Implementation method for underground heat source of oil and gas well

The invention discloses an implementation method for an underground heat source of an oil and gas well and application of the implementation method. The implementation method mainly comprises the following four steps of 1, tripping in a drilling tool; 2, opening a falling basket when the drilling tool reaches a preset position; 3, filling reaction materials for reaction; the method specifically comprises the following steps: carrying out aluminothermic reaction at a certain underground position; adding an ignition agent and a combustion improver, and reacting aluminum with metal oxides (such as iron sesquioxide, chromium sesquioxide, manganese dioxide and the like) under a high-heat condition; the released heat is used for melting the low-melting-point eutectic alloy material, the molten alloy reaches a sealed area under the action of pressure, and the reaction pressure, temperature and reaction speed are controlled by adding inhibitors such as metal oxide and silicon dioxide. Downhole sealing is achieved thr