Exploration Logging, Inc.

Henry S More

John D Jeter

Christopher E Koch

Waldemar S Wisniewski

A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well. Anchor means on the sensing means prevents it from rotating relative to the sleeve.

Method for making logging sleeve

A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well.

Well logging apparatus with replaceable sensor carrying insulating

Well logging apparatus and method for making same

Method of making well logging apparatus

In response to a signal to open and close a solenoid-operated valve, which is urged closed by flow of fluid through it, a circuit supplies a large current to the solenoid to open the valve, reduces the current to hold the valve open, and interrupts the current to close the valve. The circuit provides high electrical efficiency during operation. One embodiment of the invention is particularly suitable for use in systems in which the voltage of the power source varies over a wide range.

Solenoid control circuit

The accuracy of well logging data transmitted from a downhole location to the surface of the earth is verified by generating the data at the downhole location, storing the data in a subsurface assembly in the well, transmitting signals corresponding to the data to the surface through a first transmission system while keeping the data stored in the subsurface assembly, and recording the signals transmitted to the surface through the first transmission system. Thereafter, the subsurface assembly is transferred to the surface, and signals corresponding to the stored data are transmitted through a second transmission system from the assembly to an electronic processing system. The signals transmitted through the second transmission system are then compared with the signals transmitted through the first system. To increase the effective transmission rate of data from the downhole location to the surface, a first set of signals corresponding to the magnitude of a downhole condition as a function of time during a discrete time interval are generated and transmitted through a first transmission system to computer means at the downhole location. The first set of signals are analyzed in the computer to determine properties of the function selected from the group consisting of mean value, positive and negative peak values, standard deviation value, and fundamental and harmonic frequencies and amplitudes. A second set of signals corresponding to the selected values are generated and transmitted to the surface through a second transmission system.

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Carmichael, CA, United States of America

Henry S More