Schlumberger Technology Corporation

Martin Griffith

Frank F Chang

Mathew M Samuel

Liz Morris

Yerik Balabatyrov

A system for dynamic underbalanced perforation of a hydrocarbon well includes a perforation fluid located within the hydrocarbon well. A perforation gun is suspended within the perforation fluid and a completion fluid is located within the hydrocarbon uphole of the perforation fluid. An isolation fluid is located within the hydrocarbon well uphole of the perforation fluid and downhole of the completion fluid. A method of perforating a hydrocarbon well includes a perforation fluid placed in the hydrocarbon well. A perforation gun is placed within the perforation fluid. A completion fluid is placed in the hydrocarbon well. An isolation fluid is placed in the hydrocarbon well. A local dynamic underbalance condition is created in the hydrocarbon well. A flow of the completion fluid downhole is inhibited.

System and method of dynamic underbalanced perforating using an isolation fluid

The invention provides a method for perforating a well with a perforating fluid comprising a viscoelastic surfactant that essentially stops fluid leak-off after perforation in an overbalanced condition. Another aspect of the invention provides the perforating fluid in itself. The well has a wellbore defined by a generally cylindrical casing in at least a portion of the wellbore (i.e., the wellbore is cased, although it is not necessary cased in its entire length). The wellbore passes through a subterranean formation that comprises hydrocarbon formation fluids (such as oil and/or gas), at least in certain strata. The method comprises placing a perforating device in a wellbore which includes at least one explosive perforating charge that can be detonated in order to perforate the casing and allow the formation fluids to enter the wellbore. The casing is located between the subterranean formation and the perforating device. A perforating fluid including at least one viscoelastic surfactant is placed in the wellbore between the perforating device and the casing, in at least a portion of the wellbore. In other words, the perforating fluid is present in the wellbore adjacent to the perforating device. The explosive charge(s) in the perforating device is detonated, such that the perforating device forms at least one perforation in the casing that permits the flow of hydrocarbon formation fluids from the subterranean formation into the wellbore. As a result of the detonation, at least a portion of the perforating fluid is put in communication with the subterranean formation.

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Trincity, Trinidad and Tobago

Martin Griffith