Authors: E.D. Enina, V.V. Shishlyaev

Title of the article: Design features of hydraulic fracturing operations in a coal reservoir

Year: 2026, Issue: 1, Pages: 77-89

Branch of knowledge: 2.8.6. Geomechanics, destruction of rocks by explosion, mine aerogasdynamics and mining thermophysics

Index UDK: 622.279.6

DOI: 10.26730/1999-4125-2026-1-77-89

Abstract: Coalbed methane is a hard-to-recover mineral deposit requires the use of technologies to increase gas production, such as hydraulic fracturing (HF). The design of a fracturing operation in a coal reservoir requires consideration of specific geological and technological features such as low permeability, natural fracturing and high adsorption capacity. Successful hydraulic fracturing in such conditions is possible only after careful analysis of geomechanical parameters, selection of optimal technological agents and injection modes. Increasing the efficiency of hydraulic fracturing operations is the main condition for the successful development of coalbed methane deposits. In this paper, the features of hydraulic fracturing in coal reservoirs are considered and a methodology for designing hydraulic fracturing operations in coal is proposed. In coal seams, it is preferable to create narrow and long fractures to increase the volume of drainage. The viscosity of the fracturing fluid should be low to minimize filtration losses and prevent excessive fracture growth into unproductive areas. Synthetic polyacrylate systems have the least negative effect for permeability, whereas gel liquids can significantly reduce fracture conductivity. Fracture permeability depends on the fractional composition of the proppant, its strength properties, and the packing of the proppant in the crack. Calculations show that the initial permeability of the proppant pack can decrease by a factor of 100-250 due to over-sealing. When designing hydraulic fracturing, the injection rate, the critical rate of the hydraulic mixture and the intensity of liquid filtration are taken into account. The KGD model makes it possible to estimate the fracture geometry, and the rock bruttleness index determines the choice of hydraulic fracturing technology. The results of the study can be used to optimize the parameters of hydraulic fracturing in coal seams in order to increase the methane flow rate and reduce the operational risks of the operation.

Key words: hydraulic fracturing coal reservoir fracturing fluid proppant brittleness index rock brittleness

Receiving date: 01.04.2025

Approval date: 15.01.2026

Publication date: 19.03.2026

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