A preliminary evaluation of an LTPF process for Statfjord Field, Norway

Abstract

Abstract A preliminary laboratory study was initiated in 1991 to assess the potential of Low Tension Polymer Flood (LTPF) in the Statfjord Field Upper Brent Formation. On the basis of phase behaviour and compatibility experiments, four formulations were identified for further evaluation and a live oil core flood test was conducted to assess the oil recovery potential of one formulation under reservoir conditions. Encouraged by the initial laboratory results, a three-step LTPF process design strategy was followed. A target area of the reservoir was identified, the performance of the waterflood in this area was history-matched using the LTPF simulator and a predictive simulation of several LTPF application strategies was performed. The chemical flood simulator, BPOPE, was first employed to match the laboratory core flow test by incorporating the LTPF characteristics measured. Following this conditioning, it was then used to assess the application of LTPF in the formation selected. A variety of perforation strategies, LTPF slug sizes and operating conditions were tested, all with reservoir cooling due to the injection of cold sea water. The modelling shows LTPF to be sensitive to slug size in particular, to surfactant phase behaviour and to adsorption loss levels. It was concluded that the LTPF process could be applied to the Tarbert formation, to yield additional recovery. However, an optimization is required to make the LTPF process attractive for implementation. This paper presents the essential phase behaviour data, the results of the live oil core flow test, and discussion of the computer simulation approach and the results.