Global Patent Index - EP 1847679 A1

EP 1847679 A1 2007-10-24 - Underbalanced drilling method into a gas-bearing formation

Title (en)

Underbalanced drilling method into a gas-bearing formation

Title (de)

Unterdruck-Bohrverfahren in eine gasführende Formation

Title (fr)

Méthode de forage en sous-pression dans une formation de gaz

Publication

EP 1847679 A1 (EN)

Application

EP 06252153 A

Priority

EP 06252153 A

Abstract (en)

A method of creating a second wellbore section (19), penetrating a subterranean earth formation having at least one gas-bearing zone (3), from a selected location in an existing first wellbore section (1) using a remotely-controlled drilling device (13) under underbalanced drilling conditions, which method comprises: (a) arranging the remotely-controlled drilling device (13) at the selected location in the first wellbore section (1), in or below a production tube (6), (b) operating the remotely-controlled drilling device (13) to drill the second wellbore section (19), (c) controlling the flow of gas produced from the gas-bearing formation through the production tube (6) to the wellhead (8), (d) using a fluid stream comprising at least a portion of produced gas to transport the drill cuttings resulting from the drilling operation to the wellhead (8) and (e) controlling the pressure in the production tube (6) such that the linear velocity of the gas does not fall below 1 m/s and does not exceed 75 m/s.

IPC 8 full level (invention and additional information)

E21B 21/00 (2006.01); E21B 21/08 (2006.01); E21B 21/16 (2006.01)

CPC (invention and additional information)

E21B 21/00 (2013.01); E21B 21/08 (2013.01); E21B 21/16 (2013.01); E21B 2021/006 (2013.01)

Citation (search report)

Designated contracting state (EPC)

GB

Designated extension state (EPC)

AL BA HR MK YU

EPO simple patent family

EP 1847679 A1 20071024; WO 2007122393 A1 20071101

INPADOC legal status


2008-08-14 [REG DE 8566] DESIGNATED COUNTRY DE NOT LONGER VALID

2008-08-13 [18R] REFUSED

- Effective date: 20071205

2008-07-02 [AKX] PAYMENT OF DESIGNATION FEES

- Designated State(s): GB

2007-10-24 [AK] DESIGNATED CONTRACTING STATES:

- Kind Code of Ref Document: A1

- Designated State(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

2007-10-24 [AX] REQUEST FOR EXTENSION OF THE EUROPEAN PATENT TO:

- Countries: AL BA HR MK YU