高温热田井筒热力学及地层参数计算方法

在高温热田的井孔施工及测试实践中,通常由于高温热水在地层或井简内闪蒸汽化,形成复杂的两相流动而无法直接从单井放喷资料中计算地层参数。西藏羊八井属于高温热水型地热田,第四系热储内热液温度约介于140—155℃之间,埋藏深度大略为70—200米左右,井口闭井压力大多在2—4个大气压之间。热储流体在上述深度、温度和压力的配置下,在地层内处于单相液态,而在开发动态下则在大部分井筒上部达到饱和点而汽化,形成相对稳定的汽化面,构成双相流和单相流之间的界面。

WELLBORE THERMO-DYNAMICS AND THE METHOD OF RESERVOIR PARAMETER CALCULATION IN HIGH TEMPERATURE GEOTHERMAL FIELD

The author,using the wellhead parameters obtained in single well-blowing test: working pressure,total flow rate of water and vapor,wellhead temperature,of the Yangbajing geothermal field,Tibet,in conjunction with the wellhead shut-in pressure,flowing temperature in the wellbore,reservoir and well structure parameters,has worked out a method of determining first the flashing level in wellbore and corresponding saturation pressure using a trial-graphic method,then the reservoir rock permeability,working pressure drop and skin effect,solving a set of simultaneous equations.The results of calculation are in good agreement with the field data.