Abstract: The disclosed embodiments include a system and method in which a plurality of shock sensing subassemblies are arranged within the tool string to monitor the transient response of formation characteristics to various stimuli, including changes in pressure and temperature of a region of a wellbore that is nearby the formation. The systems and methods involve gathering measurements that reflect the transient response and comparing the measured data to predicted data. The results of the comparison can be used to determine formation properties and to refine and improve modeling processes used to generate the predicted data.

Abstract: A system, method, and circuit for determining signals. A bridge output is received from a Wheatstone bridge sensing a slow signal and a fast signal. A slow output associated with the slow signal and a fast output associated with the fast signal are determined from the bridge output utilizing a microcontroller. The microcontroller generates the offset signal in response to the slow output. Other systems, methods, and circuits are disclosed.

Abstract: Certain aspects are directed to capturing data regarding physical states associated with a perforating string. In one aspect, a sensing tool is provided. The sensing tool includes at least one sensor and a processor positioned in an isolated chamber of the sensing tool. The processor samples data from the sensor at a first sampling rate associated with the deployment of a perforating string. The data is associated with at least one parameter with respect to the perforating string. The processor detects a trigger condition associated with a perforation operation of the perforating string. The processor switches to a second sampling rate in response to detecting the trigger condition. The second sampling rate is greater than the first sampling rate and is associated with the perforation operation. The processor samples data at the second sampling rate for a period of time in which the perforation operation is at least partially performed.

Abstract: A method for forming a perforation is disclosed. The method comprises positioning a perforating gun at a desired location in the formation. The perforating gun comprises a gun body and a charge carrier. The method further comprises disposing one or more shaped charges within the charge carrier. The one or more shaped charges comprise an outer case, an inner liner, and an explosive material retained between the outer case and the inner liner. The outer case of the shaped charge comprises one or more predefined fracture lines. The method further comprises detonating at least one shaped charge, wherein detonating the at least one shaped charge forms one or more perforations in the formation.

Abstract: A perforating gun string may include a first perforating gun; a second perforating gun axially offset from the first perforating gun; a connector configured to interpose and couple the first and second perforating guns; and a detonation cord that passes axially through a central bore of the connector; and is connected to the first and second perforating guns. In some instances, the connector may have a body with an inner surface that defines the central bore, wherein the body has a ratio of an average diameter of the outer surface to an average diameter of the inner surface of about 1.2 to about 4.

Abstract: At least one crack designator for a perforating gun, wherein the gun includes a longitudinal direction, a lateral direction, and at least one scallop, wherein each crack designator is capable of redirecting crack growth from the lateral direction to the longitudinal direction of the gun. The designator may be located in one of the scallops, extend from an expected exit hole in the gun to an edge of one of the scallops, and be capable of redirecting crack growth from a lateral direction to a longitudinal direction of the gun. In preferred embodiments, the designator in each scallop is arranged in a spider pattern or concentric circles. The designator is preferably formed by machining, etching, or laser ablation. The designator may have a lower fracture toughness or lesser stiffness than surrounding material of the gun.

Abstract: In an embodiment, a sensing subassembly for use with a downhole tool comprises a housing, a cavity extending into the housing, a sensor disposed at least partially within the cavity, a shock mitigating member disposed between at least one end of the sensor and the housing, and at least one seal member disposed between the sensor and the housing. At least a portion of the sensor is in fluid communication with an exterior of the housing, and the shock mitigating member is configured to attenuate at least a portion of a shock wave between the housing and the sensor.

Abstract: A sensing subassembly for use with a downhole tool comprises a housing, a cavity disposed within the housing, an electronic board disposed within the cavity, a stiffening member engaging the electronic board and configured to limit flexing of the electronic board, and a spring member configured to provide an isolation mount for the electronic board within the cavity.

Abstract: At least one crack designator for a perforating gun, wherein the gun includes a longitudinal direction, a lateral direction, and at least one scallop, wherein each crack designator is capable of redirecting crack growth from the lateral direction to the longitudinal direction of the gun. The designator may be located in one of the scallops, extend from an expected exit hole in the gun to an edge of one of the scallops, and be capable of redirecting crack growth from a lateral direction to a longitudinal direction of the gun. In preferred embodiments, the designator in each scallop is arranged in a spider pattern or concentric circles. The designator is preferably formed by machining, etching, or laser ablation. The designator may have a lower fracture toughness or lesser stiffness than surrounding material of the gun.

Abstract: A perforation tool assembly. The perforation tool assembly comprises a tool string connector, a perforation gun coupled to the tool string connector, and a structure configured to absorb mechanical energy released by firing one or more perforation guns. The coupling is configured to provide a limited range of motion of the tool string connector relative to the perforation gun. The tool string connector and the perforation gun retain the structure configured to absorb mechanical energy.

Abstract: The disclosed embodiments include a system and method in which a plurality of shock sensing subassemblies are arranged within the tool string to monitor the transient response of formation characteristics to various stimuli, including changes in pressure and temperature of a region of a wellbore that is nearby the formation. The systems and methods involve gathering measurements that reflect the transient response and comparing the measured data to predicted data. The results of the comparison can be used to determine formation properties and to refine and improve modeling processes used to generate the predicted data.

Abstract: A system, method, and circuit for determining signals. A bridge output is received from a Wheatstone bridge sensing a slow signal and a fast signal. A slow output associated with the slow signal and a fast output associated with the fast signal are determined from the bridge output utilizing a microcontroller. The microcontroller generates the offset signal in response to the slow output. Other systems, methods, and circuits are disclosed.

Abstract: A perforating gun string may include a first perforating gun; a second perforating gun axially offset from the first perforating gun; a connector configured to interpose and couple the first and second perforating guns; and a detonation cord that passes axially through a central bore of the connector; and is connected to the first and second perforating guns. In some instances, the connector may have a body with an inner surface that defines the central bore, wherein the body has a ratio of an average diameter of the outer surface to an average diameter of the inner surface of about 1.2 to about 4.

Abstract: A sensing subassembly for use with a downhole tool comprises a housing, a cavity disposed within the housing, at least one electronic component disposed within the cavity, and at least one isolating member disposed within the cavity. The at least one isolating member is configured to attenuate at least a portion of frequency components of a mechanical wave above a threshold and transmit at least a portion of frequency components below the threshold to the at least one electronic device.

Abstract: Certain aspects are directed to capturing data regarding physical states associated with a perforating string. In one aspect, a sensing tool is provided. The sensing tool includes at least one sensor and a processor positioned in an isolated chamber of the sensing tool. The processor samples data from the sensor at a first sampling rate associated with the deployment of a perforating string. The data is associated with at least one parameter with respect to the perforating string. The processor detects a trigger condition associated with a perforation operation of the perforating string. The processor switches to a second sampling rate in response to detecting the trigger condition. The second sampling rate is greater than the first sampling rate and is associated with the perforation operation. The processor samples data at the second sampling rate for a period of time in which the perforation operation is at least partially performed.

Abstract: A method for forming a perforation is disclosed. The method comprises positioning a perforating gun at a desired location in the formation. The perforating gun comprises a gun body and a charge carrier. The method further comprises disposing one or more shaped charges within the charge carrier. The one or more shaped charges comprise an outer case, an inner liner, and an explosive material retained between the outer case and the inner liner. The outer case of the shaped charge comprises one or more predefined fracture lines. The method further comprises detonating at least one shaped charge, wherein detonating the at least one shaped charge forms one or more perforations in the formation.

Abstract: A perforating gun can include at least one explosive component, and a shock mitigation device including a shock reflector which indirectly reflects a shock wave produced by detonation of the explosive component. Another perforating gun can include a gun housing, at least one explosive component, and a shock mitigation device in the gun housing. The shock mitigation device can include a shock attenuator which attenuates a shock wave produced by detonation of the explosive component. Yet another perforating gun can include a shock mitigation device with an explosive material which produces a shock wave that interacts with another shock wave produced by detonation of an explosive component in a gun housing.

Abstract: A sensing subassembly for use with a downhole tool comprises a housing, a cavity disposed within the housing, an electronic board disposed within the cavity, a stiffening member engaging the electronic board and configured to limit flexing of the electronic board, and a spring member configured to provide an isolation mount for the electronic board within the cavity.

Abstract: A shock sensing tool for use with well perforating can include a generally tubular structure which is fluid pressure balanced, at least one strain sensor which senses strain in the structure, and a pressure sensor which senses pressure external to the structure. A well system can include a perforating string including multiple perforating guns and at least one shock sensing tool, with the shock sensing tool being interconnected in the perforating string between one of the perforating guns and at least one of: a) another of the perforating guns, and b) a firing head.

Abstract: A perforation tool assembly comprises a perforation gun, and a mass energy absorber coupled to the perforation gun. The mass energy absorber is configured to alter the propagation of mechanical energy released by firing one or more perforation guns. The mass energy absorber comprises a mass and at least one absorber, and the at least one absorber is disposed between the mass and the perforating gun.