环空液体它激振荡脉冲射流数值模拟

DATA SIMULATION ON ALLOGENIC EXCITING OSCILLATION PULSE JETTING FLOW OF ANNULUS FLUID

钻井过程中,对于如何利用井下环空液体的水力能量问题是钻井界关注的重大理论与实践问题。为此,利用这个水力能量作为它激源,形成它激振荡脉冲射流的方法,基于流体动力学、瞬变流和边界层理论,采用CFD软件,对它激共振腔的流体流动特征、几何参数和流体参数进行了数值模拟。结果表明,在相同条件下,它激振荡自增流量可达20%左右,出口动压力比自激振荡脉冲射流提高一倍左右,环空返速对自增流量的影响极小,模拟结果与实验结果十分吻合,提高了井底辅助破碎岩石的水力能量。在此基础上,对它激共振腔的结构参数进行了优化设计,为开发新产品提供了理论依据。

How to utilize downhole hydraulic power of annu-lus fluid is a priority theoretical and practical issue in drilling field.Based on theories of rheology,transient flow and bordered layer,utilizing CFD software and the method of using hydraulic power as allogenic exciting source to get pulse jetting flow,the flow character,geometry parameter and fluid parameter of the fluid in the allogenic exciting oscillation cavity has been simulated.The simulated result was quite coincident with experimental one under the same condition,and in which the flow capacity of allogenic ex-citing oscillation increased by 20%,outlet pressure increased by 100% over self- exciting oscillation pulse jetting flow condition.The influence of annulus flow back velocity on flow capacity was minimal and the downhole hydraulic power for rock cracking - aid has been improved.Furthermore,the structure design of allogenic exciting resonance cavity has been optimized and the theoretical basis for new products development has been provided as well.