不同储量丰度气藏形成的盖层封闭有效能力——以松辽盆地徐家围子断陷气藏为例

Cap Rocks Effective Sealing Capacity of Different Reserves Abundance Gas Reservoirs formation:a Case Study of Gas Reservoirs in Xujiaweizi Depression Songliao Basin

通过徐家围子断陷18个气藏盖层封闭性解剖得到,盖层对天然气封闭能力的好坏主要取决于其封闭有效能力,即盖层与储层排替压力差与气藏剩余压力的相对大小。盖层封闭有效能力大于或等于零,有利于气藏中天然气的聚集与保存;反之则不利于气藏中天然气的聚集与保存。徐家围子断陷18个气藏盖层封闭有效能力均大于零,有利于天然气的聚集与保存。通过徐家围子断陷18个气藏储量丰度与盖层封闭有效能力之间关系研究得到,二者为正相关关系,即随着盖层封闭有效能力增强,气藏储量丰度增高,反之则降低。要形成高储量丰度的气藏,盖层封闭有效能力应大于5.6 MPa,形成中等储量丰度气藏盖层封闭有效能力应介于2.50—5.6 MPa。

Though sealing capability dissection of 18 gas reservoirs cap rocks,cap rocks sealing capability is depended on their effective sealing capacity are considered,that is,the relative size of cap rocks and reservoirs displacement pressure difference and gas reservoirs excessive pressure,and if more than or equal to zero effective sealing capacity of gas reservoirs is good for natural gas accumulation and preservation,either not.effective sealing capacity of 18 gas reservoirs in Xujiaweizi depression are more than zero,in favor of natural gas accumulation and preservation.Reserves abundance of 18 gas reservoirs and effective sealing capacity of cap rocks is positive correlation by the study of their relation,that is,With the effective sealing capacity,the reserves abundance of gas reservoir increasing,either not.To form gas reservoirs with high reserves abundance,be more than 5.8 MPa,and to form gas reservoirs with middle reserves abundance,effective sealing capability of gas reservoirs cap rocks should be the range of between 2.50 MPa and 5.6 MPa.