A new optimization method for steam-liquid level intelligent control model in oil sands steam-assisted gravity drainage (SAGD) process

• Published in: Petroleum exploration and development Vol. 43; no. 2; pp. 301 - 307
• Main Authors: LIANG, Guangyue, LIU, Shangqi, SHEN, Pingping, LIU, Yang, LUO, Yanyan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2016; KeAi Communications Co., Ltd
• Subjects: coefficients optimization method; intelligent control model; oil sand; proportional-integral-derivative (PID) control function; SAGD; steam chamber; steam-liquid level; steam-liquid level; steam chamber; coefficients optimization method; oil sand; intelligent control model; proportional-integral-derivative (PID) control function; SAGD
• ISSN: 1876-3804; 1876-3804
• DOI: 10.1016/S1876-3804(16)30034-9

In order to prevent steam breakthrough and improve thermal efficiency in the process of SAGD development of oil sands by real-time adjustment on injection-production temperature difference (Subcool) according to the growth situations of steam chamber along the wellbore, a series of studies were conducted on coefficients optimization of proportional-integral-derivative (PID) control equation for the steam-liquid level intelligent control model. According to heat conservation and material balance principles, a mathematical model for determining the coefficients of PID control equation was established with the liquid pool in the steam chamber as the objective and the Subcool as the control target. The intelligent steam-liquid level control model suitable for M Block in Canada was optimized using this mathematical model, together with the Ziegler-Nichols (Z-N) tuning method. Application effects of these PID control strategies were evaluated by reservoir numerical simulation. The results show, when the combination of PID proportional, integral and derivative coefficients are used, the time scale for Subcool to evolve to the set point is minimized and the convergence speed and robustness are improved. Compared with conventional steam injection process, the intelligent steam injection based on the PID coefficient optimization method is much better in the uniform conformance of steam chambers along the wellbore, higher in oil production and lower in steam-oil ratio (SOR). Both the model optimization method and the Ziegler-Nichols tuning method are similar in simulation results. Based on the former method, however, the optimization process of the intelligent control model is simplified greatly, so it can be implemented more conveniently and rapidly.