In this paper, we propose an alternative approach to the problem of oil-production forecast based on the most straightforward feature-based machine-learning algorithm: the linear model. The method can be successfully applied to forecast both oil-rate and liquid-rate in oil fields under (i) water injection, (ii) gas injection, and (iii) simultaneous water and steam injection. Our data-driven algorithm learns the underlying reservoir dynamics from 3 sets of time-series, namely, (i) injection-rate, (ii) liquid and oil-rate, and (iii) number of producers. That is all the data we need to make reliable forecasts, no geological model or numerical reservoir simulators were used.
{"title":"Application of Machine Learning to Oil Production Forecast under Uncertainties-The Linear Model","authors":"L. Kubota, F. Souto","doi":"10.4043/29883-ms","DOIUrl":"https://doi.org/10.4043/29883-ms","url":null,"abstract":"\u0000 In this paper, we propose an alternative approach to the problem of oil-production forecast based on the most straightforward feature-based machine-learning algorithm: the linear model. The method can be successfully applied to forecast both oil-rate and liquid-rate in oil fields under (i) water injection, (ii) gas injection, and (iii) simultaneous water and steam injection. Our data-driven algorithm learns the underlying reservoir dynamics from 3 sets of time-series, namely, (i) injection-rate, (ii) liquid and oil-rate, and (iii) number of producers. That is all the data we need to make reliable forecasts, no geological model or numerical reservoir simulators were used.","PeriodicalId":10927,"journal":{"name":"Day 3 Thu, October 31, 2019","volume":"124 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85268996","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}
Organic deposition formed at high temperatures in oil and gas production systems is commonly linked to instability of asphaltenes. Recent studies revealed that deposits collected in offshore production wells produced in Gulf of Mexico exhibited compositional variation pointing to a more complex fouling process than solely related to the asphaltene fractions. To better understand the mechanism of deposition and external factors that could contribute to this precipitation, crude oils and their respective deposits collected from the field were characterized for comparison in terms of properties and composition. Moreover, crude oils were treated with Asphaltene Inhibitors (AI) and Paraffin Inhibitor (PI) and tested applying three techniques: Asphaltene Dynamic Deposition Loop (ADDL), cold finger and rheology. The deposits collected from the ADDL and from cold finger were analyzed and compared to the field deposits. A lab-to-field correlation was observed when analyzing the deposits collected from the ADDL and cold finger tests. In both deposits, asphaltenes and wax fractions were observed to co-precipitate and form "Waxphaltenes". The efficiency of the AI on dispersing the asphaltenes was observed to have a major impact on the precipitation as possibly increasing the deposition of microcrystalline waxes. The influence of the AI at certain dosage rate in the precipitation of waxes is highlighted. In this research, the mechanism of asphaltene dispersion and instability of waxes in the presence of AI at low concentrations is proposed.
{"title":"Influence of Asphaltene Inhibitors on Wax and Asphaltene Deposition - Are Problems Associated?","authors":"J. I. Aguiar, A. Punase, Claudia Mazzeo","doi":"10.4043/29817-ms","DOIUrl":"https://doi.org/10.4043/29817-ms","url":null,"abstract":"\u0000 Organic deposition formed at high temperatures in oil and gas production systems is commonly linked to instability of asphaltenes. Recent studies revealed that deposits collected in offshore production wells produced in Gulf of Mexico exhibited compositional variation pointing to a more complex fouling process than solely related to the asphaltene fractions. To better understand the mechanism of deposition and external factors that could contribute to this precipitation, crude oils and their respective deposits collected from the field were characterized for comparison in terms of properties and composition. Moreover, crude oils were treated with Asphaltene Inhibitors (AI) and Paraffin Inhibitor (PI) and tested applying three techniques: Asphaltene Dynamic Deposition Loop (ADDL), cold finger and rheology. The deposits collected from the ADDL and from cold finger were analyzed and compared to the field deposits. A lab-to-field correlation was observed when analyzing the deposits collected from the ADDL and cold finger tests. In both deposits, asphaltenes and wax fractions were observed to co-precipitate and form \"Waxphaltenes\". The efficiency of the AI on dispersing the asphaltenes was observed to have a major impact on the precipitation as possibly increasing the deposition of microcrystalline waxes. The influence of the AI at certain dosage rate in the precipitation of waxes is highlighted. In this research, the mechanism of asphaltene dispersion and instability of waxes in the presence of AI at low concentrations is proposed.","PeriodicalId":10927,"journal":{"name":"Day 3 Thu, October 31, 2019","volume":"322 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76898804","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}
David F.L. Labbé, Karim Jan, Marcelo Xavier, C.M.O. Tadeu, M. Vílchez
The international offshore oil and gas industry started numerous efficiency initiatives in 2014 and 2015 as a response to the global down-turn in field development activity. Additionally new and innovative ways of doing business were conceived and investigated. One of these was integrating the work scopes involved in subsea production and processing systems construction together with associated pipeline and controls infrastructure. The mechanisms by which integrating the subsea hardware and offshore delivery scopes yields value have been studied and compared with traditional approaches of segmenting the various elements. Previously executed projects, it was discovered, would have been delivered with different results and imporved cost performance within an integrated structure. Similarly prospective projects costed and priced using a traditionally segmented approach showed a higher cost and schedule compared with those designed from the early stages of the project by an integrated design team of equipment and installation specialists. These effects were observed on projects of different sizes and in various geographical regions. (This paper will provide anonymous examples of these cases to provide context). Our industry currently has more than 15 integrated projects underway and offshore oil and gas operators are starting publicly share their experiences of this new way of working. The result is that potential field development projects are integrating traditionally segmented subsea scopes earlier in the economic lifecycle of the project. (This paper will illustrate this trend). As the project execution phase progresses different systems and mechanisms are used to ensure that the value is captured and an acceptable project risk profile is maintained. The market for integrated subsea project delivery has grown from 8% of the market in 2015 to 35% or more in 2018 and seems unlikely to diminish in 2019. Integrated subsea delivery has emerged as an enabler of different project outcomes for international oil and gas companies and is setting new standards for efficiency in our industry.
{"title":"The Remarkable Growth of Integrated Subsea Projects from 2016 to 2019","authors":"David F.L. Labbé, Karim Jan, Marcelo Xavier, C.M.O. Tadeu, M. Vílchez","doi":"10.4043/29778-ms","DOIUrl":"https://doi.org/10.4043/29778-ms","url":null,"abstract":"\u0000 \u0000 \u0000 The international offshore oil and gas industry started numerous efficiency initiatives in 2014 and 2015 as a response to the global down-turn in field development activity. Additionally new and innovative ways of doing business were conceived and investigated. One of these was integrating the work scopes involved in subsea production and processing systems construction together with associated pipeline and controls infrastructure.\u0000 \u0000 \u0000 \u0000 The mechanisms by which integrating the subsea hardware and offshore delivery scopes yields value have been studied and compared with traditional approaches of segmenting the various elements.\u0000 Previously executed projects, it was discovered, would have been delivered with different results and imporved cost performance within an integrated structure.\u0000 Similarly prospective projects costed and priced using a traditionally segmented approach showed a higher cost and schedule compared with those designed from the early stages of the project by an integrated design team of equipment and installation specialists.\u0000 These effects were observed on projects of different sizes and in various geographical regions. (This paper will provide anonymous examples of these cases to provide context).\u0000 Our industry currently has more than 15 integrated projects underway and offshore oil and gas operators are starting publicly share their experiences of this new way of working.\u0000 The result is that potential field development projects are integrating traditionally segmented subsea scopes earlier in the economic lifecycle of the project. (This paper will illustrate this trend).\u0000 As the project execution phase progresses different systems and mechanisms are used to ensure that the value is captured and an acceptable project risk profile is maintained.\u0000 \u0000 \u0000 \u0000 The market for integrated subsea project delivery has grown from 8% of the market in 2015 to 35% or more in 2018 and seems unlikely to diminish in 2019.\u0000 \u0000 \u0000 \u0000 Integrated subsea delivery has emerged as an enabler of different project outcomes for international oil and gas companies and is setting new standards for efficiency in our industry.\u0000","PeriodicalId":10927,"journal":{"name":"Day 3 Thu, October 31, 2019","volume":"79 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78384610","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}
P. F. V. Garcia, D. F. Rossi, F. H. Ferreira, E. Santos, A. Borba
Results from mechanical tests on grainstone and dolomite wellcore samples obtained from the Quissamã formation are presented. Unconfined compressive strength (UCS) logs obtained from scratch tests are compared to known relations. Elastic compressibility moduli, obtained from cyclic hydrostatic and oedometer compression tests, are compared to analytical formulation. Mohr-Coulomb strength envelopes are obtained from compressive tests, such as Brazilian tests, drained uniaxial compression and drained triaxial compression. The mechanical test campaign consisted of the following steps: 1) scratch test of three full wellcore sets from Quissamã formation to obtain UCS logs, 2) wholecore sampling for cylindrical rock plugging, 3) microtomography imaging of new cylindrical rock samples for internal structural integrity preview and 4) compression tests of plugged rock samples to obtain static elastic properties (Poisson's ratio, Young moduli, bulk moduli, grain compressibility moduli and oedometric compressibility moduli) and mechanical resistance properties (indirect tensile strength, drained UCS and drained confined compressive strength (CCS)). Experimental results were compared to literature UCS relations and analytical compressibility moduli formulation. It was possible to observe good concordance between UCS obtained from drained uniaxial compression tests and scratch testing profiles. Using the internal friction angle obtained from Mohr-Coulomb envelopes and the UCS results, it was possible to indirectly obtain an estimation of cohesion through Mohr-Coulomb criteria relations. Compressibility moduli obtained from experiments also were in good concordance with classical formulation for elastic deformation regime. In the end, the mechanical characterization campaign was succesful in obtaining resistance and elastic static properties for loading conditions and some unloading conditions.
{"title":"Mechanical Characterization of Grainstone and Dolomite Rock Samples from Quissamã Formation, Campos Basin","authors":"P. F. V. Garcia, D. F. Rossi, F. H. Ferreira, E. Santos, A. Borba","doi":"10.4043/29770-ms","DOIUrl":"https://doi.org/10.4043/29770-ms","url":null,"abstract":"\u0000 Results from mechanical tests on grainstone and dolomite wellcore samples obtained from the Quissamã formation are presented. Unconfined compressive strength (UCS) logs obtained from scratch tests are compared to known relations. Elastic compressibility moduli, obtained from cyclic hydrostatic and oedometer compression tests, are compared to analytical formulation. Mohr-Coulomb strength envelopes are obtained from compressive tests, such as Brazilian tests, drained uniaxial compression and drained triaxial compression.\u0000 The mechanical test campaign consisted of the following steps: 1) scratch test of three full wellcore sets from Quissamã formation to obtain UCS logs, 2) wholecore sampling for cylindrical rock plugging, 3) microtomography imaging of new cylindrical rock samples for internal structural integrity preview and 4) compression tests of plugged rock samples to obtain static elastic properties (Poisson's ratio, Young moduli, bulk moduli, grain compressibility moduli and oedometric compressibility moduli) and mechanical resistance properties (indirect tensile strength, drained UCS and drained confined compressive strength (CCS)). Experimental results were compared to literature UCS relations and analytical compressibility moduli formulation.\u0000 It was possible to observe good concordance between UCS obtained from drained uniaxial compression tests and scratch testing profiles. Using the internal friction angle obtained from Mohr-Coulomb envelopes and the UCS results, it was possible to indirectly obtain an estimation of cohesion through Mohr-Coulomb criteria relations. Compressibility moduli obtained from experiments also were in good concordance with classical formulation for elastic deformation regime. In the end, the mechanical characterization campaign was succesful in obtaining resistance and elastic static properties for loading conditions and some unloading conditions.","PeriodicalId":10927,"journal":{"name":"Day 3 Thu, October 31, 2019","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77565063","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}
Polymer flooding is one of the well-established and commercially-available techniques for enhanced oil recovery in the petroleum industry. It is the most widely adopted chemical enhanced oil recovery technique in sandstones, but its application in carbonates is limited due to the harsh reservoir conditions of high temperature, high salinity, and low permeability. However, research is advancing to expand the applicability of this technique to carbonate reservoirs in a cost effective manner. In this paper, we present a comprehensive review on polymer flooding for carbonates under harsh conditions. This review includes descriptions of underlying mechanisms, polymer types, polymer screening studies, coreflood laboratory work, numerical and modeling works, and field applications. Screening of new polymers for potential field applications is also discussed. In addition, polymer rheology and challenges posed to polymer flow in the porous media are described. Moreover, summary tables of different monomers used to tailor polymers for harsh conditions as well as temperature and salinity limits of different polymers are provided, which makes this review as a guidance for implementing new projects using the polymer flooding technique. The literature review conducted shows that with the recent technology, a field-scale application of polymer flooding in carbonate reservoirs is possible. Several polymer types have been recently developed to overcome harsh carbonate conditions of high temperature, high salinity, and low permeability. This is encouraging towards conducting pilots in carbonate reservoirs in a cost effective manner. At the end of this paper, recommendations to overcome the challenges of high temperature, high salinity/hardness, and poor injectivity are provided based on this vast literature review and our experiences in polymer flooding. This paper gives more insight into polymer flooding aspects and its different applications in the oil industry. In addition, the study is considered as a guide for starting or implementing potential projects on polymer flooding in carbonate reservoirs under harsh conditions.
{"title":"Recent Developments in Polymer Flooding for Carbonate Reservoirs under Harsh Conditions","authors":"W. Diab, E. Al-Shalabi","doi":"10.4043/29739-ms","DOIUrl":"https://doi.org/10.4043/29739-ms","url":null,"abstract":"\u0000 Polymer flooding is one of the well-established and commercially-available techniques for enhanced oil recovery in the petroleum industry. It is the most widely adopted chemical enhanced oil recovery technique in sandstones, but its application in carbonates is limited due to the harsh reservoir conditions of high temperature, high salinity, and low permeability. However, research is advancing to expand the applicability of this technique to carbonate reservoirs in a cost effective manner. In this paper, we present a comprehensive review on polymer flooding for carbonates under harsh conditions. This review includes descriptions of underlying mechanisms, polymer types, polymer screening studies, coreflood laboratory work, numerical and modeling works, and field applications. Screening of new polymers for potential field applications is also discussed. In addition, polymer rheology and challenges posed to polymer flow in the porous media are described. Moreover, summary tables of different monomers used to tailor polymers for harsh conditions as well as temperature and salinity limits of different polymers are provided, which makes this review as a guidance for implementing new projects using the polymer flooding technique.\u0000 The literature review conducted shows that with the recent technology, a field-scale application of polymer flooding in carbonate reservoirs is possible. Several polymer types have been recently developed to overcome harsh carbonate conditions of high temperature, high salinity, and low permeability. This is encouraging towards conducting pilots in carbonate reservoirs in a cost effective manner. At the end of this paper, recommendations to overcome the challenges of high temperature, high salinity/hardness, and poor injectivity are provided based on this vast literature review and our experiences in polymer flooding. This paper gives more insight into polymer flooding aspects and its different applications in the oil industry. In addition, the study is considered as a guide for starting or implementing potential projects on polymer flooding in carbonate reservoirs under harsh conditions.","PeriodicalId":10927,"journal":{"name":"Day 3 Thu, October 31, 2019","volume":"115 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74547129","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}
Water-Alternating-Gas (WAG) injection is an enhanced recovery method that is being applied in some brazilian offshore oilfields as an alternative to combine effective pressure maintenance policies, flexible produced gas management strategies and increased recoveries. In this technology, gas plays the role of reducing residual oil saturation while water controls, by multiphase flow-in-porous-medium effects, gas adverse mobility. In addition to the extra engineering tasks needed to design development plans and production facilities, an intense characterization programme should be put in practice in order to reduce risks, increase predictability and optimize WAG floods. Much more complex laboratory tests than the ones usually performed for continuous water/gas floods should be done, particularly to tackle multiphase flow in porous medium phenomena. The proper characterization, modeling and simulation of these effects are vital for a representative WAG design and evaluation. This paper presents the results of a pragmatic and integrated laboratory characterization, modeling and simulation study for an offshore oilfield that was focused on relative permeability hysteresis effects. Firstly, it summarizes the best relative permeability hysteresis model (Larsen & Skauge) available in most commercial reservoir simulators. Then, it describes a special laboratory WAG multiphase flow-in-porous-media characterization program, designed and executed to obtain the parameters of this hysteresis model. Experiments were done at reservoir conditions and with rock and fluids from an actual offshore field. Following, results of these tests were evaluated in light of Larsen & Skauge model, in order to confirm its validity. Finally, WAG simulations of a sector of the target field were performed to access the impacts of including or neglecting relative permeability hysteresis phenomena. Conclusions of this work contribute to increase predictability and reduce uncertainties related to field-scale implementation of WAG technology. Knowledge acquired from this study promoted a better estimation of oil recovery, gas production and overriding. It also supports the design of subsea and topside equipment, which is critical in the offshore scenario.
{"title":"An Integrated WAG Characterization Study for an Offshore Oilfield","authors":"R. A. M. Vieira, M. A. Cardoso, J. Pizarro","doi":"10.4043/29766-ms","DOIUrl":"https://doi.org/10.4043/29766-ms","url":null,"abstract":"\u0000 Water-Alternating-Gas (WAG) injection is an enhanced recovery method that is being applied in some brazilian offshore oilfields as an alternative to combine effective pressure maintenance policies, flexible produced gas management strategies and increased recoveries. In this technology, gas plays the role of reducing residual oil saturation while water controls, by multiphase flow-in-porous-medium effects, gas adverse mobility.\u0000 In addition to the extra engineering tasks needed to design development plans and production facilities, an intense characterization programme should be put in practice in order to reduce risks, increase predictability and optimize WAG floods. Much more complex laboratory tests than the ones usually performed for continuous water/gas floods should be done, particularly to tackle multiphase flow in porous medium phenomena. The proper characterization, modeling and simulation of these effects are vital for a representative WAG design and evaluation.\u0000 This paper presents the results of a pragmatic and integrated laboratory characterization, modeling and simulation study for an offshore oilfield that was focused on relative permeability hysteresis effects.\u0000 Firstly, it summarizes the best relative permeability hysteresis model (Larsen & Skauge) available in most commercial reservoir simulators. Then, it describes a special laboratory WAG multiphase flow-in-porous-media characterization program, designed and executed to obtain the parameters of this hysteresis model. Experiments were done at reservoir conditions and with rock and fluids from an actual offshore field. Following, results of these tests were evaluated in light of Larsen & Skauge model, in order to confirm its validity. Finally, WAG simulations of a sector of the target field were performed to access the impacts of including or neglecting relative permeability hysteresis phenomena.\u0000 Conclusions of this work contribute to increase predictability and reduce uncertainties related to field-scale implementation of WAG technology. Knowledge acquired from this study promoted a better estimation of oil recovery, gas production and overriding. It also supports the design of subsea and topside equipment, which is critical in the offshore scenario.","PeriodicalId":10927,"journal":{"name":"Day 3 Thu, October 31, 2019","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81844948","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}
For the application of flexible riser in ultra-deepwater beyond 2000m water depth, one of the technical challenges is the existence of ultra-high-tension loads induced from riser self-weight and amplified by its dynamic responses. The high-tension loads impose additional equipment and operational constrains in riser installation and application. For example, the high-tension loads limit the choice of installation vessel and prohibit the use of disconnectable turret moored system technology, which protects the riser system during extreme weather events. The industry has been developing innovative technologies to mitigate the high-tension loads anticipated in ultra-deepwater riser applications, such as using light weight composite material, buoyancy modules, hybrid riser tower structures, etc. This paper presents an innovative fully flexible riser solution for deep water application: a step riser configuration and it's variation-patented by BHGE. The technology was evolved from traditional free hanging configuration and based on existing proven reliable technologies. The step riser configuration is characterized by utilizing buoyancy tank/modules arrays to maximize uplifting buoyancy efficiency and exerting the buoyancy force directly to riser midline connections instead on the riser body directly. Extensive numerical simulations were performed to better understand the step riser's dynamic response characteristics, with validation through scale-model tank tests. This paper also includes an alternative buoyancy module and buoyancy system design, for potentially significant savings in fabrication cost and improvements in offshore installation efficiency. The step riser configuration permits various buoyancy designs to suit the capacity of installation vessels and to improve the riser extreme and fatigue performance in service. The technology also enables applicability for disconnectable turret moored systems in ultradeepwater application. It shows that the presented technology is a practical and reliable solution for ultradeepwater applications, with providing potential cost saving opportunity.
{"title":"A Flexible Riser System for Ultra-Deepwater","authors":"Yucheng Hou, Jiabei Yuan, Z. Tan","doi":"10.4043/29876-ms","DOIUrl":"https://doi.org/10.4043/29876-ms","url":null,"abstract":"\u0000 For the application of flexible riser in ultra-deepwater beyond 2000m water depth, one of the technical challenges is the existence of ultra-high-tension loads induced from riser self-weight and amplified by its dynamic responses. The high-tension loads impose additional equipment and operational constrains in riser installation and application. For example, the high-tension loads limit the choice of installation vessel and prohibit the use of disconnectable turret moored system technology, which protects the riser system during extreme weather events. The industry has been developing innovative technologies to mitigate the high-tension loads anticipated in ultra-deepwater riser applications, such as using light weight composite material, buoyancy modules, hybrid riser tower structures, etc.\u0000 This paper presents an innovative fully flexible riser solution for deep water application: a step riser configuration and it's variation-patented by BHGE. The technology was evolved from traditional free hanging configuration and based on existing proven reliable technologies. The step riser configuration is characterized by utilizing buoyancy tank/modules arrays to maximize uplifting buoyancy efficiency and exerting the buoyancy force directly to riser midline connections instead on the riser body directly. Extensive numerical simulations were performed to better understand the step riser's dynamic response characteristics, with validation through scale-model tank tests. This paper also includes an alternative buoyancy module and buoyancy system design, for potentially significant savings in fabrication cost and improvements in offshore installation efficiency. The step riser configuration permits various buoyancy designs to suit the capacity of installation vessels and to improve the riser extreme and fatigue performance in service. The technology also enables applicability for disconnectable turret moored systems in ultradeepwater application. It shows that the presented technology is a practical and reliable solution for ultradeepwater applications, with providing potential cost saving opportunity.","PeriodicalId":10927,"journal":{"name":"Day 3 Thu, October 31, 2019","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89632744","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}
In this paper it is presented how the application of the Decision Tree technique (DT) with different Utility Functions (UF) and the Certainty Equivalent concept (CE) can reveal the optimal level of financial participation (OLFP) of a given decision maker in risky projects for oil and gas exploration and production. The decision whether or not to participate in an upstream project may lead to either a one-company contract orand association of several companies, with the aim of distributing the risk to levels tolerated. With this in view, this article will apply the Decision Tree (DT) with five types of Utility Functions (UF) with their respective Certainty Equivalents (CE), and discuss the different results obtained, according to the type of UF used: exponential, hyperbolic tangent, logarithmic, square root and linear, the latter being used for the case of risk indifference and the others for decision makers with risk aversion. Each company has its particularities in deciding whether or not to participate in an oil and gas exploration and production project, such as the level os risk aversion or its estimate of reserves available for the next years, given the present production. Each utility function has a distinct behavior and each one of them is presented and discussed some utility functions suiting best each decision maker profile. Additionally, the application of different attitudes towards risk in the successive phases of an upstream project is discussed, as well as Multi-Attribute Utility Theory (MAUT), which can take advantage of the five types of utility function, each one capable of representing a different dimension of the same project (e.g. economic, polytical, environmental, technological, financial). Softwares were used to obtain the graphical and numerical results presented. The results obtained are easily replicable. The novelty is an analysis that compares in detail the use of five utility functions in the study of the optimal level of financial participation in oil and gas exploration projects with risks in a clear and replicable way, applying the results obtained to the profiles of decision makers and explaining certain behaviors in the acquisition and development of oil and gas fields by companies.
{"title":"Study of the Optimum Level of Financial Participation in Risky Projects for Oil and Gas Exploration and Production","authors":"R. Motta, Lorena Alves Damacena Basílio","doi":"10.4043/29793-ms","DOIUrl":"https://doi.org/10.4043/29793-ms","url":null,"abstract":"\u0000 In this paper it is presented how the application of the Decision Tree technique (DT) with different Utility Functions (UF) and the Certainty Equivalent concept (CE) can reveal the optimal level of financial participation (OLFP) of a given decision maker in risky projects for oil and gas exploration and production.\u0000 The decision whether or not to participate in an upstream project may lead to either a one-company contract orand association of several companies, with the aim of distributing the risk to levels tolerated. With this in view, this article will apply the Decision Tree (DT) with five types of Utility Functions (UF) with their respective Certainty Equivalents (CE), and discuss the different results obtained, according to the type of UF used: exponential, hyperbolic tangent, logarithmic, square root and linear, the latter being used for the case of risk indifference and the others for decision makers with risk aversion.\u0000 Each company has its particularities in deciding whether or not to participate in an oil and gas exploration and production project, such as the level os risk aversion or its estimate of reserves available for the next years, given the present production. Each utility function has a distinct behavior and each one of them is presented and discussed some utility functions suiting best each decision maker profile. Additionally, the application of different attitudes towards risk in the successive phases of an upstream project is discussed, as well as Multi-Attribute Utility Theory (MAUT), which can take advantage of the five types of utility function, each one capable of representing a different dimension of the same project (e.g. economic, polytical, environmental, technological, financial). Softwares were used to obtain the graphical and numerical results presented. The results obtained are easily replicable.\u0000 The novelty is an analysis that compares in detail the use of five utility functions in the study of the optimal level of financial participation in oil and gas exploration projects with risks in a clear and replicable way, applying the results obtained to the profiles of decision makers and explaining certain behaviors in the acquisition and development of oil and gas fields by companies.","PeriodicalId":10927,"journal":{"name":"Day 3 Thu, October 31, 2019","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88401079","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 drill string may be considered a minute component of the complex drilling program; however, it is more essential to the program than often thought. It has also become more challenging to select the right rotary shoulder connection when many are available to the drilling engineer. There is a wide choice of technologies available that have different functionalities and limitations. One may also be hard-pressed with selecting the right drill pipe as choices can be quite confusing even to specialists, yet the drilling engineer must select the correct drill string and drill pipe connection. If not properly optimized, he/she may either over-engineer or under-engineer the drill string design for the said program and have to deal with the consequences. Often enough, original equipment manufacturers (OEM) are involved in application work, helping drilling engineers find a workable solution for a project they are working on. Finding an optimized selection of components to be assembled in as string that will be used to drill and complete a field development is essential. It requires choosing tools that will be able to resist the torsional, tensile, pressure loads, optimizing hydraulics as well as resisting fatigue and exposure to corrosive fluids. A number of technologies are available that will help to deliver challenging prospects or help maintain the cost of operation as minimum as possible. This paper lists field-proven solutions that are trending in the industry, with the hope that adopting the appropriate ones will deliver results by improving drilling and completion efficiency.
{"title":"Optimizing Rotary Shoulder Connection for Drilling Program","authors":"ShankarNayak Bhukya, Guillaume Plessis, Raza Hussain","doi":"10.4043/29955-ms","DOIUrl":"https://doi.org/10.4043/29955-ms","url":null,"abstract":"\u0000 The drill string may be considered a minute component of the complex drilling program; however, it is more essential to the program than often thought. It has also become more challenging to select the right rotary shoulder connection when many are available to the drilling engineer. There is a wide choice of technologies available that have different functionalities and limitations. One may also be hard-pressed with selecting the right drill pipe as choices can be quite confusing even to specialists, yet the drilling engineer must select the correct drill string and drill pipe connection. If not properly optimized, he/she may either over-engineer or under-engineer the drill string design for the said program and have to deal with the consequences.\u0000 Often enough, original equipment manufacturers (OEM) are involved in application work, helping drilling engineers find a workable solution for a project they are working on. Finding an optimized selection of components to be assembled in as string that will be used to drill and complete a field development is essential. It requires choosing tools that will be able to resist the torsional, tensile, pressure loads, optimizing hydraulics as well as resisting fatigue and exposure to corrosive fluids.\u0000 A number of technologies are available that will help to deliver challenging prospects or help maintain the cost of operation as minimum as possible. This paper lists field-proven solutions that are trending in the industry, with the hope that adopting the appropriate ones will deliver results by improving drilling and completion efficiency.","PeriodicalId":10927,"journal":{"name":"Day 3 Thu, October 31, 2019","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87782620","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}
G. Venero, Victor Gomes, Hugues Corrignan, D. Carneiro
Fatigue is one of the key governing conditions in the design of rigid risers, in particular those in ultra-deep water. One effective way of improving fatigue is to adopt a lazy wave configuration, rather than a simple catenary. Steel Lazy Wave Risers (SLWR) have been successfully used offshore Brazil (Hoffman et al. 2010, Oliveira et al. 2017) and in the Gulf of Mexico (Beattie et al. 2013), and have been considered for the North Sea (Felista et al. 2015) and offshore Australia (Vijayaraghavan et al. 2015). Yet, it is probably the most computational-intensive aspect of it. Fatigue analyses require a very large number of load cases to be run, on complex, non-linear models. Methods for simplifying aspects of the analysis are highly desirable, but they must be weighed to provide the required safety levels whilst not introducing uneconomical, overconservative assumptions. The top first weld is a crucial hotspot, in particular for production SLWRs (Senra et al. 2011). These typically adopt flexible joints (FJ) at the connection to the vessel/platform, and linearization of the FJ stiffness is one of these key simplifications that bring significant value in reducing analysis cost. This paper describes a method for estimating the characteristic angle used for the linearization, which results in significant stiffness reduction in contrast with the usual, simpler method. Non-linear FJ stiffness curves are usually available, and they provide stiffness associated to the FJ absolute angle. The FJ stiffness significantly reduces with the angle of rotation. The conventional method adopts the stiffness corresponding to the most likely riser angle – absolute value measured from the static configuration. Conversely, the proposed methodology for estimating the most likely change in angle. As the angles often turn up in alternate angles, the proposed method results in much higher characteristic angle, and hence much lower FJ stiffness. The outcome is significantly less conservative designs, whilst still meeting the same required safety margins.
疲劳是刚性隔水管设计的关键控制条件之一，特别是在超深水中。改善疲劳的一种有效方法是采用懒波结构，而不是简单的悬链线。钢制缓波立管(SLWR)已成功应用于巴西近海(Hoffman等人，2010年，Oliveira等人，2017年)和墨西哥湾(Beattie等人，2013年)，并已被考虑用于北海(Felista等人，2015年)和澳大利亚近海(Vijayaraghavan等人，2015年)。然而，它可能是计算最密集的方面。疲劳分析需要在复杂的非线性模型上运行大量的载荷情况。简化分析方面的方法是非常可取的，但必须加以权衡，以提供所需的安全水平，同时不引入不经济、过度保守的假设。顶部第一个焊缝是一个关键的热点，特别是对于生产slwr (Senra et al. 2011)。这些方法通常采用柔性接头(FJ)连接容器/平台，而柔性接头刚度的线性化是这些关键简化方法之一，可以显著降低分析成本。本文描述了一种估计用于线性化的特征角的方法，与通常的、更简单的方法相比，该方法可以显著降低刚度。非线性FJ刚度曲线通常是可用的，它们提供了与FJ绝对角度相关的刚度。FJ刚度随旋转角度的增大而显著减小。传统的方法采用最可能的立管角所对应的刚度-从静态结构中测量的绝对值。相反，建议的方法估计最可能的角度变化。由于角度经常以交变角度出现，因此提出的方法可以获得更高的特征角，从而大大降低FJ刚度。其结果是明显不那么保守的设计，同时仍然满足相同的安全边际要求。
{"title":"Flexible Joint Stiffness Modelling Improving Ultra Deep Water Rigid Risers Fatigue Damage","authors":"G. Venero, Victor Gomes, Hugues Corrignan, D. Carneiro","doi":"10.4043/29678-ms","DOIUrl":"https://doi.org/10.4043/29678-ms","url":null,"abstract":"\u0000 Fatigue is one of the key governing conditions in the design of rigid risers, in particular those in ultra-deep water. One effective way of improving fatigue is to adopt a lazy wave configuration, rather than a simple catenary. Steel Lazy Wave Risers (SLWR) have been successfully used offshore Brazil (Hoffman et al. 2010, Oliveira et al. 2017) and in the Gulf of Mexico (Beattie et al. 2013), and have been considered for the North Sea (Felista et al. 2015) and offshore Australia (Vijayaraghavan et al. 2015). Yet, it is probably the most computational-intensive aspect of it. Fatigue analyses require a very large number of load cases to be run, on complex, non-linear models. Methods for simplifying aspects of the analysis are highly desirable, but they must be weighed to provide the required safety levels whilst not introducing uneconomical, overconservative assumptions.\u0000 The top first weld is a crucial hotspot, in particular for production SLWRs (Senra et al. 2011). These typically adopt flexible joints (FJ) at the connection to the vessel/platform, and linearization of the FJ stiffness is one of these key simplifications that bring significant value in reducing analysis cost.\u0000 This paper describes a method for estimating the characteristic angle used for the linearization, which results in significant stiffness reduction in contrast with the usual, simpler method.\u0000 Non-linear FJ stiffness curves are usually available, and they provide stiffness associated to the FJ absolute angle. The FJ stiffness significantly reduces with the angle of rotation. The conventional method adopts the stiffness corresponding to the most likely riser angle – absolute value measured from the static configuration. Conversely, the proposed methodology for estimating the most likely change in angle. As the angles often turn up in alternate angles, the proposed method results in much higher characteristic angle, and hence much lower FJ stiffness. The outcome is significantly less conservative designs, whilst still meeting the same required safety margins.","PeriodicalId":10927,"journal":{"name":"Day 3 Thu, October 31, 2019","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85079941","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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