No abstract

Currently the flow diversion techniques (FDT) are quite often used to enhance the waterflooding efficiency at the late stage of field development. In particular, the issue of waterflooding efficiency improvement is specifically acute for the carbonate reservoirs due to complex structure of the reservoir, heterogeneity of reservoir properties as well as the presence of natural fractures. All listed factors result in significant decrease of waterflooding efficiency due to quick water breakthrough into the wells through the low flow resistance channels (LFR) which results in significant decrease of the oil recovery factor (RF). In many cases waterflooding at the similar fields is not applied at all resulting in the produced water disposal issue. It is evident that for the purpose of solving such issues application of FDT based on the injection of various polymer gel-forming compounds into the formation allowing decrease in conductivity of LFR channels resulting in increase of swept reservoir volume may seem efficient. Considering the development of chemical industry, the FDT market currently offers a lot of compositions and compounds in a wide price range having different technological characteristics and designed for different conditions. Due to this the selection of the most appropriate compositions with account of all factors is an acute task requiring thorough approach with application of often unique laboratory experiments using unconventional equipment as well as performance of pilot works at individual field areas. This paper presents the sequence of actions (from laboratory studies for the determination of the suitable polymer compositions to the selection of the specific field areas for the pilot works performance) for complete justification of FDT application at one of the Central Khoreyver Uplift fields located in the Timano-Pechora oil and gas province. Apart from presence of the heterogeneous and fractures carbonate reservoir, the field is characterized by high mineral content of the formation water what imposes significant restriction on the use of a number of polymer compositions as well as requires more thorough approach to the selection thereof. The paper also describes the flow experiments held, inter alia, using the actual core samples with use of high-mineralized formation water and shows their results. As a part of this work the justification of injection of two polymer compositions selected after laboratory studies at 2 pilot areas with assessment of incremental production using the simulation model (SM) developed with the account of the annual tracer studies allowing assessing LFR channels properties was carried out. As a result of the performed work, 2 pilot polymer compositions injection works were included into the company's business plan for 2019.

No abstract