Communications: directive radio wave systems and devices (e.g. – Transmission through media other than air or free space
Reexamination Certificate
2002-11-04
2004-08-17
Gregory, Bernarr E. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Transmission through media other than air or free space
C342S118000, C342S175000, C342S194000, C342S195000, C342S196000
Reexamination Certificate
active
06778127
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to directional drilling navigation of boreholes in coal seams, and more specifically to radars and control systems for keeping the borehole drilling to the vertical center of the coal deposit.
2. Description of the Prior Art
The production of coal and methane depends upon the environment of the original coal bed deposit, and any subsequent alterations. During burial of the peat-coal swamp, sedimentation formed the sealing mudstone/shale layer overlying the coal bed. In deltaic deposits, high-energy paleochannels meandered from the main river channel. Oftentimes, the channels scoured through the sealing layer and into the coal seam.
High porosity sandstone channels often fill with water. Under the paleochannel scour cut bank, water flows into the face and butt cleats of the coal bed. Subsequent alterations of the seam by differential compaction cause the dip, called a roll, to occur in the coal bed. Faults are pathways for water flow into the coal bed.
Drilling into the coal bed underlying a paleochannel and subsequent fracking can enable significant flows of water to enter. The current state of the art in horizontal drilling uses gamma sensors in a measurements-while-drilling (MWD) navigation subsystem to determine when the drill approaches a sedimentary boundary rock. But if sandstone is protruding into the coal, such as results from ancient river bed cutting and filling, then the gamma sensor will not help. Sandstone does not have significant gamma emissions, so this type of detection is unreliable. Drilling within the seam cannot be maintained when the seam is not bounded by sealing rock.
Methane diffusion into a de-gas hole improves whenever the drillhole keeps to the vertical center of the coal seam. It also improves when the drillhole is near a dry paleochannel. Current horizontal drilling technology can be improved by geologic sensing and controlling of the drilling horizon in a coal seam.
One present inventor, Larry G. Stolarczyk, has described methods and equipment for imaging coal formations in geologic structures in many United States Patents. Some of those Patents are listed in Table I, and are incorporated herein by reference.
TABLE I
Patent No.
Issued
Title
4577153
Mar. 18, 1986
Continuous Wave Medium Frequency Signal
Transmission Survey Procedure For Imaging
Structure In Coal Seams
4691166
Sep. 1, 1987
Electromagnetic Instruments For Imaging
Structure In Geologic Formations
4742305
May 3, 1988
Method For Constructing Vertical Images Of
Anomalies In Geological Formations
4753484
Jun. 28, 1988
Method For Remote Control Of A Coal
Shearer
4777652
Oct. 11, 1988
Radio Communication Systems For
Underground Mines
4879755
Nov. 7, 1989
Medium Frequency Mine Communication
System
4968978
Nov. 6, 1990
Long Range Multiple Point Wireless Control
And Monitoring System
4994747
Feb. 19, 1991
Method And Apparatus For Detecting
Underground Electrically Conductive
Objects
5066917
Nov. 19, 1991
Long Feature Vertical Or Horizontal
Electrical Conductor Detection Methodology
Using Phase Coherent Electromagnetic
Instrumentation
5072172
Dec. 10, 1991
Method And Apparatus For Measuring The
Thickness Of A Layer Of Geologic Material
Using A Microstrip Antenna
5087099
Feb. 11, 1992
Long Range Multiple Point Wireless Control
And Monitoring System
5093929
Mar. 3, 1992
Medium Frequency Mine Communication
System
5121971
Jun. 16, 1992
Method Of Measuring Uncut Coal Rib
Thickness In A Mine
5146611
Sep. 8, 1992
Mine Communication Cable And
Method For Use
5181934
Jan. 26, 1993
Method For Automatically Adjusting The
Cutting Drum Position Of A Resource
Cutting Machine
5188426
Feb. 23, 1993
Method For Controlling The Thickness
Of A Layer Of Material In A Seam
5260660
Nov. 9, 1993
Method For Calibrating A Downhole
Receiver Used In Electromagnetic
Instrumentation For Detecting An Under-
ground Conductor
5268683
Dec. 7, 1993
Method Of Transmitting Data From A
Drillhead
5301082
Apr. 5, 1994
Current Limiter Circuit
5408182
Apr. 18, 1995
Facility And Method For The Detection And
Monitoring Of Plumes Below A Waste
Containment Site With Radiowave Tomo-
graphy Scattering Methods
5474261
Dec. 12, 1995
Ice Detection Apparatus For Transportation
Safety
5686841
Nov. 11, 1997
Apparatus And Method For The Detection
And Measurement Of Liquid Water And Ice
Layers On The Surfaces Of Solid Materials
5769503
Jun. 23, 1998
Method And Apparatus For A Rotating
Cutting Drum Or Arm Mounted With Paired
Opposite Circular Polarity Antennas And
Resonant Microstrip Patch Transceiver For
Measuring Coal, Trona And Potash Layers
Forward, Side And Around A Continuous
Mining Machine
RE032563
Dec. 15, 1987
Continuous Wave Medium Frequency Signal
Transmission Survey Procedure For Imaging
Structure In Coal Seams
RE033458
Nov. 27, 1990
Method For Constructing Vertical Images
Of Anomalies In Geological Formations
The present inventor, Larry Stolarczyk, describes the measuring of the thickness of ground deposit layers with a microstrip antenna, in U.S. Pat. No. 5,072,172, issued Dec. 10, 1991. Interpolation tables are used to lookup the layer thickness values corresponding to antenna conductance and resonance measurements. Such resonant microstrip patch antenna (RMPA) and their resulting measurements are used to guide coal-seam drum-cutter equipment for more efficient mining of natural deposit ores. The RMPA driving-point impedance (S
11
) changes significantly when a solid, gas, or liquid layer thickness overlying the RMPA varies.
U.S. Pat. No. 5,769,503, issued Jun. 23, 1998, to Stolarczyk, et al., describes mounting such RMPA on a rotating drum or arm of a coal, trona, or potash mining machine. A ground-penetrating-radar transmitting antenna and a receiving antenna can be mounted on a cutting drum to detect deeply buried objects and anomalous geology just ahead of the mining. A radar frequency downconverter is used so low-cost yet-accurate measurement electronics can be built. A first phase-locked loop (PLL) is operated at the resonant frequency of the patch antenna or at each sequentially stepped radar frequency. A second PLL is offset from the first PLL by an intermediate frequency (IF) and is called a tracking PLL. The measurement speed can be delayed by the sequential way in which the PLL's lock on to signals, so a solution to that delay is described.
The calibration curves represent an analytical function that has been reconstructed from a set of discrete I and Q data points measured at each height (H). The discrete sensor height calibration data can be used to construct two different polynomials with the independent variable being the physical layer thickness or height (H). The physical height (H) is independently measured with acoustic height measurement electronics during the calibration process or by other means, such as an inclinometer on the boom of a mining machine. The two calibration polynomials are,
I
(
H
)=
Re H=b
n
H
n
+b
n−1
H
n−1
+ . . . +b
1
H+b
o
(1A)
and
Q
(
H
)=
Im H=a
n
H
n
+a
n−1
H
n−1
+ . . . +a
1
H+a
o
(1B)
U.S. Pat. No. 5,325,095, describes a modulator that sequentially creates in-phase (I) and quadrature phase (Q) shifts in a frequency source signal. The frequency source signal is sequentially shifted by 0° or 180° (in-phase), then by 90° or 270° (quadrature) in passing through the phase modulator to the radar transmit antenna. The electronic circuits employ isolators. Isolators and quadrature modulator transmitters are costly and difficult to build with wide bandwidth. The receiver section of the radar receives the reflected signals from the target and uses a single frequency conversion design to transpose the received radar signal frequency to a lower frequency range where the I and Q signal measurements are sequentially made at each frequency in the stepped-frequency radar method that has become one of the standard ground penetrating radar practices. The I and Q signals contain the antenna sensor inform
Stolarczyk Gerald L.
Stolarczyk Larry G.
Gregory Bernarr E.
Main Richard B.
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