基于三维激光扫描技术的裂缝发育规律和控制因素研究——以塔里木盆地库车前陆区索罕村露头剖面为例  

Fracture development characteristics and controlling factors based on 3D laser scanning technology:An outcrop case study of Suohan village,Kuqa foreland area,Tarim Basin

作　　者：曾庆鲁 张荣虎 卢文忠 王波 王春阳 

机构地区：[1]中国石油杭州地质研究院,浙江杭州310023 [2]中国石油东方地球物理公司研究院库尔勒分院,新疆库尔勒841001

出　　处：《天然气地球科学》2017年第3期397-409,共13页Natural Gas Geoscience

基　　金：国家科技重大专项(编号:2016ZX05003-001-002;2016ZX05001-002-003);国家重点基础研究发展计划"973"项目(编号:2011CB201104)联合资助

摘　　要：裂缝是影响致密砂岩储层天然气产能的主要因素,但井下裂缝的产状、规模和面孔率很难直接测量。通过选取与目的层地质情况相似的典型露头剖面,在人工测量、取样和室内分析化验的基础上,利用激光扫描技术对其进行多次覆盖以获取三维点云数据,配合高分辨率数码照片和人工实测裂缝信息,在数据体剖面上对裂缝进行精细解释,借助计算机模拟技术建立数字化裂缝模型和储层地质模型,更为准确地展示了研究区裂缝发育规律和控制因素,为井下储层预测提供更真实的地质信息。结果表明,研究区主要发育3组优势倾向剪切裂缝,倾角大,延伸长度短,裂缝间距呈略正态分布。裂缝开度与产状密切相关,具有双峰特征,分别为0.2~0.4mm和0.8~1mm。横向上单组和双组优势裂缝疏密相间分布,可划分为贯穿缝带和层间缝带,其中贯穿缝带裂缝具有较大的延伸长度和间距,较小的面密度且大部分贯穿邻近泥岩,后者正好相反。定量计算了剖面上11个单砂体的裂缝面孔率,范围为0.026%~0.081%,平均为0.05%,水下分流河道砂体要好于河口坝和远砂坝。裂缝发育规模受岩性、层厚、最大古主应力和岩矿成分等多个因素控制,之间存在较好的幂指数相关关系。Fracture is of primary importance to the productivity of gas from many tight sandstone reservoirs in the Kuqa Depression,Tarim Basin,NW China,but the orientation,size and plane porosity of fractures in the subsurface are difficult to be measured directly.In this paper,by choosing a typical outcrop which has similar geological situation with the target stratum,on the basis of the conventional observation,systematic sampling and laboratory analysis,taking advantage of holographic laser scanning technology to obtain three-dimensional point cloud data with multi-level covering,matching with high-resolution digital photos and artificially measured information,the 3-D positions of natural fractures are extracted strictly in the data volume section.Furthermore,the fracture patterns and controlling factors are revealed more accurately with the fracture and reservoir model founded by computer simulation technology.It is founded that three groups of shear fractures are mainly developed with large inclination,short trace length and small spacing of normal distribution.The fracture aperture is related to the orientation with bimodal distribution of 0.2-0.4mm and 0.8-1mm.The fracture patterns provide a literal distribution of penetrating fracture zone and interlayer fracture zone with a single and a double set of advantage orientation respectively.The fractures in the former zone have greater trace length,greater spacing,and smaller surface density and run through the adjacent shale mostly while the latter is just the opposite.The plane porosity of fractures in 11 single sandbodies of different microfacies in the study section has been calculated quantitatively with a range of0.026%-0.081% and an average of 0.05%.The sandbodies of underwater distributary channel are better than mouth bar and distal bar.It turned out that the size of fracture is controlled by lithology,bed thickness,maximum paleostress and rock composition with a good exponential relationship.

关 键 词：三维激光扫描技术 裂缝 分布规律 控制因素 野外露头 库车前陆区 

分 类 号：TE121.1[石油与天然气工程—油气勘探]