Charge phasing arrangements in a perforating gun

Abstract

Various charge phasing arrangements in a perforating gun include those uniquely associated with phasing solely along a 180 degree circumference of the perforating gun, for use in but not limited to deviated boreholes. One phasing arrangement comprises four rows of charges, four corresponding rows of recesses in the perforating gun carrier and four corresponding rows of holes in the loading tube, the recesses, holes and charges being constrained within a 180 degree circumference of the perforating gun. The two outermost rows have more recesses, more holes and more charges than do the two innermost rows, since more well fluid is interposed between the two outermost rows and the casing than is interposed between the two innermost rows and the casing of the borehole. Another phasing arrangement comprises five rows of charges, recesses and holes, in lieu of the four of the former embodiment, constrained within the 180 degree circumference, adjacent rows being disposed more closely together in this embodiment than in the former embodiment. A third phasing arrangement comprises eighteen rows of charges, recesses and holes disposed around the entire 360 degrees of the circumference of the gun and borehole. The recesses, holes and charges in all embodiments are uniformly distributed to prevent splitting of the borehole casing, and the charge density in shots per foot for all embodiments of invention is high enough to ensure that a significant quantity of formation fluid is produced from the surrounding formation.