Controlled Debris Perforating Systems: Prevention of an Unexpected Source of Formation Damage

Abstract An unexpected source of potential formation damage can be generated when controlled debris perforating systems are detonated in clear completion brines. This paper presents the results of a systematic laboratory study of this potential damage, previously unreported in the published technical literature. One source of the damage is related to the powdered metals and metal alloys incorporated into controlled debris perforating systems for the purpose of generating, upon detonation, highly desirable, finely divided residues consisting mostly of particles 200 mesh or smaller. When sprayed into clear completion brine at the high detonation temperatures, high surface area particles become activated and then react with water to form metal oxides, metal hydroxides and hydrogen gas. However, when the activated particles are sprayed into clear completion brines with certain specific compositions, cemented by-products are also generated at the formation face. These by-products can be extremely formation damaging. Fortunately, the nature and damaging characteristics of the cemented byproducts can be altered and prevented by the addition of a chemical inhibitor into the clear completion brine. Objectives of this paper are therefore to: 1) Identify clear completion brines which generate cemented byproducts and those which do not; 2) determine brine properties that control the cementing process and inhibit damage from by-products; 3) review operating conditions that accentuate the damage caused by cemented by-products; and 4) provide a chemical inhibitor for clear completion brines which prevents the formation of cemented by-products and damage to the formation. Guidelines for the selection, modification and field application of clear completion brines used with controlled debris perforating systems based are presented.