Recapturing the Value of Fractional Flow Analysis in a Modern Day Water Flood

摘要

The Champion Field is located 40 km offshore Brunei, Northern Borneo, in a water depth of 10 - 45 m. It has been on production since 1972 and secondary recovery by treated seawater injection commenced in some reservoirs in 1984. In this paper we present an analytical approach for estimating relative permeability end-points from production/injection data as a starting point for sensitivity studies on the applicability and value of expanding water flooding to the rest of the Champion field. A significant volume of special core analysis data is available, however, the representativeness of this data is limited due to differences between reservoir and laboratory conditions. The cores might also have changed properties such as wettability, depending upon coring method, cleaning etc. In order to screen the value of expanded water flooding a performance review of the Champion water flood reservoirs was carried out using reservoir engineering analytical techniques to generate reservoir fractional flow. The field's performance to fractional flow was matched using a set of Water-Oil relative permeability curves generated by Corey exponents and Buckley-Leverett / Welge theory. This match leading to an estimation of the likely uncertainty range in end point relative permeabilites of Water-Oil curves, mobility ratio and to calculate the expected production profile and ultimate oil recovery. Combined with the available SCAL data and a good understanding of past flood performance an ability to forecast future production was obtained. The work presented forms the first phase in the assessment of the value in expanding water flooding throughout the Field. In essence the work recaptures the value of analytical methods within the workflow of present-day project developments.