Seepage Features of High Production Deep Water Reservoirs

• Published in: Physical and Numerical Simulation of Geotechnical Engineering no. 24; p. 3
• Main Authors: Yuedong, Yao, Libing, Fu, Zhaojun, Hou
• Format: Journal Article
• Language: English
• Published: Brighton East St. Plum-Blossom Press Pty Ltd 01.09.2016
• Subjects: Deep water; Fluid flow; Mathematical analysis; Mathematical models; Productivity; Reservoirs; Seepage; Well drilling; ASW, Mexico Gulf; ASE, Africa; Nigeria; ASE, Angola; Africa; ASW, Brazil
• ISSN: 1838-3254; 2204-2040

The pore pressure distribution around an injection or production well is of great importance to petroleum engineers in such areas as formation evaluation, fluid flow analysis and well drilling design etc. Well testing is one of the widely used methods to obtain it. In order to gain an accurate pressure, its fundamental theory should describe the seepage characteristics correctly. However, the non-Darcy flow is usually neglected for the assumption of creeping flow. For deep water reservoirs, such as Gulf of Mexico, Brazil, West Africa (Angola, Nigeria), in order to improve development efficiency, it should drill very few wells with high productivity to reduce investment and shorten payback period. When single well production is very high, the high-velocity non-Darcy flow will occur in the near wellbore zone. Based on Izbash equation, a non-linear flow model is established which combined Darcy and non-Darcy flow in the reservoir. A methodology to solve the diffusion equation with combined flow patterns is proposed. The solution technique, which is based on Boltzmann transform, is very suitable to solve the analytic solution of pressure distribution. After analyzing the typical curves of bottom-hole pressure and pressure derivative, seepage characteristics of non-Darcy flow and its influence factors are determined. All factors, such as integrated non-Darcy coefficient combined by formation permeability, porosity and fluid property, power index and so on are discussed. The research result can be used to provide theoretical basis for well-testing interpretation and productivity evaluation in deep water reservoirs.