碳酸盐岩溶洞系统地震识别、特征描述及成因分析

Identification and characterization of carbonate cavern system,and its genetic analysis

文中对中东AD油田白垩系Kh1—Ma3碳酸盐岩溶洞系统进行了地震识别、特征描述和成因分析，发现该溶涸系统由落水洞、暗河、地缝等基本单元组成，在空间上呈网状结构，具有纵向多期性（至少发育3期）、横向分带性、低孔渗的特点。低孔、低渗的网状溶洞系统对油气运移起到纵向封堵和侧向隔挡作用，形成一个近于“箱状”的封闭区域，使得发育溶洞系统的B1—C1井区的Mi1-Ma3层段的油气充填、成藏难度大；A1井区由浅到深岩溶不发育，有利于油气在生物碎屑灰岩基质孔隙为主的储层中运移和聚集，从而形成多层系油气藏。网状溶洞系统的特征及其成因分析得到了钻井数据的验证。

In this paper,we conduct identifications, characterizations and genetic analysis for the Cretaceous Kh1-Ma3carbonate cavern system in AD Oilfield in the Middle East.The cavern system is comprised of sink holes,underground streams, and fissure distributes in spatially reticular structure.And the cavern system is characterized by multiple stages(at least 3stages),zonality and low porosity and permeability.This kind of characteristics in the cavern system plays a role of vertical sealing and lateral barrier against hydrocarbon migration,thus forming an enclosed area that is nearly'box-like'.Consequently,in Mi1-Ma3layers of the Well B1-C1Block where the cavern system is developed,hydrocarbons are hard to be filled and accumulated.In contrast,Karst is not developed from shallow to deep layers in the Well A1Block,which is good for preservation of porous reservoirs with bioclastic limestone matrix and for multi-series hydrocarbon accumulation.The analysis of reticulated cavern system and its impact on hydrocarbon accumulation has been effectively verified by drilling data.