PSI - Issue 47

Saud Alsaghir et al. / Procedia Structural Integrity 47 (2023) 437–447 Saud Alsaghir/ Structural Integrity Procedia 00 (2023) 000 – 000

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1. Introduction Casing wear due to direct contact between the hard tool joint and the tubular casing in gas and oil wells has a substantial impact on the well integrity and might cause severe accidents and high economic losses. Chu et al. (2009) stated that casing wear has been the main factor in drilling engineering's significant costs. Lian et al. (2016) claimed that drilling failures, financial losses, and possibly even the early abandonment of the wells will occur from the worn casing's decreased collapse and burst strength. Irawan et al. (2015) claimed that casing wear was not recognized as a critical issue in the oil and gas industry up to the 1980s. However, currently, casing wear became an important topic in the oil and gas industry and several studies have been conducted to estimate the wear, yet it can be difficult to obtain an accurate result. Kumar and Samuel (2015) stated that casing wear is one of the industry's ongoing challenges, and a realistic estimate of downhole wear is challenging. The tool joints are usually hard materials to prolong the joint life and protect the drill string. Kumar and Samuel (2015) stated that in comparison to a more casing-friendly hardbanding material, a more aggressive hardbanding material utilized to extend the life of the drill pipe will have a very high wear factor and result in greater downhole wear. Haberer (2014) claimed that the drilling industry has long acknowledged and employed hardbanding of drill pipe tool joints, BHA, and tools as a method to avoid the down-hole abrasive wear that can rapidly render pipe and tools unusable, increase the risk of failure, and considerably increase drilling costs. The wear factor which is related to the wear volume and contact load is a very significant parameter to predict the failure of the well to avoid disasters and reduce the casing design costs. Mittal (2021) stated that to help minimize tragedies, safety considerations are included when designing casings, and a precise forecast of casing wear can lead to more cost-effective casing designs. Gao et al. (2010) stated that casing wear prediction could effectively optimize the type of steel grade or the thickness of the well tabular casing. However, the complicity of the drilling operation could affect the accuracy of the casing wear. Williamson (1981) declared that casing wear is a complicated process that depends on several factors, including temperature, mud type, percentage of abrasives in the mud, tool joint hard-facing, revolutions per minute (second), tool joint diameter, contact pressure, and more. Radacina et al. (2020) claimed that there are both direct and indirect factors that contribute to casing wear; direct factors include wellbore dogleg severity, casing internal diameter, drill string or tool joints' exterior diameters, the nature of the surfaces on the casing and drill string, lateral stresses on tool joints, and time exposure while rotating and penetrating inside the casing; indirect causes include annulus dimensions, flow rate, and drilling fluidity. Huimei et al. (2012) conducted a study to find the most effective drilling parameters on the wear and found both rotational speed (RPM) and rate of penetration (ROP) are the most significant parameters. Yu et al. (2016) conducted an experimental study where the normal contact force was varying under constant rotational speed, and it can be observed that as the contact load increased, the higher values of worn volume. Zhang et al. (2016) provided an experimental study to understand the effect of different drilling parameters on the wear, it can be shown that increasing both contact loads and rotational speed will increase the wear amount, moreover, three different steel grades are used in the experiment and P110 steel grade was the less wear sensitive while J55 was the most wear sensitive. Lian et al. (2016) experimentally studied the effect of three varying contact loads, 60, 90, and 120 N, and rotational speeds, 60, 70, and 80 rpm for two steel grades, P110, and N80, and the result pointed that increasing the contact load and rpm for both grades result in higher wear amount, but P110 was less sensitive to the wear. Tan et al. (2018) conducted a sensitivity analysis and found that the wear depth is affected and increased by increasing the angular velocity, outer joint radius, and sliding and rolling friction. Radacina et al. (2020) discovered that increasing the drill rotation speed and decreasing the penetration rate will lead to greater vales of casing wear according to the sensitivity analysis. Osman et al. (2022) provided an experimental study for two varying contact loads, 1000N, and 1400 N, and two varying rotational speeds, 115, and 207 rpm for three lubricant conditions. The result shows that at constant load decreasing the RPM result in a higher wear factor for the oil-based lubricant condition while at constant RPM increasing the contact load results in a higher wear factor.

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