Optimization Research Of Fracturing Parameter Of Low Permeability CBM Reservoir

In this paper, based on coal bed methane geological theory, with Jiaozuo coal bed methane reservoir as the main research object and fracturing the reservoir permeability as the main purpose of the reasearch, combined with the contrasts between experiments in the laboratory and the field operation, the iMPortant fracturing parameters are optimized individually to find out the fracturing parameters and construction methods for low permeability coalbed methane reservoir.This paper introduces the reservoir characteristics in the study area and the favorable block evaluation, analyzes the reservoir characteristics, advantages and disadvantages different from other reservoirs, optimizes the fracturing parameters through experiment from the fracturing fluid, proppant and construction parameters, obtaines two different sets of construction programs to coMPare the effects with the original one, and analyzes the drainage data and obtains the facturing effects of each programs with nearly six months'drainage feedback.Fracturing fluid is key to successful fracture in low permeability coal seam and thus the success of its research is of high iMPortance. Fracturing fluid viscosity determines its carrying capacity, but the increase of fracturing fluid viscosity inevitably needs additives, however, additives are harmful for coal because the too viscous fracturing fluid will block the the acoustic micro-cracks and micro-pores in coal seam and further reduces the overall permeability of the coal seam. This paper starts from the coMPosition of fracturing fluid, conducts laboratory experiments on fracturing fluid additives, chooses the optimizations of good performance and small injury, carries gelbreaking experiments under a variety of teMPeratures and finally conducts the coMPatibility experiments with the saMPle coal in the studied area to ensure the optimal fracturing fluid formula is feasible.The performance of proppant is one of the iMPortant factors influencing conductivity of supporting fracture. If the proppant size increases, the strength will decrease and cracked sensitivity will increase. Small size sand will easily lead to local congestion and reduce the fracture permeability, so the mud and pulverized coal would be blocked. There are a lot of constructed soft coal in the upper and lower parts of reservoir, which pose new requirements for the used proppant in fracturing. This paper has done a lot of work in proppant performance characteristics, influences of particle size, embedment and spread sand concentration on the conductivity, and finally optimizes the proppant parameters combinations suitable for the studied reservoir.Operation parameters are critical to the success of fracturing. According to the special circumstances of the reservoir, this paper proposes two fracturing programs and conducts cross experiments on parameters such as open hole coMPletion, short-radius water injection, variable displacement and small displacement, to find suitable fracturing parameters for such reservoirs.