Stress wave telemetry system for drillstems and tubing strings
US4992997A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 29, 1988 |
| Grant date | Feb 12, 1991 |
| Priority date | — |
| Expiry date | Apr 29, 2008 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/16
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Downhole conditions in wellbores such as fluid pressure, temperature and flow conditions during drillstem testing or during wellbore stimulation or fracturing processes are transmitted through sensing and signal conversion circuits to axial or torsional wave vibrators secured to a drillstem or tubing string in the borehole for generating stress wave vibrations in the drillstem or tubing string for transmission to a point at or near the earth's surface. Accelerometers and/or strain gauges are mounted on the stem or tubing at a point near the earth's surface for sensing the torsional, axial or bending vibrations and converting the vibratory signals to signals for receipt and recording and correlated with the signals being transmitted from the borehole. The system includes an axial compression wave generator comprising a solenoid energized oscillator hammer member disposed on a sub which may be interposed in the drillstem. A torsional wave vibration generator may be utilized comprising a sub having motor driven eccentric rotors which are driven in timed relationship to each other to generate selected torsional and/or bending stress waves in the drillstem or tubing string.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.