D. San-Roman-Alerigi, Sameeh Batatseh, Weichang Li, Haitham A. Othman
This work is an ongoing effort to design a numerical platform based on machine learning algorithms to characterize, predict, optimize and guide the interaction of [high power] electromagnetic (HPEM) sources (laser, microwave, RF, etc.) with subsurface matter (e.g. rocks, oils, brines, etc.). Advanced statistical analysis routines are essential to identify key variables and relations in the thermal- mechanical-electromagnetic coupling in heterogeneous and anisotropic materials. Advanced statistical analysis and machine learning have been recently used to evince relations in complex environments and physical dynamics; e.g. fluid dynamics, P&ID analytics, and drill cuttings classification, to cite a few. The methods make use of sophisticated algorithms to classify and model problems in multiple areas, from image processing to certain optimization problems. In the realm of subsurface photonics, and in particular for high power electromagnetic (HPEM) interaction with subsurface matter, these routines could become essential to identify key variables, assess the environment and process, and evince models to predict the outcome of an inherently multiphysics and multi-dimensional problem. Numerical models that capture the interaction between HPEM sources and subsurface matter are essential to predict, optimize, adapt, and evaluate the process prior to, and during, deployment in subsurface. These models can come as the solution to a set of coupled partial differential equations that fully describe the physical dynamics, or as the result of supervised-learning algorithms and analysis of experimental and field data. The former is highly sensitive to dynamic material properties, environmental conditions, and source parameters. In addition, it can be challenging to characterize the properties of subsurface materials over the wide range of temperatures and pressures observed in the process. Thus, a machine learning method could provide an ever-improving alternative that learns from the available data to build a numerical platform that can predict, optimize, and guide the process. Machine learning and advanced statistics provide a compelling alternative to build numerical tools to predict, optimize, and control physical processes. This work introduces a variety of numerical approaches to identify essential variables, predict their impact, and optimize the outcome for subsurface applications. Combined, the methods described in this work can help guide the control of the governing dynamics and parameters for use in multiple applications. This numerical platform can be extended to other applications, enhance experimental prototypes, and advance the design of a comprehensive numerical tool for downhole HPEM operations.
{"title":"Machine Learning and the Analysis of High-Power Electromagnetic Interaction with Subsurface Matter","authors":"D. San-Roman-Alerigi, Sameeh Batatseh, Weichang Li, Haitham A. Othman","doi":"10.2118/195118-MS","DOIUrl":"https://doi.org/10.2118/195118-MS","url":null,"abstract":"\u0000 This work is an ongoing effort to design a numerical platform based on machine learning algorithms to characterize, predict, optimize and guide the interaction of [high power] electromagnetic (HPEM) sources (laser, microwave, RF, etc.) with subsurface matter (e.g. rocks, oils, brines, etc.). Advanced statistical analysis routines are essential to identify key variables and relations in the thermal- mechanical-electromagnetic coupling in heterogeneous and anisotropic materials.\u0000 Advanced statistical analysis and machine learning have been recently used to evince relations in complex environments and physical dynamics; e.g. fluid dynamics, P&ID analytics, and drill cuttings classification, to cite a few. The methods make use of sophisticated algorithms to classify and model problems in multiple areas, from image processing to certain optimization problems. In the realm of subsurface photonics, and in particular for high power electromagnetic (HPEM) interaction with subsurface matter, these routines could become essential to identify key variables, assess the environment and process, and evince models to predict the outcome of an inherently multiphysics and multi-dimensional problem.\u0000 Numerical models that capture the interaction between HPEM sources and subsurface matter are essential to predict, optimize, adapt, and evaluate the process prior to, and during, deployment in subsurface. These models can come as the solution to a set of coupled partial differential equations that fully describe the physical dynamics, or as the result of supervised-learning algorithms and analysis of experimental and field data. The former is highly sensitive to dynamic material properties, environmental conditions, and source parameters. In addition, it can be challenging to characterize the properties of subsurface materials over the wide range of temperatures and pressures observed in the process. Thus, a machine learning method could provide an ever-improving alternative that learns from the available data to build a numerical platform that can predict, optimize, and guide the process.\u0000 Machine learning and advanced statistics provide a compelling alternative to build numerical tools to predict, optimize, and control physical processes. This work introduces a variety of numerical approaches to identify essential variables, predict their impact, and optimize the outcome for subsurface applications. Combined, the methods described in this work can help guide the control of the governing dynamics and parameters for use in multiple applications. This numerical platform can be extended to other applications, enhance experimental prototypes, and advance the design of a comprehensive numerical tool for downhole HPEM operations.","PeriodicalId":10908,"journal":{"name":"Day 2 Tue, March 19, 2019","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73325556","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 Cambro-Ordovician succession of Saudi Arabia comprises dominantly siliciclastic sediments deposited in a passive margin intracratonic setting and includes the fluvial to marginal marine Saq Formation (Late Cambrian to early Middle Ordovician), the marine Qasim Formation (late Middle to Late Ordovician) and the glaciogenic Sarah Formation (Hirnantian, latest Ordovician). The Saq Formation is subdivided into the Risha Member (Late Cambrian) and the Sajir Member (Early to Middle Ordovician). Palynological age-control in the Risha Member is provided by a characteristic acritarch assemblage (CB1 Palynozone) which contains well-known Furongian (Late Cambrian) diagnostic taxa (e.g., Trunculumarium revinium, Timofeevia phosphoritica and Ninadiacrodium dumontii), as recorded in one subsurface locality in the Arabian Gulf. This typical assemblage occurs worldwide in Furongian-aged strata and not only permits a confident age- attribution, but also indicates an open marine facies within the predominantly fluvial to marginal marine lower Saq Formation. In Oman, the same assemblage occurs in the Al-Bashair Member of the Andam Formation. In the lower part of the Sajir Member, one acritarch assemblage characterized by the presence of Acanthodicaodium angustum and Vulcanisphaera spp., was described from a subsurface section in Eastern Saudi Arabia, indicating an earliest Ordovician (Tremadocian) age. This assemblage forms the O6 Palynozone and suggests correlation with the Mabrouk Member of the Andam Formation in Oman. The top of the Sajir Member of the Saq Formation is characterized by mud-rich bioturbated deposits which typically yield a distinct palynological assemblage (O5 Palynozone), characterized by dominance of morphologically distinctive sporomorphs (e.g., Virgatasporites spp., various hilate sporomorphs) and characteristic acritarch species such as ?Clypeolus sp., ?Cymatiosphaera sp., ?Retialetes sp., and Barakella spp. The assemblage is also characterized by the first occurrence of some typical Middle Ordovician acritarch taxa such as Arkonia, Striatotheca, and Frankea. Among the chitinozoan, Siphonochitina formosa is typically represented. The age of this assemblage spans the Dapingian to earliest Darriwilian, in agreement with faunal evidence. The assemblage indicates a marginal marine, restricted paleoenvironment. Virtually identical palynological assemblages occur in Oman in the Saih-Nihayda Formation, considered of late Dapingian to Darriwilian age. More specifically, it is suggested here that the O5 Palynozone of Saudi Arabia permits correlation of the upper Sajir Member of the Saq Formation with the lower, sand-prone, part of the Saih Nihayda Formation in Oman.
{"title":"Palynological Correlation of the Late Cambrian to Middle Ordovician Saq Formation in Saudi Arabia and Equivalent Strata in Oman Manuscript Title","authors":"M. Vecoli, C. Cesari","doi":"10.2118/195108-MS","DOIUrl":"https://doi.org/10.2118/195108-MS","url":null,"abstract":"\u0000 The Cambro-Ordovician succession of Saudi Arabia comprises dominantly siliciclastic sediments deposited in a passive margin intracratonic setting and includes the fluvial to marginal marine Saq Formation (Late Cambrian to early Middle Ordovician), the marine Qasim Formation (late Middle to Late Ordovician) and the glaciogenic Sarah Formation (Hirnantian, latest Ordovician).\u0000 The Saq Formation is subdivided into the Risha Member (Late Cambrian) and the Sajir Member (Early to Middle Ordovician). Palynological age-control in the Risha Member is provided by a characteristic acritarch assemblage (CB1 Palynozone) which contains well-known Furongian (Late Cambrian) diagnostic taxa (e.g., Trunculumarium revinium, Timofeevia phosphoritica and Ninadiacrodium dumontii), as recorded in one subsurface locality in the Arabian Gulf. This typical assemblage occurs worldwide in Furongian-aged strata and not only permits a confident age- attribution, but also indicates an open marine facies within the predominantly fluvial to marginal marine lower Saq Formation. In Oman, the same assemblage occurs in the Al-Bashair Member of the Andam Formation. In the lower part of the Sajir Member, one acritarch assemblage characterized by the presence of Acanthodicaodium angustum and Vulcanisphaera spp., was described from a subsurface section in Eastern Saudi Arabia, indicating an earliest Ordovician (Tremadocian) age. This assemblage forms the O6 Palynozone and suggests correlation with the Mabrouk Member of the Andam Formation in Oman.\u0000 The top of the Sajir Member of the Saq Formation is characterized by mud-rich bioturbated deposits which typically yield a distinct palynological assemblage (O5 Palynozone), characterized by dominance of morphologically distinctive sporomorphs (e.g., Virgatasporites spp., various hilate sporomorphs) and characteristic acritarch species such as ?Clypeolus sp., ?Cymatiosphaera sp., ?Retialetes sp., and Barakella spp. The assemblage is also characterized by the first occurrence of some typical Middle Ordovician acritarch taxa such as Arkonia, Striatotheca, and Frankea. Among the chitinozoan, Siphonochitina formosa is typically represented. The age of this assemblage spans the Dapingian to earliest Darriwilian, in agreement with faunal evidence. The assemblage indicates a marginal marine, restricted paleoenvironment. Virtually identical palynological assemblages occur in Oman in the Saih-Nihayda Formation, considered of late Dapingian to Darriwilian age. More specifically, it is suggested here that the O5 Palynozone of Saudi Arabia permits correlation of the upper Sajir Member of the Saq Formation with the lower, sand-prone, part of the Saih Nihayda Formation in Oman.","PeriodicalId":10908,"journal":{"name":"Day 2 Tue, March 19, 2019","volume":"409 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90404708","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}
Alfredo Arevalo, A. Buenrostro, Mauricio Espinosa, A. Harbi
Tight sandstone reservoirs under this project have been a challenge to stimulate due the high breakdown pressure required to create the fracture, and a challenge on production recovery due fast decline observed in some of these wells. Exploring Multi Stage Fracturing completion in horizontal wells in these tight sandstone reservoirs increases the overall reservoir exposure to stimulation treatments by Hydraulic Fracturing, and expects a better and longer production performance. This paper evaluates the recently deployed Open Hole – Multi Stage Fracturing completions (OH-MSF) over tight sandstone gas reservoirs.
{"title":"Multi Stage - Open Hole Completions: Continuous Successes in Placing Multiple Fractures in a Single Tight Gas Sandstone","authors":"Alfredo Arevalo, A. Buenrostro, Mauricio Espinosa, A. Harbi","doi":"10.2118/194908-MS","DOIUrl":"https://doi.org/10.2118/194908-MS","url":null,"abstract":"\u0000 Tight sandstone reservoirs under this project have been a challenge to stimulate due the high breakdown pressure required to create the fracture, and a challenge on production recovery due fast decline observed in some of these wells. Exploring Multi Stage Fracturing completion in horizontal wells in these tight sandstone reservoirs increases the overall reservoir exposure to stimulation treatments by Hydraulic Fracturing, and expects a better and longer production performance. This paper evaluates the recently deployed Open Hole – Multi Stage Fracturing completions (OH-MSF) over tight sandstone gas reservoirs.","PeriodicalId":10908,"journal":{"name":"Day 2 Tue, March 19, 2019","volume":"79 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77226584","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}
Oil Fingerprinting by gas chromatography techniques are among the most sensitive and accurate tools utilized to study reservoir compartmentalization and oil to oil correlations. The greatest challenge of the technique, however, lies in recognizing and identifying if any oils have undergone post-generative alteration processes such as water washing or biodegradation that may prohibit accurate correlation. These effects, even when subtle, may alter or transform oils resulting in misleading interpretations and invalid outcomes. Understanding the controls on the oil composition is critical for all fingerprinting studies and can promote new characterization methods to ensure any negative post-generative alteration effects are mitigated. The study aims to illustrate the use of various geochemical fingerprinting methods to assess the reservoir connectivity between two oil accumulations. Furthermore, the effect of water washing on the oil compositions, and its relationship with gas to oil ratio (GOR) and salinity were investigated. A total of 11 oil samples from an Ordovician siliciclastic formation across 10 locations in a field were analyzed for API gravity light hydrocarbons (C5-C7) and whole-oil fingerprinting (C8 to C20) gas chromatography (GC) characterization methods. Light hydrocarbons (LHC) analysis used to correlate different oils to their sources was interpreted using five specially selected source dependent ratios plotted in a C7 star diagram. If the oils have a similar pattern, this indicates a similar source and vice versa. The results suggest that the oils can be correlated to two different source rocks that charged the study area from independent northeast and southwest directions. A second set of light hydrocarbon ratios sensitive to water washing and biodegradation effects suggested a noticeable water washing trend increasing to the north. The whole-oil fingerprinting analysis employs a multivariate statistical model across all the samples to determine the most variant 12 ratios from the chromatograms to construct a specialized star diagram. From this analysis, five separate reservoir compartments were identified. It was further observed that a set of samples from a specific compartment differed in one of the 12 ratios. This ratio was plotted against the water washing transformation ratio from LHC and revealed a strong positive correlation. The difference in this ratio is attributed to water washing. Both parameters suggest that water washing possesses strong negative correlations with total dissolved salts (TDS) of the formation water and gas to oil ratio (GOR). These relationships accentuate the potential of utilizing the geochemical ratios to predict the GOR and consequently improve the production planning. The study shed the lights on the potential utilization of new rapid and cost-effective geochemical methods to predict some production engineering parameters.
{"title":"Reservoir Connectivity, Water Washing and Oil to Oil Correlation: An Integrated Geochemical & Petroleum Engineering Approach","authors":"B. Ghassal","doi":"10.2118/194957-MS","DOIUrl":"https://doi.org/10.2118/194957-MS","url":null,"abstract":"\u0000 Oil Fingerprinting by gas chromatography techniques are among the most sensitive and accurate tools utilized to study reservoir compartmentalization and oil to oil correlations. The greatest challenge of the technique, however, lies in recognizing and identifying if any oils have undergone post-generative alteration processes such as water washing or biodegradation that may prohibit accurate correlation. These effects, even when subtle, may alter or transform oils resulting in misleading interpretations and invalid outcomes. Understanding the controls on the oil composition is critical for all fingerprinting studies and can promote new characterization methods to ensure any negative post-generative alteration effects are mitigated.\u0000 The study aims to illustrate the use of various geochemical fingerprinting methods to assess the reservoir connectivity between two oil accumulations. Furthermore, the effect of water washing on the oil compositions, and its relationship with gas to oil ratio (GOR) and salinity were investigated.\u0000 A total of 11 oil samples from an Ordovician siliciclastic formation across 10 locations in a field were analyzed for API gravity light hydrocarbons (C5-C7) and whole-oil fingerprinting (C8 to C20) gas chromatography (GC) characterization methods. Light hydrocarbons (LHC) analysis used to correlate different oils to their sources was interpreted using five specially selected source dependent ratios plotted in a C7 star diagram. If the oils have a similar pattern, this indicates a similar source and vice versa.\u0000 The results suggest that the oils can be correlated to two different source rocks that charged the study area from independent northeast and southwest directions. A second set of light hydrocarbon ratios sensitive to water washing and biodegradation effects suggested a noticeable water washing trend increasing to the north. The whole-oil fingerprinting analysis employs a multivariate statistical model across all the samples to determine the most variant 12 ratios from the chromatograms to construct a specialized star diagram. From this analysis, five separate reservoir compartments were identified. It was further observed that a set of samples from a specific compartment differed in one of the 12 ratios. This ratio was plotted against the water washing transformation ratio from LHC and revealed a strong positive correlation. The difference in this ratio is attributed to water washing. Both parameters suggest that water washing possesses strong negative correlations with total dissolved salts (TDS) of the formation water and gas to oil ratio (GOR). These relationships accentuate the potential of utilizing the geochemical ratios to predict the GOR and consequently improve the production planning. The study shed the lights on the potential utilization of new rapid and cost-effective geochemical methods to predict some production engineering parameters.","PeriodicalId":10908,"journal":{"name":"Day 2 Tue, March 19, 2019","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91384298","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}
Crestal gas injection started in the Bahrain Field in 1938 and since then, 1,900 Bscf has been injected in Mauddud, the main oil producing reservoir in the Bahrain Field, creating a secondary gas cap. Furthermore, since 1965, an estimated 100 MMstb of Liquefied Petroleum Gas (LPG), or 14% of the bypassed oil, has been recovered from the secondary gas cap through stripping with the remaining oil volume in the secondary gas cap being approximately 700 MMstb. Today, the remaining oil saturation in the Mauddud gas cap is estimated to be approximately 40%. This paper presents the results of an extensive study that was made to forecast the Bahrain Field associated gas compositions and potential gas-liquids production recovery. Several forecast methodologies were used including data-driven analytical models, a compositional cross-section model, and a full-field compositional history matched model. The results of these forecasts and the conclusions are presented and compared. In this study, two scenarios of different gas compositions of injected gas and their impact on gas plant liquids recovery are explored. In addition, this paper addresses the challenges and uncertainties associated in forecasting the gas compositions and ways to overcome them. The data-driven models and compositional cross-section model were initially used, however, due to their inherent uncertainties, a full field compositional simulation model was necessary. This compositional model was history matched with a seven (7) component Equation of State (EOS) to capture the lighter hydrocarbon components. Moreover, this model was used in predicting the yield and composition of the existing gas recovery plant. The results from all methods recommend doubling the capacity of the existing plant, which was commissioned in late 2018. A comparative analysis found that data-driven models can be used for gas cycling when using the same gas injection compositions. However, data-driven models over-estimate the Liquefied Petroleum Gas (LPG) yield if leaner gas is used for gas injection, which is the case for the proposed gas plant expansion.
{"title":"Using Data Driven Analytical Models with Compositional Simulation in Doubling the LPG Production from Bahrain Field","authors":"A. Al-Muftah, Ebrahim AlOwainati, M. Mansoor","doi":"10.2118/194859-MS","DOIUrl":"https://doi.org/10.2118/194859-MS","url":null,"abstract":"\u0000 Crestal gas injection started in the Bahrain Field in 1938 and since then, 1,900 Bscf has been injected in Mauddud, the main oil producing reservoir in the Bahrain Field, creating a secondary gas cap. Furthermore, since 1965, an estimated 100 MMstb of Liquefied Petroleum Gas (LPG), or 14% of the bypassed oil, has been recovered from the secondary gas cap through stripping with the remaining oil volume in the secondary gas cap being approximately 700 MMstb. Today, the remaining oil saturation in the Mauddud gas cap is estimated to be approximately 40%.\u0000 This paper presents the results of an extensive study that was made to forecast the Bahrain Field associated gas compositions and potential gas-liquids production recovery. Several forecast methodologies were used including data-driven analytical models, a compositional cross-section model, and a full-field compositional history matched model. The results of these forecasts and the conclusions are presented and compared. In this study, two scenarios of different gas compositions of injected gas and their impact on gas plant liquids recovery are explored.\u0000 In addition, this paper addresses the challenges and uncertainties associated in forecasting the gas compositions and ways to overcome them. The data-driven models and compositional cross-section model were initially used, however, due to their inherent uncertainties, a full field compositional simulation model was necessary. This compositional model was history matched with a seven (7) component Equation of State (EOS) to capture the lighter hydrocarbon components. Moreover, this model was used in predicting the yield and composition of the existing gas recovery plant. The results from all methods recommend doubling the capacity of the existing plant, which was commissioned in late 2018. A comparative analysis found that data-driven models can be used for gas cycling when using the same gas injection compositions. However, data-driven models over-estimate the Liquefied Petroleum Gas (LPG) yield if leaner gas is used for gas injection, which is the case for the proposed gas plant expansion.","PeriodicalId":10908,"journal":{"name":"Day 2 Tue, March 19, 2019","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91113194","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}
O. Abdullatif, M. Osman, M. Yassin, M. Makkawi, Mohamed al-Farhan
The Miocene deep sea turbidite sandstone of Burqan Formation is important hydrocarbon reservoir target in Midyan region, Red Sea, NW of Saudi Arabia. Excellently exposed outcrops of Burqan Formation in Midyan region provide good data to examine and evaluate the reservoir rocks. This study integrates field observations (sedimentologic, stratigraphic and structural) and measurements from outcrop analog of the turbidite sandstone to investigate and characterize the reservoir heterogeneity, quality and architecture. The methods and approach followed used sedimentologic and stratigraphic analysis based on vertical and lateral outcrop sections and photomosaic so as to reveal the vertical and lateral distribution of the lithofacies and their geometries at outcrop scale. Moreover, terrestrial laser scanning (LiDAR) was utilized in this study to capture outcrop meso to macroscopic sedimentologic and stratigraphic and structural features details (strata surfaces. geometry distribution, faults, fractures). We integrated field observations with laboratory analyses to characterize the microscopic sedimentologic heterogeneity of lithofacies, texture, composition and petrophysical properties of the turbidite sandstone. The stratigraphic analysis shows variation in outcrops from proximal to distal parts, within 15 to 20 km traverse across the outcrops belt (west to east) of Burqan Formation. The sandstone body thickness varied between 2 – 4 m in the proximal parts and between 0.5 – 1 m distally. Also, these variations in thickness was associated with increasing of shale/sandstone ratio from proximal to distal parts. The sandstone bodies width revealed from outcrop mosaics extend laterally between 100 to over 150 m. The lithofacies consists of both matrix and clast supported conglomerates, pebbly sandstone and coarse to very coarse and medium grained, massive, trough and horizontally stratified sandstone. These facies were interbedded with siltstone, mudstone and shale. The sand bodies were vertically and laterally stacked in the proximal parts and decreases in the medial and distal parts, however, locally the shale and mudstone lithofacies interbeds and form baffle zones. The region is tectonically and structurally active, therefore, at outcrop scale the repeated tectonics and rifting in the region resulted in faulting, shearing and fracturing which added complexity to the turbidite sandstone reservoir architecture. Moreover, tectonic affected reservoir/seal relationship, reservoir continuity and distribution of inter-reservoir barriers and baffles. The results of this high resolution outcrop analog study might provide information and data base on types and scales of geological heterogeneities and their impact on reservoir quality and architecture within the interwell spacing. Moreover, it might also provide guides for exploration and development and help in decision making to avoid risks under the complex geological setting in the Red Sea region and other h
{"title":"Digital Outcrop Analog Reservoir Model of the Miocene Turbidite Sandstones, Midyan Area, Red Sea Region, Saudi Arabia","authors":"O. Abdullatif, M. Osman, M. Yassin, M. Makkawi, Mohamed al-Farhan","doi":"10.2118/195002-MS","DOIUrl":"https://doi.org/10.2118/195002-MS","url":null,"abstract":"\u0000 The Miocene deep sea turbidite sandstone of Burqan Formation is important hydrocarbon reservoir target in Midyan region, Red Sea, NW of Saudi Arabia. Excellently exposed outcrops of Burqan Formation in Midyan region provide good data to examine and evaluate the reservoir rocks. This study integrates field observations (sedimentologic, stratigraphic and structural) and measurements from outcrop analog of the turbidite sandstone to investigate and characterize the reservoir heterogeneity, quality and architecture. The methods and approach followed used sedimentologic and stratigraphic analysis based on vertical and lateral outcrop sections and photomosaic so as to reveal the vertical and lateral distribution of the lithofacies and their geometries at outcrop scale. Moreover, terrestrial laser scanning (LiDAR) was utilized in this study to capture outcrop meso to macroscopic sedimentologic and stratigraphic and structural features details (strata surfaces. geometry distribution, faults, fractures). We integrated field observations with laboratory analyses to characterize the microscopic sedimentologic heterogeneity of lithofacies, texture, composition and petrophysical properties of the turbidite sandstone.\u0000 The stratigraphic analysis shows variation in outcrops from proximal to distal parts, within 15 to 20 km traverse across the outcrops belt (west to east) of Burqan Formation. The sandstone body thickness varied between 2 – 4 m in the proximal parts and between 0.5 – 1 m distally. Also, these variations in thickness was associated with increasing of shale/sandstone ratio from proximal to distal parts. The sandstone bodies width revealed from outcrop mosaics extend laterally between 100 to over 150 m. The lithofacies consists of both matrix and clast supported conglomerates, pebbly sandstone and coarse to very coarse and medium grained, massive, trough and horizontally stratified sandstone. These facies were interbedded with siltstone, mudstone and shale. The sand bodies were vertically and laterally stacked in the proximal parts and decreases in the medial and distal parts, however, locally the shale and mudstone lithofacies interbeds and form baffle zones. The region is tectonically and structurally active, therefore, at outcrop scale the repeated tectonics and rifting in the region resulted in faulting, shearing and fracturing which added complexity to the turbidite sandstone reservoir architecture. Moreover, tectonic affected reservoir/seal relationship, reservoir continuity and distribution of inter-reservoir barriers and baffles.\u0000 The results of this high resolution outcrop analog study might provide information and data base on types and scales of geological heterogeneities and their impact on reservoir quality and architecture within the interwell spacing. Moreover, it might also provide guides for exploration and development and help in decision making to avoid risks under the complex geological setting in the Red Sea region and other h","PeriodicalId":10908,"journal":{"name":"Day 2 Tue, March 19, 2019","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81508993","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 corrosion behaviour of API 5L X65 carbon steel was investigated under high pressure carbon dioxide environments, containing elevated hydrogen sulfide, to simulate the condition of high carbon dioxide-containing natural gas subsea pipelines. It was systematically studied under high pressure carbon dioxide (120 bars) with a variation in other key parameters (hydrogen sulfide concentration and temperature). The corrosion rates were tested using High Pressure and High Temperature (HPHT) autoclave and measured using the techniques such as linear polarisation resistance (LPR), potentiodynamic sweep measurements, iron count, weight loss (WL) and electrochemical impedance spectroscopy (EIS). The surface morphology and the composition of the corrosion product layers were analysed using Infinite Focus Microscope (IFM), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The results showed that in the CO2- saturated water phase, the addition of 2000 ppm hydrogen sulfide (H2S) instantaneously decreased the corrosion rate of carbon steel API 5L X65 at both 25°C and 80°C. The surface morphology and the composition of the corrosion product layers reveal the formation of mackinawite. The inhibitive effect of hydrogen sulfide at elevated concentration was observed and contributed to the significant reduction in corrosion. The effect on corrosion was despite the fact that water chemistry equilibrium was unchanged with the presence of elevated hydrogen sulfide.
{"title":"The Effect of Elevated H2S on Corrosion Behaviour of API 5L X65 Carbon Steel in High Partial Pressure CO2 Environments","authors":"A. Z. Abas, A. Nor, M. Suhor, A. Rusli","doi":"10.2118/194873-MS","DOIUrl":"https://doi.org/10.2118/194873-MS","url":null,"abstract":"\u0000 The corrosion behaviour of API 5L X65 carbon steel was investigated under high pressure carbon dioxide environments, containing elevated hydrogen sulfide, to simulate the condition of high carbon dioxide-containing natural gas subsea pipelines. It was systematically studied under high pressure carbon dioxide (120 bars) with a variation in other key parameters (hydrogen sulfide concentration and temperature). The corrosion rates were tested using High Pressure and High Temperature (HPHT) autoclave and measured using the techniques such as linear polarisation resistance (LPR), potentiodynamic sweep measurements, iron count, weight loss (WL) and electrochemical impedance spectroscopy (EIS). The surface morphology and the composition of the corrosion product layers were analysed using Infinite Focus Microscope (IFM), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). The results showed that in the CO2- saturated water phase, the addition of 2000 ppm hydrogen sulfide (H2S) instantaneously decreased the corrosion rate of carbon steel API 5L X65 at both 25°C and 80°C. The surface morphology and the composition of the corrosion product layers reveal the formation of mackinawite. The inhibitive effect of hydrogen sulfide at elevated concentration was observed and contributed to the significant reduction in corrosion. The effect on corrosion was despite the fact that water chemistry equilibrium was unchanged with the presence of elevated hydrogen sulfide.","PeriodicalId":10908,"journal":{"name":"Day 2 Tue, March 19, 2019","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89186637","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}
Non-magnetic collars must be strong, tough, and corrosion resistant to withstand dynamic drillstring loads while also providing robust housings for measuring and logging-while-drilling (MWD/LWD) tool electronics. This paper describes a materials solution to problems related to the corrosion of drill collars in hostile well conditions. Typical nitrogen-strengthened chrome-manganese drill collar alloys are at risk of early retirement or downhole failure due to pitting, stress corrosion cracking (SCC), and sulfide stress cracking (SSC). Tool non-productive time due to increased maintenance, repair, overhaul frequency, and premature removal from service increases operating costs. The results of laboratory trials in conditions representative of active drilling basins show the differentiated performance of a chrome-nickel stainless steel and nickel-based alloy 718 relative to more common chrome-manganese stainless grades currently in wide-spread use. The pitting resistance, SCC resistance, and SSC resistance of both chrome-nickel stainless and nickel grade were found to be significantly better under wide ranging conditions and confirmed the capacity of both alloy systems to outlast incumbent drill collar grades.
{"title":"Increased Tool Life and Enhanced Reliability for Bottomhole Assemblies in Harsh Environments","authors":"K. Panda, Thomas Williams, A. Collins","doi":"10.2118/194784-MS","DOIUrl":"https://doi.org/10.2118/194784-MS","url":null,"abstract":"\u0000 Non-magnetic collars must be strong, tough, and corrosion resistant to withstand dynamic drillstring loads while also providing robust housings for measuring and logging-while-drilling (MWD/LWD) tool electronics. This paper describes a materials solution to problems related to the corrosion of drill collars in hostile well conditions. Typical nitrogen-strengthened chrome-manganese drill collar alloys are at risk of early retirement or downhole failure due to pitting, stress corrosion cracking (SCC), and sulfide stress cracking (SSC). Tool non-productive time due to increased maintenance, repair, overhaul frequency, and premature removal from service increases operating costs. The results of laboratory trials in conditions representative of active drilling basins show the differentiated performance of a chrome-nickel stainless steel and nickel-based alloy 718 relative to more common chrome-manganese stainless grades currently in wide-spread use. The pitting resistance, SCC resistance, and SSC resistance of both chrome-nickel stainless and nickel grade were found to be significantly better under wide ranging conditions and confirmed the capacity of both alloy systems to outlast incumbent drill collar grades.","PeriodicalId":10908,"journal":{"name":"Day 2 Tue, March 19, 2019","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87828410","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}
A technological revolution in hydraulic fracturing has occurred between early wellbore stimulation techniques and present day stimulation that has reduced cost and increased stimulation performance. Part of this revolution has been driven by the improved technology of frac plugs. This paper discusses how the evolution from cast iron frac plugs to composite plugs, then later to an interventionless stimulation completions process has enabled stimulation in extended-reach wellbores. Drillable frac plugs were initially created from cast iron. Although cast iron plugs met run-in requirements and pressure ratings, the time required to remove these plugs by milling was long. Composite frac plugs were developed to accelerate the mill-out process. The light weight of the composite frac plugs also enabled the frac plugs to be run into a horizontal section of the wellbore. This operational change, combined with the ease of milling the composite plugs, has paved the way for the horizontal completion market for the past 15 years. However, the use of composite frac plugs in extended-reach horizontal wells was limited by the need to drill out the plugs. The development of dissolvable frac plugs eliminated the need to drill out the plugs allowing operators to produce wells much sooner. This elimination of the drill-out step for dissolvable frac plugs has also enabled the successful completion of extended-reach horizontal wells which may be beyond the practical range of coiled tubing or jointed tubing. The need for efficient production in extended-reach wellbores has spurred the continuing evolution of hydraulic stimulation. This paper describes 20 years of new technology and field results to document the changes to the design and construction of frac plugs, as well as changes to the design and operation of the wellbore.
{"title":"Evolution of Frac Plug Technologies – Cast Iron to Composites to Dissolvable","authors":"Z. Walton, M. Fripp, Jesse C. Porter, Greg Vargus","doi":"10.2118/194802-MS","DOIUrl":"https://doi.org/10.2118/194802-MS","url":null,"abstract":"\u0000 A technological revolution in hydraulic fracturing has occurred between early wellbore stimulation techniques and present day stimulation that has reduced cost and increased stimulation performance. Part of this revolution has been driven by the improved technology of frac plugs. This paper discusses how the evolution from cast iron frac plugs to composite plugs, then later to an interventionless stimulation completions process has enabled stimulation in extended-reach wellbores.\u0000 Drillable frac plugs were initially created from cast iron. Although cast iron plugs met run-in requirements and pressure ratings, the time required to remove these plugs by milling was long. Composite frac plugs were developed to accelerate the mill-out process. The light weight of the composite frac plugs also enabled the frac plugs to be run into a horizontal section of the wellbore. This operational change, combined with the ease of milling the composite plugs, has paved the way for the horizontal completion market for the past 15 years. However, the use of composite frac plugs in extended-reach horizontal wells was limited by the need to drill out the plugs. The development of dissolvable frac plugs eliminated the need to drill out the plugs allowing operators to produce wells much sooner. This elimination of the drill-out step for dissolvable frac plugs has also enabled the successful completion of extended-reach horizontal wells which may be beyond the practical range of coiled tubing or jointed tubing.\u0000 The need for efficient production in extended-reach wellbores has spurred the continuing evolution of hydraulic stimulation. This paper describes 20 years of new technology and field results to document the changes to the design and construction of frac plugs, as well as changes to the design and operation of the wellbore.","PeriodicalId":10908,"journal":{"name":"Day 2 Tue, March 19, 2019","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82545716","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 reservoir compartmentalization structure and fluid contacts of a field are essential for determining the value of a reservoir asset and provide the two primary purposes of pressure gradient determination. Several new straightforward data-analytical methods have been developed to extract pressure gradient information based on physical properties of the reservoir and meta-analysis of derived pressure gradient information. These methods can be used to provide near real-time feedback about the pressure measurements quality. This paper describes two distinct methods to determine reservoir compartmentalization structure and fluid contacts. The first method implements statistical evolution to rapidly identify pressure gradients. The second method transforms identified pressure measurements into a meta-analytical visual representation of pressure gradients vs. depth with additional input from measurement consistency. Both methods rely on the accurate removal of pressure outlier data, such as that attributable to supercharging. A new technique using expert knowledge of physical constraints was implemented for reliable outlier removal. The two methods then diverge in subsequent conditioning of the data, but re-converge in adapting an efficient fitting method to extract the desired information. Both methods provide reliable removal of pressure data that are not related to formation fluid densities, regardless of reservoir number, fluid number, or fluid type. To date, the removal procedure removes more than 95% of outliers and retains more than 90% of accurate pressure data. Both methods also return the correct number and types of fluids. Although pressure gradient estimation can vary by up to 50% for fluid zones of less than 50 ft, the estimation error of the pressure gradients is reduced to less than 3% for fluid zones greater than 100 ft. Furthermore, fluid breaks can be calculated to within 8 ft for the statistical evolution method and to within 30 ft using the visual method. Finally, although the statistical evolution method is markedly faster than the visual method, both techniques provide feedback within a few minutes. The methods discussed provide feedback about the necessity to retake or take more pressure data during formation-pressure surveys within minutes. This feedback eliminates the delay in reservoir property estimation and greatly increases the reliability and quality of pressure data obtained. The methods presented also use a new application of data meta-analysis to reduce processing time and increase reliability.
{"title":"Automated Artificial Intelligent Pressure Gradient Analysis for Fluid Contact and Compartmentalization Analysis","authors":"D. Stark, C. M. Jones, Bin Dai, A. V. Zuilekom","doi":"10.2118/195083-MS","DOIUrl":"https://doi.org/10.2118/195083-MS","url":null,"abstract":"\u0000 The reservoir compartmentalization structure and fluid contacts of a field are essential for determining the value of a reservoir asset and provide the two primary purposes of pressure gradient determination. Several new straightforward data-analytical methods have been developed to extract pressure gradient information based on physical properties of the reservoir and meta-analysis of derived pressure gradient information. These methods can be used to provide near real-time feedback about the pressure measurements quality.\u0000 This paper describes two distinct methods to determine reservoir compartmentalization structure and fluid contacts. The first method implements statistical evolution to rapidly identify pressure gradients. The second method transforms identified pressure measurements into a meta-analytical visual representation of pressure gradients vs. depth with additional input from measurement consistency. Both methods rely on the accurate removal of pressure outlier data, such as that attributable to supercharging. A new technique using expert knowledge of physical constraints was implemented for reliable outlier removal. The two methods then diverge in subsequent conditioning of the data, but re-converge in adapting an efficient fitting method to extract the desired information.\u0000 Both methods provide reliable removal of pressure data that are not related to formation fluid densities, regardless of reservoir number, fluid number, or fluid type. To date, the removal procedure removes more than 95% of outliers and retains more than 90% of accurate pressure data. Both methods also return the correct number and types of fluids. Although pressure gradient estimation can vary by up to 50% for fluid zones of less than 50 ft, the estimation error of the pressure gradients is reduced to less than 3% for fluid zones greater than 100 ft. Furthermore, fluid breaks can be calculated to within 8 ft for the statistical evolution method and to within 30 ft using the visual method. Finally, although the statistical evolution method is markedly faster than the visual method, both techniques provide feedback within a few minutes.\u0000 The methods discussed provide feedback about the necessity to retake or take more pressure data during formation-pressure surveys within minutes. This feedback eliminates the delay in reservoir property estimation and greatly increases the reliability and quality of pressure data obtained. The methods presented also use a new application of data meta-analysis to reduce processing time and increase reliability.","PeriodicalId":10908,"journal":{"name":"Day 2 Tue, March 19, 2019","volume":"212 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76583086","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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