The production of heavy oil reservoirs has present anomalous phenomena, in which simultaneous mixture flow of gas as very tiny bubbles entrained in heavy oil is observed in solution gas drive and natural gas huff and puff process. The foamy oil in viscosity fluid has strong mobility to lead to high production and high recovery. Flow properties in pseudo-single phase result in a new feature of reservoir performance. The objective of this paper is to investigate the foamy oil flow characteristic taking account of relaxation effects. Assumed to dual-component of the foamy oil, heavy oil component and tiny gas component, respectively, analytical formulas of the foamy oil flowing pressure distribution during the initial and later stage are derived by the mathematical analytical model of one dimensional unsteady boundary flow in porous media. The result compared with classical Newtonian fluid flow shows that relaxation effects on flowing pressure decrease slowly. By taking L Block formation and injection parameters as an example, the flowing pressure distribution at injection well and production well reveals that effective radius of the foamy oil and injection time have optimal value. Heavy oil component volume concentration is smaller, the greater the corresponding tiny gas volume concentration, i.e., the more foamy oil flow, the greater the pressure effective radius. Through analytical calculation, the injection parameters of natural gas huff and puff for heavy oil reservoirs are assessed. In the practice of heavy oil development, the relaxation effects on heavy oil flow in porous media should be reasonably utilized.
Modeling foamy oil flow in porous media II: Nonlinear relaxation time model of nucleation
