Method for injecting heat storage material to exploit hydrates in horizontal well

Abstract

The invention relates to the technical field of natural gas exploitation, in particular to a method for injecting a heat storage material to exploit hydrates in a horizontal well. The heat storage material provides heat, during the migration process of the heat storage material, the linear loss of conventional thermal fluid is reduced, the intercommunication of the heat storage material expands the heating range of a reservoir, continuous heating of reservoir mining is maintained, the decomposition rate of the hydrates is increased, and gas is continuously and efficiently produced. The methodcomprises the following steps that S1, in a production well, the heat storage material and ceramsite are injected together into a formation, and at the same time, in an auxiliary well, the heat storage material is continuously injected into the formation to achieve the effect of perforation; and S2, when the production well begins to produce in a depressurizing mode, negative pressure is generatedinside a wellbore, the heat storage material and the ceramsite originally entering the reservoir migrate and accumulate towards the direction of the wellbore under the action of the negative pressure, during the migration process, the heat storage material is squeezed, when the pressure reaches a certain level, the internal structure of the heat storage material changes, and heat energy is released, so that the temperature of the reservoir increases, and the decomposition of the hydrates is accelerated.

Description

technical field [0001] The invention relates to the technical field of natural gas exploitation, in particular to a method for injecting heat storage materials into horizontal wells to exploit hydrates. Background technique [0002] As we all know, natural gas hydrate is widely distributed in permafrost zones and continental margins in nature, and is formed by small "guest" molecules (<0.9nm) such as CH4 contacting water molecules under low temperature and high pressure. clathrate crystalline compound. It is preliminarily estimated that the total natural gas resources of hydrate reserves in the world is about 2.1×1016m3, which is equivalent to 21 trillion tons of oil equivalent. At present, countries all over the world have gradually entered the stage of zone exploration, evaluation and trial production. [0003] Natural gas hydrate exists in the sedimentary layer on the seabed. The water depth is less than 300m, and it is in a stable state at a temperature of 0-10°C and...

AI Technical Summary

Problems solved by technology

[0008] The application number is 201710573395.8, which adopts the method of combining depressurization and heating, but has the following disadvantages: large loss of heat energy along the way, small range of action, high energy consumption, adding heat injection pipelines, increasing the difficulty of well completion and increasing operational risks