塔河油田奥陶系碳酸盐岩储层特征及成藏条件

CARBONATE ROCK RESERVOIR FEATURES AND OIL-GAS ACCUMULATING CONDITIONS IN THE ORDOVICIAN OF TAHE OILFIELD IN NORTHERN TARIM BASIN

石油地质和地球物理综合研究及油气勘探实践表明 ,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。碳酸盐岩形成于开阔—局限海台地环境 ,由于经历了后期多期次的构造运动、岩溶作用和成岩作用的叠加改造 ,因而呈现出基质孔渗性低、并受构造和岩溶作用控制的强烈非均质性的岩溶 缝洞型储层特征。塔河岩溶 缝洞型油气藏主要分布于古岩溶斜坡地带、距风化壳不整合面 2 0 0m范围内。岩溶残丘、岩溶缝洞、断裂、不整合面和输导层共同构成了塔河油气区复杂的多幕式油气成藏动力学系统。

The integral study of petroleum geology,geophysics and oil_gas exploration indicates that Tahe Oilfield formed on the basis of long_developed paleo_uplift is a large scale one which consists of karst_fracture reservoirs of Lower Ordovician carbonate rock.The carbonate rock reservoir developed on the environment of open_limited sea platform presents the features of karst_fracture reservoir of lower matrix porority,and permeability and stronge heterogeneity controlled by tectonisim and karstification because the reservoir underwent multi_stages superimposed reformation of tectonisim,karstification and diagenesis at late time.The karst_fracture reservoir of Tahe Oilfield is mainly distributed in the center platform of paleo_buried hill and the southern slope,and in the scope of 200 metres under uncomformity interface of weathering crust.A complex and multi_episodes oil_gas accumulating dynamic system in Tahe petroleum area is composed of paleo_buried hill,karst_fractures,faults,surface of uncomformity and conduit.