Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
199 words
Apparatus for determining while drilling in the earth with a drill bit the position of a gas-saturated porous rock in the vicinity of the borehole, said drill bit serving to generate seismic waves of selected characteristics as it drills the borehole in the earth comprising: (a) a plurality of seismic wave sensors positioned in the earth near the surface thereof, at a plurality of known positions with respect to said borehole; (b) said seismic wave sensors adapted to receive the seismic waves generated by said drill bit which travel directly to the sensors and in certain positions both seismic waves which travel directly from the drill bit and seismic waves from the drill bit which are reflected from the gas-saturated porous rock to produce an electrical signal facsimile at each location corresponding to the received seismic waves whereby to generate an interference signal when the sensor receives both direct and reflected seismic waves, said interference signals serving to indicate a gas-saturated porous rock formation, and means including frequency selection means connected to receive the electrical signal facsimile at each location of a selected harmonic at the rate of rotation of said drill bit and provide said interference output signals.
Claim 2
Dependent Claim
199 words
Apparatus for determining while drilling in the earth with a drill bit the position of a gas-saturated porous rock in the vicinity of the borehole, said drill bit serving to generate seismic waves of selected characteristics as it drills the borehole in the earth comprising: (a) a plurality of seismic wave sensors positioned in the earth near the surface thereof, at a plurality of known positions with respect to said borehole; (b) said seismic wave sensors adapted to receive the seismic waves generated by said drill bit which travel directly to the sensors and in certain positions both seismic waves which travel directly from the drill bit and seismic waves from the drill bit which are reflected from the gas-saturated porous rock to produce an electrical signal facsimile at each location corresponding to the received seismic waves whereby to generate an interference signal when the sensor receives both direct and reflected seismic waves, said interference signals serving to indicate a gas-saturated porous rock formation, and means including frequency selection means connected to receive the electrical signal facsimile at each location of a selected harmonic at the rate of rotation of said drill bit and provide said interference output signals.
Claim 3
Dependent Claim
47 words
Apparatus as in claim 1 wherein said means including frequency selection means includes filters tuned to a frequency representative of a harmonic of the drill bit rotational velocity for receiving the signals from the sensors and providing said output signals at the bandpass frequency of said filters.
Claim 4
Dependent Claim
21 words
Apparatus as in claim 1 wherein said means including frequency selection means includes a spectrum analyzer for providing said output signals.
Claim 5
Independent Claim
211 words
The method of determining while drilling the position of a gas-saturated porous rock formation in the vicinity of a borehole in the earth comprising the steps of: (a) drilling the borehole in the earth with a rotary drill bit which generates while rotating almost periodic seismic waves; (b) detecting such almost periodic seismic waves at a plurality of selected positions on the surface of the earth, said detected seismic waves including at all positions seismic waves which travel from the drill bit directly to the surface of the earth, and at certain other positions, additionally seismic waves which are reflected from a gas-saturated porous rock formation in the earth at a depth greater than the location of the drill bit and which travel to the surface of the earth; (c) simultaneously generating from said detected seismic waves at a given depth an electrical facsimile signal at a harmonic of said periodic seismic waves at said selected positions, said facsimile signal corresponding to the detected direct seismic waves or the combined direct and reflected seismic waves, whereby said signal at said certain other positions is an interference signal; and (d) comparing said facsimile signals at a given drill bit depth to find those which have anomalous energy to indicate an interference zone.
Claim 6
Independent Claim
211 words
The method of determining while drilling the position of a gas-saturated porous rock formation in the vicinity of a borehole in the earth comprising the steps of: (a) drilling the borehole in the earth with a rotary drill bit which generates while rotating almost periodic seismic waves; (b) detecting such almost periodic seismic waves at a plurality of selected positions on the surface of the earth, said detected seismic waves including at all positions seismic waves which travel from the drill bit directly to the surface of the earth, and at certain other positions, additionally seismic waves which are reflected from a gas-saturated porous rock formation in the earth at a depth greater than the location of the drill bit and which travel to the surface of the earth; (c) simultaneously generating from said detected seismic waves at a given depth an electrical facsimile signal at a harmonic of said periodic seismic waves at said selected positions, said facsimile signal corresponding to the detected direct seismic waves or the combined direct and reflected seismic waves, whereby said signal at said certain other positions is an interference signal; and (d) comparing said facsimile signals at a given drill bit depth to find those which have anomalous energy to indicate an interference zone.
Claim 7
Dependent Claim
48 words
The method as in claim 4 including the additional steps of: (f) drilling at a second depth whereby the drill bit generates seismic waves at a second depth; (g) repeating steps (b), (c) and (d) for the seismic waves at the second depth to indicate an interference zone.