摘要
鉴于世界上极大多数盆地模拟系统的超压史尚未达到实用水平,本文基于力平衡方程、质量守恒法则及达西定律,完整地推导出了与温度全相关的有效骨架压力史的数学模型,使之适用于盆地模拟。通过塔里木盆地库车坳陷的实际模拟,尤其是克拉2井和依南2井超压史的现今值接近于实测数据,即平均相对误差绝对值分别约为3%和5%,证明该有效骨架压力模型具有较高的精度,既能使超压数值模拟避免通过岩石力学实验来测试有效骨架压力,又能达到实用水平。库车坳陷的实例指出:1)在有效骨架压力计算中所用的孔隙流体的密度和黏度与温度相关是必要的,否则超压计算结果会远离实测压力数据。这也恰好与盆地模拟中这两个参数原本与温度相关一致了;2)影响超压的最敏感参数是渗透率,将实测压力数据作为约束条件,在容许的范围内对Kozeny-Carman渗透率公式中的Sa(骨架的颗粒比面)进行校准,这是获得正确的超压史之关键;3)剥蚀事件对地史、热史乃至超压史的模拟结果的影响。
Since the overpressure history in most basin modeling system has not attained a level of practical usefulness, fully temperature-dependent model of the effective solid matrix pressure is integrally deduced based on the force balance equation, mass conservation and Darcy＇s law,which might be capable of being used in basin modeling. The application of the model to the Kuqa Depression of the Tarim Basin, and especially the ease that the present-day values of overpressure histories of the Wells Kela 2 and Yinan 2 approaching the field-measured data with the mean absolute relative residuals of approximately 3% and 5% respectively,proved that this effective solid matrix pressure model should be of higher accuracy. This indicated that the overpressure simulation was a practical alternative to using rock mechanics experiments for effective pressure measurement. The ease studies showed that the pore fluid density and viscosity used in the calculation of effective solid matrix pressures should be temperature-dependent, otherwise the calculation results of overpressures would deviate far from the field-measured pressure data. This was consistent with the temperature-dependency of the two parameters in real life. The case studies also showed that the most sensitive parameter governing overpressure was permeability. Furthermore,it was vital for calculating an accurate overpressure history that one could calibrate S （the specific surface area of the solid matrix） in allowable range in the Kozeny-Carman permeability formula by using field-measured pressure data as a constraint. The ease studies indicated the effects that erosional events had simulation results on the geohistory,geothermal history and overpressure history.
出处
《地质科学》
CAS
CSCD
北大核心
2008年第4期798-809,共12页
Chinese Journal of Geology(Scientia Geologica Sinica)
关键词
有效骨架压力方程
超压方程
实测压力约束
渗透率校准
盆地模拟
库车坳陷
Effective solid matrix pressure equation, Overpressure equation, Field- measured pressure constraint, Permeability calibration, Basin modeling, The Kuqa Depression
