深层致密砂岩储层现今地应力场预测及应用——以塔里木盆地克拉苏构造带克深10气藏为例  

Prediction of current in-situ stress filed and its application of deeply buried tight sandstone reservoir: A case study of Keshen 10 gas reservoir in Kelasu structural belt, Tarim Basin

作　　者：徐珂 田军[1] 杨海军[1] 张辉[1] 王志民[1] 袁芳[1] 王海应[1] XU Ke;TIAN Jun;YANG Haijun;ZHANG Hui;WANG Zhimin;YUAN Fang;WANG Haiying(PetroChina Tarim Oil Company.Korla,Xinjiang 841000,China;School of Geosciences,China University of Petroleum,Qingdao,Shandong 266580,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(华东)地球科学与技术学院,山东青岛266580

出　　处：《中国矿业大学学报》2020年第4期708-720,共13页Journal of China University of Mining & Technology

基　　金：国家重大科技专项(2016ZX05051);中国石油天然气股份有限公司重大科技专项(2018E-1803);中国博士后科学基金(2019M660269)。

摘　　要：为建立一套适用于塔里木盆地复杂地质条件下深层致密砂岩储层的现今地应力预测方法,基于"单井地应力测井解释+三维地应力场模拟"开展三维非均质应力场研究,并将研究成果应用于勘探方面的井位部署、钻井工程中的井眼轨迹优化及完井工程的储层改造方式优选.本文以克拉苏构造带克深气田的克深10气藏为例开展研究,认为较宽的泥浆窗口(不低于0.3 MPa/hm)是钻井提速的安全保障,优选天然裂缝发育(裂缝密度大于0.3条/m)、水平应力低于平均值2~3 MPa、力-缝夹角小于45°且裂缝开启压力低(一般低于2.05 MPa/hm)的层位射孔是提产的关键.研究结果表明:克拉苏构造带深层致密砂岩储层现今应力场普遍属于走滑型(SHmax>SV>Shmin,III类),现今地应力数值高,最小水平主应力普遍高于110 MPa,水平应力差多大于35 MPa,且分布离散;现今最大水平主应力(SHmax)方向总体为近NS向,局部为NW或NE向;受强烈且持续的构造挤压和巨厚盐层的影响,库车山前现今地应力状态在纵向上可能发生4次转变,这种复杂应力环境、复杂构造和岩性对钻井的井壁稳定带来极大挑战;基于现今地应力研究评价井壁稳定性从而优化井眼轨迹减少了20%的钻井复杂事故,至少节约了15%的钻进时间,直接促进了钻井提速;考虑地应力因素优选射孔层位,为确定钻井揭开位置和最优储层改造方式提供直接参考.This study aims at constructing a suitable in-situ stress field forecasting method in a deeply buried tight sandstone reservoir under complex geological conditions in Tarim Basin. Logging interpretation of in-situ stress and three-dimensional(3 D) heterogeneous stress field simulation were carried out in this study, and were applied to well location deployment, well trajectory optimization in drilling engineering, and reservoir reconstruction optimization in completion engineering. Taking the Keshen 10 gas reservoir in the Kelasu structural belt as an example, it is considered that a wide mud window(no less than 0.3 MPa/hm) is the safety guarantee for speed-up drilling, and the key to improve production is to select the perforations with natural fractures(fracture density greater than 0.3/m), relatively lower horizontal stress(the average value lower than 2—3 MPa), the angle of stress orientation and fracture strike no more than 45°, and lower fracture opening pressure(generally lower than 2.05 MPa/hm). The results showed that the in-situ stress magnitudes within deeply buried tight sandstone reservoir in the Kelasu structural belt are generally high, the minimum horizontal stress is more than 110 MPa and stress difference(SHmax-Shmin) is no less than 35 MPa. The relationship between the horizontal maximum(SHmax), minimum principal stress(Shmin), and vertical stress(SV) is SHmax>SV>Shmin(Type III), showing a dominant the strike-slip faulting stress regime. The orientation of the SHmax is generally N-S-trending, locally NW-SE-trending or NE-SW-trending. Under the influence of continuously strong tectonic compression and the thick salt layer, the current in-situ stress state in Kuqa thrust belt might has changed four times in depth. The complex stress environment, complex structures and lithology bring great challenges to the borehole stability while drilling. Based on the study of current in-situ stress, the evaluation of wellbore stability and the optimization of wellbore trajectory can reduce about 20% of com

关 键 词：深层致密储层 现今地应力 三维非均质 地质力学 克深气田 克拉苏构造带 

分 类 号：P551[天文地球—构造地质学]