Method and devices for centralizing a casing

摘要

New apparatus and methods are provided for positioning and attaching centralizers to the inside sidewalls of a wellbore. One or more centralizers are maintained in the interior of a pipe that is transported downhole into a well for deployment. Preferably, the pipe is also the wellbore's casing and the centralizers are deposited in a top-down manner as the casing travels downhole. The centralizers of the present invention are constructed to have an at least partially circular structure with a central hole. The preferred centralizer has an expanding circular structure wherein the diameter of the centralizer is substantially uniform so as to form an annular construction. Once deployed, the annular centralizer expands to engage the wellbore sidewall with the central hole expanded for passage of the well casing.

主权项

1. A method of positioning casing centralizers downhole in a well comprising the steps of:
providing a well having a substantially circular sidewall, providing a pipe having a cylindrical sidewall, a central conduit, a distal extremity, and an opening at or near the pipe's distal extremity: providing an at least partially circular structure having a central hole within the pipe central conduit; positioning the pipe and the at least partially circular structure downhole with the at least partially circular structure positioned adjacent to a desired location for centralizing a well casing; ejecting the at least partially circular structure from the interior of the pipe through the pipe opening so as to be positioned at the desired location for centralizing a well casing; expanding the at least partially circular structure to be adjacent the wellbore sidewall at the desired location for centralizing a well casing; and moving a well casing downhole past the at least partially circular structure wherein the at least partially circular structure provides spacing between the well casing and the well sidewall.