Effectiveness of embedded discontinuities technique in capturing geomechanical behavior in naturally fractured reservoirs

IF 2.4 4区工程技术 Q3 ENERGY & FUELS

Journal of Petroleum Exploration and Production Technology Pub Date : 2023-12-22 DOI:10.1007/s13202-023-01735-x

Bruno Maciel, Leidy Laura Alvarez, Nayara Torres Belfort, Leonardo José do Nascimento Guimarães, Leila Brunet de Sá Beserra

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Abstract

This paper highlights the efficacy of the finite element method with embedded strong discontinuities in modeling discontinuities in porous media, specifically in the geomechanical behavior of Naturally Fractured Reservoirs (NFRs). The approach considers hydromechanical coupling and offers low computational cost. NFRs account for a significant portion of global reserves, representing approximately 60% of global oil reserves and 40% of gas reserves. Given that flow in NFRs is more complex than in conventional reservoirs due to the presence of multiple fractures, it's crucial to understand how pressure variations or effective stress during operations impact fracture closure and permeability of these reservoirs. To analyze this behavior, numerical simulation results using the proposed method were compared, under different liquid pressure depletion values, with the approach proposed by Oda, which is commonly used in commercial software for calculating fracture permeability tensors. This approach was enriched with Barton's fracture closure formulation and updates on rock matrix porosity and permeability. Four simulations were conducted: Firstly, a hypothetical scenario consistent with Oda's assumptions, where fractures are interconnected and span the entire grid cell, to validate the numerical hydromechanical model; subsequently, three representative sections of a Brazilian pre-salt carbonate reservoir were selected. The study confirms the efficacy of the technique of embedded strong discontinuities in calculating equivalent permeabilities in NFRs, considering geomechanical effects, especially in cells with high fracture frequencies and intensities. Furthermore, the relevance of analyzing the geomechanical behavior in NFRs is emphasized.

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嵌入式不连续体技术捕捉天然裂缝储层地质力学行为的有效性

摘要本文强调了嵌入强不连续性的有限元方法在多孔介质不连续性建模中的功效，特别是在天然裂缝储层（NFR）的地质力学行为中。该方法考虑了水力机械耦合，计算成本较低。天然裂缝储层占全球储量的很大一部分，约占全球石油储量的 60% 和天然气储量的 40%。由于存在多条裂缝，NFR 油藏中的流动比常规油藏更为复杂，因此了解作业过程中的压力变化或有效应力如何影响这些油藏的裂缝闭合和渗透率至关重要。为了分析这种行为，在不同的液体压力耗尽值下，使用所提出的方法得出的数值模拟结果与 Oda 提出的方法进行了比较，后者通常用于计算裂缝渗透率张量的商业软件。该方法采用了 Barton 的裂缝闭合公式，并更新了岩石基质孔隙度和渗透率。共进行了四次模拟：首先是与 Oda 假设一致的假设情景，即裂缝相互连接并跨越整个网格单元，以验证数值水力机械模型；随后，选择了巴西盐前碳酸盐岩储层的三个代表性区段。研究证实，考虑到地质力学效应，特别是在断裂频率和强度较高的单元中，嵌入强不连续面技术在计算非油层等效渗透率时非常有效。此外，研究还强调了分析非连续油气层地质力学行为的意义。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Petroleum Exploration and Production Technology Multiple-

CiteScore

5.90

自引率

4.50%

发文量

151

审稿时长

13 weeks

期刊介绍： The Journal of Petroleum Exploration and Production Technology is an international open access journal that publishes original and review articles as well as book reviews on leading edge studies in the field of petroleum engineering, petroleum geology and exploration geophysics and the implementation of related technologies to the development and management of oil and gas reservoirs from their discovery through their entire production cycle. Focusing on: Reservoir characterization and modeling Unconventional oil and gas reservoirs Geophysics: Acquisition and near surface Geophysics Modeling and Imaging Geophysics: Interpretation Geophysics: Processing Production Engineering Formation Evaluation Reservoir Management Petroleum Geology Enhanced Recovery Geomechanics Drilling Completions The Journal of Petroleum Exploration and Production Technology is committed to upholding the integrity of the scientific record. As a member of the Committee on Publication Ethics (COPE) the journal will follow the COPE guidelines on how to deal with potential acts of misconduct. Authors should refrain from misrepresenting research results which could damage the trust in the journal and ultimately the entire scientific endeavor. Maintaining integrity of the research and its presentation can be achieved by following the rules of good scientific practice as detailed here: https://www.springer.com/us/editorial-policies