William Gerald Jacobson

US Patent:

50056492, Apr 9, 1991

Filed:

Feb 28, 1990

Appl. No.:

7/486144

Inventors:

John C. Smith - Pasadena CA
William O. Jacobson - San Diego CA

Assignee:

Union Oil Company of California - Los Angeles CA

International Classification:

E21B 4326
E21B 43267

US Classification:

166308

Abstract:

The present invention achieves a more reliable multiple fracturing of a subterranean formation by inserting high pressure tubing and isolating a portion of the wellbore (including the formation of interest and an end portion of the tubing) with packers. Near the end of the tubing is a closable end and a rupturable plenum holding a sufficient volume of pressurized gas to produce a pressure ramp sufficient to cause multiple fractures in the isolated portion when the plenum is ruptured. The closable end is closed after filling the isolated portion with a fracture fluid and proppant. The rupturable means is provided by at least one rupture disc. Multiple discs can provide a step wise pressure rise ramp to tailor the multiple fracture producing pulse. By providing a known volume of pressurized gas and rupture discs, a controlled pulse loading can be achieved. Like the propellant driven pulse loading techniques, it achieves a pressure ramp, but the present invention avoids the damage potential and improves the reliability of creating multiple fractures.