断层开启与封闭的定量分析

断层的开启与封闭性与断面正压力和流体压力的耦合关系有关,据此可建立断层开启与封闭的定量数学模型,并可计算断层的封闭系数。根据模型,影响断层开启和封闭的因素主要有构造应力,断层的走向、倾角、深度,两盘岩性,流体压力等。研究表明,随着异常流体压力系数的增大、构造挤压力的减小、岩石泊松比的减小,断层的封闭性都会降低。另外,断层倾角和深度对断层封闭性的影响受构造应力性质控制,在张性盆地中,断层的封闭性随着深度的增加而增加,随倾角增大而减小;在压性盆地中则相反。断层走向对断层封闭性的影响随差异应力增大而增强。

QUANTITATIVE ANALYSIS OF FAULT OPENING AND SEALING

The opening and sealing properties of faults are closely related to reservoir formation or destruction.Based on the coupling of pressure of fault surface and fluid pressure,a quantitative mathematical model of the fault opening and sealing is developed,and the fault sealing coefficient could be calculated.The factors influencing the fault opening and sealing properties include structural stress,strike,dip angle and depth of the fault,the lithology of each wall and fluid pressure.Fault sealing property decreases as fluid pressure coefficient increases,structural compress stress and Poisson's ratio decrease.The influence of dip angle and depth of the fault on the sealing property is controlled by structural stress.