Heavy well killing fluids are an integral part of workovers in wells with abnormally high reservoir pressure. At the same time, they have a high cost and do not always meet the requirements of Gazprom Neft PJSC and other oil companies for the conditions of high-temperature reservoirs. In order to expand the range of applied compositions, lead their parameters to the requirements of regulatory documents and reduce the cost of heavy well killing fluids as part of the implementation of the technological strategy in the direction of "Long-term infrastructure development program - Production and operations", research work was carried out to develop new formulations of fluids for killing wells in complicated conditions. At the beginning of the work, the requirements were outlined to which the developed heavy well killing fluids must be met taking into account the specifics of preparing fluids at the Company's fields, as well as taking into account the reservoir conditions of the fields. Aqueous solutions of salts (brines) were considered as heavy well killing fluids. Based on literature data, patent analysis, and the Company's experience, 5 potentially promising salts and salt compositions were selected. The first part of the experimental studies was the laboratory selection of consumption rates (concentrations and ratios). Further, a study of the physicochemical properties of well killing fluids was carried out, as a result of which it was revealed that one of the salt systems does not meet the low-temperature requirements and did not participate in further studies. For the remaining formulations, work was carried out on the selection of additives with the determination of effective dosages: scale inhibitors, anticorrosive additives and oil wetting agent. The result of the work is 4 new formulations of heavy killing fluids with a density of 1600 kg/m3, adapted to the conditions of Subsidiaries of the Company - potential consumers of heavy well killing fluids. The effectiveness of the formulations has been confirmed by pilot field tests carried out at the Company's fields. The implementation of these inventions allows to achieve a reduction in the cost of heavy well killing fluids with density of up to 1600 kg/m3 by more than 20%.
References
1. Ryabokon' S.A., Tekhnologicheskie zhidkosti dlya zakanchivaniya i remonta skvazhin (Process fluids for completion and repair of wells), Krasnodar: Publ. of NPO Burenie, 2016, 382 p.
2. Kunakova A.M., Duryagin V.N., The improvement of economic efficiency of the well control process by the implementation of new process liquids (In Russ.), PROneft'.Professional'no o nefti, 2016, no. 2. pp. 61–63.
3. Patent RU 2737597 C1, Composition for preparation of heavy process fluid for well killing, Inventors: Kaybyshev R.R., Kunakova A.M., Karpov A.A., Duryagin V.N., Usmanova F.G., Rabaev R.U.
4. Shishkin A.V., Domestic solutions for killing wells with abnormally high reservoir pressures (In Russ.), Territoriya neftegaz, 2015, no. 11, pp. 68 – 71.
5. Ryabokon' S.A., Gorlova Z.A., Lamosov M.E., Solevoy sostav dlya prigotovleniya tyazhelykh tekhnologicheskikh zhidkostey bez tverdoy fazy s plotnost'yu do 1600 kg/m3 (Salt composition for the preparation of heavy process fluids without a solid phase with a density of up to 1600 kg/m3), URL: https://neftegaz.ru/science/booty/332608-solevoy-sostav-dlya-prigotovleniya-tyazhelykh-tekhnologiche...
