The authors set the actual task of developing the water shutoff technology, which includes all aspects and basic requirements for used composition: a low viscosity solution for creation of the insulating screen of long radius; adjustable gel time of the solution over a wide temperature range; high gel shearing stress; selectivity of impact. The main component of the gelling system is a reagent AC-CSE-1313 grade A (manufactured by MFC ChemServiceEngineering LLC) with a new complex mechanism of action. The working solution based on the reagent AC-CSE-1313 grade A and hydrochloric acid has a low viscosity (up to 1.0 mPa*s), and the resulting gels in reservoir conditions have high rheological properties. In the working solution there are dispersed particles around which a layer of polysilicic acid with globules forming in size of 30-40 μm, leading to increasing of the active surface and hydrophilic oil displacement. The results of filtration studies indicate the selectivity of the composition.
The first field trial on water shutoff were carried out in December 2015 in Slavneft-Megionneftegaz JSC at three wells of the Arigolskoye field in conjunction with activities on conformance control at injection wells. In 2016, the water shutoff works were performed at four wells of the Taylakovskoye field. After the water shutoff works the incremental oil rate was achieved at average 5.6 tons per day, while a decrease in the well flow rate by liquid made 30 percent. According to the results of work for 2015-2016 the specification of the criteria for applying the water shutoff technology has been performed, and it is planned to continue work in the oilfields of Slavneft-Megionneftegaz.
References
1. Petrov N.A., Mekhanizmy formirovaniya i tekhnologii ogranicheniya vodopritokov (Mechanisms of formation and technology of water influx control), Moscow: Khimiya Publ., 2005, 171 p.
2. Dubinskiy G.S., Tekhnologiya ogranicheniya vodopritoka v skvazhinu v usloviyakh razlichnykh mestorozhdeniy (Technology of water control in conditions of various deposits), Collected papers “Metody uvelicheniya nefteotdachi trudnoizvlekaemykh zapasov. Problemy i resheniya” (EOR methods for hard-to-recover reserves. Problems and solutions), 2003, V. 4, pp. 136–137.
3. Blazhevich V.A., Umrikhina E.N., Novye metody ogranicheniya pritoka vody v neftyanye skvazhiny (New technologies of water control), Moscow: Nedra Publ., 1974, р. 166.
