A gravity drainage concept has been proposed and tested for in‐situ recovery of bitumen by mobilization with soluble gases at ambient reservoir temperature conditions. Experiments were done using carbon dioxide and ethane gases at ∼ 20°C to recover Athabasca bitumen from a scaled reservoir model. Thermal gravity drainage theory has been modified for the mass transfer case. The measured drainage rates were higher than those predicted by the model using molecular diffusivity data but fit the model better using an increased effective diffusivity. Lateral dispersion theory does not predict the high measured effective diffusivities. A preliminary economic evaluation of field production indicates potential application to recovery of Lloydminster heavy oil.

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This paper is a review of current techniques available for measuring the velocity and composition in multiphase streams, to obtain the mass flow rate of the individual phases. An extensive literature search was conducted on the topic and related areas of interest. The major difficulty in measuring both the velocity and composition of multiphase streams is in dealing with the wide variety of flow regimes which are possible in multiphase flow in pipes. A device which is suitable for accurate velocity measurement in multiphase flows is not commercially available. However, if the flow is well mixed, it should be possible to calibrate a simple device, such as a nozzle or a venturi, to provide accurate total volumetric flow rates. Several commercial in-line static mixing devices are suitable for low gas concentrations (≤ 10 percent) and with superficial gas velocities higher than 10 m/s. For lower gas velocities and high gas concentrations, the suitability of these in-line mixers will have to be further assessed experimentally. Other techniques such as cross-correlation are known for two-phase flow velocity measurements, and the results of these applications look promising. A multiphase compositional meter to monitor the concentration of oil, water, and gas phases flowing in a pipeline, used in combination with a suitable homogenizer and a velocity meter, would facilitate measurement of the mass flow rates of the individual phases. Further work must be done to develop this concept.

Many operators are considering installation of flow-control devices (FCDs) in horizontal wells to improve steam-oil ratios (SOR) in steam-assisted gravity drainage (SAGD) recovery processes in heavy oil/bitumen reservoirs. The flow-control devices are used to help balance both the steam injection and fluid production in order to increase the oil recovery efficiency and use the full length of the horizontal wells. SAGD injector and producer horizontal wells are typically 3 to 6 meters apart, vertically. Because of this proximity, steam breakthrough to the producer well is possible. In order to reduce the steam loss following a steam breakthrough, operators typically try to slow the total rate of production. This paper will discuss the testing of passive inflow control devices (ICDs) and an autonomous inflow control device (AICD) in a steam-flow test loop along with testing results to help control the breakthrough of steam. Heated water flow through the ICDs and AICDs was used as the baseline case. Saturated steam simulating steam flow conditions (pressure and temperature) in a SAGD environment was flowed through the devices at two different temperatures, and the resulting flow rates were recorded at several pressure differentials. The laboratory flow testing has helped demonstrate how the ICDs and AICDs can either help prevent steam breakthrough from occurring or limit the rate of steam breakthrough in the zones of concern. By limiting the flow rate of steam breakthrough, the flow control devices will also help to protect the sand screen from erosion caused by high velocity flow.

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