塔北哈6区块奥陶系油藏地质与成藏特征

近年来,塔里木盆地北部地区通过在隆起的围斜部位和斜坡区域开展三维地震和综合研究以及钻探工作,获得重大发现。通过采样分析以及对哈6区块构造演化、地层发育特征及碳酸盐岩油藏的石油地质条件的深入研究,认为围斜区域奥陶系裂缝—孔洞型碳酸盐岩储层发育,与上覆志留系和奥陶系吐木休克组泥岩组形成储盖组合,具有良好的油气成藏条件。通过油源对比、区域构造演化、生烃史及储层流体包裹体等分析,认为哈6区块奥陶系原油来自中—上奥陶统烃源岩,在晚海西期充注成藏;燕山期以来,油藏进入调整和保存阶段。哈6区块储盖组合配置良好、优势通道和充足的油气在时空耦合关系良好,奥陶系具广阔的勘探前景。该区目前处于油气发现的初期阶段,相关地质认识较为浅显,对目前的认识进行梳理,有利于各项研究工作的进一步深化。

Geological and Accumulations Characteristics of Ordovician Oil Reservoir in Ha 6 Block of Tabei

In recent years, significant discoveries have been made in the northern part of Tarim Basin thanks to 3D seismic survey, integrated study and drilling of the pericline position and slope area of the upliR. Based on the analysis of samples and in-depth study of structural development in Ha 6 Block, characteristics of stratum development, and petroleum geological conditions of carbonate rock reservoirs, it is assumed that the Ordovician fracture-porous carbonate rock reservoirs developed in the pericline area, forming the reservoir-cap assemblage with overlying Tumuxiuke mudstone formation of Silurian System and Ordovician System and thus providing the desirable conditions for hydrocarbon accumulations. Based on comparison ofoil sources and analysis of regional structural development, hydrocarbon sourcing history and fluid inclusions in the reservoir, it is assumed that crude oil of Ordovician System in Ha 6 Block came from source rock of Middle-Upper Ordovician Series and was infilled and accumulated in the Late Hercynian period. The oil reservoirs came into adjustment and preservation stage after the Yanshanian period. The reservoir-cap rock assemblage is well matched in Ha 6 Block and the relations of time and space are well coupled, providing favorable passages and adequate oil and gas. Ordovician System has a very promising prospect for exploration. This block is currently under a preliminary stage ofoil and gas discovery with limited related geological knowledge. The combing of the current knowledge is helpful to further study of this area.