Apparatus and method for determining the position of a gas-saturated porous rock in the vicinity of a deep borehole in the earth
US4363112A · kind A · utility
Inventor
Key dates
| Filing date | Apr 18, 1980 |
| Grant date | Dec 7, 1982 |
| Priority date | — |
| Expiry date | Apr 18, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V2210/161
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus for determining the position of a gas-saturated porous rock in the vicinity of a deep borehole in the earth, drilled to a selected depth below the expected position of the porous rock. The apparatus includes a source of seismic waves of selected characteristic, positioned at a selected point in the borehole, with an array of geophones positioned on the earth in known positions around the borehole. These geophones are adapted to receive the seismic waves generated by the source in the borehole, after traveling upwardly through the earth, and to produce corresponding facsimile electrical signals. If the seismic waves from the source, in their upward movement to the surface, pass through a gas-saturated porous rock they will be attenuated, and therefore the signals from the geophones which are in the shadow of this gas-saturated rock will show a change of character and/or an attenuation. If the shadow is observed while drilling at two or more known depths, the depth, azimuth, and radial position, from the borehole, of the gas-saturated rock can be determined. Using the principle of reciprocity, the same measurements can be made by interchanging the positions of seismic sourc…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.