Abstract: Disclosed is a method of preparing a first combined digital signal to be transmitted along a wireline deployed in a well. The first combined digital signal is for controlling a wireline conveying system and a measurement tool. The method includes converting a first telemetry signal to form a digitized telemetry signal, the first telemetry signal comprising control data for measurement tool; providing a control data for controlling the wireline conveying system; and transferring the digitized telemetry signal and the control data to a unit for processing data, the unit forming the first combined digital signal by multiplexing the transferred signal and data. Also disclosed is a method of preparing and transmitting telemetry data along a wireline, the method includes the previous steps and further: modulating the first combined digital signal to form a modulated signal; and transmitting the modulated signal from one end of the wireline to another.

Abstract: Disclosed is a method of preparing a first combined digital signal to be transmitted along a wireline deployed in a well. The first combined digital signal is for controlling a wireline conveying system and a measurement tool. The method includes converting a first telemetry signal to form a digitized telemetry signal, the first telemetry signal comprising control data for measurement tool; providing a control data for controlling the wireline conveying system; and transferring the digitized telemetry signal and the control data to a unit for processing data, the unit forming the first combined digital signal by multiplexing the transferred signal and data. Also disclosed is a method of preparing and transmitting telemetry data along a wireline, the method includes the previous steps and further: modulating the first combined digital signal to form a modulated signal; and transmitting the modulated signal from one end of the wireline to another.

Abstract: The invention relates to an overvoltage protection circuit, particularly in system where the load is remote from a regulated power supply and relates to an electric power supply system comprising such overvoltage protection circuit. The invention further relates to a downhole tractor comprising such overvoltage protection circuit, and to a tethered subsea vehicle comprising the overvoltage protection circuit.

Abstract: An assembly, method and device are for performing a survey of tubing which is stuck in a borehole. The assembly has a tractor for advancing the assembly along the tubing on an inside thereof; at least one engager connected to the tractor, the engager being configured to couple the assembly to a wall of the tubing, such that a stimulus applied to the tubing, e.g. components of force or manipulation of the tubing, can be communicated to produce a response in a part of the assembly. A detector may detect the response when the assembly is coupled to the wall of the tubing, in order to produce data based on the response for determining a location at which the tubing may, or may not, be subjected to at least one operation for freeing the string or a portion thereof.

Abstract: The invention relates to an overvoltage protection circuit, particularly in system where the load is remote from a regulated power supply and relates to an electric power supply system comprising such overvoltage protection circuit. The invention further relates to a downhole tractor comprising such overvoltage protection circuit, and to a tethered subsea vehicle comprising the overvoltage protection circuit.

Abstract: A photomultiplier tube stabilization circuit is set forth. It is particularly useful in downhole logging tools exposed to increases in temperature and to overcome component aging and drift. A high voltage power supply is connected for operation of a photomultiplier tube. The output of the PMT is amplified and applied to a set of comparators forming logic levels associated with threshold values affiliated with the spectral peak anticipated for the output data. The high voltage power supply is controlled upwardly or downwardly to vary operation of the PMT by means of a relatively simple control loop utilizing the comparators and means forming a control voltage for the high voltage power supply.

Abstract: For use in downhole logging tools responsive to gamma rays or x-rays, an improved scintillation device is set forth. In the preferred and illustrated embodiment, a scintillation crystal, typically sodium iodide (thallium activated), is utilized. It is an elongated, regular structure having two ends, and separate photomultiplier tubes (PMT) are attached at the separate ends. The two PMT output signals are supplied to a circuit which forms a signal adjusted or modified to compensate for loss of light energy arising during transmission through the scintillation crystal to the PMT's.

Abstract: A well logging system for measuring the radial density distribution of earth formations in the vicinity of a well borehole is provided. The system utilizes a single position sensitive gamma ray detector capable of deriving formation bulk density using the gamma-gamma scattering technique a different radial distances from the well borehole.

Abstract: A well logging system for measuring the radial density distribution of earth formations in the vicinity of a well borehole is provided. The system utilizes a single position sensitive gamma ray detector capable of deriving formation bulk density using the gamma-gamma scattering technique at different radial distances from the well borehole.