微流量控压钻井中节流阀动作对环空压力的影响  

Effect of Choke Valve Action on Annular Pressure with Micro-Flux Control in MPD Drilling

作　　者：孔祥伟[1] 林元华[1] 邱伊婕[1] 

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),四川成都610500

出　　处：《石油钻探技术》2014年第3期22-26,共5页Petroleum Drilling Techniques

基　　金：国家科技重大专项"微流量地面自动控制技术研究"(编号:2011ZX05022-005-005HZ)部分研究内容

摘　　要：为解决窄安全密度窗口的复杂压力剖面问题,基于质量守恒方程及动量守恒方程,建立了节流阀动作引发的环空波动压力模型,并应用中心差分法对模型进行了求解。研究表明,随钻井液排量增大、节流阀动作时间减小,环空所受波动压力呈增大趋势;阀芯所受波动压力大于环空段;钻井液排量从36L/s增至56L/s时,阀芯所受波动压力峰值从1.26MPa增至1.56MPa,钻铤段波动压力峰值为0.22MPa;节流阀动作时,套管鞋处引发故障的概率比井底高至35%。研究结果表明,两步、多步线性关阀较一步关阀,不但关阀手段灵活,更可有效减小环空波动压力峰值。To address effectively the complex pressure profile with narrow density window ,the effects of choke valve action on fluctuation pressure in annulus have been studied during drilling operations .Based on the mass and momentum conservation equations ,the model was established to simulate fluctuation pres-sure in annulus caused by choke valve action ,and calculated by central difference method .In the calculation example ,the fluctuation pressure in annular space will be higher with the increases of flow rate and the shorter time of choke valve action .The fluctuation pressure in the valve core is higher than that in the an-nulus ,and the maximum fluctuation pressure increased from 1.26 MPa to 1.56 MPa with the flow rate of drilling fluids increased from 0.036 m3/s to 0.056 m3/s .The maximum fluctuation pressure is 0.22 MPa in drill collar section .When adjusting choke valve ,the trouble probability at the casing shoe is 35% greater than that at the bottomhole .The research results indicate that the two-step or multi-step valve closing line-arly is more flexible than the one-step valve closing ,and can effectively lower the peak fluctuation pressure in annular space .

关 键 词：流量控制 节流阀动作 特征线法 波动压力 控压钻井 

分 类 号：TE254[石油与天然气工程—油气井工程]