Blasingame production decline and production prediction model of inclined well in triple-porosity carbonate gas reservoir

Abstract

The inclined well is used widely to enhance the single well production of the triple-porosity carbonate gas reservoir. This work presents an analytical solution of the inclined well in triple-porosity carbonate gas reservoir by Laplace transform and pressure drop superposition. According to well deviation well deviation pseudoskin factor of inclined well and the structure of approximations solution for the vertical well during pseudo-steady flow regime, approximations solution of the inclined well during pseudo-steady flow regime is obtained and Blasingame production decline model of inclined well is constructed. Calculation method of production prediction is presented by combining with material balance equation of the closed gas reservoir. The method was verified by comparing with numerical model. According to characteristic of dimensionless pseudo-pressure and production decline integration derivative curves, the seven obvious flow regime can be distinguished and every flowing regime is analyzed. With the increasing of perforated degree and inclination degree, Blasingame production decline curves become larger before pseudo-steady flow regime and constant-rate production time become longer. The larger interporosity flow coefficient and storativity ratio of vug system and naturally fracture system lead to earlier ‘concave’ starting-time and more shallow ‘concave’ of Blasingame production decline integral derivative curve separately. The larger interporosity flow coefficient and storativity ratio of vug system and naturally fracture system can also lead to longer constant-rate production time. The larger of initial rate and constant wellbore pressure is, the longer duration of constant-rate production is. A field example is presented to demonstrate the application of the proposed model and method.