库车前陆盆地构造压实作用及其对储集层的影响

库车地区存在强烈的构造压实作用,对储集层分布及品质产生了重大影响.在分析构造压实测井响应基础上,建立了古构造应力定量评价模型,然后依据测井信息确定古地应力分布,分析构造压实作用对储集层的影响.构造压实作用对储集层物性的影响具有两面性:一方面随着构造应力增大,构造压实作用和构造成岩作用加强,储集层孔隙度,渗透率降低,尤其是渗透率下降显著;另一方面随着构造挤压作用增强,砂岩致密化程度增强,砂岩中易于发育裂缝,从而形成渗滤性能良好的裂缝性储集层.此外,封闭构造压实作用形成了本区高压一起高压流体压力,这种高异常流体压力的存在抵消了部分压实作用对储集层的影响,使储集层承载的有效应力降低,从而为储集层保持较高孔渗性创造了有利条件.

Tectonic compaction and its influence on reservoirs in the Kuqa foreland basin, Tarim

Tectonic compaction has great influence on reservoir properties in the Kuqa foreland basin. On the basis of logging responses to tectonic compaction, quantitative models were set up to determine the magnitude of palaeotectonic stress by logging data and analyze the influences of tectonic compaction on reservoirs. The influences showed dual nature: With intense tectonic compaction, both porosity and permeability become worse and worse, in particular, permeability is more sensitive to tectonic stress. On the other hand, with intense tectonic compaction, sandstone becomes densified and fractures occur, resulting in fractured reservoirs with high production. In addition, in this basin the fluid is characterized by high or hyper-high pressures. Sealing tectonic compaction contributes mainly to the abnormal fluid pressures. This provides a favorable foundation for reservoirs to keep higher porosity and permeability.