Wear Behaviors of AISI 4145H Drilling Tool Steel under Drilling Fluid Environment Conditions.

Changsheng Yue,Lingrong Kong,Yu Wang,Zhijian Peng,Chenfan Liang,Hong Cai

doi:10.3390/ma15031221

Abstract

4145H steel is a commonly used material for downhole tools. However, up to now the wear behavior of 4145H drilling tool steel under real drilling fluid environment conditions is still not clear. In this work, this was investigated using a modified ASTM B611 rubber ring wet grinding test system, in which six kinds of abrasives (talc, dolomite or fluorite, as well as their mixed abrasive with quartz) with metal hardness-to-abrasive hardness ratios (H/HA) ranging from 0.25 to 6.25 were used in the drilling fluid for experiments. The results show that the H/HA value determined the wear mechanism of 4145H steel. When a single soft abrasive was used (with H/HA higher than 1.3–1.5), polishing was the dominantly observed mechanism. While mixed abrasives were applied, a microcutting mechanism due to the ploughing of hard abrasive particles on the steel surface was also observed. The increase in mass fraction of the soft abrasives has little effect on the wear rate of 4145H steel, but its wear rate will significantly increase as the mass fraction of hard abrasives increases. Therefore, in order to extend the life of drilling tools and reduce downhole accidents, the mass fraction of hard particles in the drilling fluid should be reduced as much as possible.

Highlights

With the increase of drilling depth in oil and gas exploration, the failure of downhole drilling tools due to the wear, corrosion and erosion by drilling fluid has become a challenge that cannot be ignored [1,2], as they will shorten the service life of drilling tools and increase drilling costs [3,4,5,6]
4145H steel (Hebei Lisen Petroleum Machinery Co., Ltd., Cangzhou, China) with high strength and excellent comprehensive mechanical properties was selected for the experiment, which is an international general oil drilling tool steel certified by the American
It can be seen that when the same kind of abrasive is used, as the sliding distance extends, the wear rate of the specimen does not change significantly with the increase in the abrasive mass fraction

Summary

Introduction

With the increase of drilling depth in oil and gas exploration, the failure of downhole drilling tools due to the wear, corrosion and erosion by drilling fluid has become a challenge that cannot be ignored [1,2], as they will shorten the service life of drilling tools and increase drilling costs [3,4,5,6]. One of the main ways of wear is caused by abrasive wear against solid particles contained in the drilling fluid [7,8,9,10]. Investigating the wear mechanism of drilling tool steel exposed to various particles in the drilling fluid is essential to predict the life of the tools. The solid particles in the mud mainly include talc, dolomite, fluorite and quartz [11,12,13]. The hardness of the first three particles is lower (HA < 210), while that of quartz is greater than 1000. The working environment of the drilling tools is an abrasive one made up of a mixture of particles of different hardness

Objectives

Methods

Results

Conclusion