泥岩地层产水与地层异常压力原因分析

ANALYSIS ON WATER CUT IN MUDSTONE AND THE ABNORMAL FORMATION PRESSURE

泥岩是碎屑岩的一种,有孔隙度,也有渗透率,但因孔隙开度较小,其渗透能力极差。泥岩可以疏导地层水,只是疏导能力差而已。一些油井投产初期产出的微量水来自于储集层上下两侧的泥岩地层,而非原油溶解的地层水。异常地层压力是由突发地质事件所致,是一种暂时的压力状态,泥岩还没有足够的时间将其平衡。

Mudstone is a kind of clastic rock, which possesses pores and porosity, there is also permeability, but its permeability is quite poor due to the extremely small openness of pores. Mudstone can definitely transport water with poor permeability. Oil wells usually produce a little quantity of water at beginning of production, which comes from the mudstones lying over and under the reservoirs, not the formation water dissolved in crude oil. The abnormal pressure in formations is resulted from the geological accidents, and is a temporary status of pressure, which is so far not balanced by water transportation in mudstones during short time.