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Shaped Charges in the Oil Industry

The most extensive use today of Shaped Charges is in the oil and gas industry, where they open up the rock around drilled wells. Shaped charges are used in the oil and gas industry and in other fields to pierce metal, concrete, and other solid materials. In an oil or gas well, a metallic casing is cemented to the borehole walls to maintain the borehole integrity. Shaped charges are incorporated in a hollow carrier gun or a strip positioned in the casing. The shaped charges are activated to pierce the well casing and the geologic formation at the hydrocarbon producing zone. The hydrocarbons enter the casing through such perforations and are transmitted to the well surface.

Unlike the ripping affect achieved by bulk cutters, shaped charges are intended to sever targets by jetcutting. Shaped charges utilize special housings that are designed to create a cavity or void between the explosive material and target wall. Employing a phenomenon known as the Monroe Effect, the shock wave produced at detonation accelerates and deforms the shaped housing into a high-velocity (24,000-27,000 fps) plasma jet within the void space. The formed jet is able to cut through steel targets of various thicknesses based upon the void shape and the "stand-off" distance to the target wall. Because the "cutting" efficiency of shaped charges is several times greater than that of bulk charges, they can often greatly reduce the net explosive weight needed to sever similar-sized targets.

Linear-shaped charges (LSC) have a void shaped into a chevron or inverted "V" along its entire length, and they are designed to cut linearly through its target. Subcontractors use LSC's on a wide range of decommissioing targets in many different configurations depending on cutting requriements.

Prior to perforation technology, wells were "open hole" or "shot hole" (barefoot) completions, sometimes employing liners. But the perforated casing completion was an important and necessary development as wells got deeper, and reservoir conditions became more and more complex. Gun perforators have been successfully used as a well completion method since at least 1927; the first patent was 1926, but it did not work. Early gun perforators were "bullet" devices, utilizing actual projectiles (usually steel bullets) to penetrate the well casing. The lined shaped charge perforator a/k/a the jet perforator or jet charge has displaced the old bullet perforators

Conical-shaped charges (CSC) have the cavity created in the shape of a cone designed to cut round holes and to penetrate deep into targets. Industry's primary use of CSC's is in the development of perforating guns; multiple CSC assemblies placed down boreholes and detonated to penetrate through the drill casing and into the surrounding geologic strata for the extraction of hydrocarbons. The use of steel charge cases instead of zinc cases eliminates the decrease in formation productivity and damage to completion components associated with the detonation by-products from zinc-based charges and reduces the cost for special completion fluids. The shaped charges are designed and arranged to assist in optimum orientation and deployed with a tubing-conveyed perforating system to provide an innovative, effective solution for perforating and increasing productivity in long horizontal intervals.

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Page last modified: 06-12-2017 17:40:39 ZULU