Fracture propagation induced by hydraulic fracturing using microseismic monitoring technology: Field test in CBM wells in Zhengzhuang region, Southern Qinshui Basin, China

Abstract

Hydraulic fracturing is an important technical measure for coalbed methane (CBM) development, and the propagation of fractures in the target coal seam induced by hydraulic fracturing is related to the stimulation performance in CBM recovery. Therefore, effective monitoring of fracture development during reservoir fracturing is critical for CBM engineering. In this paper, the microseismic technology was used to monitor the spatial and temporal characteristics of the fracture extension in the CBM well during hydraulic fracturing in Zhengzhuang Region, Southern Qinshui Basin, China. Based on the microseismic fracture scanning data and imaging processing, the three-dimensional shape of fractures in vertical wells after fracturing can be quantified, and for the vertical well ZHSY-1, the main fracture direction is identified as NE106°, and the fracture length is 426 m, and the fracture area of coal seam is 1.6 × 105 m2. It is found that fracturing does not develop continuously in time and space with fracturing fluid injection, and the fracture regions are scattered throughout the space, and the formation and development of fracture regions are intermittent. After fracturing with a large amount of fracturing fluid injection in Well ZHSY-1, the fracture area has been significantly increased, and the well gas production has been significantly improved, which is confirmed by the field CBM well data. This study provides a field application case for studying the effect of hydraulic fracturing fracture propagation using microseismic technology, which can be used as a reference for fracturing engineering in CBM development.

Geological Characteristics of Low-Yield and Low-Efficiency CBM Wells and Practical Measures for Production Increase in the Qinshui Basin

“…The actual practical use of reserves and resource utilization is low. Poor adaptability of production increase measures. Hydraulic fracturing is a standard method to increase production in CBM projects . The coal seam is fractured by injecting the high-pressure liquid, thereby increasing the permeability and gas permeability and improving the gas recovery rate .…”

“…Hydraulic fracturing is a standard method to increase production in CBM projects. 28 The coal seam is fractured by injecting the high-pressure liquid, thereby increasing the permeability and gas permeability and improving the gas recovery rate. 29 In the early stage of CBM development in the Qinshui Basin, the same basic development process was used, including vertical well casing completion, coal seam perforation, active water injection with quartz sand fracturing, injection of 700–850 m 3 of fracturing fluid, fracturing displacement of 6 m 3 /min, followed by quickly increasing to significant removal of 8 m 3 /min after pumping, and a 12% high sand ratio and other measures to increase production.…”

Laboratory Study of Liquid Nitrogen Cryo-Fracturing as an Environmentally Friendly Approach for Coalbed Methane (CBM) Reservoirs

“…In contrast to conventional hydraulic fracturing, which uses a lot of water and chemicals, there are currently waterless fracturing technologies that also include natural gas fracturing [18][19][20], blasting fracturing [21][22][23], and low-temperature CO 2 fracturing [24][25][26], which have their own advantages and drawbacks. In gas fracturing, blasting fracturing, and CO 2 low-temperature fracturing, there is no use of water; hence, there are no chemical exposure risks for contaminated water horizons, and reduced wastewater management is needed [27][28][29][30][31][32]. On the other hand, there is a connection between increased seismic activity and fracking operations; large-scale infrastructure is needed for fracturing, including pipelines, access to roads, and well pads.…”