J. Alaamri, Mohammad AlDahlan, I. Al-Yami, A. Alghamdi
Waterflooding has always been considered as a favorable technology to support reservoir pressure during production and enhance recovery. The main challenge that needs to be addressed is the increase in scale potential due to incompatibility of mixing two different waters of different physical and chemical properties. Calcium sulfate scaling can form as a result of the reaction of high calcium produced water with high sulfate injection water. Since there is no feasible method that can efficiently be used to reduce the high calcium content in the formation water, treating the injection water by adding scale inhibitor or lowering its sulfate content is of high interest. Reducing the sulfate content physically through RO membranes or chemically through ion exchange methods can be considered a solution. In this study, different scenarios for using reduced sulfate simulated injection water (SIW) in addition to untreated SIW have been examined as options for waterflooding prior to field application recommendations. Three different concentrations of reduced sulfate SIW (100, 200 and 300 SO4− ppm) in addition to the untreated SIW with almost 4000 ppm of SO4− were used to study water-water reaction and water-rock interaction. The study scheme included static bottle testing for compatibility of the synthetic flooding water and SPW at different mixing ratios and coreflooding at different temperatures for the water-rock interaction. Water-water interaction tests revealed that the reduced sulfate SIW was found to be compatible, and no sign of precipitatation was observed. Untreated SIW showed white precipitates of calcium sulfate when mixed with the high calcium synthetic simulated production water (SPW) at different ratios and temperature. Coreflooding formation damage assessment indicated a reduction in the commercial core plug permeability of less than 12%. Reduced sulfate waterflooding can eliminate the risk of calcium sulfate scale formation damage and minimizing scaling mitigation and challenges requirements.
{"title":"Formation Damage Assessment and Waterflooding Incompatibility Study for Reduced Sulfate Injection Water","authors":"J. Alaamri, Mohammad AlDahlan, I. Al-Yami, A. Alghamdi","doi":"10.2118/197802-ms","DOIUrl":"https://doi.org/10.2118/197802-ms","url":null,"abstract":"\u0000 Waterflooding has always been considered as a favorable technology to support reservoir pressure during production and enhance recovery. The main challenge that needs to be addressed is the increase in scale potential due to incompatibility of mixing two different waters of different physical and chemical properties. Calcium sulfate scaling can form as a result of the reaction of high calcium produced water with high sulfate injection water. Since there is no feasible method that can efficiently be used to reduce the high calcium content in the formation water, treating the injection water by adding scale inhibitor or lowering its sulfate content is of high interest. Reducing the sulfate content physically through RO membranes or chemically through ion exchange methods can be considered a solution.\u0000 In this study, different scenarios for using reduced sulfate simulated injection water (SIW) in addition to untreated SIW have been examined as options for waterflooding prior to field application recommendations. Three different concentrations of reduced sulfate SIW (100, 200 and 300 SO4− ppm) in addition to the untreated SIW with almost 4000 ppm of SO4− were used to study water-water reaction and water-rock interaction. The study scheme included static bottle testing for compatibility of the synthetic flooding water and SPW at different mixing ratios and coreflooding at different temperatures for the water-rock interaction.\u0000 Water-water interaction tests revealed that the reduced sulfate SIW was found to be compatible, and no sign of precipitatation was observed. Untreated SIW showed white precipitates of calcium sulfate when mixed with the high calcium synthetic simulated production water (SPW) at different ratios and temperature. Coreflooding formation damage assessment indicated a reduction in the commercial core plug permeability of less than 12%.\u0000 Reduced sulfate waterflooding can eliminate the risk of calcium sulfate scale formation damage and minimizing scaling mitigation and challenges requirements.","PeriodicalId":11328,"journal":{"name":"Day 4 Thu, November 14, 2019","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80774607","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}
Expansion / Debottlenecking of Industrial or Oil & Gas plants is a common phenomenon and many a times such expansion has to be located within limited plot boundaries posing multiple challenges in locating the equipment and design & execution of supporting civil structures. In some cases, finalized supporting civil structures are not feasible to implement due to additional challenges such as additional underground utilities not identified in as-built survey that may arise during execution stage affecting project schedule. Generally, such unique design challenges are not encountered in Greenfield project development. This paper presents the typical constraints encountered in expansion projects, key parameters required to finalize the innovative solutions and measures / methods adopted to overcome the constraints in most effective and economical way in one of the major brownfield project without affecting safe functioning of existing plant. Vibration transmissibility to structures / equipment from new equipment or old equipment vice versa, physical constraints in supporting / routing new piping, underground utilities present in the plot are some of the major challenges faced during detail engineering. Enhancing existing supporting structures for new codal requirements (e.g. revised seismic definition) and enhanced design life to support additional loads of new project in addition to existing ones are some of the additional challenge faced during engineering and construction of the brown field projects Key parameters to be studied / considered while arriving optimal civil engineering solutions to challenges encountered, dynamic properties of new or existing equipment, foot print and founding details of existing foundations, underground utilities present in the plot / boundaries, presence of ground water table, execution feasibility of proposed new civil structures under plant operating conditions thereby avoiding plant or unit shutdowns etc. The solution arrived may have to be revised based on additional challenges that may unfold during execution stage. Fit for purpose supporting structure configurations, out of box structural designs, usage of unique material etc., are some of the methods adopted in arriving safe and economically sound design to overcome the constraints. Brownfield expansion in constrained plots of existing plants is a common phenomenon in all industries. Fit-for-purpose solution needs to be arrived considering constraints applicable to that equipment / plot while maintaining Plant safety and integrity. Similar approaches may be adopted to mitigate challenges in brownfield expansion of other plants to arrive at cost-effective & safe solutions.
{"title":"Civil Engineering Challenges in Brownfield Projects - A Case Study","authors":"Sreekanth Nuthanapati, Khalid Adel, I. A. Awadhi","doi":"10.2118/197858-ms","DOIUrl":"https://doi.org/10.2118/197858-ms","url":null,"abstract":"\u0000 Expansion / Debottlenecking of Industrial or Oil & Gas plants is a common phenomenon and many a times such expansion has to be located within limited plot boundaries posing multiple challenges in locating the equipment and design & execution of supporting civil structures. In some cases, finalized supporting civil structures are not feasible to implement due to additional challenges such as additional underground utilities not identified in as-built survey that may arise during execution stage affecting project schedule. Generally, such unique design challenges are not encountered in Greenfield project development.\u0000 This paper presents the typical constraints encountered in expansion projects, key parameters required to finalize the innovative solutions and measures / methods adopted to overcome the constraints in most effective and economical way in one of the major brownfield project without affecting safe functioning of existing plant.\u0000 Vibration transmissibility to structures / equipment from new equipment or old equipment vice versa, physical constraints in supporting / routing new piping, underground utilities present in the plot are some of the major challenges faced during detail engineering. Enhancing existing supporting structures for new codal requirements (e.g. revised seismic definition) and enhanced design life to support additional loads of new project in addition to existing ones are some of the additional challenge faced during engineering and construction of the brown field projects\u0000 Key parameters to be studied / considered while arriving optimal civil engineering solutions to challenges encountered, dynamic properties of new or existing equipment, foot print and founding details of existing foundations, underground utilities present in the plot / boundaries, presence of ground water table, execution feasibility of proposed new civil structures under plant operating conditions thereby avoiding plant or unit shutdowns etc. The solution arrived may have to be revised based on additional challenges that may unfold during execution stage.\u0000 Fit for purpose supporting structure configurations, out of box structural designs, usage of unique material etc., are some of the methods adopted in arriving safe and economically sound design to overcome the constraints.\u0000 Brownfield expansion in constrained plots of existing plants is a common phenomenon in all industries. Fit-for-purpose solution needs to be arrived considering constraints applicable to that equipment / plot while maintaining Plant safety and integrity. Similar approaches may be adopted to mitigate challenges in brownfield expansion of other plants to arrive at cost-effective & safe solutions.","PeriodicalId":11328,"journal":{"name":"Day 4 Thu, November 14, 2019","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80990285","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}
Cementing of a casing string or liner is always considered a crucial phase of the well construction process. The difference with the other phases, is that once cement has been mixed and pumped in the well, there is a limited amount of time for operators to take decisions for troubleshooting or surpassing any obstacles encountered, before cement is no longer pumpable, as at such point, decisions become exponentially costlier, and can even result in the loss of the well, or sidetrack. Steps to mitigate these risks involve extensive pre-planning to identify all possible risk scenarios, and prepare mitigation, elimination and correction methods. Another step is to count with appropriate equipment, backup equipment, and contingency procedures ready to be implemented if required. Decisions such as how much more volume should be pumped if plug bump is not seen, or if volume count should be reset when dart latch is seen, should be reviewed in advance, as a decision-making process cannot take place when the event is seen, as the timeframe to take these decisions are too narrow. Cementing a liner in a deepwater scenario increases the risks during the operation. Inaccuracies for volume counting during displacement are increased, and in situations when there is a small liner, and the displacement volume is greatly larger than the slurry volume, increases inaccuracies even further. Free-fall of cement is also increased, as a heavier slurry is being displaced throughout a longer interval, until it U-turns at the shoe and is finally placed on the annular space. This also increases the risk of not seeing the dart latch with the plug, not being able to reset the volume count to a more precise volume. The cementing phase of the 4.5" liner for the Deepwater Total Moho-Nord Albian Project, presented these risks due to the short 4.5" liner interval. The liner interval can be as short as 450 mts of liner length, equivalent to 10 m3 of cement slurry) in comparison with the TOL depth (average 4,100 m MD, equivalent to over 50 m3 of displacement). The risks were increased as the project relies on plug bump to set a series of annular inflatable packers to help seal the formation from water influxes. This meant that if the theoretical volume was pumped and the plug did not bump at the time, displacement had to stop, and the packers could not be inflated. Rotation, which often helps cement placement, was also not an option in this project, as T&D analysis proved that there was a high risk to exceed the torque limit of the liner connections. All these risks combined, made the cementing operation of the 4.5" liner of the Albian project, one of the most complex and crucial parts of the well operation.
套管或尾管的固井一直被认为是井施工过程中的关键阶段。与其他阶段的不同之处在于，一旦水泥混合并泵入井中，在水泥无法泵入之前，作业者就会在有限的时间内做出排除故障或克服遇到的任何障碍的决定，因为在这个时候，决策成本会成倍增加，甚至可能导致井的损失或侧钻。减轻这些风险的步骤涉及广泛的预先规划，以确定所有可能的风险情景，并准备减轻、消除和纠正方法。另一个步骤是清点适当的设备、备用设备和应急程序，以便在需要时实施。如果没有看到桥塞凸起，应该增加多少排量，或者当看到堵头闩锁时是否应该重新设置排量，这些决定都应该提前进行审查，因为当看到事件时，无法进行决策过程，因为做出这些决定的时间范围太窄。在深水作业中，尾管固井会增加作业过程中的风险。在驱替过程中，体积计数的不准确性会增加，而在衬管较小且驱替体积远大于泥浆体积的情况下，不准确性会进一步增加。水泥的自由落体也增加了，因为较重的泥浆在更长的间隔内被置换，直到它在鞋处u型转弯，最终被放置在环空空间上。这也增加了看不到堵头的风险，无法将体积计数重置为更精确的体积。在深水Total Moho-Nord Albian项目的4.5”尾管固井阶段，由于4.5”尾管间隔较短，存在这些风险。与TOL深度(平均4100 m MD，相当于超过50 m3的排量)相比，尾管间距可短至450 mts，相当于10 m3的水泥浆。由于该项目依赖于桥塞凸起来设置一系列环空膨胀封隔器，以帮助密封地层免受水流入的影响，因此风险增加了。这意味着，如果泵入了理论体积，并且桥塞没有发生碰撞，则必须停止驱油，并且封隔器无法膨胀。旋转通常有助于固井，但在该项目中也不是一个选择，因为T&D分析证明，超过尾管连接扭矩限制的风险很高。所有这些风险加在一起，使得Albian项目的4.5”尾管固井作业成为井作业中最复杂、最关键的部分之一。
{"title":"First Dual-Plug Cementing in a 4.5in Liner in Sub-Saharan Africa","authors":"Roberto Elizalde, Pierre-Marie Drevillon","doi":"10.2118/197914-ms","DOIUrl":"https://doi.org/10.2118/197914-ms","url":null,"abstract":"\u0000 Cementing of a casing string or liner is always considered a crucial phase of the well construction process. The difference with the other phases, is that once cement has been mixed and pumped in the well, there is a limited amount of time for operators to take decisions for troubleshooting or surpassing any obstacles encountered, before cement is no longer pumpable, as at such point, decisions become exponentially costlier, and can even result in the loss of the well, or sidetrack.\u0000 Steps to mitigate these risks involve extensive pre-planning to identify all possible risk scenarios, and prepare mitigation, elimination and correction methods. Another step is to count with appropriate equipment, backup equipment, and contingency procedures ready to be implemented if required. Decisions such as how much more volume should be pumped if plug bump is not seen, or if volume count should be reset when dart latch is seen, should be reviewed in advance, as a decision-making process cannot take place when the event is seen, as the timeframe to take these decisions are too narrow.\u0000 Cementing a liner in a deepwater scenario increases the risks during the operation. Inaccuracies for volume counting during displacement are increased, and in situations when there is a small liner, and the displacement volume is greatly larger than the slurry volume, increases inaccuracies even further. Free-fall of cement is also increased, as a heavier slurry is being displaced throughout a longer interval, until it U-turns at the shoe and is finally placed on the annular space. This also increases the risk of not seeing the dart latch with the plug, not being able to reset the volume count to a more precise volume.\u0000 The cementing phase of the 4.5\" liner for the Deepwater Total Moho-Nord Albian Project, presented these risks due to the short 4.5\" liner interval. The liner interval can be as short as 450 mts of liner length, equivalent to 10 m3 of cement slurry) in comparison with the TOL depth (average 4,100 m MD, equivalent to over 50 m3 of displacement). The risks were increased as the project relies on plug bump to set a series of annular inflatable packers to help seal the formation from water influxes. This meant that if the theoretical volume was pumped and the plug did not bump at the time, displacement had to stop, and the packers could not be inflated. Rotation, which often helps cement placement, was also not an option in this project, as T&D analysis proved that there was a high risk to exceed the torque limit of the liner connections.\u0000 All these risks combined, made the cementing operation of the 4.5\" liner of the Albian project, one of the most complex and crucial parts of the well operation.","PeriodicalId":11328,"journal":{"name":"Day 4 Thu, November 14, 2019","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74167438","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}
D. Hegab, S. E. Kholy, T. Banger, C. Hoelterling, O. El Shenoufy, R. Boers, W. El Wakeel, M. Najwani, H. Mobarak, B. Courtney, G. Muhiuldin
One of the most serious red-zone hazards on a rig's drill floor is in casing running operations. Manually operated power tong hanging on a rig floor tugger required up to six people to be present in the red zone of the drill floor. In this respect, it was decided to evaluate the latest technological advancements, and work on an improved solution to casing running operations. The challenge on the Maersk Discoverer is the main well center roughneck design, which has historically prevented the team from using an existing mechanized solution from the market. The Casing Running mechanization project was piloted on the Maersk Discoverer rig, in order to mechanize the casing and tubing running operations. Weatherford has specifically designed a bespoke adaptor that fits the Column Mounted Roughneck (CMR) on the main well center allowing for a remotely operated casing running operation. The adopted design overcomes the challenge of tight space between the tong and the well center which prevented the mechanized solution in the past. Weatherford casing and tubing tongs are remotely operated through Weatherford's mechanized control system. This Pilot approach has been installed and tried with multiple casing and tubing sizes. This project brought remarkable results impacting the safety and the performance of our operations through two outcomes. Zero people in the red zone on one hand and on the other hand, improving efficiency of handling the tongs in a controlled manner avoiding excessive and uncontrolled movement of these heavy loads. Consequently, hands-free casing running operations were successfully implemented!
{"title":"Casing Running Mechanization on the Semi-Submersible; Maersk Discoverer","authors":"D. Hegab, S. E. Kholy, T. Banger, C. Hoelterling, O. El Shenoufy, R. Boers, W. El Wakeel, M. Najwani, H. Mobarak, B. Courtney, G. Muhiuldin","doi":"10.2118/197878-ms","DOIUrl":"https://doi.org/10.2118/197878-ms","url":null,"abstract":"\u0000 One of the most serious red-zone hazards on a rig's drill floor is in casing running operations. Manually operated power tong hanging on a rig floor tugger required up to six people to be present in the red zone of the drill floor. In this respect, it was decided to evaluate the latest technological advancements, and work on an improved solution to casing running operations. The challenge on the Maersk Discoverer is the main well center roughneck design, which has historically prevented the team from using an existing mechanized solution from the market. The Casing Running mechanization project was piloted on the Maersk Discoverer rig, in order to mechanize the casing and tubing running operations. Weatherford has specifically designed a bespoke adaptor that fits the Column Mounted Roughneck (CMR) on the main well center allowing for a remotely operated casing running operation. The adopted design overcomes the challenge of tight space between the tong and the well center which prevented the mechanized solution in the past. Weatherford casing and tubing tongs are remotely operated through Weatherford's mechanized control system. This Pilot approach has been installed and tried with multiple casing and tubing sizes. This project brought remarkable results impacting the safety and the performance of our operations through two outcomes. Zero people in the red zone on one hand and on the other hand, improving efficiency of handling the tongs in a controlled manner avoiding excessive and uncontrolled movement of these heavy loads. Consequently, hands-free casing running operations were successfully implemented!","PeriodicalId":11328,"journal":{"name":"Day 4 Thu, November 14, 2019","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86897215","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}
Virtue Urunwo Elechi, S. S. Ikiensikimama, J. Ajienka, O. Akaranta, M. Onyekonwu, O. Okon
This paper takes a look at the performance of a Locally Sourced Material (LSM) in a laboratory mini flow loop of ½ -inch internal diameter, made from 316 stainless steel pipe sheathed in a 4-inch PVC pipe built on an external metal frame work. The performance of the LSM was measured with that of the conventional hydrate inhibitor 2-(Dimethylamino)ethylmethacrylate (2-DMAEM). The performance evaluation was based on Pressure versus time, change in pressure versus time and initial and final pressure versus time plots. These plots showed that LSM performed better than the conventional 2-DMAEM in all the weight percentages considered (0.01wt% −0.03wt %). The optimum weight percentage for inhibition was 0.02wt% with inhibition efficiency of 81.58% while that of 2-DMAEM was 73.68%. The inhibition efficiency for 0.01wt% and 0.03wt% of LSM wereboth 72.81% whereas that of 2-DMAEM were 51.75% and 76.32% respectively. The LSM is locally sourced, readily available in commercial quantity and also eco-friendly because it is plant based unlike the 2-DMAEM which is toxic and expensive. It is advised that the LSM be developed as an alternative to the conventional inhibitor for gas hydrate inhibition.
{"title":"Comparative Analysis of Gas Hydrate Inhibitors: Local and Conventional","authors":"Virtue Urunwo Elechi, S. S. Ikiensikimama, J. Ajienka, O. Akaranta, M. Onyekonwu, O. Okon","doi":"10.2118/197429-ms","DOIUrl":"https://doi.org/10.2118/197429-ms","url":null,"abstract":"\u0000 This paper takes a look at the performance of a Locally Sourced Material (LSM) in a laboratory mini flow loop of ½ -inch internal diameter, made from 316 stainless steel pipe sheathed in a 4-inch PVC pipe built on an external metal frame work. The performance of the LSM was measured with that of the conventional hydrate inhibitor 2-(Dimethylamino)ethylmethacrylate (2-DMAEM). The performance evaluation was based on Pressure versus time, change in pressure versus time and initial and final pressure versus time plots. These plots showed that LSM performed better than the conventional 2-DMAEM in all the weight percentages considered (0.01wt% −0.03wt %). The optimum weight percentage for inhibition was 0.02wt% with inhibition efficiency of 81.58% while that of 2-DMAEM was 73.68%. The inhibition efficiency for 0.01wt% and 0.03wt% of LSM wereboth 72.81% whereas that of 2-DMAEM were 51.75% and 76.32% respectively. The LSM is locally sourced, readily available in commercial quantity and also eco-friendly because it is plant based unlike the 2-DMAEM which is toxic and expensive. It is advised that the LSM be developed as an alternative to the conventional inhibitor for gas hydrate inhibition.","PeriodicalId":11328,"journal":{"name":"Day 4 Thu, November 14, 2019","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88033162","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 fluid fill concept of a complex carbonate reservoir of the Shuaiba Formation has been re-evaluated after 45 years of production. Structural changes post primary drainage resulted in a tilted contact towards the north east and water imbibition into the oil zone in a considerable volume of the reservoir. Rock facies change substantially vertically and laterally as observed from the 25+ cored wells and have camouflaged the fluid fill impact. Reservoir heterogeneity increases from the relatively homogeneous mud-dominated rock type in the central south-east to more heterogeneous grainstones and grain-dominated packstones further away. This paper demonstrates the value of using simplified and structured approaches to analyse saturation profiles to deduce possible fluid fill concept(s) and water saturation distribution. The saturation profile with core permeability and core facies interpretation were used to identify imbibition, map the water table (imbibition) surface and recognize the trend of structural tilting post-charge. The central south-east area has negligible tilting and imbibition with a saturation model that could be simplified to primary drainage. Above the water table, the mud-dominated rock saturation model was the reference point. Due to scarcity of wells unaffected by imbibition or tilt, a benchmark primary-drainage saturation model of analogue carbonate reservoirs was used to create a first-pass saturation model of the mud-dominated rock and identify entry height. The paleo-reference (original FWL) was reconstructed from the OWC picked from 72 vertical wells and smoothed by the general trend of tilt from the shallower seismic horizons. The workflow relied on using the mud-dominated rock saturation model to flag other rock types in uncored wells and possibly reducing the uncertainty in facies distribution. With the complexity at hand, difficulty in populating the facies between wells and time constraints, the water saturation below the water table was interpolated from all vertical wells. The paleo-reference reconstruction indicates substantial tilting of the structure post-charge. One-third of the hydrocarbon volumes are in the imbibed region. The reservoir has been charged close to the irreducible water saturation and the majority of logged wells display paleo imbibed transition zones so it was not possible to utilize saturation-depth signature to identify a large number of distinctive rock types. Due to the aforementioned, the saturation model for all of the reservoir rocks could be simplified by a single saturation function above the paleo-reference and a current water table depth.
{"title":"Simplifying the Complex: Saturation Modelling in a Challenging Carbonate Reservoir with a Tilted Contact & Significant Imbibition in the Sultanate of Oman","authors":"S. Hadidi, M. Ferrero, Badar Al Sadi","doi":"10.2118/197525-ms","DOIUrl":"https://doi.org/10.2118/197525-ms","url":null,"abstract":"\u0000 The fluid fill concept of a complex carbonate reservoir of the Shuaiba Formation has been re-evaluated after 45 years of production. Structural changes post primary drainage resulted in a tilted contact towards the north east and water imbibition into the oil zone in a considerable volume of the reservoir. Rock facies change substantially vertically and laterally as observed from the 25+ cored wells and have camouflaged the fluid fill impact. Reservoir heterogeneity increases from the relatively homogeneous mud-dominated rock type in the central south-east to more heterogeneous grainstones and grain-dominated packstones further away. This paper demonstrates the value of using simplified and structured approaches to analyse saturation profiles to deduce possible fluid fill concept(s) and water saturation distribution.\u0000 The saturation profile with core permeability and core facies interpretation were used to identify imbibition, map the water table (imbibition) surface and recognize the trend of structural tilting post-charge. The central south-east area has negligible tilting and imbibition with a saturation model that could be simplified to primary drainage.\u0000 Above the water table, the mud-dominated rock saturation model was the reference point. Due to scarcity of wells unaffected by imbibition or tilt, a benchmark primary-drainage saturation model of analogue carbonate reservoirs was used to create a first-pass saturation model of the mud-dominated rock and identify entry height. The paleo-reference (original FWL) was reconstructed from the OWC picked from 72 vertical wells and smoothed by the general trend of tilt from the shallower seismic horizons. The workflow relied on using the mud-dominated rock saturation model to flag other rock types in uncored wells and possibly reducing the uncertainty in facies distribution. With the complexity at hand, difficulty in populating the facies between wells and time constraints, the water saturation below the water table was interpolated from all vertical wells.\u0000 The paleo-reference reconstruction indicates substantial tilting of the structure post-charge. One-third of the hydrocarbon volumes are in the imbibed region. The reservoir has been charged close to the irreducible water saturation and the majority of logged wells display paleo imbibed transition zones so it was not possible to utilize saturation-depth signature to identify a large number of distinctive rock types.\u0000 Due to the aforementioned, the saturation model for all of the reservoir rocks could be simplified by a single saturation function above the paleo-reference and a current water table depth.","PeriodicalId":11328,"journal":{"name":"Day 4 Thu, November 14, 2019","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81248851","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}
Zhong-jian Zhang, Yan Wu, Lei Luo, Xueqin Wang, Yonghong Fan, Gang Yi, Chong Chen, Fashou Zhao, Zhang Xiaoping, Wei Liu, Hongwei Dong
In many matured fields around the world, the infill well development faces multiple challenges; reservoir depletion caused by existing wells is unavoidable, the remaining area to be targeted by infill is typically relatively marginal, with thinner formations that still bear significant subsurface uncertainty compared with sweet spot area developed in the initial phase. In addition, some fields are impacted by PSC conditions, with a strict time constraint. When developing infill wells several key aspects have to be considered: starting from potential severe mud losses, drill pipe stuck during the drilling phase, to formation damage, production interference with neighboring wells, earlier load up for gas wells etc. Shell China developed an integrated approach by considering all these challenges, and successfully implemented it for the Changbei tight gas infill well project. During the Design Phase, a series of core lab tests were carried out to evaluate the formation damage and related permeability reduction. The lab test results indicated that the permeability reduction as result of water encroaching into water wet rock formation is significant (+90%), causing a "water locking" effect. Another topic pertaining to the Desing phase in the Changbei field is the optimisation of the dual lateral well trajectory based on the expected depletion state of the reservoir. Also discussed is the horizontal well tubing size optimization, which accounted for the selection matrix based on KH, online date (related to PSC end) and expected reservoir pressure (depleted). In the Delivery phase, the surfactant additive identified through the lab testing has been used into the drilling mud and completion fluid to appropriately mitigate the water locking effect. The lab test results demonstrated that a permeability improvement of at least 10% could be achieved. Furthermore, the surfactant concentration was optimized to maximise the emulsion effect for water treatment and the foaming effect during the drilling phase. This paper also covers the well flowback efficiency improvement achieved by additional nitrogen lifting and prolonged firing time. During the Well Reservoir and Facility Management phase (WRFM), a study of infill well production interference with existing wells was carried out and the recovery could be maximized at the cluster level.
{"title":"An Integrated Approach to Tackling the Challenges of Drilling in a Highly Depleted Gas Reservoir","authors":"Zhong-jian Zhang, Yan Wu, Lei Luo, Xueqin Wang, Yonghong Fan, Gang Yi, Chong Chen, Fashou Zhao, Zhang Xiaoping, Wei Liu, Hongwei Dong","doi":"10.2118/197461-ms","DOIUrl":"https://doi.org/10.2118/197461-ms","url":null,"abstract":"\u0000 In many matured fields around the world, the infill well development faces multiple challenges; reservoir depletion caused by existing wells is unavoidable, the remaining area to be targeted by infill is typically relatively marginal, with thinner formations that still bear significant subsurface uncertainty compared with sweet spot area developed in the initial phase. In addition, some fields are impacted by PSC conditions, with a strict time constraint.\u0000 When developing infill wells several key aspects have to be considered: starting from potential severe mud losses, drill pipe stuck during the drilling phase, to formation damage, production interference with neighboring wells, earlier load up for gas wells etc.\u0000 Shell China developed an integrated approach by considering all these challenges, and successfully implemented it for the Changbei tight gas infill well project.\u0000 During the Design Phase, a series of core lab tests were carried out to evaluate the formation damage and related permeability reduction. The lab test results indicated that the permeability reduction as result of water encroaching into water wet rock formation is significant (+90%), causing a \"water locking\" effect. Another topic pertaining to the Desing phase in the Changbei field is the optimisation of the dual lateral well trajectory based on the expected depletion state of the reservoir. Also discussed is the horizontal well tubing size optimization, which accounted for the selection matrix based on KH, online date (related to PSC end) and expected reservoir pressure (depleted).\u0000 In the Delivery phase, the surfactant additive identified through the lab testing has been used into the drilling mud and completion fluid to appropriately mitigate the water locking effect. The lab test results demonstrated that a permeability improvement of at least 10% could be achieved. Furthermore, the surfactant concentration was optimized to maximise the emulsion effect for water treatment and the foaming effect during the drilling phase. This paper also covers the well flowback efficiency improvement achieved by additional nitrogen lifting and prolonged firing time.\u0000 During the Well Reservoir and Facility Management phase (WRFM), a study of infill well production interference with existing wells was carried out and the recovery could be maximized at the cluster level.","PeriodicalId":11328,"journal":{"name":"Day 4 Thu, November 14, 2019","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83886853","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 efficacy of machine learning (ML) algorithms for turbomachinery condition monitoring can be compromised by the lack of robust historical data for training. While unsupervised or deep learning (DL) algorithms may be used when sufficient volumes of ‘labeled’ data are unavailable, they offer limited insights into detected anomalies or outliers. Additionally, the inherent dependency on data volume and variety delays the deployment of these algorithms, making an ML-only approach unsuitable for situations such as a machine's first operating run. The paper discusses how a combination approach utilizing both first-principle based performance algorithms and ML algorithms can address several shortcomings of the ML-only approach. Examples are provided to demonstrate that one type of algorithm can outperform the other in the detection of specific anomalies. Therefore, when deployed in parallel, they provide the ability to predict / detect a larger universe of machine faults. The combination approach can also address the lack of interpretability inherent to ML algorithms in cases wherein both sets of algorithms show anomalous behavior. To further address the issue of data inadequacy and poor data quality, the concept of simulation-based transfer learning is introduced. A thermodynamic simulation model is used to generate performance data for a multistage, variable composition centrifugal pump. This data is then used to train two deep stateful LSTM neural network models to predict pump discharge pressure. In the first model only simulation data is used for training while for the second model both simulation and historical data are used. Prediction results from both models are compared with those from a performance algorithm and an LSTM model trained solely on historical data. Test results demonstrate that the LSTM model trained on both simulation and historical data outperforms the other algorithms. This methodology can be applied successfully to accelerate the deployment and enhance the value of deep learning algorithms for machine performance analysis. An additional benefit of training the model on simulated data derived from well proven thermodynamic/aerodynamic principles, is that the insightfulness of performance algorithms may be ‘inherited’ by the deep learning algorithms.
{"title":"Integrating Process Simulation Modeling and Predictive Analytics to Gain Deeper Insights into Machine Health and Performance","authors":"R. Homji, Akshay Bhardwaj","doi":"10.2118/197529-ms","DOIUrl":"https://doi.org/10.2118/197529-ms","url":null,"abstract":"\u0000 The efficacy of machine learning (ML) algorithms for turbomachinery condition monitoring can be compromised by the lack of robust historical data for training. While unsupervised or deep learning (DL) algorithms may be used when sufficient volumes of ‘labeled’ data are unavailable, they offer limited insights into detected anomalies or outliers. Additionally, the inherent dependency on data volume and variety delays the deployment of these algorithms, making an ML-only approach unsuitable for situations such as a machine's first operating run.\u0000 The paper discusses how a combination approach utilizing both first-principle based performance algorithms and ML algorithms can address several shortcomings of the ML-only approach. Examples are provided to demonstrate that one type of algorithm can outperform the other in the detection of specific anomalies. Therefore, when deployed in parallel, they provide the ability to predict / detect a larger universe of machine faults. The combination approach can also address the lack of interpretability inherent to ML algorithms in cases wherein both sets of algorithms show anomalous behavior.\u0000 To further address the issue of data inadequacy and poor data quality, the concept of simulation-based transfer learning is introduced. A thermodynamic simulation model is used to generate performance data for a multistage, variable composition centrifugal pump. This data is then used to train two deep stateful LSTM neural network models to predict pump discharge pressure. In the first model only simulation data is used for training while for the second model both simulation and historical data are used.\u0000 Prediction results from both models are compared with those from a performance algorithm and an LSTM model trained solely on historical data. Test results demonstrate that the LSTM model trained on both simulation and historical data outperforms the other algorithms. This methodology can be applied successfully to accelerate the deployment and enhance the value of deep learning algorithms for machine performance analysis. An additional benefit of training the model on simulated data derived from well proven thermodynamic/aerodynamic principles, is that the insightfulness of performance algorithms may be ‘inherited’ by the deep learning algorithms.","PeriodicalId":11328,"journal":{"name":"Day 4 Thu, November 14, 2019","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89234471","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}
V. Pandey, Sunil Kumar Dimri, D. Mathur, Raman R. K. Singh, A. Dutt, S. Khataniar, Ankit Agarwal, A. Herrera, K. Fischer, C. Darous, Vinil Mukku, R. Talreja, D. Gunasekaran, S. Aderemi, Somesh Bahuguna
Rock fabric characteristics of Gamij Field lies in the purview of conventional reservoirs but are as complex and uncertain as unconventional. It is a multi-layered, heterogeneous reservoir on depletion drive with very low permeability. Even after hydraulic fracturing and artificial lift, the production rate lies in the range of 3-4 m3/d. This paper evaluates the impact of past hydraulic fracture operations and uses this understanding to optimize the stimulation strategy for future wells. A customized multidisciplinary modeling and flow simulation workflow; integrating petrophysical, geomechanical, stimulation and production data was adopted and applied to sectors of the field. Two techniques were combined 1. Unconventional (Fast Loop) 2. Conventional (Slow Loop) in an intriguing and iterative manner. Hydraulic Fractures were designed, optimized and calibrated using a rigorous workflow of unstructured grid and unconventional fracture modelling/3D planar fractures in the sector models. Sector model is considered the most effective approach to characterize completion quality in Gamij Field due to the limitation of current modelling technologies to design and simulate hydraulic fractures in full-field model. The results of sector model is validated with full field model and a number of iterations were performed to match pressure from the result to the initially assumed in creation of 3D MEM (Mechanical Earth Model). Reservoir quality (RQ) estimation is affected by complex mineralogy including abundance of iron and titanium rich sediments. Stress regime shows vertical transverse isotropy nature of shales and suggest re-orientations near to fault zones. There are several areas, especially in the eastern part, where the tectonic regime changes from normal to strike-slip faulting. HF modelling not only explains the contrasting behavior of existing wells, but also discusses alternatives that could help to unlock the true potential of the pay zones. This paper elucidates techniques to maximize reservoir understanding and allow optimization of hydraulic fracture design in terms of casing diameter, job size, and design. Simulations shows multiple fractures were created from different preformation cluster in a single stage treatment. Overall, the case study showcases different factors that govern the development of a tight oil reservoir and the ways to characterize and quantify these uncertainties. This work is the first step to quantify the complex reservoir mineralogy, impact of laminations, depletion, stress variation on the efficiency of HF jobs. Identification of potential sweet spots based on reservoir quality and completion quality indexes, establishing well productivity. The uncertainty cannot be eliminated but it ought to be reduced and risk analyzed before the actual execution.
{"title":"Tailored Workflow for Optimizing the Hydraulic Fracturing in Tight Reservoir Development: A Case Study from Cambay Basin","authors":"V. Pandey, Sunil Kumar Dimri, D. Mathur, Raman R. K. Singh, A. Dutt, S. Khataniar, Ankit Agarwal, A. Herrera, K. Fischer, C. Darous, Vinil Mukku, R. Talreja, D. Gunasekaran, S. Aderemi, Somesh Bahuguna","doi":"10.2118/197642-ms","DOIUrl":"https://doi.org/10.2118/197642-ms","url":null,"abstract":"\u0000 \u0000 \u0000 Rock fabric characteristics of Gamij Field lies in the purview of conventional reservoirs but are as complex and uncertain as unconventional. It is a multi-layered, heterogeneous reservoir on depletion drive with very low permeability. Even after hydraulic fracturing and artificial lift, the production rate lies in the range of 3-4 m3/d. This paper evaluates the impact of past hydraulic fracture operations and uses this understanding to optimize the stimulation strategy for future wells.\u0000 \u0000 \u0000 \u0000 A customized multidisciplinary modeling and flow simulation workflow; integrating petrophysical, geomechanical, stimulation and production data was adopted and applied to sectors of the field. Two techniques were combined 1. Unconventional (Fast Loop) 2. Conventional (Slow Loop) in an intriguing and iterative manner. Hydraulic Fractures were designed, optimized and calibrated using a rigorous workflow of unstructured grid and unconventional fracture modelling/3D planar fractures in the sector models. Sector model is considered the most effective approach to characterize completion quality in Gamij Field due to the limitation of current modelling technologies to design and simulate hydraulic fractures in full-field model.\u0000 \u0000 \u0000 \u0000 The results of sector model is validated with full field model and a number of iterations were performed to match pressure from the result to the initially assumed in creation of 3D MEM (Mechanical Earth Model). Reservoir quality (RQ) estimation is affected by complex mineralogy including abundance of iron and titanium rich sediments. Stress regime shows vertical transverse isotropy nature of shales and suggest re-orientations near to fault zones. There are several areas, especially in the eastern part, where the tectonic regime changes from normal to strike-slip faulting. HF modelling not only explains the contrasting behavior of existing wells, but also discusses alternatives that could help to unlock the true potential of the pay zones. This paper elucidates techniques to maximize reservoir understanding and allow optimization of hydraulic fracture design in terms of casing diameter, job size, and design. Simulations shows multiple fractures were created from different preformation cluster in a single stage treatment. Overall, the case study showcases different factors that govern the development of a tight oil reservoir and the ways to characterize and quantify these uncertainties.\u0000 \u0000 \u0000 \u0000 This work is the first step to quantify the complex reservoir mineralogy, impact of laminations, depletion, stress variation on the efficiency of HF jobs. Identification of potential sweet spots based on reservoir quality and completion quality indexes, establishing well productivity. The uncertainty cannot be eliminated but it ought to be reduced and risk analyzed before the actual execution.\u0000","PeriodicalId":11328,"journal":{"name":"Day 4 Thu, November 14, 2019","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81455033","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}
F. Niccolini, Luca Antonio Chisari, Bruno Maggioni
The necessity to reduce the costs incurred in the oil and gas project lifecycle pushes the oil Companies to evaluate alternative strategies with respect to the standard logistic approach. A case study for offshore logistic optimization and cost reduction is presented for a remote (138 nm from the operating port) deep-water offshore green field exploration project in Morocco (2018). Green field exploration represents a challenging context of operations for logistics due to limited availability of already contracted services and/or infrastructures and possible limited familiarity with O&G of the hosting country. Following main elements of cost saving and optimization opportunities have been identified and pursued: i) exploitation of synergies with other company operated projects, ii) drillship storage capacity exploitation, iii) redeployment of material to reduce company stock and improve spud-in availability, iv) circular economy, v) transportation fleet sizing optimization, vi) flexible services and prompt release after operations conclusion. In presence of a drillship deployed for multiple back-to-back projects, the possibility to load the rig with required materials for the spud-in of subsequent projects represents an opportunity for overall logistic optimization. For the presented case study, the contracted drillship has been loaded at Cyprus, after relevant exploration, with redeployment materials and consumables requested for the spud-in of Morocco exploration. Demobilization from Cyprus has been exploited as mobilization for the Moroccan campaign with the drillship reaching the well site in a status of readiness for spud-in. The materials availability at rig site form the initial project stages determined an optimization of the related transportation fleet and the reduction below 5,000 sqm of the required storage areas footprint within a port that showed limited availability to dedicate existing storage areas to O&G activities. The marine base setup has been further optimized by implementing flexible contractual solutions foreseeing prompt release of unused services. Moving ahead of the standard interpretation of the drillship as only the final delivery point of the supply chain, a new approach has been analyzed and implemented to make efficient use of the drillship's storage capacity by the means of the identification and exploitation of operational logistic opportunities. Overall logistics costs incurred for the Moroccan exploration campaign were of 6.5 M$, meeting the target of capital exposure minimization before commercial discovery and the additional target to avoid binding agreements for infrastructure usage and/or refurbishment.
{"title":"Lean Logistics for Green Field Exploration Activities","authors":"F. Niccolini, Luca Antonio Chisari, Bruno Maggioni","doi":"10.2118/197705-ms","DOIUrl":"https://doi.org/10.2118/197705-ms","url":null,"abstract":"\u0000 The necessity to reduce the costs incurred in the oil and gas project lifecycle pushes the oil Companies to evaluate alternative strategies with respect to the standard logistic approach. A case study for offshore logistic optimization and cost reduction is presented for a remote (138 nm from the operating port) deep-water offshore green field exploration project in Morocco (2018).\u0000 Green field exploration represents a challenging context of operations for logistics due to limited availability of already contracted services and/or infrastructures and possible limited familiarity with O&G of the hosting country. Following main elements of cost saving and optimization opportunities have been identified and pursued: i) exploitation of synergies with other company operated projects, ii) drillship storage capacity exploitation, iii) redeployment of material to reduce company stock and improve spud-in availability, iv) circular economy, v) transportation fleet sizing optimization, vi) flexible services and prompt release after operations conclusion.\u0000 In presence of a drillship deployed for multiple back-to-back projects, the possibility to load the rig with required materials for the spud-in of subsequent projects represents an opportunity for overall logistic optimization. For the presented case study, the contracted drillship has been loaded at Cyprus, after relevant exploration, with redeployment materials and consumables requested for the spud-in of Morocco exploration. Demobilization from Cyprus has been exploited as mobilization for the Moroccan campaign with the drillship reaching the well site in a status of readiness for spud-in.\u0000 The materials availability at rig site form the initial project stages determined an optimization of the related transportation fleet and the reduction below 5,000 sqm of the required storage areas footprint within a port that showed limited availability to dedicate existing storage areas to O&G activities. The marine base setup has been further optimized by implementing flexible contractual solutions foreseeing prompt release of unused services.\u0000 Moving ahead of the standard interpretation of the drillship as only the final delivery point of the supply chain, a new approach has been analyzed and implemented to make efficient use of the drillship's storage capacity by the means of the identification and exploitation of operational logistic opportunities. Overall logistics costs incurred for the Moroccan exploration campaign were of 6.5 M$, meeting the target of capital exposure minimization before commercial discovery and the additional target to avoid binding agreements for infrastructure usage and/or refurbishment.","PeriodicalId":11328,"journal":{"name":"Day 4 Thu, November 14, 2019","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74551717","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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