The Reseach And Application On Coal Seam Well Logging Interpretation Method

Recently, due to the fact that natrural gas is safer, cleaner and renewable, it occupies more propotions in energy using in our country. To meet the enlarging desire of the market, the relating departments and reserchers make further reseaches in the techniques of oil and gas exploring. According to many exploring and developing work in coal well and oil gas at home and abroad, there are rich coalbed methane resouces in coal bed on our earth. According to estimation, the major coal producing countries’ CBM resources is about (85～262)×1012cubic meter. Russia, China, USA, etc are among the greatest potential countries for CBM resources. Therefore, the exploration and developing of CBM resources has aroused extensive attention both abroad and at home; and related exploration and developing researches has been carried out successively.Nowadays, our country has treated the exploration and developing of CBM resources as a major cause of energy developing. The combination developing of CBM resources by Geology and Mineral Resources, Coal and Petroleum systems indicates the exploration and developing of CBM resources has entered into a new developing period.As the reservoir of CBM is quite different from the normal oil and gas reservoir, the chief characteristic of the former is CBM’s gas resources rocks as well as reservoir. The traditional way of evaluating normal natural gas reservoir can’t be fully used for CBM reservoir. In addition, the existing state of CBM and the way of calculating gas content in coal seam are different from the way of calculating normal gas resources. As the gas contents in coal seam is affected by the coal, coal rank, deep lining and other factors, so the CBM reservoir has dual pore structure which includes matrix porosity and fracture porosity. Based on the above characteristics, they must lead to heterogeneity and anisotropical charactaristics, moreover, the relation between well logging and log response becomes more complicated specialised in nonlinear characteristcis, which lead to more difficulty in well logging explanation and more multiplicity of solutions, ambiguity and uncertainty. Hence, researchers at home and abroad tightly combine the CBM layout’s characteristic and successively carry out researches and exporation in the reservoir of CBM evaluation techniques of geophysical well logging data collection and the possessing and interpritating method in geophysical well logging files.Theoretical research and practical applications approve that techniques in geophisical well logging have the characteristic of higher abnormal resolution and many kinds of methods. Therefore, it can play a critical role in CBM exploring and develop-ing. As a Conventional logging exploring method, it can not only identify the coal seam, which determines the location and thickness of the coal seam, but also can figure out the porosity and penetration through all the logging data then get the air content of the coal seam and the parameter such as seam fixed carbon, volatile, ash and moisture content. Due to the intuitive,fast, high resolution and low expensive characteristics in well techniques using, it is necessary to apply this method in CBM exploration on the scene. As a indispensable method in CBM exploration,therefore,reseaches on the well logging techniques have significant meaning and widespread applying prosperity.In this paper, to start with the characteristics of seam logging, with the principal of CBM choosing, deep reseaches has been carried out on the relationship between CBM and well logging parameter. On this basis, the seam porosity, penetration can be figured out through using existing well logging files and various of mathematical models, and then get the gas content in coal seam.