Embodiments relate generally to methods for extracting a core from a percussion side wall core bullet for a digital tomographic description and direct numerical simulations. A method for extracting a core from a percussion side wall core bullet for a digital tomographic description and direct numerical simulations includes pushing a free end of a wire of a wire saw through the core. The core is positioned within the percussion side wall core bullet. In addition, the method includes attaching the free end to a locking mechanism of the wire saw. Further, the method includes cutting the core from the percussion side wall core bullet. The method also includes removing the core from the percussion side wall core bullet.

Systems for drilling or tunneling include an assembly for accelerating a projectile through a first conduit into a region of geologic material, which generates debris. The debris may be reduced in size by moving the debris to a crushing device located in a second conduit using a conveying device, such as an auger. The reduced-size debris is then moved toward the surface using fluid movement. A third conduit may be used to provide and remove material from the bottom of the first conduit to control pressure at the end of the conduit to prevent ingress of material into the first conduit. Water jets or other types of devices may be used to cut or deform a perimeter of a region of geologic material before the projectile is accelerated to control the shape of the borehole and the manner in which debris is broken from the geologic material.

Systems for forming or extending a tunnel or shaft within geologic material may include a ram accelerator assembly for accelerating one or more projectiles into geologic material to weaken a region of the geologic material. The projectile(s) pre-condition the geologic material, such as by forming one or more holes in a central region of the material or to define a perimeter of the region to be displaced. A cutting tool or subsequent projectile impacts may then be used to remove the weakened material. The voids formed by the first projectile(s) cause compressive forces from subsequent impacts or cutting operations to be converted to tension forces that more efficiently break geologic material, which may fall into the voids created by the first projectile(s). The voids created by the projectile impacts may also control the material that is removed and the shape of a resulting section of the tunnel or shaft.

To optimize the efficiency of a perforating tool system, downhole conditions may be simulated to determine the optimal configuration for the perforating tool system. A simulated wellbore is disposed in a pressure vessel and coupled to a target composite core assembly. A perforating tool system is disposed in the simulated wellbore above the target composite core assembly. The target composite core assembly includes an outer shell. The outer shell comprises a material that supports a rubber bladder or flexible jacket that is disposed about the outer shell. The outer shell isolates the overburden fluid and pressure from the inner core during a radial flow test to more accurately simulate conditions downhole. A parameter of a perforating tool system may be altered based, at least in part, on a result from the radial flow test.

Methods for generating boreholes used for generating geothermal energy or other purposes include forming the borehole by accelerating a projectile into contact with geologic material. Interaction between the projectile and the geologic material generates an acoustic signal, such as vibrations within the formation, that is detected using acoustic sensors along a drilling conduit, at the surface, or within a separate borehole. Characteristics of the geologic material, such as hardness, porosity, or the presence of fractures, may be determined based on characteristics of the acoustic signal. The direction in which the borehole is extended may be modified based on the characteristics of the geologic material, such as to create a borehole that intersects one or more fractures for generation of geothermal energy.

Methods for generating boreholes used for generating geothermal energy or other purposes include forming the borehole by accelerating a projectile into contact with geologic material. Interaction between the projectile and the geologic material generates an acoustic signal, such as vibrations within the formation, that is detected using acoustic sensors along a drilling conduit, at the surface, or within a separate borehole. Characteristics of the geologic material, such as hardness, porosity, or the presence of fractures, may be determined based on characteristics of the acoustic signal. The direction in which the borehole is extended may be modified based on the characteristics of the geologic material, such as to create a borehole that intersects one or more fractures for generation of geothermal energy.

A kinetic penetrator includes a tubular body having a first end and a second end, a nose coupled to the first end of the tubular body, the nose configured to penetrate a ground surface and subsurface materials of a subterranean ground volume, a retrieval system including a tether, a collector coupled to at least one of the nose and the tubular body, and a sample compartment configured to interface with the collector. The sample compartment is releasably coupled to at least one of the tubular body, the nose, and the collector, and the tether is coupled to the sample compartment and is configured to facilitate removal thereof from the subterranean ground volume.

A retrievable kinetic penetrator includes a tubular body having a first end and a second end, a nose coupled to the first end of the tubular body, and a retrieval system. The nose is configured to penetrate a ground surface and subsurface materials of a subterranean ground volume. The retrieval system includes a tether coupled to the tubular body and is configured to facilitate recovery of the tubular body from the subterranean ground volume.

A retrievable kinetic penetrator includes a tubular body having a first end and a second end, a nose coupled to the first end of the tubular body, and a retrieval system. The nose is configured to penetrate a ground surface and subsurface materials of a subterranean ground volume. The retrieval system includes a tether coupled to the tubular body and is configured to facilitate recovery of the tubular body from the subterranean ground volume.