A Critical Review of the Status of SAGD: Where Are We and What Is Next?

Abstract

With around 7 trillion barrels reserves and recent increase in oil demand, there is no doubt that there would be tremendous effort on the development of heavyoil/bitumen (HO-B) reservoirs in the next decades. Yet the in-situ recovery of HO-B is still not a simple process and there are many technical challenges accompanied with it.Two major techniques, namely thermal and miscible, have been considered in the HO-B development, along with several other auxiliary methods (chemical, gas, electromagnetic heating etc.) for different well configurations, steam assisted gravity drainage (SAGD) being the most popular among others. Miscible techniques did not yet go to a high commercial level, while thermal techniques have by far a stable foundation in the industry.Despite remarkable amount of laboratory experiments and computational studies on the thermal techniques for HO-B, especially SAGD, there was no extensive and critical literature review of the knowledge gained over almost three decades. We believe that a critical review of the status of the SAGD process will fill the gap by shedding light on the deficiencies and limitations of the process, further development areas, and new research topics. Specific attention, in this paper, was given to (a) the effect of geological environment on the physics of the process, (b) evaluation of the laboratory scale procedure and results (reasons of residual oil saturation, is it well configuration or pore scale dynamics?) and the reasons of the inconsistency between the lab and field scale performances, (c) problems faced in numerical modelling (capturing the physics of the process, relative permeability curves, dynamics of gravity controlled counter-current flow), (d) evaluation of the pilot and commercial level field applications, and (e) operational and technical challenges.It is believed that a good compilation of the records produced over three decades will constitute a useful reference for the industry and academic people.

Heterogeneity Impact on SAGD Process Performance in Mobile Heavy Oil Reservoirs

“…For pad D, the reservoir is thinner at the heel. Albahlani and Babadagli (2008) compiled the records produced about SAGD over the last three decades and pointed out the strengths and weaknesses in this process. Permeability is one of the most critical reservoir parameters to SAGD processes.…”

Quick Screening of Pareto-Optimal Operating Conditions for Expanding Solvent–Steam Assisted Gravity Drainage Using Hybrid Multi-Objective Optimization Approach

“…This study clarifies that Equation (12), which is in the form of an non-normalized global-objective function, is employed to track the change in the global-optimum if a different form is optimized.…”

“…The ES-SAGD process co-injects light hydrocarbon solvent with steam for enhancing the thermal injection efficiency [6][7][8][9][10][11]. Injected solvent condenses at the vapor/liquid boundary of the steam chamber and creates a diluted interface for further reducing the viscosity of heated bitumen [12]. Nasr et al [6] showed that the steam-solvent co-injection could increase bitumen production rate while decreasing steam injection rate compared to SAGD.…”

Influence of wettability and permeability heterogeneity on miscible CO2 flooding efficiency

“…The wettability of petroleum reservoirs may range from http://dx.doi.org/10.1016/j.fuel.2015. 10.090 0016-2361/Ó 2015 Elsevier Ltd. All rights reserved. strongly water-wet to strongly oil-wet, depending upon the reservoir rock mineralogy, chemistry of the fluids present, and the subsurface pressure and temperature.…”

“…Tertiary recovery methods, for example thermal enhanced oil recovery (TEOR) and chemical enhanced oil recovery (CEOR), target to influence one or more of the above parameters for improved oil recovery. Steam assisted gravity drainage (SAGD) and in-situ combustion are typical TEOR methods and they mainly target to lower the viscosity of the producing oil (displaced fluid) [10,11]. Alkaline-surfactant-polymer (ASP) flooding is a CEOR method that aims to improve the interfacial properties to reduce the capillary barrier and also to increase the viscosity of the displacing fluid for mobility control [12,13].…”