The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jul. 02, 1991

Filed:

Feb. 26, 1990
Applicant:
Inventor:

William N Wilson, Plano, TX (US);

Assignee:

Atlantic Richfield Company, Los Angeles, CA (US);

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
E21B / ;
U.S. Cl.
CPC ...
166285 ; 166 50 ; 166153 ; 166292 ;
Abstract

A method of cementing in a wellbore penetrating subterranean formations characterized by employing a graded density spacer fluid intermediate a displacing fluid and a displaced fluid. This is particularly advantageous where a cement slurry is employed as displacing fluid to displace drilling fluid employed to drill a well penetrating subterranean formations. This alleviates problem with intermixing of the two fluids. This invention is doubly advantageous where a well contains both a substantially vertical portion and a substantially horizontal portion, since in the latter portion, the use of this invention enables controlling under-running or over-running of a displacing fluid with respect to a displaced fluid.


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