塔北哈拉哈塘地区奥陶系鹰山组-一间房组岩溶储层特征及成因模式

摘要

提塔里木盆地北部哈拉哈塘地区奥陶系岩溶型储层油气勘探近年来获得了重大突破，其主要勘探目的层系为鹰山组-一间房组碳酸盐岩，进一步深化碳酸盐岩岩溶储层认识对于加快塔里木盆地海相油气勘探具有重要意义。在分析区域地质背景的基础上，结合钻井、岩心、测井、地震等资料，对研究区鹰山组-一间房组岩溶储层特征以及储层发育主控因素和成因演化模式进行了深入研究。研究认为，鹰山组-一间房组岩溶储层基质孔渗条件差，基质孔隙不能单独成为有利的油气储集空间，储层储集空间主要为溶蚀孔洞以及裂缝系统。储层经历的岩溶作用类型主要有(准)同生岩溶作用、风化岩溶作用以及埋藏热液岩溶作用等，各种岩溶作用的多期叠加改造使得鹰山组-一间房组岩溶储层极为发育。通过对储层成因过程的研究分析，认为构造隆升为岩溶储层的发育提供了有利条件并控制了储层发育格局；多期岩溶作用是形成岩溶储层的关键因素；断裂及裂缝的发育促进了岩溶储层的形成并改善了储层的储集性能。%The most important exploration target of the Ordovician strata in Halahatang area of the Tarim Basin is carbonate karst reservoir in Yingshan-Yijianfang Formation, and a breakthrough of oil-gas exploration was made in this area in recent years. Therefore, a further study of karst reservoir for marine petroleum exploration will be very important. In this paper, based on the analysis of regional geological background, in combination with drilling, core, logging and sesmic data, the authors studied in detail the characteristics, main controlling factors and genetic evolution model of karst reservoirs in Yingshan-Yijianfang Formation. The results indicate that the porosity and permeability of the matrix in Yingshan-Yijianfang Formation are poor, micropores which mainly consist of solution cave and fracture cannot serve as favorable reservoir space. The main types of karstification are penecontemporaneous or contemporaneous karstification, buried karstification, and weathering karstification. Superimposed reformation of polyphase karstification has made a great contribution to karst reservoirs. Based on synthetic analysis of the formation process of karst reservoirs, the authors have arrived at several conclusions: The distribution of karst reservoirs is controlled by tectonic uplift, polyphase karstification is the main factor for reservoir development, and faults and fractures formed during the tectonic evolution have facilitated the development of karst reservoirs and improved the reservoir property.