致密气藏压裂倾斜缝压力动态分析  

Transient Pressure Analysis of Inclined Fracture in Tight Gas Reservoirs

作　　者：贾品[1] 程林松[1] 李彩云[2] 黄世军[1] 刘红君[1] 

机构地区：[1]中国石油大学(北京)石油工程学院,北京昌平102249 [2]中国石油长庆油田勘探开发研究院,陕西西安710021

出　　处：《西南石油大学学报（自然科学版）》2015年第3期53-62,共10页Journal of Southwest Petroleum University(Science & Technology Edition)

基　　金：国家自然科学基金(51174215/E0403);国家科技重大专项(2011ZX05013-002)

摘　　要：针对致密气藏斜井筒压裂形成的倾斜缝,将裂缝离散为微元,推导了裂缝内部有限导流数值解;采用倾斜板源函数及势叠加原理得到了气藏流动解析解,通过将缝内流动和气藏流动在裂缝面上进行压力及流量耦合,建立了压裂倾斜缝不稳定流动模型。划分了流动阶段,给出了对应的拟压力或拟压力导数解析表达式,分析了储层及压裂参数对压力动态的影响。结果表明:不考虑井筒储存效应时,压裂倾斜缝流动形态分为:裂缝与地层双线性流、地层线性流、早期径向流、拟复合线性流和晚期拟径向流。井筒存储效应产生的井筒续流段会掩盖双线性流。裂缝倾斜角和储层渗透率各向异性对井底压力动态影响时间最长,会一直延续到晚期拟径向流阶段。无因次裂缝导流能力唯一决定了裂缝与地层双线性流和地层线性流的出现与否及持续时间。随着气藏厚度的增大,早期径向流的持续时间增加,拟复合线性流的出现时间推迟。最后,利用苏里格气田一口压裂定向井实例证明了该模型的正确性。In view of the inclined hydraulic fracture formed by slant well fracturing,the numerical model for fracture flow was derived based on the discrete fracture segments and the analytical model for reservoir flow was established by combining slant plane source function and the superposition principle. A semianalytical model for inclined fracture was developed by coupling the numerical fracture flow model and the analytical reservoir flow model dynamically in this paper. The flow regimes were defined,the corresponding pressure or derivate analytical equations were derived and the effect of reservoir and fracture pa-rameters on transient responses was investigated. The results show that there are five flow regimes including fracture/formation bilinear flow,formation linear flow,early radial flow,pseudo-compound linear flow and later pseudo-radial flow for inclined fracture in the absence of the effect of wellbore storage. The wellbore afterflow caused by wellbore storage may mask the frac-ture/formation bilinear flow. The period of the effect of the inclination angle and permeability anisotropy on transient pressure is very long,which will last to later pseudo-radial flow. The existence and duration of fracture/formation bilinear flow and formation linear flow is only determined by dimensionless fracture conductivity. Finally,a field test in fractured directional well from Suliger Gas Field verified the validity of the model.

关 键 词：斜井筒 压裂倾斜缝 有限导流 耦合模型 压力分析 

分 类 号：TE353[石油与天然气工程—油气田开发工程]