H. Cao, Rustem Zaydullin, Terrence Liao, N. Gohaud, E. Obi, G. Darche
Running multi-million cell simulation problems in minutes has been a dream for reservoir engineers for decades. Today, with the advancement of Graphic Processing Unit (GPU), we have a real chance to make this dream a reality. Here we present our experience in the step-by-step transformation of a fully developed industrial CPU-based simulator into a fully functional GPU-based simulator. We also demonstrate significant accelerations achieved through the use of GPU technology. To achieve the best performance possible, we choose to use CUDA (NVIDIA GPU’s native language), and offload as much computations to GPU as possible. Our CUDA implementation covers all reservoir computes, which include property calculation, linearization, linear solver, etc. The well and Field Management still reside on CPU and need minor changes for their interaction with GPU-based reservoir. Importantly, there is no change to the nonlinear logic. The GPU and CPU parts are overlapped, fully utilizing the asynchronous nature of GPU operations. Each reservoir computation can be run in three modes, CPU_only (existing one), GPU_only, CPU followed by GPU. The latter is only used for result checking and debugging. In early 2019, we prototyped two reservoir linearization operations (mass accumulation and mass flux) in CUDA; both showed very strong runtime speed-up of several hundred times, 1 P100-GPU (NVIDIA) vs 1 POWER8NVL CPU core rated at 2.8 GHz (IBM). Encouraged by this success, we moved into linear solver development and managed to move the entire linear solver module into GPU. Again, strong speed-up of ~50 times was achieved (1 GPU vs 1 CPU). The focus for 2019 has been on standard Black-Oil cases. Our implementation was tested with multiple "million-cell range" models (SPE10 and other real field cases). In early 2020, we managed to put SPE10 fully on GPU, and finished the entire 2000 day time-stepping in ~35 sec with a single P100 card. After that our effort has switched to compositional AIM (Adaptive Implicit Method), with focus on compositional flash and AIM implementation for reservoir linearization and linear solver, both show early promising results. GPU-based reservoir simulation is a future trend for HPC. The development of a reservoir simulator is complex, multi-discipline and time-consuming work. Our paper demonstrates a clear strategy to add tremendous GPU acceleration into an existing CPU-based simulator. Our approach fully utilizes the strength of the existing CPU simulator and minimizes the GPU development effort. This paper is also the first publication targeting GPU acceleration for compositional AIM models.
几十年来,在几分钟内运行数百万个单元模拟问题一直是油藏工程师的梦想。今天,随着图形处理单元(GPU)的进步,我们有真正的机会让这个梦想成为现实。在这里,我们介绍了我们在逐步将完全开发的基于工业cpu的模拟器转变为功能齐全的基于gpu的模拟器的经验。我们还演示了通过使用GPU技术实现的显著加速。为了实现最佳性能,我们选择使用CUDA (NVIDIA GPU的原生语言),并尽可能多地将计算卸载到GPU上。我们的CUDA实现涵盖了所有油藏计算,包括属性计算,线性化,线性求解等。井和现场管理仍然驻留在CPU上,需要对其与基于gpu的储层的交互进行微小的更改。重要的是,非线性逻辑没有改变。GPU和CPU部分重叠,充分利用了GPU操作的异步特性。每个储层计算可以在CPU_only(已有)、GPU_only、CPU、GPU三种模式下运行。后者仅用于结果检查和调试。2019年初,我们在CUDA中原型化了两种油藏线性化操作(质量积累和质量通量);1个P100-GPU (NVIDIA) vs 1个2.8 GHz的POWER8NVL CPU核心(IBM),两者都显示出数百倍的强大运行时加速。受到这一成功的鼓舞,我们转向线性求解器开发,并设法将整个线性求解器模块转移到GPU中。同样,实现了约50倍的强大加速(1个GPU vs 1个CPU)。2019年的重点是标准的黑油案例。我们的实现用多个“百万单元范围”模型(SPE10和其他实际现场案例)进行了测试。在2020年初,我们成功地将SPE10完全放在GPU上,并在35秒内完成了整个2000天的时间步进。之后,我们的工作转向了组合AIM(自适应隐式方法),重点研究了组合flash和AIM在油藏线性化和线性求解中的实现,两者都显示出了早期有希望的结果。基于gpu的油藏模拟是高性能计算的未来发展趋势。油藏模拟器的开发是一项复杂、多学科、耗时的工作。我们的论文展示了一种清晰的策略,将巨大的GPU加速添加到现有的基于cpu的模拟器中。我们的方法充分利用了现有CPU模拟器的优势,并最大限度地减少了GPU的开发工作量。这篇论文也是第一篇针对合成AIM模型的GPU加速的论文。
{"title":"Adding GPU Acceleration to an Industrial CPU-Based Simulator, Development Strategy and Results","authors":"H. Cao, Rustem Zaydullin, Terrence Liao, N. Gohaud, E. Obi, G. Darche","doi":"10.2118/203936-ms","DOIUrl":"https://doi.org/10.2118/203936-ms","url":null,"abstract":"\u0000 Running multi-million cell simulation problems in minutes has been a dream for reservoir engineers for decades. Today, with the advancement of Graphic Processing Unit (GPU), we have a real chance to make this dream a reality. Here we present our experience in the step-by-step transformation of a fully developed industrial CPU-based simulator into a fully functional GPU-based simulator. We also demonstrate significant accelerations achieved through the use of GPU technology.\u0000 To achieve the best performance possible, we choose to use CUDA (NVIDIA GPU’s native language), and offload as much computations to GPU as possible. Our CUDA implementation covers all reservoir computes, which include property calculation, linearization, linear solver, etc. The well and Field Management still reside on CPU and need minor changes for their interaction with GPU-based reservoir. Importantly, there is no change to the nonlinear logic. The GPU and CPU parts are overlapped, fully utilizing the asynchronous nature of GPU operations. Each reservoir computation can be run in three modes, CPU_only (existing one), GPU_only, CPU followed by GPU. The latter is only used for result checking and debugging.\u0000 In early 2019, we prototyped two reservoir linearization operations (mass accumulation and mass flux) in CUDA; both showed very strong runtime speed-up of several hundred times, 1 P100-GPU (NVIDIA) vs 1 POWER8NVL CPU core rated at 2.8 GHz (IBM). Encouraged by this success, we moved into linear solver development and managed to move the entire linear solver module into GPU. Again, strong speed-up of ~50 times was achieved (1 GPU vs 1 CPU). The focus for 2019 has been on standard Black-Oil cases. Our implementation was tested with multiple \"million-cell range\" models (SPE10 and other real field cases). In early 2020, we managed to put SPE10 fully on GPU, and finished the entire 2000 day time-stepping in ~35 sec with a single P100 card. After that our effort has switched to compositional AIM (Adaptive Implicit Method), with focus on compositional flash and AIM implementation for reservoir linearization and linear solver, both show early promising results.\u0000 GPU-based reservoir simulation is a future trend for HPC. The development of a reservoir simulator is complex, multi-discipline and time-consuming work. Our paper demonstrates a clear strategy to add tremendous GPU acceleration into an existing CPU-based simulator. Our approach fully utilizes the strength of the existing CPU simulator and minimizes the GPU development effort. This paper is also the first publication targeting GPU acceleration for compositional AIM models.","PeriodicalId":11146,"journal":{"name":"Day 1 Tue, October 26, 2021","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89985867","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}
This paper will present a robust workflow to address multi-objective optimization (MOO) of CO2-EOR-sequestration projects with a large number of operational control parameters. Farnsworth Unit (FWU) field, a mature oil reservoir undergoing CO2 alternating water injection (CO2-WAG) enhanced oil recovery (EOR), will be used as a field case to validate the proposed optimization protocol. The expected outcome of this work would be a repository of Pareto-optimal solutions of multiple objective functions, including oil recovery, carbon storage volume, and project economics. FWU's numerical model is employed to demonstrate the proposed optimization workflow. Since using MOO requires computationally intensive procedures, machine-learning-based proxies are introduced to substitute for the high-fidelity model, thus reducing the total computation overhead. The vector machine regression combined with the Gaussian kernel (Gaussian -SVR) is utilized to construct proxies. An iterative self-adjusting process prepares the training knowledgebase to develop robust proxies and minimizes computational time. The proxies’ hyperparameters will be optimally designed using Bayesian Optimization to achieve better generalization performance. Trained proxies will be coupled with Multi-objective Particle Swarm Optimization (MOPSO) protocol to construct the Pareto-front solution repository. The outcomes of this workflow will be a repository containing Pareto-optimal solutions of multiple objectives considered in the CO2-WAG project. The proposed optimization workflow will be compared with another established methodology employing a multi-layer neural network to validate its feasibility in handling MOO with a large number of parameters to control. Optimization parameters used include operational variables that might be used to control the CO2-WAG process, such as the duration of the water/gas injection period, producer bottomhole pressure (BHP) control, and water injection rate of each well included in the numerical model. It is proven that the workflow coupling Gaussian -SVR proxies and the iterative self-adjusting protocol is more computationally efficient. The MOO process is made more rapid by squeezing the size of the required training knowledgebase while maintaining the high accuracy of the optimized results. The outcomes of the optimization study show promising results in successfully establishing the solution repository considering multiple objective functions. Results are also verified by validating the Pareto fronts with simulation results using obtained optimized control parameters. The outcome from this work could provide field operators an opportunity to design a CO2-WAG project using as many inputs as possible from the reservoir models. The proposed work introduces a novel concept that couples Gaussian -SVR proxies with a self-adjusting protocol to increase the computational efficiency of the proposed workflow and to guarantee the high accuracy of the obtained
本文将提出一个强大的工作流来解决具有大量操作控制参数的二氧化碳- eor封存项目的多目标优化(MOO)。Farnsworth Unit (FWU)油田是一个成熟的油藏,正在进行二氧化碳交替注水(CO2- wag)提高采收率(EOR),将作为现场案例来验证所提出的优化方案。这项工作的预期结果将是一个多目标函数的帕累托最优解库,包括石油采收率、碳储量和项目经济性。采用FWU的数值模型对所提出的优化流程进行了验证。由于使用MOO需要计算密集型的过程,因此引入了基于机器学习的代理来替代高保真模型,从而减少了总计算开销。利用向量机回归与高斯核(Gaussian -SVR)相结合的方法构建代理。迭代的自调整过程使训练知识库能够开发健壮的代理并最大限度地减少计算时间。采用贝叶斯优化方法对代理的超参数进行优化设计,以获得更好的泛化性能。将训练好的代理与多目标粒子群优化(MOPSO)协议相结合,构建Pareto-front解库。该工作流的结果将是一个存储库,其中包含CO2-WAG项目中考虑的多个目标的帕累托最优解。将提出的优化工作流程与另一种采用多层神经网络的方法进行比较,以验证其在处理具有大量参数控制的MOO时的可行性。所使用的优化参数包括可用于控制CO2-WAG过程的操作变量,例如注水/注气周期的持续时间、生产井底压力(BHP)控制以及数值模型中包含的每口井的注水速度。结果表明,耦合高斯-SVR代理和迭代自调整协议的工作流计算效率更高。通过压缩所需训练知识库的大小,使mooo过程更加快速,同时保持优化结果的高准确性。优化研究结果表明,在成功建立考虑多目标函数的解决方案库方面取得了良好的效果。利用得到的优化控制参数,将Pareto front与仿真结果进行了验证。这项工作的结果可以为油田运营商提供一个机会,利用尽可能多的油藏模型输入来设计CO2-WAG项目。本文提出了一种新的概念,将高斯-SVR代理与自调整协议相结合,以提高所提出工作流的计算效率,并保证所获得的优化结果的高准确性。更重要的是,该工作流可以优化复杂CO2-WAG过程中使用的大量控制参数,这大大扩展了其在解决具有相似期望结果的各种项目中的大规模多目标优化问题方面的实用性。
{"title":"Optimization of Water-Alternating-CO2 Injection Field Operations Using a Machine-Learning-Assisted Workflow","authors":"You Junyu, Ampomah William, Sun Qian","doi":"10.2118/203913-ms","DOIUrl":"https://doi.org/10.2118/203913-ms","url":null,"abstract":"\u0000 This paper will present a robust workflow to address multi-objective optimization (MOO) of CO2-EOR-sequestration projects with a large number of operational control parameters. Farnsworth Unit (FWU) field, a mature oil reservoir undergoing CO2 alternating water injection (CO2-WAG) enhanced oil recovery (EOR), will be used as a field case to validate the proposed optimization protocol. The expected outcome of this work would be a repository of Pareto-optimal solutions of multiple objective functions, including oil recovery, carbon storage volume, and project economics.\u0000 FWU's numerical model is employed to demonstrate the proposed optimization workflow. Since using MOO requires computationally intensive procedures, machine-learning-based proxies are introduced to substitute for the high-fidelity model, thus reducing the total computation overhead. The vector machine regression combined with the Gaussian kernel (Gaussian -SVR) is utilized to construct proxies. An iterative self-adjusting process prepares the training knowledgebase to develop robust proxies and minimizes computational time. The proxies’ hyperparameters will be optimally designed using Bayesian Optimization to achieve better generalization performance. Trained proxies will be coupled with Multi-objective Particle Swarm Optimization (MOPSO) protocol to construct the Pareto-front solution repository.\u0000 The outcomes of this workflow will be a repository containing Pareto-optimal solutions of multiple objectives considered in the CO2-WAG project. The proposed optimization workflow will be compared with another established methodology employing a multi-layer neural network to validate its feasibility in handling MOO with a large number of parameters to control. Optimization parameters used include operational variables that might be used to control the CO2-WAG process, such as the duration of the water/gas injection period, producer bottomhole pressure (BHP) control, and water injection rate of each well included in the numerical model. It is proven that the workflow coupling Gaussian -SVR proxies and the iterative self-adjusting protocol is more computationally efficient. The MOO process is made more rapid by squeezing the size of the required training knowledgebase while maintaining the high accuracy of the optimized results. The outcomes of the optimization study show promising results in successfully establishing the solution repository considering multiple objective functions. Results are also verified by validating the Pareto fronts with simulation results using obtained optimized control parameters. The outcome from this work could provide field operators an opportunity to design a CO2-WAG project using as many inputs as possible from the reservoir models.\u0000 The proposed work introduces a novel concept that couples Gaussian -SVR proxies with a self-adjusting protocol to increase the computational efficiency of the proposed workflow and to guarantee the high accuracy of the obtained","PeriodicalId":11146,"journal":{"name":"Day 1 Tue, October 26, 2021","volume":"151 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77588830","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}
Subsurface sequestration of carbon dioxide, contaminant transport, and enhanced oil recovery processes often involve complex reaction dynamics. The rock-fluid interactions span a very wide range of length and time scales, and it is important for the numerical solutions to resolve these scales properly. To address these challenges, we extend the adaptive transport scheme for the simulation of reactive transport in heterogeneous porous media developed previously (Deucher and Tchelepi, 2021) to account for (a) higher-order approximation of the convective fluxes and (b) coupling with a chemical solver connected to geochemical databases. The numerical results demonstrate that adaptivity is more effective when a higher-order approximation of the fluxes is used. This is because of lower levels of numerical dispersion compared with low-order approximations, which helps resolve the displacement fronts more accurately. As a result, the regions that experience significant concentration and saturation gradients are more confined, and that leads to improvements in the computational efficiency of the adaptive scheme. The robustness of the approach is demonstrated using a highly heterogeneous two-phase case with multiple wells and a variable total liquid-rate. Due to the modularity of the adaptive scheme, coupling with a chemical solver module is straightforward. The scheme is tested for a three-dimensional case that considers injection of carbonated water in a reservoir matrix of calcite. The results show that the adaptive scheme leads to an accurate representation of the reference concentration distributions of the six reactive components throughout the simulation and leads to a large reduction in the number of cell updates required to achieve the solution.
{"title":"High-Order Adaptive Scheme for Reactive Transport in Heterogeneous Porous Media","authors":"Ricardo H. Deucher, H. Tchelepi","doi":"10.2118/203972-ms","DOIUrl":"https://doi.org/10.2118/203972-ms","url":null,"abstract":"\u0000 Subsurface sequestration of carbon dioxide, contaminant transport, and enhanced oil recovery processes often involve complex reaction dynamics. The rock-fluid interactions span a very wide range of length and time scales, and it is important for the numerical solutions to resolve these scales properly. To address these challenges, we extend the adaptive transport scheme for the simulation of reactive transport in heterogeneous porous media developed previously (Deucher and Tchelepi, 2021) to account for (a) higher-order approximation of the convective fluxes and (b) coupling with a chemical solver connected to geochemical databases.\u0000 The numerical results demonstrate that adaptivity is more effective when a higher-order approximation of the fluxes is used. This is because of lower levels of numerical dispersion compared with low-order approximations, which helps resolve the displacement fronts more accurately. As a result, the regions that experience significant concentration and saturation gradients are more confined, and that leads to improvements in the computational efficiency of the adaptive scheme. The robustness of the approach is demonstrated using a highly heterogeneous two-phase case with multiple wells and a variable total liquid-rate.\u0000 Due to the modularity of the adaptive scheme, coupling with a chemical solver module is straightforward. The scheme is tested for a three-dimensional case that considers injection of carbonated water in a reservoir matrix of calcite. The results show that the adaptive scheme leads to an accurate representation of the reference concentration distributions of the six reactive components throughout the simulation and leads to a large reduction in the number of cell updates required to achieve the solution.","PeriodicalId":11146,"journal":{"name":"Day 1 Tue, October 26, 2021","volume":"134 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88909512","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}
Alternative to CPU computing architectures, such as GPU, continue to evolve increasing the gap in peak memory bandwidth achievable on a conventional workstation or laptop. Such architectures are attractive for reservoir simulation, which performance is generally bounded by system memory bandwidth. However, to harvest the benefit of a new architecture, the source code has to be inevitably rewritten, sometimes almost completely. One of the biggest challenges here is to refactor the Jacobian assembly which typically involves large volumes of code and complex data processing. We demonstrate an effective and general way to simplify the linearization stage extracting complex physics-related computations from the main simulation loop and leaving only an algebraic multi-linear interpolation kernel instead. In this work, we provide the detailed description of simulation performance benefits from execution of the entire nonlinear loop on the GPU platform. We evaluate the computational performance of Delft Advanced Research Terra Simulator (DARTS) for various subsurface applications of practical interest on both CPU and GPU platforms, comparing particular workflow phases including Jacobian assembly and linear system solution with both stages of the Constraint Pressure Residual preconditioner.
CPU计算架构的替代方案,如GPU,不断发展,增加了传统工作站或笔记本电脑上可实现的峰值内存带宽的差距。这种架构对油藏模拟很有吸引力,因为油藏模拟的性能通常受到系统内存带宽的限制。然而,为了获得新架构的好处,源代码必须不可避免地重写,有时几乎是完全重写。这里最大的挑战之一是重构雅可比集合,这通常涉及大量代码和复杂的数据处理。我们展示了一种有效和通用的方法来简化线性化阶段,从主模拟环路中提取复杂的物理相关计算,而只留下一个代数多线性插值核。在这项工作中,我们详细描述了在GPU平台上执行整个非线性回路所带来的仿真性能优势。我们评估了Delft Advanced Research Terra Simulator (DARTS)在CPU和GPU平台上各种实际应用的计算性能,比较了特定的工作流程阶段,包括雅可比装配和线性系统解决方案与约束压力剩余预调节器的两个阶段。
{"title":"A GPU-Based Integrated Simulation Framework for Modelling of Complex Subsurface Applications","authors":"M. Khait, D. Voskov","doi":"10.2118/204000-ms","DOIUrl":"https://doi.org/10.2118/204000-ms","url":null,"abstract":"\u0000 Alternative to CPU computing architectures, such as GPU, continue to evolve increasing the gap in peak memory bandwidth achievable on a conventional workstation or laptop. Such architectures are attractive for reservoir simulation, which performance is generally bounded by system memory bandwidth. However, to harvest the benefit of a new architecture, the source code has to be inevitably rewritten, sometimes almost completely. One of the biggest challenges here is to refactor the Jacobian assembly which typically involves large volumes of code and complex data processing. We demonstrate an effective and general way to simplify the linearization stage extracting complex physics-related computations from the main simulation loop and leaving only an algebraic multi-linear interpolation kernel instead. In this work, we provide the detailed description of simulation performance benefits from execution of the entire nonlinear loop on the GPU platform. We evaluate the computational performance of Delft Advanced Research Terra Simulator (DARTS) for various subsurface applications of practical interest on both CPU and GPU platforms, comparing particular workflow phases including Jacobian assembly and linear system solution with both stages of the Constraint Pressure Residual preconditioner.","PeriodicalId":11146,"journal":{"name":"Day 1 Tue, October 26, 2021","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87757233","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}
Tsubasa Onishi, Hongquan Chen, Jiang Xie, Shusei Tanaka, D. Kam, Zhiming Wang, X. Wen, A. Datta-Gupta
Streamline-based methods have proven to be effective for various subsurface flow and transport modeling problems. However, the applications are limited in dual-porosity and dual-permeability (DPDK) system due to the difficulty in describing interactions between matrix and fracture during streamline tracing. In this work, we present a robust streamline tracing algorithm for DPDK models and apply the new algorithm to rate allocation optimization in a waterflood reservoir. In the proposed method, streamlines are traced in both fracture and matrix domains. The inter-fluxes between fracture and matrix are described by switching streamlines from one domain to another using a probability computed based on the inter-fluxes. The approach is fundamentally similar to the existing streamline tracing technique and can be utilized in streamline-assisted applications, such as flow diagnostics, history matching, and production optimization. The proposed method is benchmarked with a finite-volume based approach where grid-based time-of-flight was obtained by solving the stationary transport equation. We first validated our method using simple examples. Visual time-of-flight comparisons as well as tracer concentration and allocation factors at wells show good agreement. Next, we applied the proposed method to field scale models to demonstrate the robustness. The results show that our method offers reduced numerical artifacts and better represents reservoir heterogeneity and well connectivity with sub-grid resolutions. The proposed method is then used for rate allocation optimization in DPDK models. A streamline-based gradient free algorithm is used to optimize net present value by adjusting both injection and production well rates under operational constraints. The results show that the optimized schedule offers significant improvement in recovery factor, net present value, and sweep efficiency compared to the base scenario using equal rate injection and production. The optimization algorithm is computationally efficient as it requires only a few forward reservoir simulations.
{"title":"Streamline Tracing and Applications in Dual Porosity Dual Permeability Models","authors":"Tsubasa Onishi, Hongquan Chen, Jiang Xie, Shusei Tanaka, D. Kam, Zhiming Wang, X. Wen, A. Datta-Gupta","doi":"10.2118/203993-ms","DOIUrl":"https://doi.org/10.2118/203993-ms","url":null,"abstract":"Streamline-based methods have proven to be effective for various subsurface flow and transport modeling problems. However, the applications are limited in dual-porosity and dual-permeability (DPDK) system due to the difficulty in describing interactions between matrix and fracture during streamline tracing. In this work, we present a robust streamline tracing algorithm for DPDK models and apply the new algorithm to rate allocation optimization in a waterflood reservoir.\u0000 In the proposed method, streamlines are traced in both fracture and matrix domains. The inter-fluxes between fracture and matrix are described by switching streamlines from one domain to another using a probability computed based on the inter-fluxes. The approach is fundamentally similar to the existing streamline tracing technique and can be utilized in streamline-assisted applications, such as flow diagnostics, history matching, and production optimization.\u0000 The proposed method is benchmarked with a finite-volume based approach where grid-based time-of-flight was obtained by solving the stationary transport equation. We first validated our method using simple examples. Visual time-of-flight comparisons as well as tracer concentration and allocation factors at wells show good agreement. Next, we applied the proposed method to field scale models to demonstrate the robustness. The results show that our method offers reduced numerical artifacts and better represents reservoir heterogeneity and well connectivity with sub-grid resolutions. The proposed method is then used for rate allocation optimization in DPDK models. A streamline-based gradient free algorithm is used to optimize net present value by adjusting both injection and production well rates under operational constraints. The results show that the optimized schedule offers significant improvement in recovery factor, net present value, and sweep efficiency compared to the base scenario using equal rate injection and production. The optimization algorithm is computationally efficient as it requires only a few forward reservoir simulations.","PeriodicalId":11146,"journal":{"name":"Day 1 Tue, October 26, 2021","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90393387","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}
K. Wiegand, Y. Zaretskiy, K. Mukundakrishnan, L. Patacchini
When coupling reservoir simulators to surface network solvers, an often used strategy is to perform a rule or priority-driven allocation based on individual well and group constraints, augmented by back-pressure constraints computed periodically by the network solver. The allocation algorithm uses an iteration that applies well-established heuristics in a sequential manner until all constraints are met. The rationale for this approach is simply to maximize performance and simulation throughput; one of its drawbacks is that the computed allocation may not be feasible with respect to the overall network balance, especially in cases where not all wells can be choked individually. In the work presented here, the authors integrate the well allocation process into the network flow solver, in the form of an optimization engine, to ensure that the solution conforms to the network rate and pressure balance equations. Results for three stand-alone test cases are discussed.
{"title":"An Optimization-Based Facility Network Solver for Well Allocation in Reservoir Simulation","authors":"K. Wiegand, Y. Zaretskiy, K. Mukundakrishnan, L. Patacchini","doi":"10.2118/203954-ms","DOIUrl":"https://doi.org/10.2118/203954-ms","url":null,"abstract":"\u0000 When coupling reservoir simulators to surface network solvers, an often used strategy is to perform a rule or priority-driven allocation based on individual well and group constraints, augmented by back-pressure constraints computed periodically by the network solver. The allocation algorithm uses an iteration that applies well-established heuristics in a sequential manner until all constraints are met. The rationale for this approach is simply to maximize performance and simulation throughput; one of its drawbacks is that the computed allocation may not be feasible with respect to the overall network balance, especially in cases where not all wells can be choked individually. In the work presented here, the authors integrate the well allocation process into the network flow solver, in the form of an optimization engine, to ensure that the solution conforms to the network rate and pressure balance equations. Results for three stand-alone test cases are discussed.","PeriodicalId":11146,"journal":{"name":"Day 1 Tue, October 26, 2021","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81259692","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}
Changdong Yang, Jincong He, S. Du, Zhenzhen Wang, Tsubasa Onishi, X. Guan, Jianping Chen, X. Wen
Full-physics subsurface simulation models coupled with surface network can be computationally expensive. In this paper, we propose a physics-based subsurface model proxy that significantly reduces the run-time of the coupled model to enable rapid decision-making for reservoir management. In the coupled model the subsurface reservoir simulator generates well inflow performance relationship (IPR) curves which are used by the surface network model to determine well rates that satisfy surface constraints. In the proposed proxy model, the CPU intensive reservoir simulation is replaced with an IPR database constructed from a data pool of one or multiple simulation runs. The IPR database captures well performance that represents subsurface reservoir dynamics. The proxy model can then be used to predict the production performance of new scenarios – for example new drilling sequence – by intelligently looking up the appropriate IPR curves for oil, gas and water phases for each well and solving it with the surface network. All necessary operational events in the surface network and field management logic (such as facility constraints, well conditional shut-in, and group guide rate balancing) for the full-coupled model can be implemented and honored. In the proposed proxy model, while the reservoir simulation component is eliminated for efficiency. The entirety of the surface network model is retained, which offers certain advantages. It is particularly suitable for investigating the impact of different surface operations, such as maintenance schedule and production routing changes, with the aim of minimizing production capacity off-line due to maintenance. Replacing the computationally intensive subsurface simulation with the appropriate IPR significantly improves the run time of the coupled model while preserving the essential physics of the reservoir. The accuracy depends on the difference between the scenarios that the proxy is trained on and the scenarios being evaluated. Initial testing with a complex reservoir with more than 300 wells showed the accuracy of the proxy model to be more than 95%. The computation speedup could be an order of magnitude, depending largely on complexity of the surface network model. Prior work exists in the literature that uses decline curves to replicate subsurface model performance. The use of the multi-phase IPR database and the intelligent lookup mechanism in the proposed method allows it to be more accurate and flexible in handling complexities such as multi-phase flow and interference in the surface network.
{"title":"A Physics-Based Proxy for Surface and Subsurface Coupled Simulation Models","authors":"Changdong Yang, Jincong He, S. Du, Zhenzhen Wang, Tsubasa Onishi, X. Guan, Jianping Chen, X. Wen","doi":"10.2118/204004-ms","DOIUrl":"https://doi.org/10.2118/204004-ms","url":null,"abstract":"\u0000 Full-physics subsurface simulation models coupled with surface network can be computationally expensive. In this paper, we propose a physics-based subsurface model proxy that significantly reduces the run-time of the coupled model to enable rapid decision-making for reservoir management.\u0000 In the coupled model the subsurface reservoir simulator generates well inflow performance relationship (IPR) curves which are used by the surface network model to determine well rates that satisfy surface constraints. In the proposed proxy model, the CPU intensive reservoir simulation is replaced with an IPR database constructed from a data pool of one or multiple simulation runs. The IPR database captures well performance that represents subsurface reservoir dynamics. The proxy model can then be used to predict the production performance of new scenarios – for example new drilling sequence – by intelligently looking up the appropriate IPR curves for oil, gas and water phases for each well and solving it with the surface network. All necessary operational events in the surface network and field management logic (such as facility constraints, well conditional shut-in, and group guide rate balancing) for the full-coupled model can be implemented and honored.\u0000 In the proposed proxy model, while the reservoir simulation component is eliminated for efficiency. The entirety of the surface network model is retained, which offers certain advantages. It is particularly suitable for investigating the impact of different surface operations, such as maintenance schedule and production routing changes, with the aim of minimizing production capacity off-line due to maintenance. Replacing the computationally intensive subsurface simulation with the appropriate IPR significantly improves the run time of the coupled model while preserving the essential physics of the reservoir. The accuracy depends on the difference between the scenarios that the proxy is trained on and the scenarios being evaluated. Initial testing with a complex reservoir with more than 300 wells showed the accuracy of the proxy model to be more than 95%. The computation speedup could be an order of magnitude, depending largely on complexity of the surface network model.\u0000 Prior work exists in the literature that uses decline curves to replicate subsurface model performance. The use of the multi-phase IPR database and the intelligent lookup mechanism in the proposed method allows it to be more accurate and flexible in handling complexities such as multi-phase flow and interference in the surface network.","PeriodicalId":11146,"journal":{"name":"Day 1 Tue, October 26, 2021","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84855728","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}
Wai Li, Jishan Liu, J. Zeng, Y. Leong, D. Elsworth, Jianwei Tian
The process of extracting coalbed methane (CBM) is not only of significance for unconventional energy supply but also important in mine safety. The recent advance in fracking techniques, such as carbon dioxide (CO2) fracking, intensifies the complexity of stimulated coalbeds. This work focuses on developing a fully coupled multidomain model to describe and get insight into the process of CBM extraction, particularly from those compound-fractured coalbeds. A group of partial differential equations (PDEs) are derived to characterize gas transport from matrix to fractures and borehole. A stimulated coalbed is defined as an assembly of three interacting porous media: matrix, continuous fractures (CF) and radial primary hydraulic fracture (RF). Matrix and CF constitute a dual-porosity-dual-permeability system, while RF is simplified as an 1-D cracked medium. These media further form three distinct domains: non-stimulated reservoir domain (NSRD), stimulated reservoir domain (SRD) and RF. The effects of coal deformation, heat transfer, and non-thermal sorption are coupled into the model to reflect the multiple processes in CBM extraction. The finite element method is employed to numerically solve the PDEs. The proposed model is verified by comparing its simulation results to a set of well production data from Southern Qinshui Basin in Shanxi Province, China. Great consistency is observed, showing the satisfactory accuracy of the model for CBM extraction. After that, the difference between various stimulation patterns is presented by simulating the CBM extraction process with different stimulation patterns including (1) unstimulated coalbed; (2) double-wing fracture + NSRD; (3) multiple RFs + NSRD; (4) SRD + NSRD and (5) multiple RFs + SRD + NSRD. The results suggest that Pattern (5) (often formed by CO2 fracking) boosts the efficiency of CBM extraction because it generates a complex fracture network at various scales by both increasing the number of radial fractures and activating the micro-fractures in coal blocks. Sensitivity analysis is also performed to understand the influences of key factors on gas extraction from a stimulated coalbed with multiple domains. It is found that the distinct properties of different domains originate various evolutions, which in turn influences the CBM production. Ignoring thermal effects in CBM extraction will either overestimate or underestimate the production, which is the net effect of thermal strain and non-isothermal sorption. The proposed model provides a useful approach to accurately evaluate CBM extraction by taking the complex evolutions of coalbed properties and the interactions between different components and domains into account. The importance of multidomain and thermal effects for CBM reservoir simulation is also highlighted.
{"title":"Modelling Methane Extraction from Stimulated Coalbed Influenced by Multidomain and Thermal Effects","authors":"Wai Li, Jishan Liu, J. Zeng, Y. Leong, D. Elsworth, Jianwei Tian","doi":"10.2118/203990-ms","DOIUrl":"https://doi.org/10.2118/203990-ms","url":null,"abstract":"\u0000 The process of extracting coalbed methane (CBM) is not only of significance for unconventional energy supply but also important in mine safety. The recent advance in fracking techniques, such as carbon dioxide (CO2) fracking, intensifies the complexity of stimulated coalbeds. This work focuses on developing a fully coupled multidomain model to describe and get insight into the process of CBM extraction, particularly from those compound-fractured coalbeds. A group of partial differential equations (PDEs) are derived to characterize gas transport from matrix to fractures and borehole. A stimulated coalbed is defined as an assembly of three interacting porous media: matrix, continuous fractures (CF) and radial primary hydraulic fracture (RF). Matrix and CF constitute a dual-porosity-dual-permeability system, while RF is simplified as an 1-D cracked medium. These media further form three distinct domains: non-stimulated reservoir domain (NSRD), stimulated reservoir domain (SRD) and RF. The effects of coal deformation, heat transfer, and non-thermal sorption are coupled into the model to reflect the multiple processes in CBM extraction. The finite element method is employed to numerically solve the PDEs. The proposed model is verified by comparing its simulation results to a set of well production data from Southern Qinshui Basin in Shanxi Province, China. Great consistency is observed, showing the satisfactory accuracy of the model for CBM extraction. After that, the difference between various stimulation patterns is presented by simulating the CBM extraction process with different stimulation patterns including (1) unstimulated coalbed; (2) double-wing fracture + NSRD; (3) multiple RFs + NSRD; (4) SRD + NSRD and (5) multiple RFs + SRD + NSRD. The results suggest that Pattern (5) (often formed by CO2 fracking) boosts the efficiency of CBM extraction because it generates a complex fracture network at various scales by both increasing the number of radial fractures and activating the micro-fractures in coal blocks. Sensitivity analysis is also performed to understand the influences of key factors on gas extraction from a stimulated coalbed with multiple domains. It is found that the distinct properties of different domains originate various evolutions, which in turn influences the CBM production. Ignoring thermal effects in CBM extraction will either overestimate or underestimate the production, which is the net effect of thermal strain and non-isothermal sorption. The proposed model provides a useful approach to accurately evaluate CBM extraction by taking the complex evolutions of coalbed properties and the interactions between different components and domains into account. The importance of multidomain and thermal effects for CBM reservoir simulation is also highlighted.","PeriodicalId":11146,"journal":{"name":"Day 1 Tue, October 26, 2021","volume":"227 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78841948","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}
E. Ahmed, Ø. Klemetsdal, X. Raynaud, O. Møyner, H. Nilsen
We present in this paper a-posteriori error estimators for multiphase flow with singular well sources. The estimators are fully and locally computable, distinguish the various error components, and target the singular effects of wells. On the basis of these estimators we design an adaptive fully-implicit solver that yields optimal nonlinear iterations and efficient time-stepping, while maintaining the accuracy of the solution. A key point is that the singular nature of the solution in the near-well region is explicitly captured and efficiently estimated using the adequate norms. Numerical experiments illustrate the efficiency of our estimates and the performance of the adaptive algorithm.
{"title":"Adaptive Time Stepping, Linearization and a Posteriori Error Control for Multiphase Flow with Wells","authors":"E. Ahmed, Ø. Klemetsdal, X. Raynaud, O. Møyner, H. Nilsen","doi":"10.2118/203974-ms","DOIUrl":"https://doi.org/10.2118/203974-ms","url":null,"abstract":"We present in this paper a-posteriori error estimators for multiphase flow with singular well sources. The estimators are fully and locally computable, distinguish the various error components, and target the singular effects of wells. On the basis of these estimators we design an adaptive fully-implicit solver that yields optimal nonlinear iterations and efficient time-stepping, while maintaining the accuracy of the solution. A key point is that the singular nature of the solution in the near-well region is explicitly captured and efficiently estimated using the adequate norms. Numerical experiments illustrate the efficiency of our estimates and the performance of the adaptive algorithm.","PeriodicalId":11146,"journal":{"name":"Day 1 Tue, October 26, 2021","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82534341","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}
Usuf Middya, A. Manea, Alhubail Maitham Makki, Todd R. Ferguson, T. Byer, A. Dogru
Reservoir simulation computational costs have been continuously growing due to high-resolution reservoir characterization, increasing model complexity, and uncertainty analysis workflows. Reducing simulation costs by upscaling is often necessary for operational requirements. Fast evolving HPC technologies offer opportunities to reduce cost without compromising fidelity. This work presents a novel in-house massively parallel full-physics reservoir simulator running on the emerging GPU architecture. Almost all the simulation kernels have been designed and implemented to honor the GPU SIMD programming paradigm. These kernels include physical property calculations, phase equilibrium computations, Jacobian construction, linear and nonlinear solvers, and wells. Novel techniques are devised in various kernels to expose enough parallelism to ensure that the control and data-flow patterns are well suited for the GPU environment. Mixed-precision computation is also employed when appropriate (e.g., in derivative calculation) to reduce computational costs without compromising the solution accuracy. The GPU implementation of the simulator is tested and benchmarked using various reservoir models, ranging from the synthetic SPE10 Benchmark (Christie & Blunt, 2001) to several industrial-scale models. These real field models range in size from tens of millions of cells to more than billion cells with black-oil and multicomponent compositional fluid. The GPU simulator is benchmarked on the IBM AC922 massively parallel architecture having tens of NVidia Volta V100 GPUs. To compare performance with CPU architectures, an optimized CPU implementation of the simulator is benchmarked on the IBM AC922 CPUs and on a cluster consisting of thousands of Intel's Haswell-EP Xeon® CPU E5-2680 v3. Detailed analysis of several numerical experiments comparing the simulator performance on the GPU and the CPU architectures is presented. In almost all of the cases, the analysis shows that the use of hardware acceleration offers substantial benefits in terms of wall time and power consumption. This novel in-house full-physics, black-oil and compositional reservoir simulator employs several novel techniques in various simulation kernels to ensure full utilization of the GPU resources. Detailed analysis is presented to highlight the simulator performance in terms of runtime reduction, parallel scalability and power savings.
{"title":"A Massively Parallel Reservoir Simulator on the GPU Architecture","authors":"Usuf Middya, A. Manea, Alhubail Maitham Makki, Todd R. Ferguson, T. Byer, A. Dogru","doi":"10.2118/203918-ms","DOIUrl":"https://doi.org/10.2118/203918-ms","url":null,"abstract":"\u0000 Reservoir simulation computational costs have been continuously growing due to high-resolution reservoir characterization, increasing model complexity, and uncertainty analysis workflows. Reducing simulation costs by upscaling is often necessary for operational requirements. Fast evolving HPC technologies offer opportunities to reduce cost without compromising fidelity.\u0000 This work presents a novel in-house massively parallel full-physics reservoir simulator running on the emerging GPU architecture. Almost all the simulation kernels have been designed and implemented to honor the GPU SIMD programming paradigm. These kernels include physical property calculations, phase equilibrium computations, Jacobian construction, linear and nonlinear solvers, and wells. Novel techniques are devised in various kernels to expose enough parallelism to ensure that the control and data-flow patterns are well suited for the GPU environment. Mixed-precision computation is also employed when appropriate (e.g., in derivative calculation) to reduce computational costs without compromising the solution accuracy.\u0000 The GPU implementation of the simulator is tested and benchmarked using various reservoir models, ranging from the synthetic SPE10 Benchmark (Christie & Blunt, 2001) to several industrial-scale models. These real field models range in size from tens of millions of cells to more than billion cells with black-oil and multicomponent compositional fluid. The GPU simulator is benchmarked on the IBM AC922 massively parallel architecture having tens of NVidia Volta V100 GPUs. To compare performance with CPU architectures, an optimized CPU implementation of the simulator is benchmarked on the IBM AC922 CPUs and on a cluster consisting of thousands of Intel's Haswell-EP Xeon® CPU E5-2680 v3. Detailed analysis of several numerical experiments comparing the simulator performance on the GPU and the CPU architectures is presented. In almost all of the cases, the analysis shows that the use of hardware acceleration offers substantial benefits in terms of wall time and power consumption.\u0000 This novel in-house full-physics, black-oil and compositional reservoir simulator employs several novel techniques in various simulation kernels to ensure full utilization of the GPU resources. Detailed analysis is presented to highlight the simulator performance in terms of runtime reduction, parallel scalability and power savings.","PeriodicalId":11146,"journal":{"name":"Day 1 Tue, October 26, 2021","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87979323","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}