Foam Performance Under Reservoir Conditions

Abstract

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.

Stability and texture of CO 2 /N 2 foam in sandstone

“…It was also concluded that effective foam can be generated in an oil-wet environment provided appropriate foaming agents are selected. [33] Osterloh and Jante (1992) studied the effects of gas and liquid velocities on steady-state foam flow in porous media at high temperatures. Experiments were performed at 150 o C using nitrogen gas along with C16-18 alpha-olefin-sulfonate (AOS) and pressure gradients were measured in a 6.2 mD sand pack over a wide range of fractional flows and gas and liquid velocities.…”

Development of More-Efficient Gas Flooding Applicable to Shallow Reservoirs

“…Foam stability varies widely in the presence of different oil types as has been observed by some researchers (Suffridge et al, 1989;Novosad, 1990, 1992). However, surfactant type is also a contributing factor to the effect of oil presence.…”

“…The effect of oil on foam depends on the interaction between the oil and the surfactant (Suffridge et al, 1989;Meling and Hanssen, 1989). Therefore, both the oil and surfactant properties may be the important factors.…”

Technology on In-Situ Gas Generation to Recover Residual Oil Reserves

“…Contaminants such as methane and nitrogen significantly increase the CO 2 minimum miscibility pressure, and H 2 S, C 2 H 6 or intermediate hydrocarbons have the opposite effect. [28] Figure 6. Slim-tube oil recoveries for fixed oil composition and temperature over pressure [12] Improved oil recovery by CO 2 flooding results from: In miscible flooding all the above phenomena are responsible for improving the oil recovery but the first two outweigh the rest.…”