一种转化钻柱振动能量的井底高压喷射钻井装置

A downhole high-pressure jet drilling device transforming drilling string vibration energy

通过转化井下钻柱振动能量来增加井底钻井液喷射压力是提高钻井速度的重要途径,而现有技术还未能充分合理地利用钻柱振动能量。为此,基于井下钻柱振动能量的利用理论,提出了钻井液井下增压、增排量的井底高压喷射钻井理念,设计出了井底高压喷射钻井装置,并对其进行了数值仿真研究。结果表明:(1)井底高压喷射钻井装置可以将钻柱振动能量有效转化给井底钻井液从而实现井下高压喷射钻井;(2)井底高压喷射钻井装置增加了喷嘴钻井液过流流量,在?215.9 mm井眼中,其输出的钻井液流量可以提高5 L/s;(3)增大了钻井液喷射压力,喷嘴处钻井液脉冲压力最高达到11.3 MPa;(4)深井内井底高压喷射钻井装置应用效果比上部地层更加显著。结论认为,井底高压喷射钻井装置为高压喷射钻井技术的实现提供了一种新的手段,可以解决现有高压喷射钻井技术设备费用昂贵、安全性差、适用范围有限的问题。

The important way to improve the rate of penetration （ROP） is to increase the jet pressure of downhole drilling fluid by trans- forming the vibration energy of downhole drilling string. However, the existing technologies cannot make full use of the vibration energy of drilling string rationally. In this paper, the concept of downhole high-pressure jet drilling to increase the downhole pressure and dis- placement by using drilling fluid was put forward based on the utilization theory of vibration energy of downhole drilling string. Then, a bottom-hole high-pressure jet drilling device was designed and numerically simulated. It is shown that via this device, the vibration energy of drilling string can be transformed effectively to the drilling fluid at the bottom hole, so that downhole high-pressure jet drilling is realized; that via this device, the flow rate of drilling fluid through the nozzle is increased, in a O215.9 mm borehole, for example, the outflow rate of drilling fluid can be increased by 5 L/s; that the jet pressure of drilling fluid is increased and the pulse pressure of drilling fluid at the nozzle is up to 11.3 MPa; and that the application effect of this device in deep formations is more remarkable than that in shallow formations. It is concluded that downhole high-pressure jet drilling device provides a new means for the realization of high-pressure jet drilling technology, and it can solve the problems in high-pressure jet drilling equipments, such as high cost, poor security and limited application ranges.