塔中隆起碳酸盐岩叠合复合岩溶模式与油气勘探

Superimposed Compound Karst Model and Oil and Gas Exploration of Carbonate in Tazhong Uplift

塔里木盆地大型碳酸盐岩台地形成与构造演化过程中,发育了台缘礁、台内滩与深层白云岩等巨厚的碳酸盐岩建造,经过多期构造运动形成了种类繁多、规模巨大的岩溶缝洞系统,是台盆区海相碳酸盐岩油气勘探开发的重要领域.基于野外露头与井下地质、岩样分析、地球物理预测及岩溶地质刻画,静态特征与生产动态等多学科动静态一体化研究,阐明了洞穴、溶蚀孔洞、裂缝等储集空间发育特征及大型岩溶缝洞系统的形成机理;创建了与不整合暴露、断裂破碎相关的岩溶叠合复合发育模式;揭示了不整合面相关岩溶横向广泛分布、断层相关岩溶纵向局部拓展及其三维展布规律;提出叠合复合岩溶缝洞系统是油气复式成藏的关键,亦是复式油气聚集区立体勘探开发的基础,叠合复合岩溶模式的建立有效指导了塔中隆起碳酸盐岩凝析气田的重大发现与高效开发.

In the process of large carbonate platform formation and tectonic evolution of Tarim basin, the thick platform margin reef, intra-platform beach and deep dolomite carbonate sediments were developed, which formed the various types and large scale of karst fracture-cave systems by the reconstruction of multi period tectonic movement, and the system is an important field of oil and gas exploration and development inside the platform basin transitional area marine carbonate. Based on the mul- tidisciplinary static and dynamic comprehensive analysis of the field outcrop, underground geology, geophysical prediction, karst geological description, static characteristics and production dynamic data, this paper described the characteristics of reser- voir space development, such as caves, dissolved pores and fractures as well as the formation mechanism of the large-scale karst fracture-cave system, and established the superimposed development model of unconformity exposed and fracture karst, and revealed the horizontal distribution of unconformity related karst and the longitudinal distribution and three-dimensional distribution of the fault karst. The comprehensive study shows that the composite karst fracture-cave system is the key to oil and gas accumulation, and is also the basis for the exploration and development of the complex oil and gas accumulation area. The establishment of the superimposed compound karst model is an effective way to guide the significant discovery and efficient development of the carbonate condensate gas field in Tazhong uplift area.