Optimization Methodology for Cyclic Steam Injection with Horizontal Wells

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractHorizontal wells are becoming a very important component in the thermal recovery of heavy oil reservoirs. The success of a cyclic steam injection project depends strongly on the selection of key parameters, such as cycle length and amount of steam injected. The numerical simulation of horizontal wells, especially under non-isothermal conditions, is computationally demanding. When optimization is combined with numerical simulation, the computing time requirement may be prohibitive and it is not guaranteed that the optimal conditions will be found.In this research, a new methodology has been developed for optimizing the cyclic steam injection process for vertical and horizontal wells. The procedure integrates oil production characterization using numerical simulation, net present value maximization through a Quasi-Newton method, and model validation/tuning. The three-stage procedure provides the optimum number and/or duration of cycles, the optimal amounts of steam to be injected in each cycle and the optimal value of the overall economic indicator.The optimization algorithm was successfully validated with published results obtained from the discrete maximum principle. The methodology was then applied to determine the optimal conditions of cyclic steam injection for a horizontal well located in Bachaquero field, Venezuela.

Integrated Economic Model for Evaluation and Optimization of Cyclic-Steam-Stimulation Projects

“…CSS is a widely used thermal-recovery process for enhanced production of heavy oil reservoirs. CSS has been used since the early 1960s on a commercial scale in the US, Canada, Venezuela, and Indonesia (Escobar et al 2000).…”

“…The selection of a horizontal vs. vertical well is dependent on reservoir properties and economic considerations. When selecting an orientation, factors such as vertical-and horizontalpermeability anisotropy, reservoir thickness, and sand production must be considered, as discussed by Escobar et al (2000). Compared with vertical wells, horizontal wells typically have increased steam injectivity and reserves attributed to each well, whereas at the same time, fewer horizontal wells are required for field development, as shown by Joshi (1991).…”

Optimization of Cyclic Steam Stimulation Under Uncertainty

“…This process is divided in to three parts: (a) Steam Injection (b) Steam soak (c) Oil production (6,7) .…”

Investigation of a Smart Steamflood Pattern to Enhance Production From San Ardo Field, California

“…In addition, a horizontal producer drains a larger volume of the reservoir and thus increases sweep efficiency and reserves, resulting in fewer wells required for development of a field (compared to vertical wells). [1][2][3][4][5][6][7] We have enhanced the advantages of a horizontal well in a steamflood by utilizing a smart horizontal producer. The novel system developed consists of a vertical injector with a smart horizontal producer (Fig.…”

“…[3][4] Some field applications of cyclic steam injection using horizontal wells have also been reported in the literature, generally indicating favorable performance with horizontal wells. [3][4][5][6][7]8 A number of studies on cyclic steam injection using horizontal wells indicate their better performance compared to that of vertical wells. 1-4, 7,9-12 Butler et al (1981) 10 presented an analytical model for the then-novel steam assisted gravity drainage (SAGD) method.…”