辽河坳陷双清地区古近系沙河街组四段孔隙度演化模拟

Porosity evolution simulation of the Member 4 of Shahejie Formation of Paleogene in Shuangqing area,Liaohe Depression

在综合考虑沉积微相和成岩作用对储集层孔隙度影响的基础上,建立了辽河坳陷双清地区不同沉积微相成岩指数ID与储集层平均孔隙度的相关关系,预测了该地区沙四段储集层在各沉积时期的平均孔隙度,恢复了孔隙演化史,确定了不同沉积时期有效油气储集层的分布范围。孔隙度预测结果表明,有效油、气储集层分布于研究区北部孔隙度大于5.8%的地区。孔隙演化史的模拟结果表明,储集层孔隙度在埋藏早期主要受沉积相的影响,而在晚期则主要受成岩作用的控制。储集层预测孔隙度与实测孔隙度的绝对误差为2.7%,而研究区储集层的填隙物含量在1.0%～40.0%之间,平均为21.7%,由此可见,所建预测模型可用于填隙物含量较高的储集层钻前孔隙度预测和孔隙演化史模拟。

Based on the studies of the influence of sedimentary microfacies and diagenesis on the reservoir porosity, the reservoir porosity of the Member 4 of Shahejie Formation was predicted, the porosity evolution history was modeled, and the distribution areas of effective petroleum reservoirs were determined by establishing correlation relationships between the diagenetic intensity index （ⅠD） and reservoir average porosity for various sedimentary microfacies in Shuangqing area of the Liaohe Depression. The results of porosity prediction show that the effective oil and gas reservoirs are distributed in areas with the porosity larger than 5.8% in the northern part of the study area. The porosity history simulation results suggest that the reservoir porosity during the early burial period was mainly affected by sedimentary microfacies, while in the late burial period controlled by diagenesis. The absolute error between the predicted porosity and practically measured porosity is less than 2.7%. However, the pore-filling material content is up to 1.0% -40. 0%, averaging at 21.7%. It means that these kinds of porosity simulating models are suitable for predrilling porosity prediction of reservoirs with higher content of pore-filling materials and simulation of porosity evolution history.