Optimization of Mud Injection Pressure in Oil Drilling Using Duelist Algorithm

Abstract

Drilling fluid or commonly called mud, is used to lift drilling cutting to the surface, cool and lubricate the bit and drill string, as supporting walls in the borehole using mud cake, and control the formation pressure. The injection pressure is very important because if the injection pressure of the mud is not right, it is going to cause various effects, such as causing fracture in the wellbore, causing heat in the bit and drill string, weak wall since weak mud cake formed in the well, and being able to cause kick or stuckpipe. Because of the impact of the mud injection pressure is significant to drilling performance, the pressure of mud injection in the oil drilling needs to be optimized using Duelist Algorithms to minimize the amount of pressure drop at each hole diameter, i.e. at 17 in. hole diameter in 1269.68 ft depth and at 12.25 in. hole diameter in 2132.55 ft depth. Before being optimized, the pressure of mud injection was modeled first using bingham-plastic method for calculating pressure drop in six different sections of the wellbore, i.e. surface equipment, drill pipe, drill collar, bit, annulus around drill collar, and annulus around drill pipe. Afterwards, it was summed to calculate the total pressure drop in each hole diameter. The total initial pressure drop for 17 in. hole diameter was 978 psi and for 12.25 in. hole diameter was 1875 psi. In order to minimize the pressure drop, it was necessary to do optimization using Duelist Algorithm. The optimized variables were mud density and flow rate. Sensitivity analysis was utilized to obtain behaviour of the system. Duelist Algorithm optimization was performed using 200 iterations, 200 duelists, 80% learning probability, 10% innovate probability, 95% luck coefficient, and 10% board of champion. After being optimized using Duelist Algorithm method, for 17 in. hole diameter, mud density became 9 ppg and flow rate became 505 gpm. Therefore, the pressure drop became 695 psi. Meanwhile, for 12.25 in. hole diameter, mud density became 9.18 ppg and flow rate became 603 gpm. Therefore the pressure drop became 1145 psi. The results show that the optimization of mud injection operating condition in drilling process provide reduction of pressure drop in mud injection that would be give good impacts in the drilling efficiency and safety. This result will be useful for drilling engineer to set up the drilling equipment and mud properties.