Day 2 Tue, October 01, 2019最新文献

{"title":"Flowback Production Optimization for Choke Size Management Strategies in Unconventional Wells","authors":"S. Baǧci, S. Stolyarov","doi":"10.2118/196203-ms","DOIUrl":"https://doi.org/10.2118/196203-ms","url":null,"abstract":"\u0000 The flowback period of the unconventional wells is very critical as it can cause determential ecomonical effects if not properly optimized. The success of the well is as dependent of the completion program as it is from the flowback program applied during the initial production period of the well. If ineffective operations are performed on the flowback phase {independently on the completion technology}, the well can underperform and become unsuitable for development.\u0000 In unconventional wells, it is necessary to develop the safe well operating envelope in safe zone to prevent the early proppant flowback based on the reservoir parameters and the completions in place. The well can start producing in this developed safe well operating envelope by controlling the wellhead pressure and surface valves and optimizing the proper choke size to keep the well with free proppant production.\u0000 Proppant flowback production modeling captured decline of water production as well as the increase of liquid production when a selected choke sizes is applied. By controlling the flowing bottomhole pressure (FBHP) during defined flowback period, the volume of proppant production decreased with decreasing chokes sizes and increasing long flowback periods. This study showed that the optimized choke sizes to improve the longer production periods depended on the sensitivity of pressure drawdown, liquid rates, wellhead pressure, and fracture geometry parameters. Numerical results showed that the critical parameters affecting the stability of the proppant pack are fracture closure pressure, reservoir pressure, proppant type and size, and type of fracturing fluid. Proppant flowback program developed by using optimized choke size, wellhead pressure (WHP) and FBHP, and amount of producible proppant volume predicted for designed flowback production periods. At the beginning of the flowback period, the wellbore is filled with fracturing fluid and the minimum choke size should be used as small as possible (12/64\"). The controlled FBHP management over 45 days of flowback period corresponds to an average drawdown rate of 10 psi/day to 200 psi/day. Finally, the developed workflow applied to design flowback periods and selection of choke sizes to prevent excessive proppant production and proppant crushing in hydraulically fractured unconventional wells.\u0000 This paper presents the methodology and workflow for selecting the required choke sizes and flowback periods to minimize the risk of production of high volume proppant during the flowback period after fracturing. The case study presented here in will present the benefits of optimizing choke sizes and flowback programs for reducing the damage to fracture conductivity and to increase the cumulative production. The optimized choke sizes, flowback strategies and workflow established with this case study have proven to increase the performance of fractured unconventional wells.","PeriodicalId":10909,"journal":{"name":"Day 2 Tue, October 01, 2019","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84840031","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}

{"title":"How Malaysia Late Life Field Benefited From Well Intervention Efficiency Improvements Through Integrated Operations","authors":"S. Mokhtar, Rahmat Wibisono, M. Zakaria","doi":"10.2118/195843-ms","DOIUrl":"https://doi.org/10.2118/195843-ms","url":null,"abstract":"\u0000 In 2016, Malaysia Petroleum Management (MPM), the regulatory body of PETRONAS launched a 3 year dedicated strategy to intensify the idle wells restoration and production enhancement activities in order to maximize profitability through efficiency and success rate improvement. The basis of this strategy is the risk-sharing integrated operations in which the industry embraced it in all major well intervention activities. As the drilling activities dropped drastically over the past few years, it was crucial that the well intervention activities are carried out with high efficiency and success rate to restore the production.\u0000 The strategy went through various development changes throughout the 3 year journey. As the well intervention scope covers a wide range of activities, the framework of this integrated risk sharing mechanism provided the flexibility that is required for the execution of the various scopes and meet specific value targets either profitability from production gain or cost saving from decommissioning and infill drilling. Each of the project carried unique Key Performance Indicators (KPIs) as the guiding principles to drive the efficiency improvement that was required. A unique process called Total Wells Management (TWM) was implemented as the overlaying guide to further improve the uncertainty of subsurface challenges, operation optimization and commercial risk exposure.\u0000 This paper outlines the overall post mortem analysis of the 22 projects that were executed under this integrated operations strategy between MPM, ten operators and five main service companies. This strategy, known to the industry as the Integrated Idle Wells Restoration (IIWR) program, has become the new norm on how well intervention and subsurface assessments are executed to yield the best results especially in late life fields. The risk sharing integrated framework have proven to be a win-win scenario for all involved parties. The scope was also extended to cover non production adding activities such as wells decommissioning, well startups and pre drilling zonal isolation. IIWR have also opened up the opportunities for many ‘first in Malaysia’ projects such as the first subsea hydraulic intervention, first subsea decommissioning and also the reinstatement of technologies such as coiled tubing catenary. The biggest impact from this 3 years strategy implementation can be seen from the Unit Enhancement Cost (UEC) improvement where the average UEC was reduced from 14 to 17 USD per barrel of oil to about 4 to 7 USD barrel of oil.\u0000 Although there were major challenges, the overall results have been very encouraging. This framework is also being replicated for drilling and completion activities as well. Specific to well intervention, this IIWR framework is currently being put through an enhancement process to further expand the landscape of well intervention activities without compromising safety, operational efficiency and business profitability.","PeriodicalId":10909,"journal":{"name":"Day 2 Tue, October 01, 2019","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76741498","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}

{"title":"Nanopaint-Aided Electromagnetic Pigging in Pipelines and Production Tubing","authors":"Ningyu Wang, M. Prodanović, H. Daigle","doi":"10.2118/196112-ms","DOIUrl":"https://doi.org/10.2118/196112-ms","url":null,"abstract":"\u0000 Precipitation and deposition of paraffin wax and hydrates is a major concern for hydrocarbon transport in pipelines, tiebacks, and other production tubing in cold environments. Traditionally, chemical, mechanical, and thermal methods are used to mitigate the deposition at the expense of production interruption, complex maintenance, costs, and environmental hazards.\u0000 This paper studies the potential of nanopaint-aided electromagnetic pigging. This process has potentially low production impact, simple maintenance, low energy cost, and no chemical expense or hazards. The electromagnetic pig contains an induction coil that emits an alternating magnetic field. The alternating magnetic field induces heat in the nanopaint coating (i.e. coating with embedded paramagnetic nanoparticles) on the pipeline's inner wall and in the pipeline wall itself. The heat then melts and peels off the wax and hydrates adhering to the pipeline, allowing the hydrocarbon to carry them away.\u0000 We analyze the heating effectiveness and efficiency of electromagnetic pigging. The heating effectiveness is measured by the maximum pigging speed that allows deposit removal. The heating efficiency is measured by the ratio of the heat received by the wax over the total emitted electromagnetic energy, which we define as the pig induction factor.\u0000 Based on our numerical model, we compare the pig induction factor for different coil designs, different hydrocarbon flow rates, and different pig traveling speeds. We find that slower pig speed generally improves the pigging performance, that shorter solenoids with larger radius have higher efficiency, and that the oil flow does not considerably affect the process. We re-evaluate the maximum pig speed defined by the static pig model and confirm that a solenoid with larger radius allows higher pig speed.\u0000 We investigate the potential of a novel, low-maintenance electromagnetic pigging method that poses minimal interruption to production. This investigation is a basis for a new technology that stems from initial experimental investigation done by our collaborators. We here provide parameters for pig design and pigging protocol optimization, and will put them in practice in our future lab experiments.","PeriodicalId":10909,"journal":{"name":"Day 2 Tue, October 01, 2019","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77023108","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}

{"title":"Monitoring Dynamic Reservoir Pressure Responses Through Cement","authors":"Elias Garcia, Gerald Stutes, Christoffer Nåden, K. Borgersen","doi":"10.2118/196168-ms","DOIUrl":"https://doi.org/10.2118/196168-ms","url":null,"abstract":"\u0000 During the last five years, the use of permanent downhole gauges has proliferated in the industry. The availability of true bottomhole pressure (BHP) is imperative in validating/improving reservoir models. Similarly to the extrapolation of BHP from surface readings, the use of BHP to extrapolate formation pressure may lead to significant errors in reservoir models that do not provide operators with the competitive edge needed in the current market. Consequently, there is a drive to monitor formation pressure in-situ by placing pressure and temperature gauges in direct contact with the formation.\u0000 In recent years, operators have been drilling larger holes, deploying gauge systems on the exterior of the casing, and cementing the gauge systems in place for multiple purposes. In artificial lift applications, cemented gauge systems have helped operators to avoid costs of decompleting and redeploying gauge systems on tubing whenever the electric submersible pumps (ESP) must be serviced, or perhaps whenever operators want to convert an observation well to a producing well.\u0000 In unconventional plays, technologies involving quartz pressure and temperature gauges, oriented perforating, and well conditioning practices can enable operators to deploy multiple real-time downhole pressure and temperature gauges on casing across long horizontal sections of a wellbore. This, in turn, can provide valuable production data with which to understand cluster production performance, cross-well communication, fracture azimuth, well spacing, and stage-length production implications.\u0000 Cemented gauges enable operators to understand pressure dynamics in the overburden, cap rock, or reservoir sections. The permanently installed, casing-deployed gauges connect to the surface through cable or through deployment of wireless inductive coupling technology.","PeriodicalId":10909,"journal":{"name":"Day 2 Tue, October 01, 2019","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75716542","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}

{"title":"Enhanced Problem Solving Approach to Tackle Repetitive System Failures","authors":"Assel Mukhamediyeva, Francesco Gigli Sutcliffe, Sezim Kaitupov","doi":"10.2118/196034-ms","DOIUrl":"https://doi.org/10.2118/196034-ms","url":null,"abstract":"\u0000 The paper describes an innovative approach to performance improvement using Causal Learning (CL), a method based on the general observation that a business performance is largely the outcome of the organization, processes and procedures, ways of working, constraints and norms – the systems that the business applies to itself. These system causes are often remote from physical causes of equipment failures and as such remain hidden until revealed by appropriate analysis. The objective of CL is discovering these system causes that ultimately lead to an undesired outcome or event. CL helps us \"learn\" the performance system, develop insights from these discoveries and recognize the specific aspects of a system that require change to shift business performance.\u0000 The Company adopted this approach to improve problem solving and root cause analysis of machinery failures. The initial decision to apply CL followed several outages of power generation systems that continued to occur after previous analyses of similar events in the past.\u0000 An Enhanced Problem Solving Team (EPST) was established and trained to apply Causal Learning principles to reveal the underlying system causes of these outages. In the time since that first analysis the tools and techniques of CL have been applied to other undesired or unexpected business outcomes including HSE and project work with little or no direct technical content.\u0000 CL reveals the contribution of well-intended human behaviours behind unwanted outcomes (e.g. hardware failures), and importantly the underlying system causes of these human behaviours. This is predicated on the basis that people do their best to achieve the goals they believe they need to achieve. When it is revealed why those goal were important and why the actions taken were \"their best\" with the time, tools, processes available to the individual at that time at that place the systems causes can be properly understood. These findings often surprise the organization, particularly when it is made visible to Leaders at all levels how they created, or are responsible for, the systems that influenced those human behaviours.","PeriodicalId":10909,"journal":{"name":"Day 2 Tue, October 01, 2019","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73338056","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}

{"title":"An Assessment Of The Current Regulatory Frameworks For Onshore, Upstream, Unconventional Well Integrity And Strategies For Improvement","authors":"T. Thomas, Raymond L. Johnson","doi":"10.2118/195967-ms","DOIUrl":"https://doi.org/10.2118/195967-ms","url":null,"abstract":"\u0000 This paper reviews existing analysis of well integrity related regulation in upstream unconventional oil and gas projects and proposes a methodology to enhance such regulation in the future.  This paper has compiled findings from a number of peer-reviewed sources assessing regulatory systems across a number of jurisdictions. These findings were based around four key questions that this paper has assessed (1) what is the overall assessment of current regulatory systems; (2) where to-date are the key areas that current research have focused on; (3) what are the key strengths identified in current research; and (4) what are the key gaps in current research? \u0000 This paper demonstrates that the body of work provides a wide array of assessments and conclusions. Whilst some are quite explicit in their judgment of a particular system’s effectiveness, many refrain from making a holistic assessment in a particular jurisdiction. Much of the research involves the application of prisms, such as environmental risks or local government jurisprudence. Along with these prisms, a number of common aspects of research are identified that strengthen the analyses, such as the use of ‘as drilled’ data and the use of relevant data samples. Some research gaps remain despite these strengths.\u0000 The majority of previous researchers can identify some degree of ineffectiveness in various regulatory regimes. Further, a number of gaps exist as a result of regulatory systems being incomplete or inadequate, potentially masking other inadequacies. To address these gaps, this paper proposes a methodology to improve and clarify knowledge and practical recommendations to improve the effectiveness of assurance activities by both regulatory agencies and operators. Specifically, this methodology focuses on a typological assessment of written rules in a number of jurisdictions. As an example, we present an ‘as built’ dataset to assess compliance with rules and identify means of assurance. This methodology proposes surveying of regulatory agencies and operators to validate the assertion that gaps can be identified and corrected and provide more insight into how regulatory systems function and the systematic causes of gaps.","PeriodicalId":10909,"journal":{"name":"Day 2 Tue, October 01, 2019","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84904217","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}

{"title":"Standardization: Successful Implementation of Driving Consistency in Deepwater Operations","authors":"D. Durey, D. Murphy, Beatriz E Rueda","doi":"10.2118/196166-ms","DOIUrl":"https://doi.org/10.2118/196166-ms","url":null,"abstract":"\u0000 Deepwater wells are the most complex and challenging operations for today's petroleum workforce. These challenges push the limits of technology requiring high level personnel competencies and stringent safety requirements. Robust and consistent procedures aid in implementing reliable operational execution. When complex operations include multiple drill ships and TLPs, and when these activities are mirrored by separate support teams of engineers and operations there are opportunities for varying procedures, content, format, and technology applications. This misalignment evolves over time, based on individual preferences, lessons learned, and varying procedures from different service providers.\u0000 This paper discusses the efforts and outcomes of bringing standardization to Deepwater operations in the Gulf of Mexico (GOM) and to Shell's broader global Deepwater organization (DWO). Standardization efforts include full End-to-End well delivery from engineering design documents, recommended/best practices, operational procedures, workflow processes, after-action-reviews, knowledge sharing, and refreshing standards as required.\u0000 Ensuring a learning loop process is in place and actively used is a key element in keeping standard documents evergreen and has the overarching goal of preventing repeat failures and NPT events. An additional benefit is the ability to deliver documents with structured content, aligned format and standard language to both the operations teams and service providers.\u0000 The formation of a core team and central department has driven global standards, active sharing of learnings across all Deepwater business units, opened communication lines with areas previously siloed due to location, reduced cycle time for the engineering teams in re-creating procedures and demonstrated sustainable reductions in operational costs.","PeriodicalId":10909,"journal":{"name":"Day 2 Tue, October 01, 2019","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85454271","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}

{"title":"Human Factors and Non-Technical Skills: Towards an Immersive Simulation-Based Training Framework for Offshore Drilling Operations","authors":"R. Kiran, S. A. Naqavi, S. Salehi, C. Teodoriu","doi":"10.2118/195838-ms","DOIUrl":"https://doi.org/10.2118/195838-ms","url":null,"abstract":"\u0000 Human factors are identified as the major contributor to oil and gas drilling and other operations related accidents. Offshore oil and gas operations involve complex scenarios and decision-making with potentially catastrophic consequences. The current simulation-based training modules are often criticized for their lack of objective and validated measures for human factors and non-technical skills. There is also a need to include measures for enhanced situational awareness and decision-making for the offshore drilling crew. In this study, we present holistic human-centered training framework equipped with assessment techniques to analyses situational awareness of partcipants in customized well-control operations.\u0000 The training exercise used in this work included real-time well control operation customized for drilling break and kick detection scenarios. The assessment approach consisted of eye-tracking data analysis, questionnaire analysis, checklist score analysis, and communication log analysis. After individual analysis from each technique, a new framework was developed to triangulate results from each technique to provide a comprehensive assessment. The participants included seven group of novices and one group of experts. The preliminary results indicate significant differences between the situation awareness and performance of participants. Furthermore, there were observed notable differences between the perceptual, comprehensive, and projection ability of novices and experts in routine jobs on a drilling platform. The eye-tracking data features included fixation count and fixation duration, and it was inferred that eye-tracking results can be representative of cognitive abilities of the partcipants. Furthermore, the fixation count and duration results were highly correlated with the checklist scores.\u0000 Overall, the adopted methodology in this study have potential to open new avenues for human- centered training framework and improvement in traditional assessment approach. Furthermore, it can also be helpful in understanding of cognitive responses of the offshore professionals.","PeriodicalId":10909,"journal":{"name":"Day 2 Tue, October 01, 2019","volume":"1083 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80593326","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}

{"title":"Poroelastic Analytical Solution for the Nonlinear Productivity Index of Wells in Stress-Sensitive Reservoir Rocks","authors":"Wei Zhang, A. Mehrabian","doi":"10.2118/195947-ms","DOIUrl":"https://doi.org/10.2118/195947-ms","url":null,"abstract":"\u0000 Reservoir depletion can induce substantial changes in the stress state of the rock. The coupled interaction between the pore fluid pressure and rock stress will then alter the reservoir permeability, which in turn reversely affects the productivity index of the production well. A new nonlinear analytical solution is developed for the drawdown-dependent productivity index of reservoirs under steady-state flow. Biot's theory of poroelasticity is used to derive the depletion-induced changes in the reservoir rock porosity and permeability. The well-known Mindlin's solution for a Nucleus of Strain in a semi-infinite elastic medium is applied as Green's function and integrated over the depleted volume of reservoir rock to obtain the 3D distribution of stress and volumetric strain distributions. The fluid transport equation is nonlinearly coupled to the solid mechanics solution via the stress-dependent permeability coefficients. A perturbation technique is applied to mathematically treat the described nonlinearity to solve for the coupled equations of pore fluid flow and rock stress under steady-state flow. The good match between the obtained analytical approximations for productivity index and the numerical solutions verifies the correctness and robustness of the proposed model.\u0000 Results indicate and confirm the expected strong dependency of the well productivity index to the drawdown magnitude as well as the poroelastic constitutive parameters of the reservoir rock, with the highest sensitivity to drained bulk modulus, followed by the reservoir depth and solid-grain modulus. The lowest PI sensitivity is to the pore fluid modulus and Poisson's ratio. The resulting productivity index is found out to be drawdown-dependent, which can render values substantially different than the productivity index estimate from the conventional flow-only analysis. The presented estimates for the related nonlinear productivity index can be readily used by the practicing engineers.","PeriodicalId":10909,"journal":{"name":"Day 2 Tue, October 01, 2019","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83069319","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}

{"title":"An Accelerated Adjoint Method for Model Maturation to Update Static Models with Time-Lapse Reservoir Surveillance Data","authors":"F. Alpak, J. W. Jennings","doi":"10.2118/196119-ms","DOIUrl":"https://doi.org/10.2118/196119-ms","url":null,"abstract":"\u0000 We develop a novel ensemble model-maturation method that is based on the Randomized Maximum Likelihood (RML) technique and adjoint-based computation of objective function gradients. The new approach is especially relevant for rich data sets with time-lapse information content. The inversion method that solves the model-maturation problem takes advantage of the adjoint-based computation of objective function gradients for a very large number of model parameters at the cost of a forward and a backward (adjoint) simulation. The inversion algorithm calibrates model parameters to arbitrary types of production data including time-lapse reservoir-pressure traces by use of a weighted and regularized objective function. We have also developed a new and effective multigrid preconditioning protocol for accelerated iterative linear solutions of the adjoint-simulation step for models with multiple levels of local grid refinement. The protocol is based on a geometric multigrid (GMG) preconditioning technique. Within the model-maturation workflow, a machine-learning technique is applied to establish links between the mesh-based inversion results (e.g., permeability-multiplier fields) and geologic modeling parameters inside a static model (e.g., object dimensions, etc.). Our workflow integrates the learnings from inversion back into the static model, and thereby, ensures the geologic consistency of the static model while improving the quality of ensuing dynamic model in terms of honoring production and time-lapse data, and reducing forecast uncertainty. This use of machine learning to post-process the model-maturation outcome effectively converts the conventional continuous-parameter history-matching result into a discrete tomographic inversion result constrained to geological rules encoded in training images.\u0000 We demonstrate the practical utilization of the adjoint-based model-maturation method on a large time-lapse reservoir-pressure data set using an ensemble of full-field models from a reservoir case study. The model-maturation technique effectively identifies the permeability modification zones that are consistent with alternative geological interpretations and proposes updates to the static model. Upon these updates, the model not only agrees better with the time-lapse reservoir-pressure data but also better honors the tubing-head pressure as well as production logging data. We also provide computational performance indicators that demonstrate the accelerated convergence characteristics of the new iterative linear solver for adjoint equations.","PeriodicalId":10909,"journal":{"name":"Day 2 Tue, October 01, 2019","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89469713","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}