General Electric Company

Nl Industries

Eugene L Berger

Marion M Ringo

Richard A Koseluk

Determination of drilling mud thermal conductivity for estimation of earth formation temperature through a well bore thermal model. Borehole annulus and drill pipe bore temperature measurements are taken over a relatively short period of time when circulation of drilling mud is interrupted and temperature differentials maximized. The dynamic temperature response characteristics related to the heat transfer and storage parameters of the drill pipe, mud and bit are integrated into a mathematical borehole model incorporating the thermal resistance, heat capacity, and heat generation of the mud and drill pipe and the drill bit. The maximum temperature differential is then determined and the response characteristics used to establish the requisite parameters for the thermal conductivity and temperature calculations. In this manner, formation temperatures can be estimated to monitor downhole mud behaviour and geothermal gradients.

System for calculating formation temperatures

Pressure measurements of drilling mud inside the drill string and outside by transducers mounted in an instrumentation sub near the drill bit provide rapid notice of the instrusion of fluids or solids into the borehole and also permit appropriate adjusting of the mud pumping pressure.

Downhole pressure measurements of drilling mud

An apparatus and a method are provided for detecting and measuring vibrations of a selected portion of a drill string in a bore hole. The vibrations are detected by a transducer which produces an electrical signal representative of the vibrations. The signal is applied to a band-pass filter which produces an output signal representative of vibrations occurring at frequencies within the pass band of the filter. The pass band is repetitively stepped through a predetermined frequency range under the control of digital circuitry.

Growing community of inventors

Houston, TX, United States of America

Eugene L Berger