ALEXANDRIA, Va., Feb. 26 -- United States Patent no. 12,235,404, issued on Feb. 25, was assigned to Welldata (Subsurface Surveillance Systems) Ltd. (Fife, Great Britain).
"Measurement method and apparatus" was invented by Sydney Joseph Littleford (Fife, Great Britain).
According to the abstract* released by the U.S. Patent & Trademark Office: "There is disclosed in one implementation a method of or for use in or for detecting, measuring and/or determining at least one variable or characteristic in a space, such as a well, container or vessel. In one implementation the method comprises: transmitting a first electromagnetic signal from a first position to a feature within the space; receiving a second electromagnetic signal at a second posi...