Fracturing Pressure Analysis Of New Technologies, The Diagnosis Of Fracture Morphology

Since hydraulic sand fracturing is the major measures of coal seam stimulation, correct understandings of fracture morphology are the premise and the key problems. In other words, coal seams hydraulic fracturing forms vertical cracks or horizontal ones? In what conditions are they vertical cracks or horizontal cracks? They are the basic key technical problems, which can not be avoided, but has not been resolved.In this paper, on the base of the classical fracturing stress analysis, through establishing sophisticated wellbore flow model, simple formula the friction coefficient, selecting the appropriate fracture closure pressure and so on, we studied the formation of a new method of calculating the net pressure, then improved and perfected the method; Combining the relationship between bottom hole pressure and the vertical stress, we introduced the concept of net overburden pressure. By determining the the positive and negative forms of net overburden pressure of fracture initiation value to diagnose fracture morphology. This analysis techniques standard together with the former net pressure technology constituted the double standards of diagnosing fracture morphology. Ultimately, the comprehensive new frac pressure analysis technologies of diagnosing fracture morphology were established.Optimizing representative layers and using the above techniques, we analyzed and processed total of 77 layers of three blocks coal seam fracturing data, which contained Hancheng, Sanjiao and Daning-Jixian blocks. As 14 layers fracture data for examples, the application of the technology were detailed description. Firstly and initially, the results showed Hancheng block fracture morphology rules:almost all forms of hydraulic fracturing of 3# coal seam were horizontal fractures; 5# coal seam would like to form amounts of vertical fractures and a small amount of horizontal fractures, while 11# coal seam formed amounts of horizontal fractures, a small amount of vertical fractures. To Sanjiao block and Daning-Jixian block, at present, the number of the application layers was so small that the laws of their fracture morphology needed further observation..