Optimization Methodology for Cyclic Steam Injection With Horizontal Wells

摘要

Horizontal wells are becoming a very important component inrnthe thermal recovery of heavy oil reservoirs. The success of arncyclic steam injection project depends strongly on thernselection of key parameters, such as cycle length and amountrnof steam injected. The numerical simulation of horizontalrnwells, especially under non-isothermal conditions, isrncomputationally demanding. When optimization is combinedrnwith numerical simulation, the computing time requirementrnmay be prohibitive and it is not guaranteed that the optimalrnconditions will be found.rnIn this research, a new methodology has been developedrnfor optimizing the cyclic steam injection process for verticalrnand horizontal wells. The procedure integrates oil productionrncharacterization using numerical simulation, net present valuernmaximization through a Quasi-Newton method, and modelrnvalidation/tuning. The three-stage procedure provides thernoptimum number and/or duration of cycles, the optimalrnamounts of steam to be injected in each cycle and the optimalrnvalue of the overall economic indicator.rnThe optimization algorithm was successfully validatedrnwith published results obtained from the discrete maximumrnprinciple. The methodology was then applied to determine thernoptimal conditions of cyclic steam injection for a horizontalrnwell located in Bachaquero field, Venezuela.