Abstract
The endeavor of this study is to evaluate the economic potential of the Norne Field's E-Segment (a Norwegian Offshore Oil Field) under different cost structure for six different field development strategies based on the simulation results of low salinity water-flooding (LSW).
The ultimate oil recovery of the Norne Field's E-Segment is ca. 40% after employing the combination of primary and seawater-flooding as a secondary recovery technique. Therefore, there is about 60% oil is still trapped as a result of high capillary action of water. This trapped oil could be extracted by introducing a novel recovery mechanism. In this case, LSW is considered to extract this residual oil adhered to rock wall. LSW simulation studies using original wells indicated that the water injection with optimal salt concentration of 1,000 ppm TDS (total dissolved salts) or 1.0 kg/m3 yields substantially higher oil production compared to sea water-flooding. Having found that the LSW is an effective Improved Oil Recovery (IOR) technique for the Norne Field's E-Segment, the next tasks are to find the different ways to increase oil recovery using LSW followed by economic feasibility study. Six different well development plans are investigated. For example, case 1 is the base case with seawater- flooding using the existing wells. The other five cases are all LSW, with the following well configurations: (2) using the original wells, (3) using the original wells in addition to a new producing well, (4) using the original wells in addition to a re-completed producing well, (5) using the original wells in addition to a new injection well, and (6) using the original wells in addition to a re-completed injection well. Economic feasibility study has been conducted for all these six cases using Net Present Value (NPV), Profitability Index (PI), and Internal Rate of Return (IRR) methods.
Analyzing the simulation results of the above six field development plans, it has been revealed that the oil production for five LSW cases are higher than the seawater-flooding case which, in turn, result more NPV, more PI, and more IRR for LSW cases. Among the six field development cases, Case- 3 has been indicated the highest cumulative oil recovery compare to other five cases and give the highest NPV. Thus, it could be concluded that the Norne Field's E-Segment is a good candidate for LSW to extract the residual or trapped oil.
In this study, LSW simulation results are found to give a favorable mobility ratio, which in turn is resulting the highest oil recovery and the highest revenue.
