天然气超深井井底压力计算与应用

On Bottom-Hole Pressure Calculation of Ultra-Deep Natural Gas Wells

钻井液喷空后的井底压力可以精确计算,为正确地保证井底压力大于或等于地层压力提供了科学的数据。钻井液喷空后的深井超深井的天然气井,关井后的静气柱压力不是很小。井内有钻井液(或修井液)井底进入天然气时,井底压力在合理地处理井内天然气在井内的运移(体积法放压法)与二次循环法压井循环出进入井内的天然气是相同的,为钻井井控现场为避免压裂套管鞋处或地层压力低的地层提供了可靠的依据。

Bottom--hole pressure without drilling fluid can be accurately calculated to provide the scientific information for ensuring a bottom--hole pressure greater than or equal to formation pressure. Shut--in static gas pressure is not very small in deep or ultra--deep natural gas wells without drilling fluid. The bottom--hole pressure is the same while volumetric pressure release method or two--cycle method is used to deal with downhole natural gas, providing a reliable basis for avoiding fracturing on casing shoe or on the formation with low pressure.