Temperature Effect on Formations During Jet Perforating

Abstract

Abstract An investigation into the thermal reactions during jet perforating has been conducted over a period of years. Theoretical considerations have been investigated and correlated to experimental laboratory tests. The tests have been conducted under a variety of simulated well conditions and into sandstone, limestone, and dolomite cores. Various well fluids were used in the tests. Jet charges contained in steel guns and self-contained or directly exposed jet charges were both used in this investigation. Introduction For almost a decade now jet perforating has been used in well completions. With the introduction of this radically different tool, misconceptions as to its method of penetration arose. In some instances it was thought that the jet stream itself burned its way through the casing, cement and into the formation. This, of course, was a misconception. Numerous surface tests have indicated no burning action. The mechanics of penetration of a formation or target is altogether a different subject and is not covered in this paper. A direct mathematical explanation of the thermal aspects of jet perforating, especially the heat transfer relations, is very complicated. It is probably for this reason that very little work has been done on this problem. With the ever increasing use of jet perforating, the question of what happens to the formation during perforating is of interest to the petroleum industry. Theoretical Considerations The nature of an explosion or decomposition of a high explosive is a complex phenomena and entails unusual heat flow conditions. Actual well conditions present many variables that vastly complicate the calculations by having multiple explosions occurring with the jet charges cased in various materials in both dry and in fluid filled holes. These extremely complex conditions result in laboratory measuring methods as a practical approach to temperature reactions. Types of Jet Perforators A conventional jet perforating carrier has a number of ports or holes in a hollow steel tube with a jet charge arranged to shoot through each port. At the time of firing, all charges in a gun are detonated, resulting in an explosion in each jet charge.