Hydraulic fracturing design for coalbed methane in Barito Basin, Indonesia

Abstract

The coalbed methane (CBM) reservoir in Barito Basin, Indonesia may be stimulated by hydraulic fracturing to efficiently recover methane gas from low permeability reservoirs. The permeability of coalbed may be quite diverse, ranging up to a few thousand mD. If the reservoir permeability is too low (less than a tenth md), hydraulic fracturing could be considered to improve gas productivity as a stimulation treatment method. In this study, hydraulic fracturing treatment design is conducted to determine total slurry volume and proper pump rate upon different fracture lengths. To set an optimal treatment schedule, fracture geometry and fracture efficiency were compared depending on the increase of fracture length and pump rate by fracturing stages. The proper pump rate was determined to be 40 bpm and resulting from high fracture efficiency. Furthermore, usage of proppant was determined using definite proper pump rate and slurry volume determined by highest pump rate in this study. All calculated fracture lengths of treatment with proppant were shorter than the fracture length of treatment without proppant. Also, fracture widths and heights were larger than treatment without proppant. However, the fracture efficiency in treatment with proppant was higher than in treatment without proppant. Therefore, proppant would contribute to improving the fracture efficiency of hydraulic fracture treatment in the CBM reservoir in Barito Basin. Consequently, the 3D-propped fracture model was designed for the CBM. Developed hydraulic fracturing model would be useful for the hydraulic treatment of CBM especially in Barito Basin for fracture design and treatment analysis prior to the actual treatment.