Perpustakaan Digital ITB

This study is design multistage hydraulic fracturing in low-resistivity reservoirs X-33 and X-35 in Field X, Indonesia, to boost oil and gas production from zones. These reservoirs are made of shaly sandstone with low resistivity of 1-2 ohm.m, porosity between 13-18%, permeability of 0.86-2.43 mD, and water saturation from 40-90%, under initial pressures of 1420-1450 psig. The goal is to address production decline in old fields by using the Multifrac Pseudo-Perkins, Kern & Nordgren (MLF_PKN) model to create fractures that increase well-reservoir contact, lower skin effect, and raise the productivity index. The research focuses on choosing the right fracture model, proppant, and fluid, while analyzing sensitivities in well placement and design to find the most cost-effective options. Using the FracCADE 5.1 software, the MLF_PKN model was applied with simplifications fracture width of 0.3 inches and average permeability to calculate dimensionless fracture conductivity (FCD). For the X-33 zone at depths of 4585-4665 ft true vertical depth (TVD), the optimized four-stage design produced fracture half-lengths ranging from 51.5 to 85.1 feet, average widths from 0.281 to 0.393 inches, effective FCD values from 3.5 to 5.9, and conductivities between 3221 and 4159 millidarcy-feet (md.ft). The chosen proppant was 20/40 Brady sand, which can handle closure stresses up to 2969 psi for X-35 and 2824 psi for X-33, combined with YF560HT cross-linked fluid at 60 pounds per thousand gallons gel loading, plus additives like KCl, stabilizers, and fluid loss agents to reduce leak-off and keep proppant in place. Sensitivity analysis tes showed that adding more fracturing stages has a bigger impact on production than changing half-lengths, since FCD variations in this range give only small improvements in fold-of-increase (FOI). Economic analysis, varying proppant placement area (PPA) from 3 to 11, highlighted net present value (NPV) benefits. X-33 well, increasing proppant concentration resulted in higher production performance and a clear improvement in NPV, demonstrating the positive impact of greater fracture conductivity. This improvement came with a significant rise in proppant cost, which reduces the overall economic efficiency. X-35 well, use of higher proppant concentration also contributed to better production outcomes and NPV growth. The cost escalation was relatively moderate, making this case more economically attractive. These results evaluates importance of balancing proppant concentration and cost, where optimization is necessary to achieve maximum productivity while maintaining economic feasibility.