A FOAM PILOT TEST AIMED AT REDUCING GAS INFLOW IN A PRODUCTION WELL AT THE OSEBERG FIELD

In June 1994 a foam pilot test was performed in a production well at t he Oseberg Field, North Sea. The Oseberg Field is developed by up-dip gas injection and is currently experiencing gas breakthrough in some o f the production wells. The production well, B-27, chosen for the test is located in the Gamma structure and produces from the Oseberg Forma tion, a highly permeable (2-3 Darcy) homogeneous sandstone. B-27 is pe rforated in 5 intervals in the lower section of the Oseberg Formation. To evaluate the gas-blocking effect of foam within a short time frame , and to increase the accuracy of measurements, only the top perforati on interval of B-27 was treated and back-produced. Foam was generated by slug-injection of gas and surfactant dissolved in seawater. Gas-oil ratio (GOR) was reduced by about 50% after foam treatment, compared t o pre-foam production tests. The foam pilot-test in production well B- 27 was operationally successful. The test has shown that foam can be g enerated by slug injection of gas and surfactant solution and that foa m can reduce GOR even in zones with high oil influx. The foam treatmen t was effective in reducing gas inflow over the six month period of th e test.