IOR 1995 - 8th European Symposium on Improved Oil Recovery

Differences in recovery under several displacement mechanisms, for successive increases in reservoir detail, are outlined for the Brent-NI reservoir in the Visund field off Western Norway.

The aim of this work is to model complex petroleum reservoirs in terms of relevant but arbitrarily shaped heterogeneities. This removes the constraint of describing heterogeneiries as constant property regions confined to cartesian grid blocks.

Carbonate oil reservoirs begin to play an ever increasing role in the development of oil production in Russia, as new oilbearing regions and deeper lying formations become involved in geological prospecting works.

Coreflood experiments for obtaining relative permeability curves are often subjected to capillary effect which is neglected in the laboratory data interpretation. Due to the well-known capillary end-effect the water saturation distribution prior to start of a flooding experiment is often non-uniform. In addition the saturation at different location of the core has experienced different saturation history, which might make hvsteresis effect significant in the final relative permeability curves.

Tracer tests can be used to investigate reservoir heterogeneity which we define as reservoir characteristics which effect the sweep efficiency and fluid flow behaviour on a scale of practical interest, and which can be very important information especially for the design of IOR applications. It is helpful to understand the mechanism of tracer transport in various heterogeneous reservoirs before any interpretation of tracer test result is used to deduce reservoir heterogeneity.

Spurred by the enormous expense of developing heterogeneous fields and by the desire of oil companies to increase ultimate recovery, the science of reservoir characterization is making rapid progress. Reservoir characterization encompasses all techniques and methods that improve understanding the geological and petrophysical controls of fluid flow. The objective is to provide practical reservoir models for optimum field development.

The giant Troll gas field offshore Norway also contains one of the largest oil accumulations in the North Sea. The oil is located in thin layers sandwiched between the gas cap and an active aquifer. Its development is based on long, horizontal wells tied back to a concrete semi-submersible production platform. The oil will be developed stagewise with first oil planned in late 1995.

In this paper we study the effects of variations in relative permeabilities for threephase flow on predicted oil and gas production behavior when immiscible gas displacement is used to enhance oil recovery from waterflooding.

The carnet level of novel technologies for oil fields development is sufficiently high. The common world practice includes oil reservoir water flooding, chemical and thermal EOR, miscible/immisible oil displacement - injection of hydrocarbon gases, carbon dioxide etc. In the practical development of heavy oil fields, thermal drive plays an especial role. However, this is a common knowledge, that even the application of high efficient EOR/IOR technologies for oil fields development using vertical wells does not enable to achieve the final oil recovery for more than 40-50% of the estimated reserves.

This paper is the second in a series of papers dealing with various aspects of the hydrocarbon gas-foam pilot project planned for the Snorre Field. The first paper summarized the project plans and detailed the laboratory work leading to the selection of a surfactant for the field test.