倾斜油水界面成因分析与非稳态成藏理论探索

ORIGIN OF TILTED OIL-WATER CONTACT AND PROBE INTO THE THEORY OF UNSTEADY HYDROCARBON ACCUMULATION

以塔里木盆地哈得逊油田所存在的倾斜幅度很大的油水界面的东河砂岩油藏为例,系统分析了倾斜油水界面油藏的成因,排除了水动力和毛细管压力两种引起油水界面倾斜的原因,通过精细的构造演化分析和物理模拟实验研究,认为新构造运动引起的构造变动是东河砂岩油藏油水界面大幅度倾斜的主要原因。该油藏现今正处于油藏的调整过程之中,油气富集具有明显的非稳态性,进而提出了非稳态成藏的理论构想,认为油气从生成到成藏到油气藏枯竭是一个连续的动态过程。将油气从生成到散失的全过程分为前油藏阶段、油藏阶段和后油藏阶段,3个阶段形成了不同的油气聚集类型。

Aiming at Donghe sandstone oil reservoir with significantly titled oil-water contact in the Hadson Oilfield,Tarim Basin,an investigation into the origin of titled oil-water contact is conducted,which excludes the possibility that hydropower and capillary pressure resulted in the tilted contact.Structural evolution analysis and physical modeling show that the inclination of oil-water contact in sandstone oil reservoir results from tectonic inversion by neotectonic movement.The oil reservoir has been undergoing adjustment with evidently unsteady hydrocarbon accumulation,so a hint about theoretical presumption of unsteady hydrocarbon accumulation is given,in which the process from hydrocarbon generation and accumulation to hydrocarbon depletion is regarded as a continuous dynamic process and may be divided into pre-reservoir stage,reservoir stage and post-reservoir stage with different hydrocarbon accumulation style in different stages.