Laboratory Study On The Hydraulic Injection Process Of Coalbed Methane Horizontal Wells

As clean and high-grade unconventional natural gas, coalbed methane (CBM) has attracted widely attention of scholars all over the world. With abundant CBM resource in China, efficient exploitation and utilization of CBM is of significant importance in terms of environmental protection, energy security and economic development.It is the perforation completion method of perforating cartridge in CBM that can establish the channel between the wellbore and reservoir, however it can also damage the formation by compaction etc. and greatly reduce the permeability near the wellbore.The horizontal hydraulic perforation is feasible in CBM. It can remove the congestion and compaction near the wellbore, restore the permeability, and make the directional perforation. Besides due to its simple construction process, the cost of CBM mining can be reduced.Based on this issue, with the support of existing research achievements, by taking advantage of rock mechanics, hydromechanics, and petroleum engineering etc., we had the research to horizontal hydraulic injection forming pore technology with the combination of physical experiment and numerical simulation, so the following work is finished:(1) In the physical simulation, the hole is inverted cone, which is mainly composed of circular section and V-shaped vertical surface. The hole wall is smooth, which proved the effect of anti-abrasion splash particles.(2) Physical simulation experiments show that, degree of effects of all parameters on the depth is followed by pump pressure, abrasive concentration and diameter of nozzle; and influence on the pore diameter is followed by nozzle diameter, abrasive concentration and pump pressure, which is consistent with the experimental results obtained by numerical simulation.(3) The experimental results and the experimental results have some differences, but the difference is within 15%. Physical simulation is more realistic, but the repeatability is poor. Besides, numerical simulation can be repeated for many times, which is suitable for complex conditions.(4) Through the analysis of physical experiments’results, we optimized a series of construction parameters for pump pressure 35MPa, nozzle diameter 6mm, abrasive concentration 10%.