摘要
以鄂尔多斯盆地西南部红河油田长8致密砂岩储层为例,根据铸体薄片、扫描电镜分析,结合岩心和测井资料,采用地质学统计的方法,对微观裂缝的发育特征及控制因素进行系统分析,在此基础上,分析典型区块Q1井区的微观裂缝分布特征。结果表明:从地质成因上,该区致密砂岩储层的微观裂缝可以分为构造、成岩、构造-成岩和异常高压成因4种类型,其中以构造成因的微裂缝和构造-成岩成因的微裂缝为主,该区微观裂缝大部分为有效裂缝,少量无效裂缝被方解石、石英及炭质等充填。该区微观裂缝的发育程度受沉积作用、成岩作用、构造作用及异常高压作用控制。云母、岩屑等塑性成分含量越高,杂基含量越多,岩石颗粒越细,微裂缝发育程度越差;压实作用越强,越有利于构造-成岩成因的粒内缝、粒缘缝发育;随着胶结强度增强,粒内缝和粒缘缝发育程度降低,利于发育构造成因的微裂缝。典型区块Q1井区,在细砂岩强压实方解石强胶结相中,微观裂缝发育程度最强;其次为细砂岩强压实相和中-细砂岩方解石中胶结相;在细砂岩高岭石胶结相和绿泥石胶结中溶解相中,微观裂缝发育程度较弱;在泥岩中微观裂缝发育程度最弱。
Based on the analysis of thin sections and scanning electron microscope,in combination with cores and well logs,microfracture characteristics and its controlling factors were systematicly analyzed in the tight sandstone reservoir of the eighth member of the Yanchang Formation in the Honghe Oilfield in the southwest Ordos Basin. Then,the distribution characteristics of microfractures in the typical Q1 well area were analyzed.The results show that from the perspective of geologic origins,microfractures can be divided into four types in the study area,i. e.,tectonic origin,diagenetic origin,tectonic-diagenetic origin and overpressure origin.Among these microfractures,tectonic origin and tectonic-diagenetic origin microfractures are the most abundant. Most microfractures are effective,while some micorfractures are filled with calcite,quartz,mud and so on. Microfracture development degree is influenced by sedimentation,diagenesis,tectonism and overpressure.With the increase of matrix content and plastic element content such as mica debris,and the decrease of grain size,microfracture intensities decrease. The stronger the compaction is,the more abundant intragranular and grain edge fractures are developed,which are tectonic-diagenetic origins. Intragranular and grain-edge fracture intensities decrease as the cementing strength increases,thus being favorable for the development of tectonic origin microfractures. In the typical Q1 well area,microfractures are most developed in the fine sandstones with strong compaction and strong calcite cementation;next being fine sandstones with strong compaction and medium-fine sandstone with moderate calcite cementation. Microfractures are relatively weakly developed in fine sandstone with kaolinite compaction and fine sandstone with chlorite cementation and moderate dissolution. The development of microfractures is the weakest in mudstones.
作者
吕文雅
曾联波
周思宾
吉园园
梁丰
惠晨
尉加盛
LÜWen-ya;ZENG Lian-bo;ZHOU Si-bin;JI Yuan-yuan;LIANG Feng;HUI Chen;WEI Jia-sheng(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China;College of Geosciences,China University of Petroleum,Beijing 102249,China;Exploration and Development Research Institute of North China Company,Sinopec,Zhengzhou 450006,China;The First Oil Production Plant of North China Company,Sinopec,Qingyang 745000,China;The Sixth Gas Production Plant of PetroChina Changqing Oilfield Company,Xi’an 710016,China)
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2020年第1期37-46,共10页
Natural Gas Geoscience
基金
国家科技重大专项（编号：2017ZX05009001-002,2016ZX05002-005）
中国石油大学（北京）青年拔尖人才科研启动基金项目（编号：2462017YJRC057）联合资助~~
