Enhanced Oil Recovery - Wisting Development

Abstract

The average oil recovery on the Norwegian Continental Shelf is 47% (NPD 2017b). Until today, most of the oil and gas fields at the Norwegian Continental Shelf have been produced with pressure depletion or gas/water injection. Enhanced oil recovery (EOR) techniques are now necessary in order to maintain the production and increase the oil recovery. The use of EOR methods have so far been limited on the Norwegian Continental Shelf due to high cost and uncertainty regarding their performance.

The purpose of this Master s thesis was to further investigate the technical and economical feasibility of the EOR methods identified as technically feasible for the Wisting field in Kalsås and Marthinussen (2017). Four EOR methods have been investigated: polymer flooding, surfactant flooding, alkaline/surfactant/polymer flooding, and miscible CO2 water alternating gas injection. The technical evaluation was conducted using the Eclipse black oil simulator E100, using data based on laboratory experiments and previous field experience reported in the literature. The economical evaluation was conducted by calculating cost per ultimate incremental barrel of oil produced.

The technical and economical evaluation showed that the potential of the different EOR methods reviewed are limited. Polymer flooding shows the greatest potential among the EOR methods studied, where the Central East segment s base case has an ultimate incremental oil production of 57200 Sm3 at a cost of $6.01 per incremental barrel of oil produced. Both surfactant flooding and miscible CO2 water alternating gas injection show no potential in the Wisting field. Alkaline/surfactant/polymer flooding has the highest incremental oil recovery, however, the cost per incremental barrel of oil is $43.64 in the Central East segment base case, mainly due to the cost of the ineffective surfactant.