致密砂岩气储层多尺度“地质-工程”双甜点评价新方法  

A multi-scale geology-engineering sweet spot evaluation method for tight sandstone gas reservoirs

作　　者：朱海燕 龚丁 张兵[2] ZHU Haiyan;GONG Ding;ZHANG Bing(State Key Laboratory of Oil&Gas Reservoir Geology and Exploitation//Chengdu University of Technology,Chengdu,Sichuan 610059,China;China United Coalbed Methane Co.,Ltd.,Beijing 100016,China)

机构地区：[1]油气藏地质及开发工程全国重点实验室•成都理工大学 [2]中联煤层气有限责任公司

出　　处：《天然气工业》2023年第6期76-86,共11页Natural Gas Industry

基　　金：国家自然科学基金联合基金重点项目“四川深层页岩智能传控靶向复合压裂基础研究”(编号:U20A20265);四川省杰出青年科技人才项目“页岩气加密井压裂复杂裂缝扩展机理研究”(编号:2022JDJQ0007)。

摘　　要：勘探开发实践证实水平井分段体积压裂是致密砂岩气储层开发的关键技术,其中储层甜点是井位部署和储层压裂分段和射孔位置优选的主要依据,但由于致密砂岩气储层通常为砂泥岩不等厚互层,天然裂缝展布情况与地应力状态复杂,且“地质—工程”双甜点识别精度低、重合度低、压裂改造参数优化缺乏依据。为此,基于地质—工程一体化思路,建立了考虑全烃含量、储层孔隙度等因素的地质甜点预测模型,提出了考虑岩性、破裂形态、断裂力学特征、扩容剪胀效应等因素的多尺度三维工程甜点评价新方法,随后形成了致密砂岩气储层“地质—工程”双甜点评价新模型。最后,以鄂尔多斯盆地临兴地区致密砂岩气田为例,建立了多尺度三维双甜点模型,并优选两口井,对其双甜点剖面与施工压力和改造体积进行对比分析。研究结果表明:①剪胀角对研究区域工程甜点分布影响最大,其次为耗散能、弹性模量和断裂能;②高地质甜点段并不一定是页岩气高产段;③高工程甜点段施工压力相对较低,改造相对充分;④优质地质甜点与优质工程甜点在空间位置上一致性较差。结论认为,致密砂岩气储层的改造应以地质甜点为基础,工程甜点为核心,综合考虑双甜点的分布,该多尺度“地质—工程”双甜点评价新方法为致密砂岩气储层甜点预测及开发方案的优化提供了重要技术支撑。It is proved in exploration and development practices that horizontal well staged volumetric fracturing is a key technology in tight sandstone gas development,and reservoir sweet spot is an important basis for the perforation position selection and staged fracturing in the process of well location deployment and reservoir stimulation.In tight sandstone reservoirs,however,sandstone and mudstone are usually interbedded with each other with different thicknesses,and natural fracture distribution and in-situ stress states are complex.In addition,the"geology-engineering"sweet spot identification of tight sandstone reservoirs is of low precision and coincidence.As a result,there is a lack of basis for the optimization of fracturing parameters.Based on the idea of geology-engineering integration,this paper establishes a geological sweet spot prediction model which takes into account total hydrocarbon content,reservoir porosity and other factors,and puts forward a new multi-scale 3D engineering sweet spot evaluation method which takes into account lithology,fracture morphology,fracture mechanical behavior,and dilatation and shear dilation effect.Then,a new"geology-engineering"sweet spot evaluation model of tight sandstone reservoir is established.Finally,with the tight sandstone gas field in the Linxing Block of the Ordos Basin as an example,a multiscale 3D sweet spot model is established,and two wells are selected for the comparative analysis in terms of double sweet spot profile,construction pressure and stimulated reservoir volume(SRV).And the following research results are obtained.First,the influence of shear dilation angle on the distribution of engineering sweet spots in the study area is the greatest,followed by dissipated energy,elastic modulus and fracture energy.Second,the high geological sweet spot interval is not necessarily the high yield interval of shale gas.Third,the high engineering sweet spot interval has lower construction pressure and is stimulated relatively sufficiently.Fourth,high-quality geologic

关 键 词：致密砂岩气储层 复杂地质条件 多尺度 地质工程一体化 双甜点评价 扩容剪胀效应 布井 井眼轨迹 射孔位置 压裂设计优化 

分 类 号：TE37[石油与天然气工程—油气田开发工程] P618.13[天文地球—矿床学]