(19)
(11) EP 0 288 238 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
18.10.1989 Bulletin 1989/42

(43) Date of publication A2:
26.10.1988 Bulletin 1988/43

(21) Application number: 88303500.8

(22) Date of filing: 19.04.1988
(51) International Patent Classification (IPC)4: E21B 43/116, E21B 43/1185, E21B 34/10
(84) Designated Contracting States:
DE ES FR GB IT NL

(30) Priority: 20.04.1987 US 40218

(71) Applicant: HALLIBURTON COMPANY
Duncan Oklahoma 73536 (US)

(72) Inventors:
  • George, Flint R.
    Katy Texas 77449 (US)
  • George, Kevin R.
    Columbus Texas 78934 (US)

(74) Representative: Wain, Christopher Paul et al
A.A. THORNTON & CO. Northumberland House 303-306 High Holborn
London WC1V 7LE
London WC1V 7LE (GB)


(56) References cited: : 
   
       


    (54) Method and apparatus for perforating well bores


    (57) A method and apparatus for perforating oil well casing in a well bore, with particular advantage in highly deviated well bores, uses a perforating gun assembly (15) run into the well bore (10) using the production tubing (12). A sliding sleeve (14) is connected in the tubing above the gun and a packer (13) is run in for setting above the sliding sleeve and gun. The assembly is run into the well bore until the gun extends into the highly deviated portion of the bore where the well casing is to be perforated. The packer is set into place, isolating that portion of the well bore below the packer from that portion above the packer, and the sliding sleeve is opened using a wireline or other means. The well bore below the packer is pressurized through the tubing to ensure that the packer is properly set. The pressure is then allowed to bleed off and the sliding sleeve is closed. The gun uses a differential pressure-actuated firing head which is actuated upon a predetermined differential pressure between the production tubing bore and the annulus between the tubing and the casing. Thus, a well casing can be perforated using relatively low values of actuating pressure, which provides greater control over perforating conditions such as underbalance.







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