Schlumberger Technology Corporation

Taylor Green

Robert L Horton

Mark Luyster

Bethicia B Prasek

Frank E Evans

Mike Frels

Steve Mason

Methods and apparatus for use with gas-filled downhole tools are disclosed herein. A disclosed example method includes opening an isolation valve of a downhole tool, wherein the isolation valve is in fluid communication with first and second ports of the downhole tool, and wherein the first and second ports are in fluid communication with respective first and second ends of an interior cavity of the downhole tool; coupling a source of inert gas to the first port and flowing the inert gas into the interior cavity of the downhole tool to expel air from the interior cavity through the second port; closing the second port when the air is expelled from the interior cavity; and closing the isolation valve to seal the inert gas in the interior cavity.

Method and apparatus for use with downhole tools having gas-filled cavities

A method of controlling and delaying the inversion of a drilling fluid and the wettability of a filtercake by using a delayed phase changing agent. The filtercake is preferably formed while drilling a subterranean formation using a drilling fluid includes: an oleaginous fluid; a non-oleaginous fluid; an amine surfactant having the structure: wherein R is a C&#x2013;Caliphatic hydrocarbon; R' is an independently selectable from hydrogen or Cto Calkyl; A is NH or O, and 1&#x2266;x+y&#x2266;3. In the method, the filter cake is exposed to a delayed phase changing agent selected from the group consisting of aliphatic amine acids, salts of aliphatic amine acids and combinations thereof. In one preferred illustrative embodiment, the delayed phase changing agent is delivered in the form of a pill, the pill including a carrier fluid, a viscosifier and the delayed phase changing agent. The delayed phase changing agent may be selected from ethylene diamine tetraacetic acid, alkali metal salts of ethylene diamine tetraacetic acid and combinations of these and similar compounds.

Delayed phase changing agent for invert emulsion drilling fluid

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Houston, TX, United States of America

Taylor Green