基于最小耗能原理的库车坳陷超深致密砂岩裂缝定量预测  

Quantitative fracture prediction of ultra-deep tight sandstone in Kuqa Depression based on principle of minimum energy consumption

作　　者：汪如军[1] 赵力彬[1,2] 张永灵 WANG Rujun;ZHAO Libin;ZHANG Yongling(Tarim Oilfield,PetroChina,Korla 841000,China;College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油塔里木油田公司,新疆库尔勒841000 [2]中国石油大学(北京)地球科学学院,北京102249

出　　处：《中国石油大学学报（自然科学版）》2022年第5期23-35,共13页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：中国石油天然气股份有限公司重大科技专项(2018E-1803)。

摘　　要：构造裂缝是库车坳陷超深层致密砂岩A气藏的重要渗流通道和储集空间,但由于钻井密度低、取芯资料少、地震资料品质差等原因,井间裂缝预测难度极大。通过将最小耗能原理与损伤力学原理融合,明确裂缝发育的极值条件,构建统一理论框架下的岩石强度破裂准则,推导裂缝参数的应力-耗能耦合表征模型,并基于关键造缝期古构造应力场有限元模拟预测裂缝三维分布特征。结果表明:上新世库车期—第四纪西域期NW-SE向强烈构造挤压作用是A气藏高角度—直立有效缝形成的关键时期;平面上,裂缝在背斜高部位最发育,在鞍部稍低,在两翼呈低值;东部背斜高点裂缝密度高值区连片发育,明显高于西部背斜高点;垂向上,在背斜高部位及背斜转折端位置,裂缝发育程度从浅部向深部逐渐降低,但在背斜翼部具有相反的趋势;褶皱是A气藏裂缝发育的首要主控因素,断层次之,岩性仅在局部影响着裂缝发育,高产井基本上位于线密度中—高、倾角近直立、充填较低的裂缝发育区;12口井的分层平均裂缝线密度预测结果与成像测井解释结果相吻合,平均相对误差为23.94%,能够满足气藏高效开发的生产需求。Structural fracture is an important seepage channel and reservoir of ultra-deep tight sandstone gas reservoir A in the Kuqa Depression.However,due to low drilling density,limited coring data and poor quality of seismic data,it is very difficult to predict inter well fractures.This study proposes to combine the principle of minimum energy consumption with the principle of damage mechanics,to first determine the extreme conditions in which a large number of fractures occur,and then construct the rock failure criterion under an unified theoretical framework.Based on this,the stress-energy coupling model of fracture parameters is deduced,and the 3D distribution of fractures is predicted using simulations of paleotectonic stress field.The results show that the strong NW-SE tectonic compression in the Kuqa period of the Pliocene quaternary western region period was the key period for the formation of high-angle effective fractures in gas reservoir A.On the plane,the fracture development was high at the high parts of the anticline,less at the saddle and least at the two limbs.The high value area of fracture density at the high parts of the eastern anticline was developed widely,which was significantly higher than the western anticline.Vertically,at the high parts of the anticline and the turning end of the anticline,the fracture development decreased from shallow to deep,but had the opposite trend at the limb of the anticline.Folding was the primary controlling factor of the fracture development in gas reservoir A,followed by faulting.Comparatively,lithology only affects the fracture development locally.High-yield wells were basically located in the fracture developed area with medium-high linear density,with large dip angles and low filling degree.The prediction of the fracture linear density of 12 wells was consistent with the interpretation results of imaging logging,and the average relative error was 23.94%,which meets the production demand of efficient development of gas reservoir.

关 键 词：库车坳陷A气藏 超深致密砂岩 最小耗能原理 古构造应力场 裂缝定量预测 

分 类 号：TE371[石油与天然气工程—油气田开发工程]