古岩溶与油气运移和成藏关系浅析

A preliminary analysis on relation between palaeokarst and migration and accumulation of oil/gas

发育于碳酸盐岩中的古岩溶构成了重要的油气储集体,溶蚀水源、水化学场和水动力场是影响古岩溶发育的3个主要因素。对长庆油田、川中磨溪气田和塔河油田碳酸盐岩岩溶储层的研究表明,压释水作为溶蚀水源在岩溶形成和油气运移聚集过程中发挥着重要的作用;古岩溶的发育受后期构造活动的影响,古岩溶的演化控制了磨溪气田L11储层岩溶气藏的储集特征;古构造、古断裂、古水文系统和古岩溶地貌是造成古洞穴型碳酸盐岩储层平面非均质性的主要因素,储集性能较好的古洞穴型碳酸盐岩储层为未充填洞穴储层和大型洞穴充填孔隙型砂岩储层。随着岩溶型储层概念和含油气系统理论的提出,古水文地质分析工作在储层预测研究中将发挥更大的作用。

Palaeokarst developed in Carbonate rocks is a kind of important oil/gas reservoir. The dissolution water source, hydro-chemical field and hydrodynamic field are the three main factors influencing palaeokarst development. The research of carbonate palaeokarst reservoir in Changqing oilfield, Moxi gas field of the Central Sichuan, and the Tahe oilfield showed that the compaction - released water as the dissolution water source that performed an important function in the process of karst formation, migration and accumulation of oil/gas; The palaeokarst development was affected by later tectonic activity;The palaeokarst evolution controlled reservoir character of karst gas reservoir in L1 reservoir of Moxi gas field;The palaeo - structure , palaeo - fault, palaeohydrological system and palaeokarst topography were main factors caused planar heterogeneity of palaeocave - type carbonate reservoirs. The palaeocave - type carbonate reservoirs with better reservoir behavior were unpacked cavernous reservoir and large - scale packed cavernous sandstone reservoir. Along with the appearance of concept of cavernous reservoir and theory of petroleum system, hydrogeo logical analysis will play a great role in reservoir prediction re-search.