OPTIMIZATION OF HYDRODYNAMIC PARAMETERS OF DRILLING FLUIDS FOR IMPROVED CUTTINGS TRANSPORT IN HORIZONTAL WELLS
Authors: Turgay Isgandarli Turgay Isgandarli 
Published: December 2024

In horizontal portions of small-bore well holes, improper cuttings transportation results in high torque and raises the possibility of the drill being stuck, shortening its service life and endangering safe operation. A transport approach utilizing pulsed drilling fluid based on a shunt relay mechanism is suggested since the traditional cuttings transport method is ineffective at removing the cuttings bed. The transport of cuttings in horizontal small-bore wells is modeled numerically using three layers. The cuttings transport is examined in terms of the cuttings concentration, cuttings velocity, and cuttings bed movement distance using both numerical models and tests. The best pulse parameters are identified by adjusting the pulsed drilling fluid velocity cycle, amplitude, and duty cycle at the annulus inlet and assessing the impact on cuttings transport. The findings demonstrate that pulsed drilling fluid can be used to improve wellbore cleaning, lower cuttings concentration, and increase the cuttings bed's transport distance and moving cutting velocity.
A steady flow rate of drilling fluid is used in the traditional cuttings transportation method. Simulations using the three-layer numerical model show that the cuttings bed's movement distance is decreased to the point where the wellbore's cleaning effect falls short of its intended level when the cuttings bed's height in the annulus surpasses a critical value. A technique using pulsed drilling fluid has been suggested to enhance transportation. By altering the drilling fluid's flow rate, this continuously affects the cuttings. Because pulsed jet drilling technology can effectively boost drilling speed, downhole drilling instruments that use pulsed jets are outfitted with spiral pressure intensifiers and variable-frequency pulse jet generators. According to field tests, using pulsed drilling fluid improves cuttings transport efficiency and lessens the impact of chipping.
The majority of cuttings transport research to date has been on how cuttings behave under typical drilling fluid flow conditions. Relatively few studies exist about the destruction of the cuttings bed or the transportation of cuttings under conditions of pulsed drilling fluid. This research establishes a three-layer numerical model under pulsed fluid circumstances based on a shunt relay mechanism. This research describes the transport of cuttings in horizontal well sections under pulsed drilling fluid circumstances in terms of factors, such as the cuttings concentration, the cuttings bed's distance traveled, and the moving cuttings velocity, using both numerical models and tests. Furthermore, the ideal pulse parameters are found, which serves as a crucial guide for designing cuttings transport using pulsed drilling fluid tools. A three-layer numerical simulation model of cuttings transport utilizing a pulsed drilling fluid in the horizontal section of a narrow-bore hole is constructed in the second section of the article, which is based on actual onsite working conditions. The experimental apparatus and procedures are presented in the third section, and the experimental data are used to study the behavior of cuttings transport by the pulse drilling fluid. The cuttings transport behavior for various values of th is examined in the fourth section using finite element software.
Keywords: CFD model, cuttings bed, pulsed drilling fluid, and horizontal well drilling