Research and application experience of water Huff and Puff technology on low-permeability oil field

Abstract

Background. This paper presents a study of the applicability and the first results of pilot works of the technology of periodic water injection into production wells with subsequent oil production (Huff and Puff ), which was not previously used in Russia. The oil field of the company “Gazprom Neft” with a terrigenous reservoir of low permeability is considered. Aim. It is planned to use the technology at marginal waterless wells with hydraulic fracturing, which are on the verge of profitability, to increase oil production. Materials and methods. The physical principles of capillary impregnation in a hydrophilic reservoir were presented, which, under given conditions, should lead to an increase in oil production in waterless wells during cyclic water injection and shutdown with subsequent production. Since this technology was not previously used in Russia, a review and analysis of the unsuccessful application in the United States and the successful experience in China in fields with similar properties and wells was carried out. For the design of pilot works, calculations were made on a synthetic hydrodynamic model with double porosity and permeability, according to which a significant increase in oil production in a marginal well was obtained relative to standard operation. Pilot work was carried out on four oil wells of the company’s field, which were previously planned to be transferred to the reservoir pressure maintenance stock. Only two of them managed to meet the required injection and shutdown periods. Results. Pilot work didn’t show significant increase in oil production after the application of the technology. At the same time, there was no decrease in representative wells, which should have occurred due to a decrease in the phase permeability of oil, which indicates the work of the effect of capillary imbibition during water injection. Conclusions. Based on the analysis of the ambiguous results of pilot works, a conclusion is made about the ineffectiveness of the huff and puff technology in the specified modes, the necessity of their optimization and further research.