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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In this paper, an experimental study will be conducted using a modified lathe machine that is connected to an acquisitions system to measure the wear volume and calculate the wear factor for three different types of steel grades and two varying contact loads under constants rotational speed and penetration rate and study the effect of those parameters on real field casings. 2. Experimental Procedure The modified lathe machine used for this experimental study is shown in Figure (1). A programmed closed-loop system is used to keep a constant contact load on the tool joint using a feedback loop. Two servomotors coupled with a gearbox are used for applying both normal load and sliding along the real drill pipe joint (DPJ). The forces were measured using a dynamometer type 9139AA. A circular section from the field casing pipe was cut to a width of 25 mm. A casing holder with casing support is used to fit different casing sizes, and then it is mounted on the dynamometer as shown in Figure (2). The temperature, rotational speed, normal force, tangential force, penetration rate, and radial displacement were measured and recorded during the experimental test. The servomotor was programmed to repeat the sliding cycle during the experiment. The wear volume was measured in-situ using calibrated displacement indicator to previous experiments with 3D profilometer measurement. Two varying contact loads (1000 and 1400N) under constant RPM (115 rpm) and ROP (2.5 mm/s) were applied to investigate the wear volume and factor. The experiment was conducted under oil-based conditions. To measure the average temperature using a waterproof DS18B20 digital thermal probe sensor with an operational temperature range of -55 °C to +125 °C and precision of ±0.5 °C, a small hole was drilled in the side of the casing samples, close to the casing-tool joint contact area. The radial displacement was measured during the test using an electronic digital micron indicator with a measurement range of 0-12.7 mm, a precision of 0.001 mm, and an accuracy of 0.004 mm. The origin (zero point) of the digital indicator was found when the chosen load was applied at the specified rotating speed, and the radial displacement of the casing sample was recorded every two minutes. The average time duration of each test was almost 60 minutes.

Tool Joint

Casing & Casing Holder

Casing Support

Rotational & Sliding Motion Stepper Motors

Dynamometer

Figure 1. Three-dimensional model of the modified system.