塔里木盆地塔河油田下奥陶统油藏特征及成藏条件分析

CHARACTERISTICS AND POOL-FORMING CONDITIONS OF THE LOWER ORDOVICIAN RESERVOIRS IN TAHE OILFIELD, THE TARIM BASIN

地质综合研究和勘探实践表明,塔河油田是在长期发育的古隆起基础上形成的下奥陶统碳酸盐岩岩溶-缝洞型大型油气田。该油田主力产层下奥陶统碳酸盐岩发育孔、洞、缝3类储集空间,组成裂缝型、孔洞-裂缝型、裂缝-孔洞型和生物礁(滩)相孔隙型4类储层。长期生烃、多期构造运动和多期岩溶作用使塔河油田不同区块原油性质有一定差异。下奥陶统油气聚集成藏主要受阿克库勒凸起、碳酸盐岩溶蚀孔洞缝发育程度和石炭系巴楚组泥岩覆盖等多种因素综合控制。

The integral geological study and petroleum exploration indicated that Tahe oilfield formed on the basis of longdeveloped paleouplift was a large scale one which consisted of karstfracture reservoirs of the Lower Ordovician carbonate rocks. Karst holes, cracks and pores developed in the Lower Ordovician carbonate rock constitute four types of oil and gas reservoirs, including crack type, porecrack type, crackpore type and reef type. Long lasting generation of hydrocarbon, multiphase tectonic movement and multistage karstification resulted in quite different oil characteristics in different part of the oilfield. Petroleum accumulation and pool forming were controlled by the Akekule Uplift, development level of karstfracture in carbonate rocks and distribution of mudstones of the Carboniferous Bachu Formation.