Geothermal well, method of establishing thereof and method for geothermal energy production

A method for establishing a geothermal well from an existing well having a second tube (2), formed by a casing tube, having a closed bottom in a second depth, a second inner diameter, and a second outer diameter and a third tube (3), formed by a casing tube, having a closed bottom in a third depth, and a third inner diameter larger than the second outer diameter, and a third outer diameter,

• wherein the second tube (2) is inside the third tube (3), a second interspace (30) is present between the second tube (2) and the third tube (3);
• wherein the third depth is smaller than the second depth,
• forming at least one through-hole (21) in the second tube (2) above the bottom end of the third tube (3);
• inserting a first tube (1) into the second tube (2) to a first depth that is smaller than the second depth and larger than the third depth, wherein the first tube (1) comprises at least one opening in the first depth and having a first inner diameter, a first outer diameter, and a side wall which is thermally insulated along at least a segment thereof, and wherein a first interspace (20) is formed between the first tube (1) and the second tube (2), wherein the first tube (1) has at least one opening in fluid communication with the first interspace (20), wherein the through-holes (21) allow fluid communication between the first interspace (20) and the second interspace (30);
• inserting a first sealing element (22) above the through-holes (21) into the interspace (20) between the first tube (1) and the second tube (2);
• and
• inserting a thermally insulating material into the interspace (20) above the first sealing element (22).

A method for geothermal energy production using a geothermal well including:

• a first tube (1) comprising at least one opening in a first depth and having a first inner diameter, a first outer diameter, and a side wall which is thermally insulated along at least a segment thereof;
• a second tube (2) having a closed bottom in a second depth, a second inner diameter larger than the first outer diameter, and a second outer diameter;
• a third tube (3), formed by a casing tube, having a closed bottom in a third depth, a third inner diameter larger than the second outer diameter, and a third outer diameter,
• wherein the first tube (1) is inside the second tube (2), a first interspace (20) is formed between the first tube (1) and the second tube (2), wherein the first tube (1) has at least one opening in fluid communication with the first interspace (20),
• wherein the second tube (2) is inside the third tube (3), a second interspace (30) is present between the second tube (2) and the third tube (3);
• at least one through-hole (21) is formed in the second tube (2) above the bottom of the third tube (3), which allow fluid communication between the first interspace (20) and the second interspace (30), a first sealing element (22) is disposed in the first interspace (20) above the through-holes (21) for preventing an upward flow of fluid in the first interspace (20), and a heat insulating material is disposed in at least a portion of the first interspace (20) above the through-holes (21),
• the method comprising:
• introducing a fluid into the second interspace (30) of the geothermal well;
• directing the fluid from the second interspace (30) through the through-holes (21) of the second tube into the first interspace (20);
• directing the fluid from the first interspace (20) through the at least one opening of the first tube (1) into the inner space (10) of the first tube (1) and bringing the fluid to the surface through the inner space (10) of the first tube (1);
• and
• extracting heat from the fluid,
• wherein the fluid directed from the second interspace (30) through the through-holes (21) of the second tube into the first interspace (20) is guided further downward in the first interspace (20) to the first depth, which is greater than the third depth.