Systems, apparatus and methods for measuring while drilling
This invention is concerned with downhole measurements while drilling a borehole in the earth with a drill bit at the lower end of the drill string and transmitting such measurements to the surface. The drilling fluid is forced through a fluid passage which includes a drill string, a bit at the lower end thereof and the annulus surrounding the drill string. There is a restriction in the passage causing a pressure drop creating a high pressure zone and a low pressure zone within said passage, and a drilling fluid bypass comprising a bypass valve provides fluid communication between the high pressure zone and the low pressure zone. By means of a downhole sensor and associated equipment a plurality of pulse or electrical voltage change signals representing downhole information is produced. Each of these signals is arranged to generate several electrical voltage changes. A control means is provided to cause opening of the bypass valve responsive to one of these signals and for causing closing of the valve responsive to another of said signals.
- Assignee:
- IFI; EDB-86-104032
- Patent Number(s):
- US 4553226
- OSTI ID:
- 5845933
- Country of Publication:
- United States
- Language:
- English
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