Design and Qualification of an Ultra-High Pressure Perforating System

Abstract

With the steadily increasing demand for oil and gas, operators have been forced to explore deeper and hotter areas to find the most prolific reservoirs. This paper hightlights the design and qualification steps performed during development of a 7.0-in. O.D. 16 shots per foot (SPF) 30,000 psi perforating gun system. Finite-element modeling was used to optimize the gun design for 30,000 psi external pressure, and 400° F. As part of the qualification requirements, ballistic survival testing was conducted using low-debris gravel pack shaped charges.Comprehensive knowledge of the post-perforated condition of the gun body is required, as its failure may lead to an expensive fishing operation and possible damage of the oil well casing. Survival testing was conducted under two different conditions, no load on the gun body and the second contion with a tensile load equivalent to the weight of 1,500 ft of perforating guns.The methodology of finite-element modeling is discussed along with experimental data obtained by collapse testing of perforating hollow carriers (HC) of different diameters and shot densities. Data from computer simulations and physical testing in the lab are presented to provide better insight into the behavior of perforating guns under external pressure. The data from the survival tests showed virtually no change in the swell of the HC when subjected to a high tensile load as compared to the no-load condtion. This testing method provides insight into the behavior of perforating systems under different loading parameters.The results described in this paper highlight the need to apply rigorous methods for design and qualification of ultra-high pressure gun systems when exploring new oilfield frontiers characterized by extremely harsh environmental conditions.