低渗透储集层中的泥岩裂缝储集体

在低渗透储集层中,由于泥岩夹层的成份不纯,常含灰质、云质、钙质等脆性矿物,极大地提高了泥岩的脆性程度,它们在构造应力作用下容易形成裂缝,使泥岩中构造裂缝较发育。泥岩层中不同组系与不同倾角的构造裂缝和非构造裂缝相互沟通,常组成裂缝三维网络系统,使泥岩夹层的渗透性大大增加,泥岩中裂缝一般具有较好的含油性。因此,低渗透储层中的泥岩一般不能起真正的隔层作用,应划分为准储层或泥岩裂缝储集体,其油藏类型为块状油藏。

FRACTURES IN THE MUDSTONE OF TIGHT RESERVOIRS

In tight reservoirs,lime,mica,calcareous and other brittle mineral often exist because the composition of mudstone interbeds is impure.This greatly heightens the brittle degree of mudstone,and makes it liable to form fractures under tectonic stress.So tectonic fractures are relatively developed in mudstone.Different series and different dips of tectonic fractures in mudstone interbeds are interconnected with nontectonic fractures often to form the 3 D network ststem of fractures.This makes the permeability of mudstone interbeds greatly increased and the fractures in mudstone commonly have better oil bearing features.Thus,the mudstone in tight reservoirs generally cannot perform a true sealing function and can be classified as quasireservoirs or fractures reservoirs of mudstone.Their accumulation patterns are massive.