The Successful Application of MPD Technology in Drilling Horizontal Wells in a High Pressure Formation Heterogeneity to Mitigate Drilling Hazards: Case Study

Abstract

The highly pressurized intervals coupled with high permeability makes the drilling of the 6-1/8” horizontal hole section particularly challenging in the water injector wells, as mud losses are frequently encountered with differential sticking events. The objective of the workover operations in the objective field is to sidetrack the power water injector from the existing well's motherbore, converting the well in to a dual lateral, which will maintain the reservoir pressure and enhance oil recovery from the oil bearing formation. This variance in formation pressure distribution makes drilling with high mud density systems a challenge, and increases the risk of encountering losses and differential sticking. To overcome the challenges mentioned, the application of MPD technology with the Constant Bottom-Hole Pressure (CBHP) method during the drilling of the 6-1/8” hole section enables utilizing a mud system that is statically below the formation pressure, while keeping the Equivalent Circulating Density (ECD) slightly over the formation pressure and constant at static and dynamic conditions. This objective is achieved by applying surface back pressure using an Automated MPD control choke manifold. As the drilling continued in the lateral, dynamic formation pressure evaluation was performed to assess the changing formation pressure, and to adjust the drilling parameters. This paper will summarize the results of the MPD campaign, compares conventional drilling methods, and highlights the lessons learned from the application of the MPD (CBHP variant), to enhance drilling efficiency, and to mitigate drilling hazards such as losses and differential sticking. The analysis will further enhance the drilling practices of the Power Water Injector wells.

A feasible study for the working mechanism and parameter optimization of the agitator

“…The BHA in this study is a single-stabilizer BHA: ;216 mm PDC bit + ; 165 mm screw motor (with ;214.1mm stabilizer) 3 6.5m+;172 mm agitator 3 2.742m + ;159mm drill collar (DC) 3 140m + ; 127mm drill pipe (DP) 3 1850 m. The drilling fluid density is 0.07 g/cm 3 (g is the acceleration of gravity, which is 9.8 m/s 2 ), viscosity is 30 cst, and WOB is 8.5 tons. The physical properties of the rock are shown in Table 1, and the primary parameters of the agitator are shown in Table 2.…”

“…2. The optimal installation position of the ;172 mm agitator simulated in this study is [200,300] m away from the bit, the optimum frequency is [3,17] Hz, and the optimal impact load is 100 kN. 3.…”

“…The ROP rising percentages under various vibration frequencies of the agitator are depicted in Figure 11, the ROP increased more than 40% when the vibration frequency is between [3,17] Hz, and the variation is relatively small. Therefore, the vibration frequency of the agitator has a small effect on the ROP increase when the frequency is less than 17 Hz.…”

“…From the perspective of antifriction technology, many investigations have been made to solve this problem. [1][2][3][4][5][6] Various tools such as agitator have been developed and designed to resolve contradictions and improve the extended limits of horizontal wells. [7][8][9] Engineering applications have shown that a small number of anti-frictional tools, such as agitator, had a certain effect on drilling engineering.…”

“…The results show that using agitator can improve the weight-on-bit transmission efficiency and reduce the frictional drag, tropsh-pressure, and occurrence probability of drill string buckling. The optimal installation position of the ;172 mm agitator obtained in this study is [200, 300] m away from the bit, the optimum frequency range is [3,17] Hz, and the optimal impact load is 100 kN.…”