In this paper, recent EOR field trials are discussed to demonstrate the value of in-well fiber optic (FO) applications. The trials are in a field in Oman that has been considered for an enhanced oil recovery (EOR) development. Polymer Flood and Steam Injection have been proposed as alternative EOR methods and both are being studied. A recent polymer injectivity test and steam trial were conducted in order to de-risk uncertainties in a full field development and this paper presents the application of FO in these EOR trials to help meet these objectives.
The fiber optic approach is viewed as an alternative technology to production logging and it provides the option of real time acquisition. In one area of the field, a shut-in well was converted to a polymer injection well and utilized for a single well injection test (SWIT). The test was carried out for six months to quantify the inflow profiles and injectivity to the reservoir under matrix conditions. For the steam trial in another area of the field, three producers and one injector with FO were utilized to demonstrate the feasibility of a horizontal well steam development and to evaluate the requirement and effectiveness of injection conformance.
FO analysis from both trials concluded that the Distributed Temperature Sensing (DTS) and Distributed Acoustic Sensing (DAS) combination can be successfully used for injection conformance profiling. DTS/DAS measurements were taken during the course of the polymer injection test. These indicated that conformance was incomplete from the onset and deteriorated during the course of the test, with a large proportion of fluids in-fluxing into the reservoir through a narrow section at the toe of the well. One of the main objectives from the steam trial was to measure and manage conformance along the horizontal steam injector. Use of FO helped demonstrate the importance of managing conformance in order to achieve satisfactory sweep efficiency.
This paper explains how these new technologies play a key role in reducing the uncertainties in reservoir performance in EOR developments. The combination of FO (DTS and DAS) data sets allowed the interpretation of data gathered to complement each other and provide more comprehensive conclusions.