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.
Patent No.:
Date of Patent:
Apr. 06, 1999
Filed:
Feb. 25, 1997
Schlumberger Technology Corporation, Sugar Land, TX (US);
Abstract
A wiper plug launching tool includes a body arranged to be lowered into a liner on a running string, the body having a tubular upper portion and a cylindrical lower portion, upper and lower wiper plugs loaded into the lower portion, each of the plugs having upwardly facing elastomer cups that are reduced in diameter during loading, a drive rod movably mounted in the upper portion of the body, a first piston or dart that is pumped down the running string and into engagement with the drive rod so that pressure applied to the first dart forces the rod downward to cause ejection of the lower wiper plug into the liner where cups of the plug expand to provide a moving seal at the lower end of a column of cement, and a second piston or dart that is pumped down into engagement with the first dart to force the rod further downward and cause ejection of the upper wiper plug into the liner where the cups of this plug expand to provide a moving seal at the upper end of the column of cement. A slidable valve is provided adjacent the upper end of the drive rod and is effective to close lateral flow ports upon downward movement of a dart and initial engagement with the drive rod. The drive rod has a piston mounted within a cylinder for cushioned movement upon metering of hydraulic fluid between the piston and cylinder during downward movement of the drive rod. A modification of the invention shown in FIGS. 9-11 utilizes three wiper plugs for sealing the liner.