Several multirate separator tests (MRTs) have been undertaken on wells in the Veslefrikk field that are on commingled production from the Brent Group and Intra Dunlin Sand (IDS). During these tests, produced-water (PW) samples were also collected. Integrated analysis of the results of interpretion of the PW analyses and the MRT results has provided a range of information for each production zone, including the nature and composition of the PW, the seawater fraction of these produced waters, the fraction of total water flow being produced, pressure, productivity index, oil and water rates, and water cut. This information can reduce the need for running production-logging tools (PLTs), allows the scaling potential between the deeper and the shallower zones to be evaluated, aids squeeze-treatment design, is beneficial for predicting formation damage from crossflow, and aids water-shutoff decisions.
In an accompanying paper, McCartney et al. (2012) describe how PW analyses from the MRT are interpreted to determine— among other parameters—the amount of water produced from each zone (water allocation) at each of the test rates during an MRT. In this paper, the methods of analyzing these results in combination with separator-test data are described with the aid of a field example to demonstrate how they provide detailed information about the downhole conditions and zone properties of the well. On the basis of the analysis, a set of well interventions was recommended. Following confirmation of the principal MRT results by a PLT, some of the recommended interventions have been performed successfully. Experience from Veslefrikk suggests that MRTs can be considered as a possible replacement for running PLTs or as an additional source of data that can be acquired more frequently.