鄯善油田三间房组油藏油水界面分布状态的主导因素分析

近期的新钻加密井发现鄯善油田三间房组油藏油水界面与开发初期所认为的形态有明显不同.通过对油水界面分布情况及地层水矿化度、化学成分、水型等方面的研究,认为造成这种状况的主导因素是鄯善油田正好位于地下水排泄区内,地下水自西北部侵入鄯善油田,使西区、北区油水界面严重抬升,地层水矿化度及化学成分也发生了相应的变化.这对确定新钻加密井井深,提高水淹层解释符合率具有现实的指导作用.

Analysis of dominant factors of the oil-water interface in the oil reservoir of Sanjianfang Formation, Shanshan Oilfield

Shanshan Oilfield lies in Taibei Sag of Tuha Basin.The regional groundwater in this sag is gravity flow,and it flows from north to south.The recharge area of the groundwater is in the Bogeda mountain front zones in northern Taibei Sag and the drainage area is in the north border of the central faulted zone of Taibei Sag.From the recent drilling data of infill wells,it is found that there is an obvious difference between the recent cognition and the original cognition of the oil-water interface.Through analyses of the oil-water interface distribution and the salinity,chemical composition and type of the groundwater,it is held that the difference is caused by the rise of the oil-water interface.Shanshan Oilfield is just in the drainage area of the groundwater,and the groundwater flow into the oilfield from the north-western basin,which makes the oil-water interface in the western and northern parts rise and makes the salinity and chemical composition of the groundwater changed.The finding can provide guidance for determining the depth of infill wells and improving the precision of the interpretation of water-flooded reservoirs.