油气藏评价与开发

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基于机器学习的裂缝水驱气藏采收率预测方法

孙秋分1, 秦佳正2, 冯乔1, 乔宇2,3, 刘雅昕2, 赵启阳1, 徐良1, 闫春1   

  1. 1.中国石油杭州地质研究院,浙江 杭州 310023;
    2.西南石油大学油气藏地质及开发工程全国重点实验室,四川 成都 610500;
    3.中国石油冀东油田分公司储气库建设项目部,河北 唐山 063000
  • 收稿日期:2024-08-01
  • 通讯作者: 秦佳正(1993—),女,博士,副研究员,从事储气库及CO2埋存、人工智能在油气领域的应用等方面的工作。地址:四川省成都市新都区新都大道8号,邮政编码:610500。E-mail:jqin_swpu@163.com
  • 作者简介:孙秋分(1981—),男,硕士,高级工程师,从事油气储量评估方面的工作。地址:浙江省杭州市西湖区西溪路920号,邮政编码:310023。E-mail:sunqf_hz@petrochina.com.cn
  • 基金资助:
    中国石油科学研究与技术开发项目课题“国内已开发气田储采平衡分析与SEC增储评估技术研究”(2022DJ7902)

A machine learning-based method for predicting recovery rate in fractured water-drive gas reservoirs

SUN Qiufen1, QIN Jiazheng2, FENG Qiao1, QIAO Yu2,3, LIU Yaxin2, ZHAO Qiyang1, XU Liang1, YAN Chun1   

  1. 1. Hangzhou Geological Research Institute, China National Petroleum Corporation, Hangzhou, Zhejiang, 310023, China;
    2. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan,610500, China;
    3. Gas Storage Construction Project Department, Jidong Oilfield Company, China National Petroleum Corporation, Tangshan, Hebei, 063000, China
  • Received:2024-08-01

摘要: X气藏为受背斜构造控制的块状裂缝性边水气藏,受边水水侵的影响,气藏见水迅速,严重降低采收率,亟须科学的理论与方法指导开发实践。为此,研究在系统分析关键参数对采收率的影响规律基础上,构建裂缝水驱气藏采收率预测方法,为动态优化开发方案提供科学依据。基于气藏基础地质与生产数据,运用EDFM(嵌入式离散裂缝模型)建立单井机理模型,通过单因素敏感性分析,揭示水体倍数、采气速度、基质渗透率、渗透率各向异性的作用规律:水体倍数与采收率呈负相关,随着水体倍数增加,气井水气比上升速率显著加快,稳产时间大幅缩短;采气速度对气藏稳产时间影响尤为突出,存在特定的最佳采气速度阈值,可使采收率达到最大值;基质渗透率与采收率呈正相关,基质渗透率越低,气藏采收率越低,水气比上升速度越快,稳产时间越短;渗透率各向异性过低时,由于渗流能力较差导致采收率降低,比值增大则加速水侵使采收率降低。在此基础上,设计125组交叉实验方案,通过数值模拟获取基础数据,进而建立裂缝性水驱气藏采收率预测模型。为提升模型预测精度,对原始数据进行离散化处理,并采用决策树算法构建预测模型。经参数优化后,模型预测精度达到96%。基于X气藏2口生产井的实际动态数据,将该模型预测结果与Blasingame产量递减分析法进行对比验证,结果表明:该模型预测结果与实际生产数据高度吻合,具有较高的可靠性与实用性,为裂缝性水驱气藏采收率预测提供了一种高效、精准的技术手段。

关键词: 机器学习, 嵌入式离散裂缝模型, 采收率预测, 裂缝性水驱气藏, 数值模拟

Abstract: X gas reservoir is a massive fractured edge-water gas reservoir controlled by anticline structures, where rapid water breakthrough induced by edge water invasion significantly compromises recovery efficiency, thereby necessitating scientific theories and methodologies to guide development practices. This study systematically investigates the influence of key parameters on recovery efficiency and establishes a prediction model for recovery efficiency in fractured water-drive gas reservoirs, aiming to provide a scientific basis for dynamic optimization of development strategies. Leveraging basic geological and production datasets of the reservoir, a single-well mechanistic model was constructed using the Embedded Discrete Fracture Model (EDFM). Through single-factor sensitivity analysis, the study elucidates the governing mechanisms of water body multiple, gas production rate, matrix permeability, and permeability anisotropy: recovery efficiency exhibits a negative correlation with water body multiple, characterized by accelerated water-gas ratio growth and shortened stable production duration as the multiple increases; gas production rate exerts a pronounced impact on stable production time, with an optimal operational threshold identified to maximize recovery efficiency; matrix permeability demonstrates a positive correlation with recovery efficiency, where lower permeability correlates with faster water-gas ratio escalation and shorter stable production time; excessively low permeability anisotropy ratios degrade recovery efficiency due to inadequate seepage capacity, while higher ratios exacerbate water invasion and further diminish recovery efficiency. 125 sets of cross-experimental schemes were designed. Basic data were obtained through numerical simulation to establish a recovery rate prediction model for fractured water-driven gas reservoirs. Raw data were discretized to enhance predictive accuracy, and a decision tree algorithm was employed to construct the model, which achieved a prediction accuracy of 96% following parameter optimization. Validation against Blasingame production decline analysis using field dynamic data from two production wells in the X gas reservoir demonstrates a high degree of consistency between model predictions and actual production data, underscoring the model's reliability and practical utility. This research provides an efficient and precise technical methodology for predicting recovery efficiency in fractured water-drive gas reservoirs, offering valuable insights for similar reservoir systems.

Key words: machine learning, embedded discrete fracture model, recovery rate prediction, fractured water-drive gas reservoirs, numerical simulation

中图分类号: 

  • TE319