构造抬升剥蚀与异常压力形成

Relationship between tectonic uplifting & erosion and formation of abnormal pressure

包友书

Bao Youshu

根据物理化学原理,建立了完全封闭条件下构造抬升剥蚀后地层流体压力的定量计算公式。公式显示,在完全封闭条件下构造抬升后的地层压力取决于抬升前的地层压力、地层流体的压缩系数、地层流体的膨胀系数、岩石孔隙体积的压缩系数、抬升前后地层温度的变化和剥蚀厚度。根据流体的压缩系数和膨胀系数及岩石孔隙体积压缩系数的特点,经分析认为对于水层砂岩岩体,构造抬升剥蚀趋向于形成异常低压;对于气层,构造抬升剥蚀趋向于形成异常高压。

Based on the principles of physical chemistry,a formula is established for quantitatively calculating formation fluid pressure after tectonic uplifting and erosion in a closed system.The calculation results with the formula show that formation pressure after tectonic uplifting and erosion in a closed system depends on such factors as initial formation pressure before tectonic uplifting,compressibility coefficient and expansion coefficient of formation fluid,compressibility coefficient of pore volume,temperature variation before and after uplifting,and erosion thickness.An analysis of compressibility coefficient and expansion coefficient of formation fluid as well as compressibility coefficient of pore volume reveals that an abnormal low pressure is likely to be formed in water-bearing sandstone formations,while an abnormal high pressure is more possible in gas-bearing formations after the uplifting.

10.11743/ogg20090602