基于自适应观测器的控压钻井气侵早期检测方法

打开文本图片集

中图分类号：TE928 文献标志码：A

Abstract：Drilingintoformations with narrowsafety presure windowsmayleadtoabnormaldownholeconditionssuchasgas kick．Aimingatgasickearlydetectioninthemanagedpressuredrilingprocess，anadaptiveobserverisappiedtoestimate downholeuncertainparametersandunknownstates，andbasedonthis，agas kickdetection method is established.Asimplifiedgas-liquidtwo-phaseflowmodelisestablishedbasedonthe"dual-shape"bubblerepresentationapproach，andiscomparedwithOLGAsimulationdatatoverifythevalidityofthemodel.ALuenberger-likeadaptiveobserverisdesignedandappliedtoestimatethekeyparametersandstatesofdownholegaskickconditions，thenagaskickdetectionmethodisconstructed bycombining the Hotelling's T2 test statistics.The results indicate that the designed adaptive observer canreal-timely estimate thegasvolumeandacurately track changesofbottomhole pressureandoutletflowrate.Compared withacoustic method，deltaflowmethodandpitvolumemethod，thegas kickdetectionmethodcanquicklyandsignificantlyachieveearly detection of different gas kick situations.

Keywords：gaskick；managed pressuredriling；adaptiveobserver；uncertainparameters；gas-liquid two-phase flow； test statistic

钻遇窄安全压力窗口地层时，易出现气侵等井下异常工况，严重威胁着钻井安全[1]。（剩余13608字）