塔里木山前区块超深井尾管塞流固井技术

克深905井是克深气田克深9井区中部的一口开发评价井，四开完钻需进行尾管固井，井深为7368.2m，井底静置温度为164℃，压力为180MPa，在钻进过程中易发生溢流、井漏等复杂情况，且环空间隙小，安全密度窗口窄，为保证固井质量，防止井漏发生，全程采用塞流注替。根据现场水泥浆情况进行了水泥浆流变学设计和塞流顶替计算；优选了抗高温、抗盐高密度水泥浆体系及与钻井液相容性好的冲洗型隔离液；设计了能够压稳地层密度为2.58g/cm3的抗高温水泥浆；对现场泵压与返出量进行了实施监控。现场固井过程中未发生漏失，施工顺利，所封固井段的固井质量合格率为99.2%，该井尾管塞流顶替为中国首次在井深7368.2m的井段使用。 

Plug Flow Liner Cementing Technology for Ultra Deep Well in Piedmont Tarim

The well Keshen-905 is an appraisal well drilled in the middle of the block Keshen-9, Keshen gas field, the fourth interval of which was going to be cemented with liner string. The well is 7,368.2 m in depth, and has bottom hole static temperature of 164℃ and pressure of 180 MPa. Well flow and mud losses have been encountered during drilling. Narrow annular space and small difference between the formation pressure and the pressure at which mud loss will occur all contribute to lost circulation during well cementing. To ensure the quality of well cementing and prevent lost circulation, plug flow was adopted in the whole process of cementing. In field operations, cement rheology was designed and plug flow calculated. The cement slurry was designed to be used at high temperature and have salt contamination tolerance, and high density (2.58 g/cm3). A flushing spacer compatible with drilling fluid was used. Monitoring of pump pressure and the volume of cement slurry returned showed that no lost circulation had ever happened during cementing. 99.2%of the hole cemented had job quality passed the requirements.