A safety mechanism and method for downhole perforating are disclosed. In one example, a mechanical firing head includes a firing pin carried on a pin carrier within a housing. The firing pin is movable from a retracted position to a firing position for striking an explosive initiator. A retention member retains the firing pin in the retracted position with the safety member in the armed position. A safety member is biased to a safety position that additionally blocks movement of the firing pin. The safety member is moveable to an armed position that unblocks movement of the firing pin in response to an arming pressure supplied to the housing bore. The retention member releases the firing pin in response to a firing pressure supplied to the housing in excess of the firing pressure.

A safety mechanism and method for downhole perforating are disclosed. In one example, a mechanical firing head includes a firing pin carried on a pin carrier within a housing. The firing pin is movable from a retracted position to a firing position for striking an explosive initiator. A retention member retains the firing pin in the retracted position with the safety member in the armed position. A safety member is biased to a safety position that additionally blocks movement of the firing pin. The safety member is moveable to an armed position that unblocks movement of the firing pin in response to an arming pressure supplied to the housing bore. The retention member releases the firing pin in response to a firing pressure supplied to the housing in excess of the firing pressure.

An anti-blast concrete and a method of fabricating an anti-blast structure member using such anti-blast concrete are disclosed. The composition of the anti-blast concrete according to the invention includes, in parts by weight, 1.0 part by weight of cement, 1.0 to 2.5 parts by weight of fine aggregates, 1.0 to 2.5 parts by weight of coarse aggregates, and a plurality of reinforcing fibers. The weight ratio of the reinforcing fibers to the cement ranges from 0.5% to 3%. The plurality of reinforcing fibers are a plurality of carbon fibers or a plurality of aramid fibers. A test body, made of the anti-blast concrete of the invention, has an average number of times of repeated impacts at an impact energy of 49.0 Joules equal to or larger than 41 times at 28 days of age.

An anti-blast concrete and a method of fabricating an anti-blast structure member using such anti-blast concrete are disclosed. The composition of the anti-blast concrete according to the invention includes, in parts by weight, 1.0 part by weight of cement, 1.0 to 2.5 parts by weight of fine aggregates, 1.0 to 2.5 parts by weight of coarse aggregates, and a plurality of reinforcing fibers. The weight ratio of the reinforcing fibers to the cement ranges from 0.5% to 3%. The plurality of reinforcing fibers are a plurality of carbon fibers or a plurality of aramid fibers. A test body, made of the anti-blast concrete of the invention, has an average number of times of repeated impacts at an impact energy of 49.0 Joules equal to or larger than 41 times at 28 days of age.

A non-detonable shaped charge capable of becoming detonable upon activation. The shaped charge may be utilized for use with a perforating gun in oilfield applications. In this regard, during transport and other handling in advance of reaching the application site, the charge may be non-detonable. However, upon an intentionally directed activation, such as through heating, the shaped charge may be detonable.

A non-detonable shaped charge capable of becoming detonable upon activation. The shaped charge may be utilized for use with a perforating gun in oilfield applications. In this regard, during transport and other handling in advance of reaching the application site, the charge may be non-detonable. However, upon an intentionally directed activation, such as through heating, the shaped charge may be detonable.

A safety arrangement for a wireless blasting system which includes a plurality of wireless detonator assemblies located at a blast zone wherein each route which provides access to the blast zone is monitored to detect removal of a wireless detonator assembly which is in an operative mode from the blast zone.

A safety arrangement for a wireless blasting system which includes a plurality of wireless detonator assemblies located at a blast zone wherein each route which provides access to the blast zone is monitored to detect removal of a wireless detonator assembly which is in an operative mode from the blast zone.

An impact sleeve is used for mitigating damage in a perforating gun resulting from shaped charge detonation. In one example, a perforating gun includes a gun carrier, with a charge holder and the impact sleeve inside the gun carrier. The charge holder holds a plurality of shaped charges capable of being detonated with sufficient explosive energy to generate high-velocity fragments inside the gun carrier. The impact sleeve comprises an energy-absorbing material and optional raised features for absorbing at least some energy of the high-velocity fragments. The materials, raised features, positioning, and geometry of the impact sleeve and raised features may be tuned to optimize energy absorption.

An impact sleeve is used for mitigating damage in a perforating gun resulting from shaped charge detonation. In one example, a perforating gun includes a gun carrier, with a charge holder and the impact sleeve inside the gun carrier. The charge holder holds a plurality of shaped charges capable of being detonated with sufficient explosive energy to generate high-velocity fragments inside the gun carrier. The impact sleeve comprises an energy-absorbing material and optional raised features for absorbing at least some energy of the high-velocity fragments. The materials, raised features, positioning, and geometry of the impact sleeve and raised features may be tuned to optimize energy absorption.