利津油田利95-利98井区沙四段砂砾岩储层有效性研究及预测

The Effect and Prediction of Glutenite Reservoir of the Fourth Member of Shahejie Formation in Wellblock Li 95-98 of Lijin Oilfield

利95-利98井区沙河街组四段砂砾岩储层主要为多期叠合的近岸水下扇-浊积扇沉积复合体,岩性复杂多样,分选差,物性变化大,整体表现为低孔、低渗储层,勘探开发难度大。对砂砾岩储层有效性及有效储层预测的研究,首先要利用经验统计法和正逆累积法综合确定有效储层的物性下限,其中渗透率下限为0.878mD,不分岩性时孔隙度下限为8.0%(砾岩+砾状砂岩组合孔隙度下限为6.0%,砂岩+含砾砂岩组合孔隙度下限为10%);然后通过储层电性分析,落实油层、油水同层、干层的电性界限。考虑到实际操作的可行性,通过地震正演模拟分析,优选出均方根振幅进行孔隙度预测,最终在各期次砂砾岩体的孔隙度预测平面图基础上,勾绘出有效储层分布范围。

The glutenite reservoir in the fourth Member of Shahejie Formation in Wellblock Li95-98 was complex in the offshore sub-water apron and the turbidite fan,its lithology was complex with poor sorting,physical property changed greatly,it was the reservoir with low-porosity and low permeability,and difficult for exploration.For the research and study of the effective glutenite reservoir,first of all,the thumb rule and the positive and negative cumulative method were used to establish the low limit of the physical property of the effective reservoir,and the low limit of permeability was 0.878 mD,the low limit of the porosity of all the lithology was 8.0%,but the low limit of the porosity of gravel rock was 6.0%,the low limit of the porosity of sand rock was 10.0%.After the analysis of the electrical property of the glutenite reservoir,the electrical property boundary of the oil layer,oil/water layer and dry layer was established.In consideration of the feasibility of the forecasting method,the RMS is optimized to forecast the porosity by the seismic forward modeling,and the porosity distribution of the different glutenite depositional times is forecasted,the effective reservoir is chosen on the basis of a graph of porosity prediction for the glutenite of each period.