Slotted liners are used extensively in the majority of steam assisted gravity drainage (SAGD) operations conducted in Western Canada due to their superior mechanical strength and integrity in contrast to other mechanical sand-control devices. These liners are required because of the generally poorly or unconsolidated nature of the majority of formations in which SAGD applications are conducted. These liners can have a variety of configurations with varying slot density, slotting patterns, slot apertures and slot internal geometries. The overall objective of a successful slotted liner design is to ensure that the liner allows the maximum production of bitumen and other fluids with a minimum pressure drop, while retaining the majority of the formation sand and preventing infill of the horizontal section of the well with solids and erosion and failure of downhole pumps and surface equipment. This paper describes a detailed lab test protocol which was successfully developed over a number years for the design and evaluation of slot geometry for SAGD applications, describes test procedures used and quantifies some of the major mechanisms discovered that lead to the plugging of slots. It has been found that in addition to grain size of the sand under consideration and slot geometry, that clay content of the formation, flow velocity, wetting phase type and pH play crucial roles in the plugging mechanism of slotted liners. Clay plugging at the top portion of the slots has been found to be the dominant damage mechanism.
Gas condensate reservoirs exhibit complex coupling between phase behaviour, interfacial tension, velocity and pore size distribution. Appropriate characterization of the in situ fluids and relevant flow testing can provide valuable insight into gas condensate reservoir forecasting. The following insights were obtained during the course of this testing:
This paper discusses performance of gas condensate reservoirs.These reservoirs have a reservoir temperature located between the critical point and the cricondentherm on the reservoir fluid's pressure-temperature diagram. This is the only unique and accurate means of identifying gas condensate reservoirs; any other definition [condensate-gas ratio, C7+ molecular weight (MW) or C7+ API gravity] is specious and ersatz.
In these reservoirs, as the pressure drops, vapour and liquid phases result.Capillary pressure causes phase interference which usually reduces gas productivity. A cross-section of interesting topics that show the complexities of gas-condensate reservoir production have been reported in the literature(1-7). All of the relevant parameters, if well understood, will lead to more accurate evaluation of the amount of hydrocarbon in place, the rate at which the resource can be produced and the optimization strategies as the reservoir matures.
Bennion, D.B. (Hycal Energy Research Laboratories Ltd.) | Ma, T. (Hycal Energy Research Laboratories Ltd.) | Thomas, F.B. (Hycal Energy Research Laboratories Ltd.) | Romanova, U.G. (Hycal Energy Research Laboratories Ltd.)
Bennion, D.B. (Hycal Energy Research Laboratories Ltd.) | Thomas, F.B. (Hycal Energy Research Laboratories Ltd.) | Schulmeister, B. (Hycal Energy Research Laboratories Ltd.) | Ma, T. (Hycal Energy Research Laboratories Ltd.)