Perpustakaan Digital ITB

This study aims to evaluate the drilling hydraulics of Well Y located in Jambi Province, which is characterized by dominant claystone, sandstone, shale, and siltstone formations. Well Y also exhibits pore pressure and fracture gradient conditions that are closely spaced, indicating the presence of a narrow mud window that increases the technical risks during drilling operations. The research focuses on analyzing the relationship between minimum flow rate and rate of penetration (ROP), pressure losses, equivalent circulating density (ECD), flow regime, annular velocity, as well as bit optimization using the hydraulic horsepower per square inch (HSI) parameter. The study was conducted using reference data from wells X-1 and X-2, and modeling was performed with Landmark software. Compass was used for trajectory design, StressCheck for casing design and strength evaluation, and WellPlan for BHA design and hydraulic optimization. The evaluation covered the relationship between minimum flow rate and ROP, distribution of pressure losses, ECD analysis, flow regime and annular velocity, and bit optimization by considering nozzle size and pump rate. The results indicate that the minimum flow rate requirement increases with higher ROP. In Section 9 5/8”, the required flow rate ranged from 380–410 GPM at low ROP and increased to >740 GPM at 320 ft/hr, while in Section 7” the requirement was lower, ranging from 170–340 GPM, and started to increase after the ROP exceeded 160–200 ft/hr. The relationship between flow rate and ROP was strongly influenced by annulus geometry. The largest pressure losses occurred in the drill string, recorded at 1,448.96 psi (59.05%) in Section 9 5/8” and 1,761.76 psi (70.55%) in Section 7”, although the resulting standpipe pressure remained below the maximum operating limit of 2,500 psi. The ECD values were within the mud window, ranging from 9.13–9.16 ppg in Section 9 5/8” and 10.17–10.32 ppg in Section 7”. Flow regime analysis showed laminar flow in Section 9 5/8” at pump rates below 1,100 GPM, while in Section 7” turbulent flow occurred beyond 3,653 ft MD at pump rates greater than 350 GPM. HSI evaluation also indicated optimum conditions, with HSI of 3.0 (TFA = 0.862 in², pump rate 916.5 GPM) in Section 9 5/8” and HSI of 2.1 (TFA = 0.985 in², pump rate 602.6 GPM) in Section 7”, ensuring effective hole cleaning without exceeding the surface pressure limit. This study provides a comprehensive approach to drilling hydraulics optimization by integrating casing design, BHA configuration, and hydraulic system performance. It presents an evaluation of the interaction between flow rate, pressure losses, ECD, and bit hydraulics optimization under geological conditions with a narrow mud window.