摘要
对于超深超高压裂缝性致密砂岩气藏,综合考虑孔缝并存、离散裂缝与连续介质裂缝并存、应力敏感效应及3个物性分区的影响,建立裂缝性致密砂岩气藏气井不稳定压力模型,采用Pedrosa变换、摄动变换、Laplace变换等方法求解模型,通过编程绘制不稳定压力典型曲线;根据不稳定压力典型曲线特征划分流动阶段,对影响因素进行敏感性分析。结果表明:复杂气藏压裂井渗流过程划分14个典型流动阶段;存在应力敏感效应时,导数曲线中后期位置更高;钻遇离散裂缝长度越长,Ⅰ区缝网系统线性流等阶段的导数曲线位置越低;流度比主要影响相应拟径向流和窜流等阶段的压力导数曲线。各区储容比越小,相应窜流阶段压力导数曲线上的凹子越深;各区窜流系数越小,相应窜流阶段压力导数曲线上的凹子出现时间越晚。该结果为超深超高压裂缝性复杂气藏试井解释提供支撑。
Considering the coexistence of matrix pores and fractures,the coexistence of discrete fractures and continuous medium fractures,stress sensitivity effect and the influence of three zones with different physical properties,this paper presents a transient pressure analysis model for wells intersecting with discrete fractures in the ultra-deep and ultra-high pressure fractured tight sandstone gas reservoirs.The Laplace transformation,Pedrosa's transformation and perturbation technique are adopted to solve the proposed model,and the type curves are calculated and plotted by programming.Flowing periods were identified according to the characteristics of type curves and the sensitivity analysis of influencial factors were conducted.The results show that up to fourteen typical flowing periods can be observed on the type curves of the fractured wells in this kind of complex gas reservoirs.When there is a stress sensitive effect,the position of the pressure derivative curves during the middle and later flowing periods will be higher.The longer the discrete fractures encountered by the gas well,the lower the position of the derivative curve during the linear flow stage and other flowing stages of the fracture network system in zone I.The mobility ratio mainly affects the height of the pressure derivative curves during the pseudo-radial flow and inter-porosity flow stages.The smaller the storage capacity ratio,the deeper the corresponding concave on the pressure derivative curve.The smaller the inter-porosity flow coefficients of each region,the later the corresponding concave on the pressure derivative curve appears.This work can provide support for well testing interpretation techniques for the ultra-deep and ultra-high pressure naturally fractured complex gas reservoirs.
作者
李道清
汪洋
王彬
闫利恒
赵传凯
王海涛
LI Daoqing;WANG Yang;WANG Bin;YAN Liheng;ZHAO Chuankai;WANG Haitao(Research Institute of Exploration and Development,PetroChina Xinjiang Oilfield Company,Karamay,Xinjiang 834000,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China)
出处
《东北石油大学学报》
CAS
北大核心
2023年第5期71-81,I0005-I0006,共13页
Journal of Northeast Petroleum University
基金
国家自然科学基金项目(52174036)
四川省科技计划项目(2021YJ0345)。
关键词
超深
超高压
裂缝性
三区复合
致密气藏
应力敏感
离散裂缝
不稳定压力分析
ultra-deep
ultra-high pressure
naturally fractured
three-zone composite
tight gas reservoirs
stress sensitivity
discrete fracture
transient pressure analysis
