Coalbed Methane Enhancement in Low-Permeability Reservoirs by Hydraulic Fracturing with Coated Ceramsite

Abstract

The overall fracturing stimulation effect using quartz sand as a proppant is poor, resulting in no breakthrough in the production of coalbed methane (CBM) wells in the low permeability coal reservoir of Lu’an Mining Area. In this study, the mixed coated ceramsite of three particle sizes (40–60, 16–40, and 12–20 mesh) was selected as a proppant to conduct a hydraulic fracturing field experiment on CBM wells, located near the three wells fractured with quartz sand in the study area. The drainage and production effects of mixed particle size-coated ceramsite and quartz sand fractured wells in the area were compared. The results show that the cumulative gas production from the coated ceramsite fractured CBM well was approximately 93,004 m3 in 238 days of gas production, with a maximum daily gas production of 825 m3/d, approximately 3.3 times that of the quartz sand fractured wells. After 400 days of gas production, the two types of proppant-fractured CBM wells differed notably, the daily gas production of the coated ceramsite-fractured well being 450–825 m3/d and that of the quartz sand-fractured wells being only 150–250 m3/d. In the stable production stage, the coated ceramsite-fractured well displayed a better gas production potential. Therefore, in view of the low permeability of the coal reservoir, the use of coated ceramsite to fracture CBM wells can achieve a more satisfactory production enhancement effect. The research findings can provide a reference for fracturing-induced production enhancement of low-permeability reservoirs.

Effects of Liquid CO2 Phase Transition Fracturing on Methane Desorption of Coal

“…Therefore, the CBM productivity can be jointly dominated by the permeability and desorption capacity . The previous studies focused on the permeability-enhanced effect of LCPTF. , The adsorption-reduced effect and desorption-enhanced effect were illustrated by our previous research . Consequently, this study provides insight into the mechanism of LCPTF to enhance CBM recovery, from the perspective of the dynamic desorption process.…”

“…Coalbed methane (CBM) is a kind of unconventional natural gas, and its recovery and utilization are significant for furnishing clean energy and reducing carbon emissions. , However, the prospect of CBM recovery is limited significantly in the coal reservoir with low permeability, − and it is necessary to adopt effective reservoir stimulation measures. , The geologic sequestration and reservoir stimulation techniques based on CO 2 were widely used in unconventional energy recovery, including gas hydrate, shale gas recovery, geothermal energy harvest, etc. Besides, liquid CO 2 phase transition fracturing (LCPTF) is a novel reservoir simulation technology to improve CBM transportation capacity. , A series of field application studies indicated that LCPTF has unique advantages, including raw materials with stable sources, low cost, and high safety performance without generating sparks. , …”

Review and Outlook on the Utilization of Low-Concentration Coalbed Methane for Power Generation by Solid Oxide Fuel Cells

“…For example, the SOFC technology development in China commenced relatively late, and the research on the SOFC technology in China has mainly taken the route of independent development, starting from 2007 when China started to research key materials and basic science related to the SOFC. In China, CBM is a very abundant resource associated with coal. − The extraction and utilization of CBM is very important, and a lot of research has been done on the enhancement of CBM production; − however, in the industrial chain of “exploration–extraction–utilization” of CBM, the utilization of low-concentration methane has been a key factor restricting the development of the industry. The SOFC has the unique advantage of being able to utilize CBM directly with high conversion efficiency, and its working principle is shown in Figure b.…”

Effect of Surfactant Modification on Coalbed Methane Desorption and Its Behavioral Mechanism

“…Fracturing fluid is a medium used in hydraulic fracturing and acts to produce a wide range of fractures in the coal seam, thereby facilitating the smooth injection of the proppant. Consequently, hydraulic fracturing has played an important role in successful methane reservoir exploitation . While the fracturing fluid systems used in the United States have been applied in China, the complex reservoir conditions in China, in particular low permeability and low pressure, have limited the success of these systems. , These systems since the first CBM well was drilled in Panzhuang, China, in 1992, have included guar gum fracturing fluid, cross-linked fracturing fluid, clean fracturing fluid, CO 2 foam fluid, nitrogen foam fluid, pure nitrogen fluid, and composite fluid .…”