Directional drilling with adjustable bent housings

摘要

Adjustable drill string housings are described for use in the directional drilling of wellbores, e.g. wellbores for hydrocarbon recovery wells. The adjustable drill string housings permit adjustment of a bend angle in the housings without removing the housings from a wellbore. The bend angle can be adjusted by changing the internal stresses in a support member carried by the housings. The bend angle may also be adjusted by causing failure of sacrificial support members carried by the housings, and the failure may be caused by delivering chemicals through a chemical delivery system to the sacrificial support members. Methods of operating the adjustable drill string housings include multi-lateral drilling operations wherein the bend angle is adjusted when a casing window has been detected.

主权项

1. A method of forming a branch wellbore, comprising:
running a bottom hole assembly into a main wellbore on a drill string; adjusting a bend angle, within the main wellbore at a location remote from and above a window defined in a casing, of an adjustable drill string housing defined by the bottom hole assembly to thereby induce a contact between the bottom hole assembly and the casing in the main wellbore, wherein adjusting the bend angle within the main wellbore comprises sending a signal to the bottom hole assembly that induces an adjustment mechanism on the bottom hole assembly to change an internal stress on at least one support member carried by the adjustable drill string housing; moving the bottom hole assembly in contact with the casing to the window defined in the casing such that the contact is relieved; detecting the relief of the contact; altering the bend angle, subsequent to detecting the relief of the contact, to define a direction of the branch wellbore; and commencing drilling the branch wellbore through the window in response to detecting the relief of the contact.