摘要
为明确伊拉克A油田渐新统—下中新统Asmari组碳酸盐岩储层天然裂缝发育特征,综合岩心、铸体薄片、常规测井、成像测井、三维地震等资料,剖析研究区裂缝成因类型、分布特征、形成期次及主控因素。结果表明,Asmari组天然裂缝按地质成因可以分为构造裂缝和非构造裂缝。其中,构造裂缝是该地区天然裂缝的主要类型。构造裂缝以高角度剪切裂缝为主,为三期构造应力作用形成,走向多为NNE-SSW和NNW-SSE向,也可见部分NWW-SEE、NEE-SWW走向的裂缝;非构造裂缝主要有缝合线、层理缝、溶蚀裂缝、收缩裂缝等。研究区天然裂缝的发育程度主要受沉积、成岩、构造作用的影响。裂缝发育的基础是岩性,白云岩中裂缝最为发育,灰岩次之,碎屑岩、膏岩发育最弱。裂缝发育的饱和程度由层厚控制,地层厚度越小,裂缝密度越大。在成岩过程中,压实和压溶作用、胶结作用、溶蚀作用都会影响裂缝的发育。断层和地层变形程度控制相关裂缝分布。
In order to clarify the development characteristics of natural fractures in the carbonate reservoirs of Oligocene-Lower Miocene Asmari Formation in A oilfield of Iraq,the genetic types,distribution characteristics,formation stages and main controlling factors of fractures in the study area are analyzed according to the core,casting thin section,conventional log,imaging logging and 3D seismic data.The analysis results show that according to the geological origin,the natural fractures of Asmari formation can be divided into tectonic fractures and non-tectonic fractures,in which the tectonic fractures are the main type.The tectonic fractures are mainly high-angled shearing fractures,which are formed in three tectonic stress stages.The strike angles of structural fractures are mainly NNEcSSW and NNW-SSE.Meanwhile,some fractures with strike angles of NWW-SEE and NEE-SWW can also be found.Non-tectonic fractures mainly include stylolites,beddings,dissolution fractures,contraction fractures and so on.The development degree of the natural fractures is mainly affected by sedimentation,diagenesis and structure.Lithology is the basis of the development of natural fractures.In dolomite,fractures are the most developed,followed by limestone,and clastic rock and gypsum rock are the weakest.The fracture density increases with the decrease of formation thickness.In diagenesis process,compaction,pressure solution,cementation,and dissolution will affect the development of fractures.The distribution of related fractures is controlled by faults and the deformation degree of formation.
作者
董少群
孙福文
何娟
孙福亭
曾联波
杜相仪
DONG Shaoqun;SUN Fuwen;HE Juan;SUN Futing;ZENG Lianbo;DU Xiangyi(State Key Laboratory of Petroleum Resources and Prospecting,Beijing 102249,China;College of Sciences,China University of Petroleum (Beijing),Beijing 102249,China;College of Geosciences,China University of Petroleum (Beijing),Beijing 102249,China;International Company Limited of CNOOC,Beijing 100028,China)
出处
《西安石油大学学报（自然科学版）》
CAS
北大核心
2022年第3期34-43,共10页
Journal of Xi’an Shiyou University（Natural Science Edition）
基金
国家自然科学基金青年项目(42002134)
中国博士后科学基金第14批特别资助(2021T140735)
中国石油大学(北京)科研基金资助(2462020XKJS02和2462020YXZZ004)。
