Schlumberger Technology Corporation

Edward M Tollefsen

Dean M Homan

John C Rasmus

William Lesso

Sameer Bhoite

John James

Barbara J A Zielinska

Jaroslav Dobos

Alexis S Husser

Scott Paul

Amanda L Weber

Marcus Turner

Jung Kee Chung

Daniel Crowel

An electromagnetic (EM) telemetry system includes an EM transmitter configured to transmit EM signals downhole and multiple sensors each configured to communicate with the EM transmitter and with another of the multiple sensors. Each sensor is placed a distance from another sensor along a length of a wellbore in the EM telemetry system. The EM telemetry system also includes a processor configured to select two or more sensors of the multiple sensors based on a signal to noise ratio (SNR) of an EM signal received from the two or more selected sensors, a depth of the EM transmitter, or both.

Downhole electromagnetic sensing techniques

A method evaluating a cuttings density while drilling a subterranean wellbore includes acquiring first and second axially spaced pressure measurements in the wellbore. The pressure measurements may then be processed to obtain an interval density of drilling fluid between the measurement locations. A tool string including a large number of axially spaced pressure sensors (e.g., four or more or even six or more) electronically coupled with a surface processor via wired drill pipe may be used to obtain a plurality of interval densities corresponding to various wellbore intervals. The interval density may be measured while drilling and may be further processed to compute a cuttings density in the annulus. Moreover, changes in the computed interval density with time while drilling may be used as an indicator of a change in cuttings density.

Methods for evaluating cuttings density while drilling

A system and a method manage temperature in a wellbore. A thermal barrier may be positioned within the drill pipe and/or the drill collars to obtain a desired downhole temperature and/or control the effect of thermal energy in high-angle and horizontal wellbores. Downhole measurements, such as real-time measurements and/or recorded measurements, may be used to update models, such as steady state models and/or dynamic models. The downhole measurements may validate the static temperature gradient and may provide information about the thermal characteristics of the one or more formations in which the wellbore is located.

System and method for managing temperature in a wellbore

This invention provides a method and system for logging an earth formation with a logging tool that is stuck (lodged) in a well bore traversing the earth formation while fishing for the stuck logging tool. This procedure is accomplished by re-establishing communication between the stuck logging tool and surface equipment during the fishing process. Communication is established by reconnecting the electrical conductors in the supporting cable after the cable has been severed in order to install fishing equipment in the well bore around the cable supporting the logging tool. The procedure to reconnect the electrical conductors requires identifying conductors in each end of the severed cable and appropriately matching conductors from each cable end to achieve electrical communication. Once there is electrical communication between the stuck logging tool and surface logging equipment, logging procedures can be continued even during the fishing for the stuck logging tool.

Method and system for logging a well while fishing for the logging tool

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Katy, TX, United States of America

Edward M Tollefsen