Abstract:

Horizontal well technology had been widely used in developing heavy oil reservoir. But for the high viscosity of heavy oil, the pressure drop along the horizontal wellbore had been a problem that can not be ignored in studying the productivity of horizontal well. Based on the productivity analysis theory of conventional horizontal well, this paper used the method put forward by Joshi to divide the three-dimensional seepage field into two two-dimension seepage fields, applied the conformal mapping method and law of equivalent percolation resistance to get the flow model in porous media of horizontal well in heavy reservoir, and considering the variable mass flow along the horizontal wellbore, built the coupling model between reservoir and wellbore. Case study shows that the pressure drop along the horizontal wellbore makes the absolute open flow decreased by 7.7%, moreover the value of pressure drop in the horizontal wellbore in heavy reservoir is far greater than that in conventional reservoirs. Sensibility analysis indicates that as the increasing of horizontal well length, power law index and reservoir thickness, the pressure drop along the wellbore also increases, while as the increasing of wellbore radius, the pressure drop decreases. This study can offer a new idea to research the law of pressure drop in the horizontal wellbore in heavy reservoir.

Key words:  reservoir sensitivity, evaluation method, evaluation criteria, Gaoshiti-Moxiblock, reservoir sensitivity')">Sichuan Basin