海上HTHP气井井口关井冲击效应与井底压力的准确计算  

Offshore HTHP well shut-in impact effect and accurate calculation of bottom hole pressure

作　　者：熊钰 白坤森 李丹 XIONG Yu;BAI Kun-sen;LI Dan(Petroleum Engineering College of Southwest Petroleum University,Chengdu 610500,China;Coalbed Methane Company Limited,Xiʼan 710000,China;China National Offshore Oil Corporation,Beijing 100020,China)

机构地区：[1]西南石油大学石油与天然气工程学院,成都610500 [2]中石油煤层气有限责任公司,西安710000 [3]中海石油气电集团有限责任公司,北京100028

出　　处：《水动力学研究与进展（A辑）》2019年第6期803-813,共11页Chinese Journal of Hydrodynamics

基　　金：国家自然科学基金项目(51534006);四川省应用基础研究项目(2019YJ0424)~~

摘　　要：受井深结构影响,海上大斜度井和水平井压恢测试时压力计难以下到井底,同时受海水对流换热、大气辐射,相再分布以及水击效应等的影响,井口压恢曲线常呈现规律性的波动和下降趋势。采用传统静压力模型往往使得关井初期井底压力计算过小,给试井解释带来了很大困难。在井底压力温度耦合计算控制方程的基础上,通过建立单相气体波速模型,实现了对高温高压气井井口快速关井恢复时水击效应中气流动能的损失、水击波传递速度和摩阻损失的定量描述,采用特征线法对方程进行改进求解,使模型能够准确计算井筒不同位置处续流量的变化。计算结果表明,随井深增加,压力恢复开始时间越慢,水击强度越弱;关阀速度越慢,井口压力上升越慢,水击强度越弱,持续时间越短;井底续流量在短时间内迅速下降且可能呈现波动变化。进一步考虑多重效应耦合的模型可消除温度、续流和水击效应等对井口关井初期井口压力过度上冲的影响,利用井口压力计算的井底压力精度达到5‰以内,计算结果可以用于试井解释。Because of the wellbore structure of highly-deviated wells and horizontal wells,the pressure gauge is difficult to reach the bottom of the wells during productivity tests.At the same time,influenced by convective heat transfer,atmospheric radiation,phase redistribution and water hammer,the restore curve of wellhead pressure often presents the regularity of the wave and downward trend.The traditional static pressure model often makes the calculation of bottom hole pressure too small at the initial stage of shut-in,which brings great difficulty to well test interpretation.By establishing the single phase flow wave velocity model and using the characteristic line method to solve the modified control equations,meanwhile coupling with the temperature and pressure models,the loss of gas kinetic energy,the transmission of the water hammer waves and the viscous dissipation are quantitative description.In addition,the model can also be used to accurately calculate the continuous flow at different positions of wellbore.The calculation results show that with the increase of well depth,the starting time of pressure recovery is slower and the strength of water hammer is weaker.The slower the valve closing speed is,the slower the wellhead pressure rises,the weaker the water hammer intensity and the shorter the duration.And the afterflow rate at downhole drops rapidly and shows fluctuations in a short period of time.The coupling model considering multiple effects eliminates the effects of temperature,flow continuity and water hammer,and can achieve satisfactory calculation accuracy.The results can also be used for well test interpretation.

关 键 词：气井 压力 水击效应 续流量 试井解释 

分 类 号：TE3[石油与天然气工程—油气田开发工程]