Boosting well performance in geothermal systems
Methods and systems are provided for extracting thermal energy from a conventional geothermal reservoir. One aspect involves drilling or accessing a production well that intersects the conventional geothermal reservoir, and detonating at least one linear shaped charge to enlarge or open a naturally-occurring fracture of the conventional geothermal reservoir at the intersection of the naturally-occurring fracture and the production well, which reduces pressures loss of fluid flow into the production well from the naturally-occurring fracture. The reduction in pressure loss can increase fluid flow into the production well to increase the amount of captured heat. The detonation of the linear shaped charge(s) can increase aperture size of at least one naturally-occurring fracture at a wellbore surface.
1 . A method for extracting thermal energy from a conventional geothermal reservoir that includes a natural source of pressurized hot water or brine and at least one naturally-occurring fracture, the method comprising:
drilling or accessing a production well that intersects the conventional geothermal reservoir;
determining a position of a naturally-occurring fracture from well log data, wherein the naturally-occurring fracture carries a flow of the pressurized hot water or brine into the production well, the naturally-occurring fracture having a major width dimension and a minor height dimension, wherein the major width dimension of the naturally-occurring fracture is larger than the minor height dimension of the naturally-occurring fracture;
deploying a downhole tool in the production well, wherein the downhole tool has a tool body that supports at least one linear shaped charge having a major length dimension and a minor width dimension, wherein the major length dimension of the at least one linear shaped charge is larger than the minor width dimension of the at least one linear shaped charge, wherein the major length dimension of the at least one linear shaped charge is larger than the minor height dimension of the naturally-occurring fracture and the minor width dimension of the at least one linear shaped charge is smaller than the major width dimension of the naturally-occurring fracture;
aligning a position of the downhole tool in the production well to the position of the naturally-occurring fracture as determined from the well log data; and
detonating the at least one linear shaped charge supported by the tool body to enlarge or open an aperture of the naturally-occurring fracture at an intersection of the naturally-occurring fracture and the production well, which reduces pressure loss of fluid flow into the production well from the naturally-occurring fracture, wherein the downhole tool is positioned with the major length dimension of the at least one linear shaped charge extending in a direction generally orthogonal to the minor height dimension of the naturally-occurring fracture and the minor width dimension of the at least one linear shaped charge extending parallel to the major width dimension of the naturally-occurring fracture,
wherein:
the downhole tool has a central axis, and the at least one linear shaped charge is supported by the tool body of the downhole tool in an orientation generally parallel to the central axis of the downhole tool;
the at least one linear shaped charge comprises a continuous core of explosive material enclosed in an elongate seamless metal sheath housing having an inverted V-shape;
the elongate seamless metal sheath housing and the continuous core of explosive material produce a uniform linear cutting action upon detonation; and
the tool body further supports a detonation control module operably coupled to the at least one linear shaped charge and remotely controllable from a surface to activate detonation of the at least one linear shaped charge.
2 . The method according to claim 1 , wherein:
a reduction in pressure loss increases fluid flow into the production well to increase an amount of captured heat.
3 . The method according to claim 1 , wherein:
detonating the at least one linear shaped charge increases size of the aperture of the naturally-occurring fracture at a wellbore surface.
4 . The method according to claim 1 , wherein:
the downhole tool is positioned in the production well to position and orient the at least one linear shaped charge such that penetration pattern of the at least one linear shaped charge that results from detonation intersects the naturally-occurring fracture.
5 . The method according to claim 1 , wherein:
the position of the downhole tool and the position of the naturally-occurring fracture are defined in a reference coordinate system.
6 . The method according to claim 5 , wherein:
the reference coordinate system includes well depth and azimuth angle.
7 . The method according to claim 1 , wherein:
the production well is configured to carry a flow of the pressurized hot water or brine through the production well for delivery to a wellbore surface.
8 . The method according to claim 1 , further comprising:
determining a position of at least one additional naturally-occurring fracture from well log data, wherein the at least one additional naturally-occurring fracture carries another flow of the pressurized hot water or brine into the production well;
aligning the position of the downhole tool in the production well to the position of the at least one additional naturally-occurring fracture as determined from the well log data; and
detonating at least one additional linear shaped charge supported by the tool body to enlarge or open an aperture of the at least one additional naturally-occurring fracture at an intersection of the at least one additional naturally-occurring fracture and the production well, which reduces pressure loss of fluid flow into the production well from the at least one additional naturally-occurring fracture.