A modified cell-to-cell simulation model to determine the minimum miscibility pressure in tight/shale formations

IF 1.8 4区工程技术 Q4 ENERGY & FUELS

Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles Pub Date : 2021-01-01 DOI:10.2516/ogst/2021031

Hao Sun, H. Li

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引用次数: 2

Abstract

A new oil–gas Minimum Miscibility Pressure (MMP) calculation algorithm is developed in this work based on the classic cell-to-cell simulation model. The proposed algorithm couples the effects of capillary pressure and confinement in the original cell-to-cell simulation model to predict the oil–gas MMPs in a confined space. Given that the original cell-to-cell algorithm relies on the volume predictions of the reservoir fluids in each cell, a volume-translated Peng-Robinson Equation of State (PR-EOS) is applied in this work for improved accuracy on volume calculations of the reservoir fluids. The robustness of the proposed algorithm is examined by performing the confined MMP calculations for four oil–gas systems. The tie-line length extrapolation method is used to determine the oil–gas MMP in confined space. The oil recovery factor calculated by the proposed MMP calculation algorithm is then used to validate the results. First, to achieve stable modeling results for all four examples, a total cell number of 500 is determined by examining the variations in the oil recovery as a function of cell number. Then, by calculating the oil recovery factor near the MMP region, it is found that the MMP determined by tie-line length method is slightly lower than the inflection point of the oil recovery curve. Through the case studies, the effects of temperature, pore radius, and injection gas impurity on the confined oil–gas MMP calculations are studied in detail. It is found that the oil–gas MMP is reduced in confined space and the degree of this reduction depends on the pore radius. For all the tested pore radii, the confined MMP first increases and then decreases with an increasing temperature. Furthermore, compared to pure carbon dioxide (CO2) injection, the addition of methane (CH4) in the injection gas increases the oil–gas MMP in confined nanopores. Therefore, it is recommended to control the content of CH4 in the injection gas in order to achieve a more efficient gas injection design.

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改进的单元间模拟模型，用于确定致密/页岩地层的最小混相压力

本文基于经典的单元间模拟模型，提出了一种新的油气最小混相压力(MMP)计算算法。该算法将毛细管压力和约束的影响耦合到原始的单元间模拟模型中，以预测密闭空间中的油气MMPs。考虑到原始的细胞到细胞算法依赖于每个细胞中储层流体的体积预测，在这项工作中应用了体积转换的Peng-Robinson状态方程(PR-EOS)，以提高储层流体体积计算的准确性。通过对四种油气系统进行受限MMP计算，验证了该算法的鲁棒性。采用联络线长度外推法确定了密闭空间内的油气MMP。利用所提出的MMP计算算法计算出的采收率系数对结果进行了验证。首先，为了获得所有四个示例的稳定建模结果，通过检查油采收率的变化作为单元数的函数来确定总单元数为500。然后，通过计算MMP区域附近的采收率系数，发现由联络线长度法确定的MMP略低于采收率曲线的拐点。通过实例研究，详细研究了温度、孔隙半径、注入气体杂质对承压油气MMP计算的影响。研究发现，油气MMP在密闭空间中会发生减少，减少程度与孔隙半径有关。对于所有测试的孔隙半径，随着温度的升高，承压MMP先增大后减小。此外，与纯二氧化碳(CO2)注入相比，在注入气体中加入甲烷(CH4)增加了受限纳米孔内油气的MMP。因此，建议控制注气中CH4的含量，以实现更高效的注气设计。

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

Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 工程技术-工程：化工

CiteScore

2.70

自引率

0.00%

发文量

审稿时长

2.7 months

期刊介绍： OGST - Revue d''IFP Energies nouvelles is a journal concerning all disciplines and fields relevant to exploration, production, refining, petrochemicals, and the use and economics of petroleum, natural gas, and other sources of energy, in particular alternative energies with in view of the energy transition. OGST - Revue d''IFP Energies nouvelles has an Editorial Committee made up of 15 leading European personalities from universities and from industry, and is indexed in the major international bibliographical databases. The journal publishes review articles, in English or in French, and topical issues, giving an overview of the contributions of complementary disciplines in tackling contemporary problems. Each article includes a detailed abstract in English. However, a French translation of the summaries can be provided to readers on request. Summaries of all papers published in the revue from 1974 can be consulted on this site. Over 1 000 papers that have been published since 1997 are freely available in full text form (as pdf files). Currently, over 10 000 downloads are recorded per month. Researchers in the above fields are invited to submit an article. Rigorous selection of the articles is ensured by a review process that involves IFPEN and external experts as well as the members of the editorial committee. It is preferable to submit the articles in English, either as independent papers or in association with one of the upcoming topical issues.