考虑渗透率时变及启动压力梯度的特低渗油藏CO_(2)吞吐裂缝参数优化  

Optimization of CO_(2) Huff and Puff Fracture Parameters in Ultra-low Permeability Reservoir Considering Time Variation of Permeability and Starting Pressure Gradient

作　　者：袁钟涛 杨胜来[1] 张政[1] 张希胜 王萌 YUAN Zhong-tao;YANG Sheng-lai;ZHANG Zheng;ZHANG Xi-sheng;WANG Meng(School of Petroleum Engineering,China University of Petroleum(Beijing),Beijing 102249)

机构地区：[1]中国石油大学(北京)石油工程学院,北京102249

出　　处：《科学技术与工程》2022年第27期11904-11910,共7页Science Technology and Engineering

基　　金：国家科技重大专项(2016ZX05016-001)。

摘　　要：对于冀东G5区块特低渗偏致密油藏的地质特点,注CO_(2)吞吐开发是一种很有效的开发方式,而吞吐裂缝参数是关键问题。考虑到特低渗的非线性渗流特征,表现为CO_(2)吞吐过程的变启动压力梯度以及注采中地层压力交替变化引渗透率时变的耦合性影响,在此基础上研究了水平井裂缝级数、分布方式、裂缝长度、导流能力等参数对CO_(2)扩散以及吞吐效果的影响,并对裂缝参数进行了优化。结果表明:变启动压力梯度和渗透率时变效应都会减弱CO_(2)吞吐的效果,其中变启动压力梯度的影响远大于渗透率时变,同时在考虑变启动压力梯度和渗透率时变情况下,交错布缝效果更佳,最优裂缝条数为8条,裂缝长度为150 m,裂缝导流能力为20μm^(2)·cm。For the geological characteristics of ultra-low permeability and partial tight oil reservoirs in Jidong G5 block,CO_(2) injection huff and puff development is a very effective development method,in which the parameters of fracturing and fractures are the key issues.Considering the nonlinear seepage characteristics of ultra-low permeability,the variable starting pressure gradient of the CO_(2) huff and puff process and the coupling effect of the time-varying permeability caused by the alternating change of formation pressure during injection and production was considered.On this basis,the influences of horizontal well fracture series,distribution mode,length,conductivity and other parameters on CO_(2) diffusion and huff and puff effect were studied and optimized.Result Showes that the influence of the pressure gradient is much greater than the time-varying permeability.At the same time,considering the variable starting pressure and the time-varying permeability,the effect of staggered fractures is better.The optimal number of fractures is 8,the fracture length is 150 m,and the fracture conductivity is 20μm^(2)·cm.

关 键 词：渗透率时变 启动压力梯度 CO_(2)吞吐 裂缝参数优化 

分 类 号：TE357[石油与天然气工程—油气田开发工程]