刘永, 付颖, 冯昕媛,等.考虑应力敏感的基岩气藏离散裂缝网络模型与数值模拟[J].河南理工大学学报（自然科学版）,2021,40(3):26-33.

LIU Y, FU Y, FENG X Y,et al.Discrete fracture network model and numerical simulation of bedrock gas reservoirsconsidering stress sensitivity[J].Journal of Henan Polytechnic University(Natural Science) ,2021,40(3):26-33.

考虑应力敏感的基岩气藏离散裂缝网络模型与数值模拟

刘永1, 付颖1, 冯昕媛1, 任广聪2, 陈铭2, 张成娟1

1.中国石油青海油田公司 钻采工艺研究院，甘肃 敦煌 736200;2.中国石油大学（北京） 石油工程学院，北京 102249

摘要:为了准确模拟裂缝性基岩气藏产能，以柴达木盆地东坪区块为例，将区块内裂缝性基岩气藏视为离散裂缝与基质岩体介质，建立裂缝性基岩气藏产能有限元计算模型。在考虑水力压裂裂缝应力敏感性、气藏流体的高压物性非线性和随机分布天然裂缝基础上，采用Galerkin 加权残值法将渗流方程进行空间离散，并通过Newton-Raphson迭代求解非线性方程组，实现裂缝型基岩气藏离散裂缝网络产能模拟，分析天然裂缝、人工裂缝对研究区块内水平井分段压 裂后产能模拟结果的影响规律。结果表明：忽略应力敏感会过高估计产量，相比而言，考虑水力裂缝应力敏感性的产能拟合结果更符合实际；基岩气藏渗流压力场主要受主裂缝导流能力控制，离散分布的不连通天然裂缝对压力场的影响较弱；离散不连通的天然裂缝对增产作用效果不明显，水力压裂应重点提高人工裂缝导流能力或沟通天然裂缝；东坪区块基岩气藏最优导流和最优缝长分别为15 D • cm和200~250 m。

关键词:东坪区块;基岩气藏;离散裂缝网络;应力敏感;渗流特征;数值模拟

doi:10.16186/j.cnki.1673-9787.2019080026

基金项目:中国石油天然气股份公司重大专项项目（2016E-01）

收稿日期:2019/08/07

修回日期:2020/03/20

出版日期:2021/05/15

Discrete fracture network model and numerical simulation of bedrock gas reservoirsconsidering stress sensitivity

LIU Yong1, FU Ying1, FENG Xinyuan1, REN Guangcong2, CHEN Ming2, ZHANG Chengjuan1

1.Drilling and Production Technology Research Institute， PetroChina Qinghai OH Field， Dunhuang  736200 ， Gansu， China;2.College Petroleum Engineering， China University of Petroleum （ Beijing ） ， Beijing  102249 ， China

Abstract:In order to accurately simulate gas well productivity in fractured bedrock gas reservoirs， taking Dongping block in the Qaidam basin as an example and regarding the fractured bedrock gas reservoir in the study area as the dual medium of discrete fracture medium and matrix rock mass， the production model of fractured bedrock gas reservoir based on discrete fracture model was established. The stress sensitivity of hydraulic fractures ，the nonlinearity of gas flow viscosity， density with pressure， and the random distribution of natural fractures in the formation were considered in the model. The discretized equation was obtained by Galerkin weighted residual method and the nonlinear equations were solved iteratively by the Newton-Raphson method. Furtherly， The effect of fractures， including natural fractures and hydraulic fractures ， on the productivity simulation results of horizontal well after segmented fracturing in the study block was analyzed. The results showed that the production prediction was overestimated without considering stress sensitivity， while the results could be more accurate by considering stress sensitivity. The seepage pressure field of bedrock gas reservoir was mainly controlled by the hydraulic fracture conductivity， and the influence of the discrete distribution of natural fracture permeability on the pressure field was weak ； The effect of discrete distribution of natural fractures on productivity was not obvious， hydraulic fracturing should mainly improve the conductivity of hydraulic fractures or connect more natural fractures by hydraulic fractures. For the bedrock gas reservoirs in Dongping block， the optimal conductivity and fracture half-length for the case study were 15 D ， cm and 200  m， respectively.

Key words:Dongping block;bedrock gas reservoir;discrete fracture network;stress sensitivity;seepage characteristic;numerical simulation

 考虑应力敏感的基岩气藏离散裂缝网络模型与数值模拟_刘永.pdf