Abstract:

Layer selection for fracturing requires thorough consideration of many factors,which represent clear nonlinear characteristics.In addition to empirical analogy methods,nonlinear mathematical theories are also nee-ded to meet the requirements of fracturing operation.A geological optimization method consisting of partial and grey correlation for selecting layers for fracturing operation has been established after an analysis of all available layer selection methods.Fourteen parameters(such as net thickness,porosity and stress difference of layers to be fractured,and the average thickness of top and bottom barriers) are involved in the application of the method. The calculation result shows a good coincidence with that of in-site fracturing test.The method features in easy and fast calculation and yielding reliable results,and therefore can be used as reference in well evaluation and layer selection for fracturing in the same types of gas reservoirs.

Key words: grey correlation, partial correlation, fracturing, layer selection, tight reservoir