东营凹陷岩性油气藏成藏条件的地震分析

A seismic analysis with reservoir condition of lithological reservoir.

利用东营凹陷的地震资料,探讨了在缺少钻井、测井资料地区岩性油气藏的预测方法,其核心是影响成藏条件主要因素的预测和定量计算,以及最终成藏指数的求取。①岩性成藏条件的分析表明,当烃源岩与砂岩体之间的剩余压力大于砂体本身的渗透性(等效排烃压力)时,易于形成岩性油气藏;②烃源岩剩余围岩压力可以通过利用地震速度谱计算砂岩体内的孔隙压力来得到;③利用砂岩透镜体的地震反射振幅和频率估算砂体厚度,从而预测砂体孔隙度,然后用实验中进汞50%时的排替压力与孔隙度的经验关系式求得等效排烃压力;④成藏指数可以通过计算烃源岩剩余围岩压力与等效排烃压力的比值来获得。本方法的预测结果与实钻结果显示了较高的吻合程度。

Under the condition of lacking drilling and logging data, it is hard to predict effectively and make a quantity computation on the main factors of reservoir-forming. We use statistic-geology method to summarize seismic velocity spectrum and reflect amplitude of sand body and relationship between hydrocarbon pressure and equivalent ranking hydrocarbon pressure. First, according to seismic velocity spectrum calculate the porosity pressure in sand body to obtain hydrocarbon sand remainder neighboring rock pressure, and at the same time use seismic reflect amplitude and frequency to evaluate sand body thickness, to predict sand body porosity. Then we use the experience relations between expulsion pressure and porosity to calculate reservoir index. Finally, we evaluate the reservoir conditions to realize the quantity calculation and of reservoir index.