地质钻探复杂地层固壁堵漏新工艺

基于现有地质钻探护壁堵漏技术手段的局限性和约束性,本文提出一种新的复杂地层固壁堵漏工艺。在钻遇松散破碎地层的孔段时,将一个喷嘴下入孔内,到达松散破碎段附近,然后把浆液高速、均匀地喷射在其周围,达到加固孔壁、堵塞漏失通道的效果。通过三维建模软件Solid Works建立此喷嘴的4种模型,并使用CFD软件Flowsimulation对4种模型进行了模拟和分析;通过改变喷嘴出口角度,对喷嘴内流体流场速度、压力等物理量进行仿真分析。结果表明:进口体积流量为50 L/min时,除了出口角度为60°的模型出口端泄压较为严重外,其余3种模型喷嘴内部压力分布基本无变化;出口角度不同的喷嘴其喷射速度差异明显,出口角度为30°时,喷嘴的喷射速度最大,达到1.25 m/s,使浆液能够喷射渗入地层进行有效地固壁堵漏。

New technology of geological drilling for borehole-wall reinforcement and leaking stoppage in complex formation

In view of the limitation and constraints of the currently existing methods for borehole-wall reinforcement and leaking stoppage in geological drilling, this work proposes a new complex solid wall plugging procedure. In this approach, when drilling a hole section in a loosely fractured stratum, a nozzle is placed into the hole. It reaches near the loose broken section, and then spraying the slurry at high speed and evenly around it, realizing the effect of reinforcing the hole wall and blocking the leaking path. Four models of the nozzle were established by 3D modeling software SolidWorks, on which simulation and analysis are performed by CFD software Flowsimulation. The physical quantities such as fluid velocity and pressure in the nozzle are simulated and analyzed by changing the nozzle exit angle. The results show that when the inlet volume flow rate is 50L/min, except for the relief pressure at the outlet end of the model with an exit angle of 60°, the internal pressure distribution of the other three models is largely unchanged and the nozzles with different outlet angles have different jetting speeds. When the outlet angle is 30°, the jetting speed of the nozzle is the largest, reaching 1.25 m/s, thus the slurry can be sprayed into the formation to effectively stabilize the wall and plug the leakage.