Foams that effectively reduce gas permeability were formed over a wide range of experimental conditions. The ability of selected foaming agents to form foam was evaluated in bulk foam measurements, screening core tests, and in reservoir condition core tests. Results reported show that oil usually adversely affected foam performance with higher molecular weight alkanes showing less of an adverse effect for the foaming agents tested. Foam can be effectively generated in an oil-wet porous medium but was shown to be much less effective than in a water-wet medium for the foaming agents studied. High pressure gradients of up to 4524 kPa/m (200 psi/ft) resulted in effective foam generation with an effective foam continuing to 8500 pore volumes of injected nitrogen. The enriched gas mixture used in this study was shown to adversely affect foam even though the foaming agent was selected through screening testing. This showed the importance of including reservoir condition testing prior to the final selection of a foaming agent for a given reservoir application. Effective foaming agents were identified for use in pilot tests in a typical West Texas CO2 flood and in a typical Canadian hydrocarbon miscible flood.

Seabed data acquisition methods offer numerous advantages over towed streamer data. These advantages can lead to improved static and dynamic reservoir characterization. By recording complete vector field data at the sea floor with full azimuth acquisition improved shallow resolution, signal-to-noise ratio, spectral content, deep imaging and 3D illumination can be achieved. Also in the presence of obstacles such as production facilities a regular coverage can be assured.Autonomous node technology has been developed to a fully commercial system. It has demonstrated improved imaging of complex reservoir with both pressure (PP) and converted shear (PS) with stable and consistent measurements achieved by very well planted nodes into the sea floor and full azimuth acquisition with densely sampled shots.It has been experienced that the background response from well planted nodes can be repeated in a 4C-4D scenario when the coupling conditions are the same. The vector fidelity in the node system will secure this behavior. In addition, the accurate positioning and re-positioning of the nodes under realistic water depth ranges gives positioning accuracy close to permanently buried cable systems. An experiment performed on the Volve field in the North Sea with pairs of nodes planted side by side clearly confirmed the high degree of stability in the coupling and the repeatability of the measurements from all components. At 100 m water depth all the planted nodes were within a short radius around the pre-plot position.A cost sensitivity study of different 4C-4D node scenarios depending of field size, water depths and node spacing indicates that, for larger field sizes (300-600km2 receiver coverage), the alternative use of nodes could be significantly more cost effective than permanently buried cable systems. Moreover, there are advantages linked to the acquisition geometry, operation, zero equipment life time risk and low initial investment.