Test Study On Borehole-ground Electrical Method

Our country is rich in coalbed methane resources.But the coal reservoir has the characteristics of low permeability. It brings certain difficulties to the recognition and extraction of CBM. Some production technology is used to increase production of coalbed methane and improve the efficiency of the mining of coal bed methane. For the exploitation of coalbed methane,hydraulic fracturing technology is an effective method to increase production.But because of that the range of hydraulic fracturing can not be accurately sure,it makes a certain amount of inconvenience for coal-bed methane.So carrying out borehole-ground electrical method detection technology on the ascertainment of the range of hydraulic fracturing diffusion has strong practical value and provide certain guiding significance for coalbed methane exploration.In order to verify the validity and reliability of borehole-ground electrical method exploration technology analysis in the field of practical detection.The paper use the method of numerical simulation and physical model experiment of combining inspection to determine the applicability of borehole-ground electrical technology.The author carry out the numerical and physical experiment on the basis of the summary of existing borehole-ground electrical method technology.Under a certain geo-electric conditions,the paper carry out the numerical simulation for four different observation systems. According to the analysis of the results, it show that the detection effects of cross observation system and ring observation system are better than array and radiation observation system.This paper has carried on the analysis to the influence of casing produced in the probing process.The paper analyses the effects of the casing produced in the detection process, further discusses the casing influence coefficient correction and ratio processing method.The results of analysis show that the direct slicing for water injection has low resistance to reflect; due to the influence of different correction coefficient,the method of correction coefficient of casing correction can not achieve the desired results;and the ratio analysis method have better reflected for the low resistance caused by water flooding.The borehole-ground electrical method of physical model test is carried out in the paper. Through constructing borehole-ground3-D observation system, the corresponding experimental test is carried out to verify. The two water injection experiment data inversion of resistivity image response good diffusion radius on water flooding. Numerical and physical model experiment results prove that the effective of borehole-ground electrical technique has certain recognition effect to limit the range of hydraulic fracturing.The exciting deficiencies of borehole-ground electrical inversion method is further discussed in the paper.The resolution of borehole-ground electrical method detecting result needs to be further improved.And the development of specialized borehole ground electrical processing software is imminent.