Efficient cuttings transport and improving rate of penetration (ROP) are two major challenges in horizontal drilling and extended reach drilling. A type of jet mill bit (JMB) may provide an opportunity to catch the two birds with one stone: not only enhancing cuttings transport efficiency but also improving ROP by depressuring at the bottom hole. In this paper, the JMB is further improved and a new type of depressure-dominated JMB is presented; meanwhile, the depressurization capacity of the depressure-dominated JMB is investigated by numerical simulation and experiment. The numerical study shows that low flow-rate ratio helps to enhance the depressurization capacity of the depressure-dominated JMB; for both depressurization and bottom hole cleaning concern, the flow-rate ratio is suggested to be set at approximately 1:1. With all other parameter values being constant, lower dimensionless nozzle-to-throat-area ratio may result in higher depressurization capacity and better bottom hole cleaning, and the optimal dimensionless nozzle-to-throat-area ratio is at approximately 0.15. Experiments also indicate that reducing the dimensionless flow-rate ratio may help to increase the depressurization capacity of the depressure-dominated JMB. This work provides drilling engineers with a promising tool to improve ROP.

高效的钻屑运输和提高的钻速（ROP）是水平钻井和大范围钻井的两个主要挑战。一种喷射式铣刀（JMB）可能会提供一个机会，用一块石头抓住两只鸟：不仅可以提高切屑的输送效率，而且可以通过降低井底压力来提高ROP。本文对JMB进行了进一步的改进，并提出了一种新型的以减压为主的JMB。同时，通过数值模拟和实验研究了以减压为主的JMB的降压能力。数值研究表明，低流量比有助于提高以减压为主的JMB的降压能力。考虑到减压和井底清洁问题，建议将流量比设置为大约1：1。在所有其他参数值保持不变的情况下，较低的无量纲喷嘴与喉咙面积之比可能会导致更高的降压能力和更好的井底孔清洁，并且最佳无量纲的喷嘴与喉咙面积之比约为0.15。实验还表明，降低无量纲流量比可能有助于增加以减压为主的JMB的减压能力。这项工作为钻井工程师提供了改善ROP的有前途的工具。实验还表明，降低无量纲流量比可能有助于增加以减压为主的JMB的减压能力。这项工作为钻井工程师提供了改善ROP的有前途的工具。实验还表明，降低无量纲流量比可能有助于增加以减压为主的JMB的减压能力。这项工作为钻井工程师提供了改善ROP的有前途的工具。