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Abstract

Some low and ultra-low permeability reservoirs are tested by recording the flow rate variation while the well-flowing pressure is kept constant. A typical situation occurs in shale formations which permeability goes to the order of nanodarcies. The mentioned procedure is normally referred as rate transient analysis and the interpretation of the reciprocal of the flow rate is very similar to the interpretation of a pressure test. The application of the TDS Technique for transient-rate analysis of horizontal wells in oil and gas homogeneous anisotropic reservoirs is presented here. New governing equations for hemilinear flow, parabolic flow, several situations of steady-state and pseudo steady-state flows are introduced and used to generate practical analytical expressions for the determination of well and reservoir parameters. The developed equations were successfully tested with synthetic examples.