第37卷第4期 2016年8月
文章编号：1001-3873(2016)040383-08
新疆石油地质
XINJIANG PETROLEUMGEOLOGY DOI:10.7657/XJPG20160402
Vol.37,No.4 Aug.2016
低渗透砂砾岩储集层粒内缝成因机制及油气勘探意义
以准噶尔盆地玛湖凹陷三叠系百口泉组为例
徐洋，孟祥超，刘占国，单祥
（中国石油杭州地质研究院实验研究所，杭州310023）
摘要：准噶尔盆地西北缘玛湖凹陷三叠系百口泉组砂砾岩属于低孔低渗储集层，粒内缝是百口泉组储集层重要的渗流通道，国内外对于粒内缝的成因机制、发育规律的研究成果较少。根据粒内缝发育的宏观和微观特征、结合钻并和地震资料，采用古构造应力值一粒内缝关系表征、粒内缝发育物理模拟实验等手段，系统分析了低孔低渗砂砾岩储集层粒内缝的识别特征、成因机制、发育过程及分布规律。认为百口泉组砂砾岩储集层粒内缝从成因上属于构造-成岩缝，其形成与颗粒抗压性、抗剪-抗扭性、内部缺陷、构造应力大小和应力作用方式有关；粒内缝对百口泉组砂殊岩储集层的影响主要在于提高渗透率，粗粒的砾级颗粒粒内缝与砂级颗粒粒间基质孔-微孔的有效配置是形成百口泉组优质高效储集层的关健；粒内缝垂向上主要发育于以百口泉组为主的中一下三叠统，平面上乌夏断裂带粒内缝最为发育，克百断裂带因应力作用方式及刚性颗粒含量的变化，粒内缝发育程度与鸟夏断裂带存在明显差异，受逆冲断
裂带展市控制，自断裂带至斜坡区粒内缝发育程度逐渐变聘，但在走滑断聚发育处，粒内缝发育程度局部增强。关键词：准噶尔盆地；玛湖回陷；三叠系；百口泉组；砂砾岩；粒内缝；逆冲断裂；走滑断裂
中图分类号：TE112.221
文献标识码：A
Genetic Mechanism of Intragranular Fractures in Low-Permeability Sandy Conglomerate Reservoirand Their Significance inPetroleum Exploration:ACase Studyfrom Triassic
BaikouquanFormationinMahu Sag,JunggarBasin XU Yang, MENG Xiangchao, LIU Zhanguo, SHAN Xiang
(PetroChina Hangzhou Research Institute of Geology, Hangzhou, Zhejiang 310023, China)
Abstract: The sandy conglomerate reservoirs of Baikouquan formation of Mahu sag in northwestem margin of Junggar basin are low-porosi-ty and low-permeability reservoirs, where the intragranular fractures act as the important flow paths, Less researches have been made in terms of genetic mechanism and development of intragranular fractures at home and abroad. This paper systematically analyzes the identify ing characteristics, genetic mechanism, development process and distribution of intragranular fractures in low-porosity and low-permeabili ty sandy conglomerate reservoins, according to themacroscopic and microscopic characteristies of intragranular fractures development, com-bining with drilling and seismic data, by means of relationship characterization of the palaeotectonic stress value-the intragranular frac tures, and intragranular fracture physical modeling experiment, It is considered that the intragranular fractures in Baikouquan formation are structural-diagenetic fractures genetically, the generation of the fractures is related to the properties of compression, shearing and torsion intermal defect of grains, tectonic stress and stress effect; the main influence of intragranular fractures on the reservoir is to improve reser-voir permeability, and the effective configuration of intragranular fractures in coarse grains-intergranular matrix pores among sand grains microfissures is the key factor to generate high-quality and high-efficiency reservoirs of Baikouquan formation; the intragranular fractures are mainly distributed in Middle-Lower Triassic Baikouquan formation vertically and mostly in Wuerhe-Xiazijie faulted belt in plane.The development degrees of-intragranular fractures in Karamay-Baikouquan and Wuerhe-Xiazijie faulted belts are different due to the changes of stress effect mode and rigid grain content. Constrained by thrust fault distribution, the development degree of intragranular fractures is weakening from the faulted zone to slope area, but tends to increase at strike-slip faults.
Keywords: Junggar basin; Mahu sag; Triassic; Baikouquan formation; sandy conglomerate; intragranular fracture; thrust fault; strike-slip fault
裂缝是油气储集层中一种重要的储渗空间，前人对储集层裂缝做过诸多研究，将裂缝分为构造缝、成岩缝（层间缝、龟裂缝、冷凝收缩缝、溶蚀缝）、节理缝、晶间缝等类型，并指出裂缝作为储集空间和渗流通道的双重作用"-3]。文献[4]和文献[5]对裂缝发育程度
收稿日期：2016-05-23
修订日期：2016-06-14
基金项目：中国石油科技重大专项(2012E-34-01)
与岩层厚度关系进行了研究，指出在一定岩层厚度范围内，裂缝的平均开度与裂缝化的岩层单层厚度具较好的线性关系，随岩层厚度增大，裂缝开度呈线性增大，而裂缝密度减小；当岩层单层厚度大于3m，裂缝一般不发育。上述研究主要集中于火山岩、泥灰岩-
作者简介：徐洋（1970-），男，江西九江人，高级工程师，石油地质，（Tel)13958069286(Email)xuy_hz@petrochina.com.en 万方数据