大牛地气田致密砂岩优质储分布预测

Prediction of High Quality Reservoir’s Distribution in Tight Sandstone in Daniudi Gas Field

摘要: 综合运用薄片观察、测录井数据以及试油试采数据，明确了鄂尔多斯盆地北部大牛地气田上古生界石炭系太2段优质储层的控制因素。利用测井数据反演实现不同岩相和成岩相的平面分布的预测，同时结合产能特征，明确了相对优质储层的分布规律。研究表明：大牛地气田上古生界石炭系太2段优质储层整体受控于相对粗粒岩相和优势成岩相的分布，呈现“岩相控制优质储层分带性”和“成岩相主导区带内优质储层再分布”的特点。粗粒岩相是致密储层中相对高产的标志，高产气层整体受控于粗粒岩相(厚度>7 m)，而低产气层整体受控于中粒岩相(厚度>12 m)的分布。在中粒岩相控制区，溶解成岩相进一步控制气层的分布。

Abstract: Based on the observation of thin sections, logging data and oil test data, the paper reveals the control factors on the high quality reservoir in the Second Member of Carboniferous Taiyuan Formation (C3t2) of the Upper Paleozoic in Daniudi Gas Field, and explicates the prediction of horizontal distribution of reservoir’s accumulated thickness of different types of lithofacies and different types of diagenetic facies by the inversion of logging data, and summarizes the distributional principle of high quality reservoirs. The results show that: the high quality reservoirs in the C3t2 in Daniudi Gas Field are mainly controlled by the lithofacies and diagenetic facies and present the patterns of “lithofacies controlling the districts of high quality reservoirs” and “diagenetic facies controlling the redistribution of high quality reservoirs”. The remarkable symbols are the centres of accumulative thickness of those two diagenetic facies. The high capacity gas-bearing layers are controlled by the thickness of coarsed lithofacies (>7 m) and the low capacity gas-bearing layers are controlled by the accumulative thickness centres of medium-grained lithofacies (>12 m), among which the dissolution diagenetic facies controls the further distribution of gas-bearing reservoirs.