高酸性气井钻井过程中的井控机理  

MECHANISM OF WELL CONTROL DURING DRILLING IN SOUR GAS WELLS

作　　者：张智[1] 付建红[1] 施太和[1] 袁长帅[2] 史学枝[2] 

机构地区：[1]“油气藏地质及开发工程”国家重点实验室·西南石油大学 [2]中国石化西南油气分公司

出　　处：《天然气工业》2008年第4期56-58,共3页Natural Gas Industry

基　　金：中国石油天然气集团公司应用基础研究项目(编号:06A100101);四川省应用基础研究项目(编号:07JY029-043)的资助

摘　　要：川东北高含硫气田的CO2、H2S含量较高,部分气井中的CO2、H2S已处于超临界状态。CO2、H2S在环空流动过程中离井口很近的距离才发生体积突变,极易诱发井喷。为此,从分析超临界状态CO2、H2S的特殊相态特征入手,建立了相应的数学模型,编写了计算机程序,模拟了高酸性高压气井环空温度场、压力场、压缩因子和体积膨胀情况。从模拟计算结果可以看出,在深井中,常规天然气的溢流通常有足够的预警时间,而高酸性气体则在井筒的上部位置发生突然膨胀,引起的天然气溢流几乎没有预警时间。在高酸性气井钻井过程中,需要加强对环空钻井液瞬时流量的监测,尽早发现溢流,确保安全钻井。The content of CO2 and/or H2S is so high even to the supercritical state in some sour gas wells in the northeastern Sichuan basin.The volume of CO2 and H2S only expand abruptly when returning very close to the wellhead in the annulus,which often induces blowouts.In this paper the corresponding mathematical model has been established and a software program developed based on the analysis of the special phase behavior of supercritical CO2 and H2S.And the annular temperature field,pressure field,compressibility factor and volumetric expansion in critical sour gas wells have been simulated.The results indicate that there is enough time to warn overflows in conventional deep gas wells,while there is hardly sufficient time to warn gas overflows in sour gas wells due to the abrupt expansion of sour gas in the upper annulus.So the monitoring of instantaneous flow rate of drilling fluid in annulus should be stressed during drilling of sour gas wells in order to detect the overflow as early as possible to ensure safe drilling.

关 键 词：天然气 酸性气体 二氧化碳 硫化氢 井喷 井控 四川盆地 东北 

分 类 号：TE24[石油与天然气工程—油气井工程]