the accuracy of the depositional transformation, and consequently ensure both the quality of the generated grid and the consistent representation of the property models. A variety of quality assurance metrics applied to the depositional/geological grid geometries provide spatial measures of the ‘quality’ of the gridding and modeling workflow, and the ultimate validation of the structural quality of the input data.\u0000 Two case studies will be used to demonstrate this novel workflow for creating high-quality unstructured grids in structurally complex areas. The improved quality is validated by monitoring downstream impacts on property prediction and reservoir simulation; these improved prediction scenarios are a more accurate basis for history matching approaches.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76628224","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}
JZS oilfield is an offshore metamorphic rock fractured buried hill oilfield. It was put into development in July 2010. The overall production situation of the oilfield is good, but some problems have been exposed. The main performance is as follows: It is difficult to accurately characterize the heterogeneity of fracture space distribution; In the numerical simulation of fractured reservoir, it is impossible to accurately describe and predict the fracture flow of fluid channeling in corner point grid system. In order to solve the above problems, this study presents a new integrated fractured reservoir geological modeling and numerical simulation research method based on unstructured grid. There are three key aspects to this method. (1) The multi-scale (large, middle and small) discrete fracture system is established by combining outcrop measurement data with well point information and seismic attributes. On the basis of post-stack 3D seismic data, ants attributes are extracted, then the ant body results are transformed into large scale fractures; Using azimuth anisotropy attribute based on pre-stack inversion and combining the distribution orientation of large-scale fractures, the middle-scale fractures are established; According to the power law distribution relation between the cumulative frequency and the fracture length of large scale and small scale which based on outcrop observation, the imaging logging data and pre-stack inversion azimuth anisotropy attribute, small scale fractures are constructed by DFN technology.(2) For multi-scale fractures, the unstructured grid division technique is used to build a 3D model that conforms to the heterogeneity of dual media. In this study, a layered triangular prism grid generation technique is proposed. It is used to establish model of multi-scale fractures based on unstructured grid. Using large-scale fractures as a constraint, full 3D unstructured grid model is set up, and the discrete fracture model can accurately describe the fracture system and the coupling relationship between matrix and the fracture;(3)The triple-medium numerical simulation of the reservoir in the study area is carried out by using the automatic history fitting technology of ensemble kalman filter (EnKF). After several parameter adjustments, both the coincidence rate of the index and the fitting precision are higher than before. Multi-scale discrete fracture model based on the large-scale fractures discretization processing, equivalent medium processing to middle and small scale fractures, keeps the seepage characteristic of the large-scale discrete fractures model and ensures the calculation efficiency. The results show that the new method has obvious advantages in computing speed and that the fitting effect is closer to the actual production performance.
{"title":"Application of an Integrative New Technique on Modeling and Numerical Simulation for Fractured Reservoir Based on Unstructured Grid: A Case Study of JZS Buried Hill Reservoir","authors":"Zuobin Lv, Chunliang Huo, Lizhen Ge, Jing Xu, Zhiqiang Zhu","doi":"10.2523/IPTC-19267-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19267-MS","url":null,"abstract":"\u0000 JZS oilfield is an offshore metamorphic rock fractured buried hill oilfield. It was put into development in July 2010. The overall production situation of the oilfield is good, but some problems have been exposed. The main performance is as follows: It is difficult to accurately characterize the heterogeneity of fracture space distribution; In the numerical simulation of fractured reservoir, it is impossible to accurately describe and predict the fracture flow of fluid channeling in corner point grid system.\u0000 In order to solve the above problems, this study presents a new integrated fractured reservoir geological modeling and numerical simulation research method based on unstructured grid. There are three key aspects to this method. (1) The multi-scale (large, middle and small) discrete fracture system is established by combining outcrop measurement data with well point information and seismic attributes. On the basis of post-stack 3D seismic data, ants attributes are extracted, then the ant body results are transformed into large scale fractures; Using azimuth anisotropy attribute based on pre-stack inversion and combining the distribution orientation of large-scale fractures, the middle-scale fractures are established; According to the power law distribution relation between the cumulative frequency and the fracture length of large scale and small scale which based on outcrop observation, the imaging logging data and pre-stack inversion azimuth anisotropy attribute, small scale fractures are constructed by DFN technology.(2) For multi-scale fractures, the unstructured grid division technique is used to build a 3D model that conforms to the heterogeneity of dual media. In this study, a layered triangular prism grid generation technique is proposed. It is used to establish model of multi-scale fractures based on unstructured grid. Using large-scale fractures as a constraint, full 3D unstructured grid model is set up, and the discrete fracture model can accurately describe the fracture system and the coupling relationship between matrix and the fracture;(3)The triple-medium numerical simulation of the reservoir in the study area is carried out by using the automatic history fitting technology of ensemble kalman filter (EnKF). After several parameter adjustments, both the coincidence rate of the index and the fitting precision are higher than before.\u0000 Multi-scale discrete fracture model based on the large-scale fractures discretization processing, equivalent medium processing to middle and small scale fractures, keeps the seepage characteristic of the large-scale discrete fractures model and ensures the calculation efficiency. The results show that the new method has obvious advantages in computing speed and that the fitting effect is closer to the actual production performance.","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76202731","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}
Jian Zhao, J. He, Yong He, P. Sun, Yanbo Li, Hongliang Chen, Shengliang Zhang, Y. Guo
The poor quality of resources, low utilization of reserves,high investment in capacity building are the main problems faced in low permeability reservoir in Jilin Oilfield.The objective of this research is to form a intensive drilling model of large platforms which can improve the drilling quality,efficiency and management level. By applying this model,we can increase the single well production,block recovery rate and reduce the production construction investments,the development and production costs in low permeability oilfield. This research based on the production capacity construction in the Jilin Oilfield.This drilling model is different from the traditional model which is inefficient and the investments are higher.Our main procedures included the drilling plan optimization,intensive drilling application,efficient drilling technology application and drilling production management optimization. From 2015 to 2017,we have applied this drilling model successfully in Jilin Oilfield. 1 Drilling Plan Optimization Technology The single well and small platforms are commonly used in the reservoir development of Jilin oilfield. Because of the low oil price,we changed our train of thought from traditional development mode to intensive drilling model of large platforms large platforms.It can reduce the land occupation area of well sites,reduce integrated management costs,and improve economical benefits of development effectively.By applying the lowest costs of investment principles,drilling engineering formed integrated drilling plan optimization technology which satisfied the requirements of geological deployment,fracturing and lifting,ground engineering,intensive drilling,economical development.It formed the platform size optimization technology that determined the most economical well number of the platforms.The oil field development investments contain 6 main parts,including drilling engineering,mud log engineering,logging engineering,oil recovery engineering,surface construction engineering and land occupation investments.With the increasing of the platform scale,the investments of drilling engineering increases,because the costs of drilling bits,drilling mud,casing,cement increase,which caused by the increasing of the well depth.The increasing of mud log engineering and logging engineering are not obviously which can be not considered.The investments of oil recovery engineering increases,because the costs of oil lifting,oil pumping machine,well perforation,water flooding increase,which caused by the increasing of the well depth.The investments of surface construction engineering and land occupation investments decrease because of the reduction of well sites pipe network and ground roads.In a word,the investments of drilling and oil recovery engineering increase and the investments of surface construction engineering and land occupation decrease with the increase of platform scale,which exists the optimum interval.By building di
{"title":"Research and Application on Intensive Drilling Model of Large Platforms","authors":"Jian Zhao, J. He, Yong He, P. Sun, Yanbo Li, Hongliang Chen, Shengliang Zhang, Y. Guo","doi":"10.2523/IPTC-19374-MS","DOIUrl":"https://doi.org/10.2523/IPTC-19374-MS","url":null,"abstract":"\u0000 \u0000 \u0000 The poor quality of resources, low utilization of reserves,high investment in capacity building are the main problems faced in low permeability reservoir in Jilin Oilfield.The objective of this research is to form a intensive drilling model of large platforms which can improve the drilling quality,efficiency and management level. By applying this model,we can increase the single well production,block recovery rate and reduce the production construction investments,the development and production costs in low permeability oilfield.\u0000 \u0000 \u0000 \u0000 This research based on the production capacity construction in the Jilin Oilfield.This drilling model is different from the traditional model which is inefficient and the investments are higher.Our main procedures included the drilling plan optimization,intensive drilling application,efficient drilling technology application and drilling production management optimization. From 2015 to 2017,we have applied this drilling model successfully in Jilin Oilfield.\u0000 \u0000 \u0000 \u0000 1 Drilling Plan Optimization Technology\u0000 The single well and small platforms are commonly used in the reservoir development of Jilin oilfield. Because of the low oil price,we changed our train of thought from traditional development mode to intensive drilling model of large platforms large platforms.It can reduce the land occupation area of well sites,reduce integrated management costs,and improve economical benefits of development effectively.By applying the lowest costs of investment principles,drilling engineering formed integrated drilling plan optimization technology which satisfied the requirements of geological deployment,fracturing and lifting,ground engineering,intensive drilling,economical development.It formed the platform size optimization technology that determined the most economical well number of the platforms.The oil field development investments contain 6 main parts,including drilling engineering,mud log engineering,logging engineering,oil recovery engineering,surface construction engineering and land occupation investments.With the increasing of the platform scale,the investments of drilling engineering increases,because the costs of drilling bits,drilling mud,casing,cement increase,which caused by the increasing of the well depth.The increasing of mud log engineering and logging engineering are not obviously which can be not considered.The investments of oil recovery engineering increases,because the costs of oil lifting,oil pumping machine,well perforation,water flooding increase,which caused by the increasing of the well depth.The investments of surface construction engineering and land occupation investments decrease because of the reduction of well sites pipe network and ground roads.In a word,the investments of drilling and oil recovery engineering increase and the investments of surface construction engineering and land occupation decrease with the increase of platform scale,which exists the optimum interval.By building di","PeriodicalId":11267,"journal":{"name":"Day 3 Thu, March 28, 2019","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74263376","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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