CALCULATION OF TECHNOLOGY ALGORITHM AND SUCCESSFUL APPLICATION OF THERMOCHEMICAL METHOD DURING WELL WORKOVER
Authors: Gusakov V.N. , Silnov D.V. , Petrenko S.N. , Semenovyh A.N. , Pegov A.V. 
Published: December 2023

This article is devoted to the analysis of the success of the thermochemical method of generating and transferring thermal energy for underground workover technologies of producing wells. In order to justify the design and consumption of reagents, an algorithm and calculator were compiled based on the well design and thermophysical properties of consumables and fluids: heat capacity of steel, water, ice, enthalpy of ice melting and chemical reaction, the length of the paraffin hydrate plug interval.Thermophysical calculations have shown that for a well with a diameter of 146 and a 73 mm tubing lift, 153 kg of fuel reagent is required for thermal destruction of a paraffin hydrate plug 100 meters long. Based on the geometry of the candidate well and the expected intervals of waxhydrate plug formation, reagent consumption is determined, and a design and work plan are drawn up. The algorithm makes it possible to calculate the flow rate and concentration of working solutions of reagents in order to reach the target temperature at the thermal exposure interval.Measurements of the deep thermometer made it possible to determine that the selected composition of reagents and the exothermic reaction with a delay in heat generation allow to achieve a loss of heat to dissipation at the level of 17 % by 2500 meters of the tubing elevator.The technology of thermal destruction of paraffin-hydrate plugs in gascondensate wells was implemented at the East-Tarkosalinskoye oil and gas condensate field and the Komsomolskoye field with achievement of the specified success criteria.Technologies for development and removal of water from the bottomhole of gas and gas-condensate wells ensure formation of a gas-liquid mixture and removal of water from the bottomhole at the wellhead. The technologies were used at the production facilities of the Vuktyl field (Komi Republic), Amangeldygaz (Kazakhstan Republic), and the East-Tarkosalinsky field (Yamalo-Nenets Autonomous Okrug). As a result of water development, gas wells are switched from pulsating to permanent operation. Heat (thermal) treatment of producing wells uses injection of heat and nitrogen-generating solutions with transfer of thermochemical energy of reagents through permafrost and low-temperature intervals with minimal heat losses. The efficiency of the heat transfer technology was confirmed by temperature measurement by downhole sensors at 139–147 °C at development facilities with reservoir temperatures of 41–43 °C (Ural-Volga region, Purovsky region).The technology of restoring the productivity of gas and gas condensate wells using aerated acids makes it possible to increase the success of subsequent development. The use of the technology of foam acid treatment with methanol makes it possible to successfully restore the productivity of gas and gas condensate wells prone to water removal. Aeration and heating of process solutions of reagents makes it possible to carry out comprehensive measures for treatment of the bottomhole zone of the well with acid and thermochemical impact.