Non-isothermal mathematical model of blocking tecnogenic fractures

A. M. Kasperovich ; A. P. Shevelev ; A. Ya. Gilmanov

Vestnik Samarskogo universiteta. Estestvennonaučnaâ seriâ, Tome 30 (2024) no. 4, pp. 101-115

Résumé

Nowadays, large oil fields have moved to the stage of declining production, to maintain reservoir pressure, it is necessary to apply flooding technologies. To maintain the previous rates of oil production, it is necessary to force selections by increasing the value of downhole pressure on the injection wells. However, the risks of exceeding the fracturing pressure are increasing, which can lead to the formation of technogenic fractures. An intensive increase in the fracture can lead to an increase in the risks of premature water reaching through it into the drainage zone of the producing wells, which will lead to an increase in the value of the water oil ratio. The analysis of current numerical mathematical models of colmatation of technogenic fracture has shown the status of determining the volume of leaks of the colmatation agent beyond the fracture, considering changes in the temperature field at the bottom of the injection well. This problem is relevant, since special research complexes have been conducted at several oil and gas fields to determine the growth of technogenic fractures that arose because of excess fracturing pressure and fell into the drainage zone of producing wells. A change in the temperature field of the reservoir will allow direct changes in the viscosity of the injected colmatation agent, as well as determine the amount of leakage of the agent beyond the limits of the technogenic fractures. The article describes the construction of a non-isothermal physico-mathematical model of injection of a suspension system (water-reagent) into the reservoir, considering changes in the temperature field of the reservoir, the volume of reagent leaks beyond the limits of the technogenic fracture, considered for the first time. The aim of the work is to establish the dependences of the leakage volume of the colmatation agent, the critical time of filling the fracture from changes in the temperature field at the bottom of the injection well. A nonisothermal reservoir simulation model has been constructed showing the stages of initiation of a technogenic fracture with its subsequent colmation. The distribution of the concentration of the colmatation reagent both in the fracture and outside it, depending on the change in the temperature field at the bottom of the well, is obtained. It is determined that the volume of reagent leaks decreases if changes in the temperature field at the bottom of the injection well are considered with identical well operation parameters and geological and physical characteristics of the formation.

Détail

Keywords: non-isothermal reservoir simulation modeling, reagent leakage volume, reservoir properties, temperature field.