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US 4,351,037 AGranted
Systems, apparatus and methods for measuring while drilling
OwnerSerge A. Scherbatskoyinventor
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OwnerSerge A. Scherbatskoyinventor
Estimating the term…
A method and apparatus for continuously logging while drilling a well bore with a rotary drilling rig comprising a drill string, a jet type drill bit, and mud pump means for circulating fluid under pressure. The apparatus generally includes means for sensing one or more downhole parameters near the drill bit, means for generating a sequence of electrical pulses representative of said parameter, and means for generating negative mud pressure pulses in the drilling fluid ("drilling mud") within the drill string in response to said electrical pulses. Receiving means at the earth's surface detect the negative mud pressure pulses and utilize the sequence of these pulses to produce signals representative of said parameter. The receiving means employ means to substantially eliminate the effects of the pressure pulsations generated by the mud pump and to extract the negative mud pressure pulses the sequence of which represent the downhole parameter. The means for generating the negative mud pressure pulses involves utilization of the existing energy on the high pressure side of the drill bit through a bypass to the low pressure side of the drill bit controlled by a valve mechanism and arrangement. The design of the valve mechanism and arrangement is such that the valve can be powered for actuation as necessary over a requisite time period by self-contained downhole power source, and is not subject to unacceptable wear.
For use in a system for conducting drilling operations employing a string of drill pipe extending from the earth's surface having a drilling means at the lower end, a pump by which drilling fluid is forced downwardly through the drill string interior and drilling means to flow back to the surface through the well annulus, the drilling means imposing a restriction to the drilling fluid flow forming a high pressure zone in the interior of the drill string and a low pressure zone in the well annulus, a telemetering system comprising a drilling fluid bypass above the drilling means providing fluid communication between the interior of the drill string and the well annulus, the bypass having an inlet portion within said drill string and being defined in part by a valve seat having an inlet and outlet, a valve stem moveable to and away from the inlet end of said valve seat and in a linear path within said drill string forming a valve in said bypass, the bypass having an outlet portion extending from the outlet end of said valve seat to said annulus, a means for detecting the magnitude of a downhole parameter and for producing an electrical signal comprising a succession of electrical pulses which are arranged in a sequence having a time distribution representing said magnitude, an electrical energy source, means responsive to each said electrical pulse for supplying a relatively large amount of electrical power to initiate opening said valve, and substantially less power when the valve is open or closed, to generate pressure pulses in the drilling fluid, and means at the earth's surface to detect such pressure pulses and to provide a measure of the magnitude of said parameter.
For use in a system for conducting drilling operations employing a string of drill pipe extending from the earth's surface having a drilling means at the lower end, a pump by which drilling fluid is forced downwardly through the drill string interior and drilling means to flow back to the surface through the well annulus, the drilling means imposing a restriction to the drilling fluid flow forming a high pressure zone in the interior of the drill string and low pressure zone in the well annulus, a telemetering system comprising a drilling fluid bypass above the drilling means providing fluid communication between the interior of the drill string and the well annulus, the bypass being defined in part by a valve seat, a valve stem moveable to and away from said valve seat forming a valve to close and open said bypass, a means for detecting the magnitude of a downhole parameter and for producing an electrical signal comprising a succession of electrical pulses which are arranged in a sequence having a time distribution representing said magnitude, a cylinder in communication with the bypass having a compensating piston therein connected to said valve stem so that fluid pressure exerts a first hydraulic force on the compensating piston in the direction corresponding to the opening of the valve and fluid pressure exerts a second hydraulic force on the valve stem in the direction corresponding to the closing of the valve, the net hydraulic force on the valve stem being proportional to the difference between said first force and said second force, and means responsive to said electrical pulses to rapidly actuate said valve stem to generate pressure pulses in the drilling fluid, and means at the earth's surface to detect such pressure pulses and to provide a measure of the magnitude of said parameter.
Dependencies are inferred from the claim text.