Steam-assisted gravity drainage (SAGD) has become the de-facto standard for commercial development of heavy oil and bitumen (HO-B) reserves in a significant number of fields. Although SAGD has proved to be a highly effective technique, many uncertainties and unanswered questions still exist, leaving room to improve production and optimize the economics of a SAGD installation. One notable improvement originating from recent field experience is the novel usage of injection/inflow control devices (ICDs) in a conventional SAGD well pair. The use of a properly designed ICD completion is proving beneficial to both steam chamber development as well as improving the inflow profile of the producing well of the SAGD pair. Work conducted in the Surmont field of Alberta, Canada provided an excellent starting point to optimize flow control improvements to the SAGD process. However, significantly more needs to be added to the discussion to establish best practices for ICD selection and usage and to quantify the benefits gained from using autonomous ICDs in HO-B reservoirs. It is the goal of this paper to provide a useful reference for ICD behavior and theory, selection criteria, the unique role of ICDs in managing steam chamber development, steam fingering control, and management of the subcool temperature (steam trap control). Representative field simulations of Albertan bitumen sand are used as the basis for describing overall trends in the use of flow control in the SAGD process.

Waterflood implementation accounts for more than half of the oil production worldwide. Despite the observations and extensive research from a large number of floods and thousands of simulation studies, managing waterfloods and Enhanced Oil Recovery (EOR) floods is still a technical challenge. A major contributor to this challenge are waterflood induced fractures (WIF). Managing waterfloods is a multivariable problem although WIF are one aspect, it is by no means the only controlling factor.The best evidence that WIF are one of the main factors controlling flow in reservoirs is the insensitivity of injection pressure to injection rates. With our experience, in hundreds of waterfloods, we have frequently observed this phenomenon in the field data. If fluid flow depended on diffusive Darcy flow alone, we would expect higher injection rates with higher injection pressures. However, it is common to observed relatively constant injection pressures over a wide range of water injection rates. Rapid well communication and changes in water cuts that vary with injection rates also support an interpretation of high permeability induced fractures between injector and producer. In some reservoirs, interwell tracer data can be used to determine the influence of induced fracture features. The interwell tracers usually show very fast water movement.Induced fractures in waterfloods and EOR projects can be caused by a number of mechanisms such as but not limited to, pressure depletion, changing pressure regimes, thermal effects, or plugging effects. These fractures can either be beneficial to the reservoir performance or effect performance negatively. Benefits include improved injectivity and increased throughput of the displacing fluid. Negative effects can come in the form of reduced volumetric sweep efficiency, impaired ultimate recovery or injected fluid losses out of zone.Case studies, theory, and available literature from Western Canada will be reviewed in order to suggest and improve reservoir management strategies for waterfloods. We have completed hundreds of waterflood feasibility, waterflood management and EOR flood studies worldwide and continue to be amazed and humbled by the complexity that many waterfloods and EOR floods exhibit due to induced fracturing. WIF and EOR induced fractures (EIF) are common and should be analysed to optimize production. Growth of the WIF, response to waterflood with the presence of WIF, implication of WIF and reservoir management are the main areas which will be addressed.

Over a thousand well pairs in five different fields in Western Canada have been examined using communication analysis techniques. The results of this analysis strongly suggest that in addition to conventional Darcy type flow through the matrix rock, there is also strong communication between wells through induced fractures, and/or natural fractures. Most of these five fields are not typically thought of as naturally fractured. Nonetheless this type of fracture flow exists. It is highly likely that these hot streaks are pressure sensitive and therefore have a geo-mechanical component that controls permeability. The geo-mechanical component means that permeability can vary with time and injection pressure. This work on the Western Canadian Sedimentary Basin (WCSB) is similar to work done by Heffer in the North Sea.

In Steam Assisted Gravity Drainage (SAGD) operations, steam is the primary means of mobilizing the in-situ bitumen or heavy oil-Bitumen (HO-B) resource. The cost of steam generation and delivery accounts for a significant portion of ongoing operational expenditures of the recovery process, thus any efficiency gains in delivering steam to the reservoir makes the entire process more cost effective. Two significant challenges that impact the process efficiency are the occurrence of steam breakthrough along the lateral and steam non-conformance. Both of these issues are largely due to the presence of reservoir heterogeneities. A possible solution to address these challenges is the inclusion of flow control devices (FCDs) in SAGD completions. In order to quantify the impact of including FCDs in the SAGD process, this study was performed by numerical analysis with a model built from publicly available geological data representing the Surmount field of Alberta. The model has the reservoir fully coupled to a discretized wellbore. With this model, the study is able to capture the presence of heterogeneities and the effect with respect to steam breakthroughs and non-conformance. Several wellbore variations are tested in this study, including a Base Case having a traditional completion (long string/short string completion) and other cases with various FCD configurations and arrangements. The results of the modeling process show that the inclusion of FCDs positively impacts the SAGD process by minimizing the occurrences of breakthroughs, improving conformance and by increasing the volumetric sweep efficiency of the process. Included is a comparison of the results from the Base Case versus other cases. The comparison presents a conclusion which demonstrates that deploying FCDs in SAGD wells provides an economic benefit. The economic comparison is based on net present value (NPV) analysis and payout of the various cases. This study is relevant because it demonstrates how FCDs can be employed to overcome geological challenges that would otherwise result in non-conformance and steam breakthrough. By overcoming these challenges the project economics improve. The functionality of these devices also presents the possibility of using slimmer and longer completions for the SAGD well pairs which will improve project economics even more.

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