Abstract: A secondary barrier for use in conjunction with an isolation device in a portion of a non-vertical wellbore comprises: a swellable material, wherein the swellable material: (A) has dimensions such that, prior to swelling, the secondary barrier is capable of being placed into the portion of the non-vertical wellbore, and (B) fills a void within the portion of the non-vertical wellbore, wherein the swellable material fills the void after the swelling of at least a portion of the swellable material has occurred, wherein the secondary barrier is positioned adjacent to the isolation device in the portion of the non-vertical wellbore. A method of creating a secondary barrier comprises: introducing the secondary barrier into the portion of the non-vertical wellbore; and contacting or allowing the swellable material to come in contact with the swelling fluid or the increase in temperature.

Abstract: A wellbore apparatus includes a connector sub assembly having a body, the body having a first end adapted to couple to a first perforating sub component and a second, axially opposed end adapted to couple to a second perforating sub component. The connector sub body defines a cavity proximate the second end of the connector sub body; and a flow path in fluid communication with the cavity and a location exterior to the wellbore apparatus. The apparatus includes a valve residing in the flow path and actuatable to block or allow fluid flow from the cavity, through the flow path, to the location exterior to the wellbore apparatus.

Abstract: A perforation tool assembly is provided. The perforation tool assembly comprises an energy train, a first perforation gun, and a second perforation gun. The energy train comprises a moderator to reduce the speed of propagation of a detonation in a direction parallel to the axis of the perforation tool assembly. The first perforation gun comprises a plurality of explosive charges coupled to a first portion of the energy train. The second perforation gun comprises a plurality of explosive charges coupled to a second portion of the energy train, wherein the second portion of the energy train is coupled to the first portion of the energy train.

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 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 wellbore apparatus includes a connector sub assembly having a body, the body having a first end adapted to couple to a first perforating sub component and a second, axially opposed end adapted to couple to a second perforating sub component. The connector sub body defines a cavity proximate the second end of the connector sub body; and a flow path in fluid communication with the cavity and a location exterior to the wellbore apparatus. The apparatus includes a valve residing in the flow path and actuatable to block or allow fluid flow from the cavity, through the flow path, to the location exterior to the wellbore apparatus.

Abstract: A wellbore perforation tool comprises an explosive charge, a tool body containing the explosive charge, and a flowable material carried with the tool. The flowable material is released by detonation of the explosive charge and, after perforation of the tool body by the explosive charge to form an aperture in the tool body, flows to form at least a partial barrier of the aperture.

Abstract: A perforation tool assembly is provided. The perforation tool assembly comprises an energy train, a first perforation gun, and a second perforation gun. The energy train comprises a moderator to reduce the speed of propagation of a detonation in a direction parallel to the axis of the perforation tool assembly. The first perforation gun comprises a plurality of explosive charges coupled to a first portion of the energy train. The second perforation gun comprises a plurality of explosive charges coupled to a second portion of the energy train, wherein the second portion of the energy train is coupled to the first portion of the energy train.

Abstract: A perforating system and method for use in a wellbore. In operation, the perforating system is disposed in the wellbore and used to form perforations in the wellbore. Thereafter, the perforating system is used to perform a sequence of underbalance pulsations in the wellbore, wherein a first underbalance pulsation has a first underbalance signature and a second underbalance pulsation has a second underbalance signature that is different from the first underbalance signature such that perforating tunnel clean up can be optimized based upon wellbore conditions and without causing damage to the perforating tunnels.

Abstract: A perforation tool assembly is provided. The perforation tool assembly comprises an energy train, a first perforation gun, and a second perforation gun. The energy train comprises a moderator to reduce the speed of propagation of a detonation in a direction parallel to the axis of the perforation tool assembly. The first perforation gun comprises a plurality of explosive charges coupled to a first portion of the energy train. The second perforation gun comprises a plurality of explosive charges coupled to a second portion of the energy train, wherein the second portion of the energy train is coupled to the first portion of the energy train.

Abstract: A method can include interconnecting a well tool in a well tool assembly with a shock mitigating connection, the interconnecting being performed without threading, and positioning the well tool assembly in a wellbore. A well perforating assembly can include at least two perforating devices, a detonation train extending through the perforating devices, and a shock absorber positioned between the perforating devices. A method of assembling a perforating assembly can include, prior to installing the perforating assembly in a wellbore, pushing one perforating device connector into another perforating device connector without threading the connectors together, thereby: a) preventing disconnection of the connectors and b) making a connection in a detonation train. A well system can include a perforating assembly including multiple perforating guns and multiple shock absorbers. Each shock absorber may be interconnected between at least two of the perforating guns.

Abstract: A method can include interconnecting a well tool in a well tool assembly with a shock mitigating connection, the interconnecting being performed without threading, and positioning the well tool assembly in a wellbore. A well perforating assembly can include at least two perforating devices, a detonation train extending through the perforating devices, and a shock absorber positioned between the perforating devices. A method of assembling a perforating assembly can include, prior to installing the perforating assembly in a wellbore, pushing one perforating device connector into another perforating device connector without threading the connectors together, thereby: a) preventing disconnection of the connectors and b) making a connection in a detonation train. A well system can include a perforating assembly including multiple perforating guns and multiple shock absorbers. Each shock absorber may be interconnected between at least two of the perforating guns.

Abstract: A perforating gun gravitational orientation system includes a perforating gun and a swivel device connected to the perforating gun to permit rotation of the perforating gun within casing, and the perforating gun spaced apart from the casing by the swivel device. Another perforating gun gravitational orientation system includes the swivel device having an axis of rotation which is spaced apart from a center of gravity of the perforating gun. Yet another perforating gun gravitational orientation system includes the swivel device having an axis of rotation which is spaced apart from a center axis of the perforating gun.

Abstract: A perforating gun gravitational orientation system includes a perforating gun and a swivel device connected to the perforating gun to permit rotation of the perforating gun within casing, and the perforating gun spaced apart from the casing by the swivel device. Another perforating gun gravitational orientation system includes the swivel device having an axis of rotation which is spaced apart from a center of gravity of the perforating gun. Yet another perforating gun gravitational orientation system includes the swivel device having an axis of rotation which is spaced apart from a center axis of the perforating gun.

Abstract: A perforating apparatus (190) used to perforate a subterranean well. The perforating apparatus (190) includes a generally tubular gun carrier (106) and a charge holder (192) rotatably mounted within the gun carrier (106). At least one shaped charge (102) is mounted in the charge holder (192) and is operable to perforate the well upon detonation. A dynamically adjustable weight system (194) including a plurality malleable weight members (196) is operably associated to the charge holder (192). The dynamically adjustable weight system (194) is operable to adjust the center of gravity (120) of the charge holder (192) such that gravity will cause the charge holder (192) to rotate within the gun carrier (106) to position the at least one shaped charge (102) in a desired circumferential direction relative to the well prior to perforating.

Abstract: A perforating apparatus (240) used to perforate a subterranean well. The perforating apparatus (240) includes a generally tubular gun carrier (106) and a charge holder (242) rotatably mounted within the gun carrier (106). At least one shaped charge (246) is mounted in the charge holder (242) and is operable to perforate the well upon detonation. A dynamically adjustable weight system including a weight tube (250) that is selectively rotatable relative to the charge holder (242) is operable to adjust the center of gravity (120) of the charge holder (242) such that gravity will cause the charge holder (242) to rotate within the gun carrier (106) to position the at least one shaped charge (246) in a desired circumferential direction relative to the well prior to perforating.

Abstract: Pressure cycle operated apparatus and methods. A method of actuating a firing head includes the steps of: reciprocably displacing an actuator piston of the firing head, the displacing step including the piston being alternately pressure balanced and unbalanced; and igniting a combustible material in response to the piston displacing step. A method of generating electricity includes: reciprocably displacing a piston, the displacing step including the piston being alternately pressure balanced and unbalanced; and generating electricity in response to the piston displacing step. A firing head includes an actuator piston separating at least two chambers; a check valve which permits one-way flow between the chambers; a flow restrictor which restricts flow between the chambers; a biasing device which biases the piston toward one of the chambers; and a firing pin releasing device which releases a firing pin in response to displacement of the piston.

Abstract: A downhole oilfield completion method comprises determining a surge profile for a wellbore and assembling a downhole completion tool having an interior surge volume and comprising a surge attenuation system operable to reduce a surge of the downhole completion tool based at least in part on the surge profile. The method also comprises running the downhole completion tool into the wellbore and surging the wellbore by admitting wellbore fluid into the interior surge volume, the surge reduced at least in part by the surge attenuation system.

Abstract: Pressure cycle operated apparatus and methods. A method of actuating a firing head includes the steps of: reciprocably displacing an actuator piston of the firing head, the displacing step including the piston being alternately pressure balanced and unbalanced; and igniting a combustible material in response to the piston displacing step. A method of generating electricity includes: reciprocably displacing a piston, the displacing step including the piston being alternately pressure balanced and unbalanced; and generating electricity in response to the piston displacing step. A firing head includes an actuator piston separating at least two chambers; a check valve which permits one-way flow between the chambers; a flow restrictor which restricts flow between the chambers; a biasing device which biases the piston toward one of the chambers; and a firing pin releasing device which releases a firing pin in response to displacement of the piston.

Abstract: A perforating apparatus (170) used to perforate a subterranean well. The perforating apparatus (170) includes a generally tubular gun carrier (106) and a charge holder (172) rotatably mounted within the gun carrier (106). At least one shaped charge (102) is mounted in the charge holder (172) and is operable to perforate the well upon detonation. A dynamically adjustable weight system (174) is operably associated to the charge holder (172). The dynamically adjustable weight system (174) includes a plurality of longitudinally extending tubes (176) that are operable to contain a weighted material therein and are operable to adjust the center of gravity (120) of the charge holder (172) such that gravity will cause the charge holder (172) to rotate within the gun carrier (106) to position the at least one shaped charge (102) in a desired circumferential direction relative to the well prior to perforating.