WO2001048353A1

WO2001048353A1 - Autonomous omnidirectional driller

Info

Publication number: WO2001048353A1
Application number: PCT/US2000/034672
Authority: WO
Inventors: Robert Arthur Wootten
Original assignee: Ball Corporation
Priority date: 1999-12-27
Filing date: 2000-12-19
Publication date: 2001-07-05
Also published as: AU2282501A

Abstract

A drilling or boring system (112) provides one or both of a thrust generator (136) or torque generator (174) positioned down-hole coupled to a drill head (132). Thrust and/or torque forces are reacted to the bore hole wall by a stabilizer system (154) such as a spoke system (220) or a drum brake system (220'). The system can achieve relatively a small turning radii such as less than 25 feet, preferably less than 15 feet. Down-hole deployment sensing systems including down ground-penetrating radar (146) and/or inertial navigation (152) and/or global positioning systems can provide obstacle detection (166), preferably with fine resolution, such as less than 3 inches, and/or accurate, preferably real time and preferably three-dimensional as-drilled mapping.

Description

AUTONOMOUS OMNIDIRECTIONAL DRILLER

The present invention relates to an apparatus, method and system for drilling and in particular to a driller which can, if desired, position any of various components down-hole, including some or all portions of any of a guidance system, steering system, power system, sensing system and the like.

BACKGROUND INFORMATION Numerous systems have been developed or proposed for underground drilling including substantially horizontal drilling or boring (e.g. for installing water, power, communication or other utility lines, conduits, other trenchless underground construction and the like or other purposes). A common configuration involves coupling a drilling head to a rigid-link drive train, and connecting the drill head to surface facilities for providing both torque and thrust to the drill head. Often, a fluid or slurry is used for removing spoils, lubrication, and the like.

A rigid-link drive train is associated with a number of disadvantages. Typically, systems which have relatively long and rigid links or other components have limited maneuverability such that it is typically impossible to provide a drilled path having relatively tight curves and thus require a turning radius of, e.g., about 150 feet or more. Accordingly, it would be useful to provide a drilling system which can achieve relatively small-radius path changes such as path changes approximating a radius of less than about 150 feet, such as less than 25 feet, and/or less than 20 feet, and/or less than 15 feet.

At least in part due to the inability to achieve relatively high maneuverability, many previous drilling approaches or systems required careful surveying and planning of a drilling or boring route, especially in areas that may have many obstacles (such as preexisting utility conduits, lines or other utility items, building foundations, basements or other structures and similar man-made objects, as well as obstacles such as underground rocks or particularly hard geologic formations). The inability to design small-radius drill paths meant that such paths typically needed to be carefully designed beforehand (rather than in real time) adding to the cost of the project. Accordingly, it would be useful to provide a system which can more readily accommodate a degree of real-time path design, reducing the cost of planning phases for a drilling project.

Even with relatively careful planning, it is not uncommon to encounter unexpected obstacles during a drilling project. In many typical previous systems, encountering such an obstacle could not be readily solved by changing the path, in real-time, to go around obstacles. This is in part because of lack of capability for achieving small-radius curves as well as a general inability to sense obstacles until it is "too late", i.e., inability to sense relatively small obstacles (such as obstacles less than about 1 foot diameter) and/or inability to sense obstacles relatively far in advance of the drill head meeting such obstacles (e.g., compared to the turning radius of the system). In many such systems, when a drill path met an unexpected obstacle, it became necessary to perform a trenching operation or otherwise reach the drill path from the surface, adding to expense and delay of the project. Accordingly it would be useful to provide a system which can detect relatively small obstacles, including obstacles less than about a foot in diameter, such as 3 inches or less in diameter, and which can detect such obstacles at a significant distance from the drill head, compared to turning radius (such as at a distance of about 3 feet), permitting a change in the drill paths so as to avoid the obstacle.

Using rigid-link drill strings, as is typical with previous horizontal boring devices, can also have a number of other disadvantages. When a drill string is used to provide rotation and/or thrust to the drill head, there is typically an amount of power loss through the drill string, particularly if the drill path is relatively long, owing, at least in part, to factors such as linkage play or tolerance, friction and the like. Prior devices not untypically experienced power loss of nearly 25% due to transmission of torsional energy and thrust over large distance through the tunnel. Certain systems provide "mud motors" for achieving desired power. However, such devices require a relatively long fluid path for a power transfer and are relatively inefficient and difficult to control. Failures in the drill string can be relatively expensive to correct, often requiring full or partial withdrawal of the drill string and reinsertion. Even in the absence of drill string failures, the cost of providing the drill string, the cost of connecting links, inserting and controlling the drill string and like can undesirably inflate the cost of the project. Furthermore, drill strings often occupy a relatively large proportion of the bore hole cross section thus undesirably limiting the amount of cross sectional area available for other functions such as fluid or slurry transport. Accordingly, it would be useful to provide a drilling or boring system which can avoid some or all of the costs and inconveniences associated with reliance on a rigid-link drill string for transmitting rotation and/or thrust. In addition to advantages that would be obtained from the ability to sense relatively small objects, preferably significantly in advance of the drill head, it would also be advantageous to provide a system which can permit highly accurate determination of the location of the drill head, both to assure that the drill path follows the plan and also to provide relatively accurate information on the location of the drill path, e.g., for use in planning future projects. Accordingly it would be useful to provide a system which can determine drill head location in real-time, preferably with a high degree of accuracy such as with errors of no more than about 10 cm, and/or no more than about 5 cm.

SUMMARY OF THE INVENTION

The present invention includes a recognition of problems in previous approaches including as described herein. In one aspect, a ground drilling machine and system is provided which includes any of a number of control, sensing or steering features down hole and accordingly provides autonomous functionality. Preferably, the system has the capability to detect objects in front of and around the hole as it is propagating through the ground. The system preferably utilizes a steerable section which can direct the drill away from sensed obstacles. The system applies drilling forces to the drill head using a hydraulic (or other) unit which has the capability to drill through various materials. The position of the drill head is sensed or controlled using an in-hole inertial guidance (or other) system (IGS) preferably correlated to an external global positioning system (GPS), thereby defining position in three dimensional space. Drilling spoils are routed through the center in a reverse circulation (or other) system that removes spoils from the hole. The torsional drive train, aft of the cutter head, is located down-hole and generates the torque required to drill through various media. The drilling device and its operation are controlled by a control system, such as a computer system, some or all of which may be downhole or may be external of the hole. The torsional and axial loads required for the drill train to propagate through the hole are controlled by a stabilizer that reacts some or all of these loads to the hole around the drill head. The stabilizer may secure to the perimeter of the hole, e.g. by friction resistance or radial penetration of supports to the surrounding environment. Although in some embodiments, aspects of steering, control or other systems may be performed fully or partially down-hole, in one aspect operation can be controlled by an operator via a digitally-controlled graphical interface or the driller can be pre-programmed for partially or fully automatic operation. Control may be maintained by a feedback system including INS, GPS, ground penetrating radar (GPR), casing payout measurement, head direction feedback, orientation feedback and/or drilling head monitoring.

In one aspect, a drilling or boring system provides one or both of a thrust generator and torque generator positioned down-hole, coupled to drill head. Thrust and/or torque forces are reacted to the bore hole wall by a stabilizer system such as a spoke system or drum brake system. The system can achieve relatively small turning radii such as less than 25 feet, and/or less than 15 feet. Surface and/or down-hole-deployed sensing systems including, if desired, down ground-penetrating radar and/or inertial navigation and/or global positioning systems can provide obstacle detection, preferably with fine resolution, such as less than about 3 inches, and/or accurate, preferably real time and preferably three-dimensional as- drilled mapping.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram depicting components of a drilling system according to one embodiment of the present invention; and

Fig. 2 is a perspective view, partially broken away, of down-hole components of a drilling system according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE

PREFERRED EMBODIMENT

In the embodiment depicted in Fig. 1, the system includes a plurality of components 112 which are preferably positioned in-hole. The in-hole components 112 are preferably in effective communication with components positioned on the surface 114 and may be coupled by sensing 116 control 118 and power 122 communication links, e.g., carried over one or more cables 212 (Fig. 2) in addition to a water feed 124 and slurry return 126. Although water may be used as the fluid, other fluids are possible including, without limitation, oils, natural or synthetic lubricants or solvents, combinations of the above, and the like. In the embodiment of Fig. 1, a drill head 132 is coupled to a torque system 134, a thrust system 136 (providing both translation 138 and steering 142) a sensing system 144 (which can include all or some of a GPR system 146 and associated antenna 148 and/or components of an inertial guidance and navigation system 152), and a stabilizer 154. Preferably a fluid delivery system 156 provides filtered fluid to the drill head 132, e.g., for lubrication and/or to a spoils pump 158 for spoils removal in the return slurry 126.

Control logic 162 which may include one or more programmed computers such as a personal computer (PC) workstation, and the like, and which may include two or more computers (such as networked to remotely located computers). Although control logic 162 is depicted as surface-located, in other embodiments, some or all control logic components maybe downhole. The control logic 162 receives feedback and sensing data 116 from down- hole sensors and casing payout information 164 (e.g., indicative of bore hole path links) and, possibly with the assistance of obstacle detection hardware or software 166, provides information to an operator terminal 168, preferably displaying pertinent information in real time such as a map or other positional display (preferably a three dimensional display) depicting such items as the actual bore hole path, planned path, location, size and nature of detected obstacles, and the like. In response to operator commands and/or programmed controls, control logic 162 outputs control signals 118 and/or controls a power supply 172 for activating, deactivating and/or steering or otherwise controlling the drilling operation.

The drill head 132 functions to break up rock, gravel and soil into small fragments

(called spoils), sufficiently small so they can be transported by the spoils system outside of the tunnel. A number of types of drilling bits can be used including, without limitation, a disc cutter bit, a tri-cone bit and/or a spade bit. A disc cutter bit employs a series of rotating discs densely packed to minimize the spacing between cuts. Thrust applied through the head forces the disc edges into the rock and the skewed orientation of the discs exert lateral loads by rotation of the entire head. Disc cutter bits are considered, in the present invention, to offer relatively high efficiency, such as high (horsepower-hour per cubic yard) efficiency and to be particularly useful for hard rock in variable soil conditions. A tri-cone bit includes three conical elements that project from the head, e.g. in a symmetrical 120-degree spacing. The cones are constructed with surface features, called buttons or nubs, that protrude from the surface for scarfing, or scraping the ground material. Typically the cones are made of tungsten carbide or other high abrasion resistance material. As the drilling head rotates, the cones revolve, typically in the opposite direction relative to the head. Tight positioning of the cones ensures that the resulting fragments are relatively small. A spade bit provides (typically 2 to 8) spade components protruding radially outward to scoop and direct ground to the spoils removal system. The spade bit is considered, in the present invention, particularly useful in clay or sand soil conditions.

In the depicted embodiment, rotation or torque is provided to the drill head by a torque system 134 provided in a torque system housing 174. Although a number of torque systems can be used, in the depicted embodiment a direct current (DC) brushless motor 176 is coupled to two harmonic gear trains 178a 178b by a coupling shaft 180. The gear trains 178a and b transmit torque to a central auger that is the driving mechanism for the drill head 132. The housing 174 provides support for drilling thrust loads, and protects the power train from dirt moisture and other contaminants. Because the torque system 134 is positioned close to, and preferably coupled directly to, the drill 132, it is possible to avoid power losses of a type associated with fluid or mechanical or power transmission through the length of the bore hole and it is believed the present invention can achieve efficiencies substantially in excess of 75%, preferably as much as 85% (or more) efficiency from the torque source to the drill head. Furthermore, the close, preferably direct, coupling of the torque drive to the drill head permits the present invention to achieve a device in which the rigid or stiff portion of the down-hole device has a relatively short length 214 (Fig. 2). The short length 214, especially when combined with the preferably articulated attachment with respect to the drill head 132 facilitates the system achieving a relatively small drill path turning radius such as a radius less than 150 feet, and/or less than 50 feet, and/or less than 25 feet, and/or less than 20 feet and/or than about 15 feet. Because the torque drive (as well as other components) is not only positioned down-hole but travels with the drilling head as it moves through the tunnel, a number of disadvantages associated with previous approaches (including as described above) can be avoided.

The fluid delivery system 156 is useful for a number of purposes. The system creates a liquid medium for the cutting environment to achieve high efficiency. The system transforms spoils or drilled material into a slurry, preferably highly dilute, such as more than 90% fluid by weight, so that it can be removed 126 by the spoils system. The fluid delivery system assists in cutting the tunnel when soft materials such as clay and sand are encountered. The fluid delivery system 156 can assist in reducing the potential for clogging cutters during operation and can assist in declogging when clogging has occurred. In one embodiment, several fluid jet lines having a fluid pressure, e.g., of about 80 psi, are routed through the drill train 216 to the drill head 132. Preferably, surface pumps 184, possibly assisted by a down-hole-spoils pump 158, provide the slurry to a system of screens, filters, 186 centrifugal separators or pumps and the like. Preferably the filtered fluid contains substantially no particles greater than a threshold, such as 15 microns. The filtered fluid is recirculated 124 for use again as a drilling lubricant and/or slurry component, possibly with the addition of makeup fluid 188.

The thrust system 132, in the depicted embodiment, includes a plurality, such as four, preferably independently controllable linear translators such as hydraulic cylinders 218a, b. Other embodiments can use pneumatic, electric or other actuators. The hydraulic cylinders 218, depending on control, can provide thrust force to the drilling head, for advancing or translating the system along the desired drill path, and/or can angle or tip the drill head 132 to generate a cutting angle of the head to define an angled or curved bore hole or drilling path. In order to angle or tip the drilling head 132, the connection between the torque system 134 and thrust system 136 is an articulated system, e.g., using a universal clevis design of a type that will be understood by the those of skill in the art after understanding the present disclosure. In addition to the clevis design, a multiple-hinge or flexible link (or other) design can be used, as will be understood by those of skill in the art. In one embodiment, the hydraulic cylinders 218ab are relatively high pressure devices in which pressures of up to 5000 psig will generate thrust loads at the drilling head of up to about 55,000 lbs or more. In the depicted embodiment the cylinders 218ab (two of which are shown in the view of Fig. 2) are controlled with servo valves and positional feedback from low voltage displacement transducers (LVDT 190) located within or coupled to the cylinders 218ab. In other embodiments, control can involve linear actuators, electric motors or the like.

As the drilling head 132 migrates down the length of the tunnel, large thrust and torsion loads maybe required, depending on the soil conditions the drilling head encounters. For example, in at least some applications, it is anticipated that the system will experience thrust requirements on the order of about 55,000 lbs or more and torsion requirements of 2500 foot lbs. or more. In the depicted embodiment, these loads are reacted directly into the ground in the proximity of the drilling head, thus avoiding the need to transmit such loads all the way back to the tunnel entrance. In the embodiment depicted in Fig. 2, the stabilizer 154 includes a plurality of anchor bolts or spokes 220a- f. The spokes are activated by an internal hydraulic system that, e.g. rotates to force the spokes or rods to penetrate the tunnel wall in a spoke or vault door configuration. In addition to a hydraulic system, pneumatic, electric or other systems can be used. By penetrating the walls of the tunnel with anchor bolts, the drilling head can continue to move forward using the thrust system 136, excavating the tunnel. In place of, or in addition to, the spoke stabilizer depicted in Fig. 2, is also possible to implement a drum brake system (similar to automobile brakes) in which a drum or drum components (not shown) are expanded against the walls of the tunnel or the casing using hydraulic power 192 ' . In one embodiment a single hydraulic cylinder (not shown) with stroking heads on each end will drive a pair of pads or shoes into the inner surface of the stationary tunnel wall. Other embodiments can use, for example, pneumatic, electric or other brake actuators, can position brakes at only one end, or between the ends, can use a single pad or more than two pads and the like. Such a brake type mechanism develops large contact pressure and hence makes friction available for reacting the drilling loads. Preferably, the stabilizer 154 reacts both thrust loads and torque loads. Additionally, the stabilizer system 154 may be configured to form a seal (e.g., using a drum brake configuration) that precludes water and spoils from undesirably entering or flowing around the casing 222. In the depicted embodiment, the sensing unit 144 includes ground penetrating radar

146 which operates by using reflected electromagnetic radiation to produce profiles of subsurface features. In addition to GPR, other sensing systems can use sonar, magnetic or gravitational sensing and the like. Typical previous GPR systems were surface-deployed radar systems for producing 2-D and psuedo-3-D maps of subsurface terrain. In one aspect of the present invention, GPR which is deployed directly on the driller provides continuous look-ahead imaging during the drilling process and can be used, e.g., by combining with surface GPR and/or internal guidance and navigation systems 154 and/or global positioning systems, to produce a true 3-D picture of the tunnel, where it is going or is planned to go, what potential obstructions lie ahead and/or how best to negotiate them. In one embodiment, the in-hole GPR system 146 uses frequency modulated continuous wave (FMCW) radar packaged in a conformal wrap-around antenna 148 which may be deployed in or around the torque system or GPR housing 174. In other embodiments, phased array, synthetic aperture or other radar systems can be employed. The wrap-around antenna creates several antenna nodes in a beam former behind the antenna array. Each of the antenna nodes will use coaxial cable and route it through the umbilical cable 212 to the control logic 162 for appropriate display on the operator terminal 168. The waveform generator transmits through one of the node cables while the other node cables are monitored as receivers. Although, in the depicted embodiment, the radar electronics 146 are depicted as down-hole, it is also possible to provide a configuration in which only the antenna 148 is down-hole and receives signals from surface-located electronics. In other embodiments, some or all parts of the antenna can be located other than downhole. Preferably, the GPR provides relatively fine resolution such as resolution of objects having a diameter of about 3 inches, preferably as small as about 1 inch or less. In some embodiments, 3-D synthetic aperture radar imaging is provided. Although prior GPR systems typically operate in a range of about 300 MHz to about 1,000 MHz, preferably, the GPR system according to the present invention operates in a wide bandwidth such as including 200 MHz to about 2,000 MHz. The actual frequency range may depend on the dielectric constant of the soil. In general, electromagnetic penetration and range may be relatively reduced when operating in wet soil, or below water line. In such conditions, it may be possible to implement electromagnetic induction systems which measure the conductivity of the surrounding area. Preferably, the system provides adequate isolation between transmit and receive antenna modes, since inadequate isolation may limit maximum transmission power as well as the frequencies and bandwidth of operation. It is believed that transmit- receive isolation requirements will vary with the surrounding material. Some ground material will require greater radio frequency energy operation but not necessarily proportionally greater isolation (since these material also exhibit greater RF energy loss). The initial guidance and application system 152 can facilitate extensive knowledge, command and control of the drill head and the tunnel direction. Preferably, the system provides the control logic at 162 with substantially instant and accurate information regarding the location of the drill head 132 and in what direction it is traveling. In response, the control logic 162 will be able to effect turning and thus control drilling direction. The initial guidance and navigation system receives information regarding the attitude and translation of the drill head 132, including receiving the information from the LVDT hydraulic (or other) sensors 190 to provide head direction and orientation information 194. Navigation and mapping software, e.g., in the control logic 162 or in a separate system, will determine and log the drill head position and/or orientation e.g., calculated from dead reckoning based on previous known positions and drill head translation and orientation, and will log the drill head position and preferably display the actual and planned tunnel path to the operator on the operator terminal 168. Preferably the initial point or entrance point for the tunnel (and, where applicable, the tunnel exit port) is determined with high accuracy using a GPS receiver. In one embodiment, the user interface at the terminal 168 can include a laptop computer. Preferably, computer software will acquire, process, display data from various systems. In one embodiment, Lab View communication software available from National Instruments Corporation, can be used. Preferably, capability for closed loop software control of all systems is provided. Preferably, all control loops will have operator override capability. A summary of high priority telemetry data will be continuously displayed to the operator 168 while more detailed and less critical data will be provided as requested. The system preferably provides capability of providing drill motor speed closed-loop control. In this way, drill speed will be automatically adjusted to maintain maximum efficiency. Obstacle avoidance will be achieved using data received from the GPR and/or IGN systems. In one embodiment, the control logic 162 will suggest best path, turn rates and directions and the like during operation.

As the tunnel is excavated and the drill head 132 bores forward, casing 222 is continuously left in place. The casing protects the hole from the external environment and from collapsing. In one embodiment, casing is installed by pushing casing substantially continuously into the hole as it is drilled. When the drilled path is to have relatively tight- radius curves, the casing must be sufficiently flexible to accommodate such curves. Nevertheless, the casing shall be strong enough to withstand external ground pressures and pushing forces. In some embodiments, the stabilizer may engage the casing. Thus the casing, in these embodiments would need to have sufficient strength to react the thrust and torsion load as needed for the drilling head. In one embodiment, high density polyethylene (HDPE) piping can be used such as that available from Plexco Corporation (a division of Chevron). Preferably the system depicted in Fig. 1 is substantially transportable and may be readily transported by truck and/or trailer to a j ob site with casing material and spoils deposits being handled separately.

In light of the above description, a number of advantages of the present invention can be seen. By positioning some or all of sensing, stabilizing, thrust, torsion or other systems down-hole, the system avoids power loss and expenses associated with many previous systems which typically provided such components on the surface. By avoiding a long rigid- link drill string and by providing an articulated down-hole system, the present invention can achieve a relatively tight radius of curvature. Advanced sensing such as high resolution GPR (or other systems, including as described herein), make possible on-the-fly directional changes and, when combined with a tight (e.g. 15 ft.) turning radius, allows operation in areas where a survey of the environment is not possible or practical or which indicates tunneling cannot be done with conventional systems. Drill mounted imaging such as drill mounted GPR, can image in areas not visible to surface-deployed systems. As compared to previous systems which might initiate a tunnel and encounter an unavoidable obstruction (and the consequent costs and delays of re-navigation, pulling out and restarting, trenching and the like) the present system will be able navigate around difficult areas without drilling a new tunnel. Inertial guidance and navigation allow substantial knowledge, command and control of the drill head and the tunnel direction. The operation of a system, particularly involving GPR on the drill body, coupled with internal guidance and navigation, and a short turning radius, allows safe tunneling in areas where surface mapping alone does not make tunneling possible or practical, such as drilling in complex infrastructure areas, under streams and rivers, in regions with existing building foundations, rough or rugged terrain and the like. The baseline GPR configuration is simple, robust and reduces risks to the system. The system is substantially self-contained, e.g., in terms of thrust and torsion generation, making it extremely energy efficient. The system can generally achieve single pass-through tunneling, saving time, energy, equipment usage and translating into direct savings. Provision of tight turning radius can achieve savings through better path selection and the avoidance of redrilling. Ground penetrating radar (and 3-D synthetic aperture radar) imaging in real-time permits effective obstacle avoidance and reduces failures in path selection to provide cost savings. Inertial guidance and navigation further allows mapping of drilling in real time and assists in obstacle avoidance. Preferably, the drilling head is configured such that, in the event of repairs, the drilling apparatus can be removed while leaving the casing in place. The present system also enables drilling situations for blind hole drilling as required. Preferably the system is provided as a complete integrated system packaging the drilling apparatus, spoils handling system, ground penetrating radar, inertial navigation, and a casing system to provide a "turnkey" solution. In one embodiment, the driller can excavate 12 inch diameter tunnels. Although tunnels having other diameters can also be excavated. The present invention can simplify spoils handling, compared with systems having a long drill string or drive shaft, since in the present system there is reduced competition with the drive shaft for available space for routing the spoils. The system can preferably detect relatively small objects such as less than about 3 inches in diameter preferably less than about 1 inch in diameter and can detect obstacles sufficiently far in advance of the drilling head (considering, or in relation to, the available turning radius) to permit effective drilling around obstacles, as well as being able to delete larger (greater than 3 inch) objects in some embodiments. The sensing system can be used in planning the tunnel location and route, tracking its progress, and documenting the "as drilled" location of the tunnel.

A number of variations and modifications of the invention can be used. It is possible to use some features of the invention without using others. For example, it is possible to use down-hole thrust and/or torsion sources without providing down-hole GPR electronics and vice versa. It is possible to use a drum brake system for reacting torque forces without using the drum brake system for reacting thrust forces and vice versa Although features of the present invention are preferably provided using computer-based calculations, suggestions, controls and the like, it is possible to provide some or all of these operations by human decision making. Although the present invention has been described by way of a system which includes a number of components positioned on the surface, and communicating with the down-hole components, e.g., by cable, it is possible to position some or all of such components down-hole thereby reducing or eliminating the need for surface-to-drill head signal communications. Although communications have been described as occurring over a cable, other communication links can be used including optical fiber, radio, infrared or other wireless links and the like. Although embodiments of the present invention have been described in connection with horizontal boring devices, some or all aspects of the present invention can also be used for other types of drilling such as substantially vertical or angled drilling, e.g. for water or mineral exploration or extraction and the like. The present invention, in various embodiments, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various embodiments, subcombinations, and subsets thereof. Those of skill in the art will understand how to make and use the present invention after understanding the present disclosure. The present invention, in various embodiments, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments hereof, including in the absence of such items as may have been used in previous devices or processes, e.g. for improving performance, achieving ease and\or reducing cost of implementation. The present invention includes items which are novel, and terminology adapted from previous and/or analogous technologies, for convenience in describing novel items or processes, do not necessarily retain all aspects of conventional usage of such terminology. The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. Although the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g. as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.

Although hydraulic force/steering embodiment was described it is also possible to use pneumatic, electric or other force/steering devices. Although an inertial guidance embodiment was described, other guidance, including gyroscopic, radio or other electromagnetic wave or force, global positioning, optical or other systems may be used for guidance. Although a centered reuse circulation spoils system was described, other systems can include a forward circulation system, a make-up (non-circulating) system and the like.

Claims

What is claimed is:

1. Apparatus for underground boring comprising: a drill head; a motor which provides drilling torque to said drill head, said motor positioned in said bore hole and receiving a power supply substantially without the need for a rigid-link drive train to provide such torque; and a stabilizer which reacts said torque to ground surrounding at least a portion of said bore hole.

2. Apparatus wherein said motor is an electric motor.

3. Apparatus as claimed in claim 1 further comprising at least a first electrically- powered thrust actuator, positioned in said bore hole, which provides drilling thrust to said drill head.

4. Apparatus as claimed in claim 1 wherein said thrust actuator is electrically powered.

5. Apparatus as claimed in claim 1 further comprising a drill head tip device, positioned down hole which, in response to at least the first command signal, alters the boring direction of said drill head.

6. Apparatus as claimed in claim 5 wherein said tip device also provides drilling thrust for said drill head.

7. Apparatus as claimed in claim 1 further comprising a sensor which outputs a signal indicative of current drilling direction of said drill head.

8. Apparatus as claimed in claim 1 further comprising a sensor which outputs at least a first signal indicative of the presence of obstacles in the vicinity of said drill head and wherein at least a portion of said sensor is positioned in said bore hole.

9. Apparatus as claimed in claim 1 further comprising a surface-positioned data processing and display station, coupled to down hole sensing apparatus by a first communication link, wherein said surface-positioned station uses sensor information for displaying at least one of a drill head position, a drill head direction and an indication of obstacles in the vicinity of said drill head.

10. Apparatus as claimed in claim 1 wherein said drilling head can achieve a bore hole curvature with a radius of curvature less than about 25 feet.

11. Apparatus as claimed in claim 9 wherein said sensing apparatus includes a sensor selected from the group consisting of ground penetrating radar and inertial navigation.

12. Apparatus as claimed in claim 9 wherein said sensing apparatus includes a sensor which can detect obstacles having a largest dimension less than about 3 inches.

13. Apparatus for underground boring comprising: a drill head; an actuator for providing thrust to said drill head, said actuator positioned in said bore hole and receiving a power supply substantially without the need for a rigid-link drive train to provide such thrust; and a stabilizer for reacting said thrust to ground surrounding at least a portion of said bore hole.

14. Apparatus as claimed in claim 13 wherein said power supply is an electrical power supply.

15. A method for underground boring comprising: coupling a drill head to an electric motor for providing drilling torque to said drill head, said electric motor positioned in said bore hole and receiving an electrical power supply substantially without the need for a rigid-link drive train to provide such torque; and reacting said torque to ground surrounding at least a portion of said bore hole.

16. A method as claimed in claim 15 further comprising providing drilling thrust to said drill head using at least a first electrically- powered thrust actuator, positioned in said bore hole.

17. A method as claimed in claim 15 further comprising altering the boring direction of said drill head using a drill head tip device, positioned down hole which, in response to at least the first command signal.

18. A method as claimed in claim 17 further comprising providing drilling thrust for said drill head using said tip device.

19. A method as claimed in claim 15 further comprising providing a downhole sensor which outputs a signal indicative of current drilling direction of said drill head.

20. A method as claimed in claim 15 further comprising providing a sensor which outputs at least a first signal indicative of the presence of obstacles in the vicinity of said drill head and wherein at least a portion of said sensor is positioned in said bore hole.

21. A method as claimed in claim 15 further comprising coupling a surface- positioned data processing and display station to down hole sensing A method by a first communication link, wherein said surface-positioned station uses sensor information for displaying at least one of a drill head position, a drill head direction and an indication of obstacles in the vicinity of said drill head.

22. A method as claimed in claim 15 further comprising controlling said drill head to drill a curved borehole with a radius of curvature less than about 25 feet.

23. A method as claimed in claim 20 further comprising detecting obstacles having a largest dimension less than about 3 inches using said sensing method.

24. A method as claimed in claim 20 further comprising detecting obstacles having a smallest dimension greater than about 3 inches using said sensing method.

25. Apparatus for underground boring comprising: a drill head; first means, for providing thrust to said drill head positioned in said bore hole and receiving an electrical power supply substantially without the need for a rigid-link drive train to provide such thrust; and second means, for reacting said thrust to ground surrounding at least a portion of said bore hole.

26. Apparatus for underground boring comprising: first means for providing drilling torque to said drill head, said first means positioned in said bore hole and receiving an electrical power supply substantially without the need for a rigid-link drive train to provide such torque; and second means for reacting said torque to ground surrounding at least a portion of said bore hole.

27. Apparatus as claimed in claim 26 further comprising means for providing drilling thrust to said drill head, positioned in said bore hole.

28. Apparatus as claimed in claim 26 further comprising means for altering the boring direction of said drill head, in response to at least the first command signal, positioned down hole.

29. Apparatus as claimed in claim 28 wherein said means for altering said boring direction also is a means for providing drilling thrust for said drill head.

30. Apparatus as claimed in claim 26 further comprising downhole sensor means for outputting a signal indicative of current drilling direction of said drill head.

31. Apparatus as claimed in claim 26 further comprising sensor means for outputting at least a first signal indicative of the presence of obstacles in the vicinity of said drill head and wherein at least a portion of said sensor means is positioned in said bore hole.

32. Apparatus as claimed in claim 26 further comprising means for coupling a surface-positioned data processing and display means to down hole sensing means, wherein said surface-positioned means includes means for displaying at least one of a drill head position, a drill head direction and an indication of obstacles in the vicinity of said drill head.

33. Apparatus as claimed in claim 26 further comprising means for controlling said drill head to drill a curved borehole with a radius of curvature less than about 25 feet.

34. Apparatus as claimed in claim 26 further comprising means for controlling said drill head to drill a curved bore hole with a radius of curvature greater than about 25 feet.

35. Apparatus as claimed in claim 31 further comprising means for detecting obstacles having a largest dimension less than about 3 inches using said sensor means.

36. Apparatus as claimed in claim 31 further comprising means for detecting obstacles having a smallest dimension greater than about 3 inches using said sensor means.