Patent Grant
8944186
This is a national stage application under 35 U.S.C. 371 et. seq. of International Application PCT/SK2010/050002 filed 3 Feb. 2010 and claiming priority to and the benefit of Slovak Republic Application No. 5011-2009 filed 5 Feb. 2009, the entire disclosures of which are incorporated herein by reference.
The invention relates to a system for performing deep drillings, and in particular geothermal deep drillings. The system is intended for underground work in geological formations and is adapted especially for working in depths of up to 10 km and more, at a pressure of up to 1000 bar and more, and at a temperature of adjacent rock up to 400° C. The invention also relates to a method of performing deep drillings.
At present, oil and gas extraction and geological and geothermal probing are carried out by drilling rigs, where disintegration of the rock is performed by rotating drilling heads. The drilling heads are secured at the end of assemblies of connected basic pipes, and the drilling heads are rotated at the surface by driving units. The disintegrated rock is transported to the surface by a special liquid, circulating in the piping and in the borehole formed by the drilling heads. In the past, turbine driving units have been used near the drilling head wherein the energy is supplied from the surface by an aqueous carrier, which also flushes the crushed rock from the system. Energy has also been supplied by electrical cable. Nevertheless, the transport of the disintegrated rock is performed in both systems by classical method—using a viscous circulating liquid.
Especially in the last decade, new methods of more efficient performing of rock disintegration and of its transport to the surface have been searched for.
The study of MIT (USA) “The Future of Geothermal Energy”—Impact of Enhanced Geothermal Systems (EGS) on the United States in the 21st Century 2006-points to the crucial importance of developing economically efficient technology of drilling deep geothermal boreholes. The price of the borehole increases exponentially with depth when using present drilling technologies. Therefore, there exists an urgent need to find drilling technology for which the price of the borehole would increase approximately linearly with the borehole depth.
A coauthor of the above study, Jefferson Tester, characterizes in his presentation requirements for a new, quick, and ultradeep drilling technology as follows:
Over twenty innovative technologies of drilling in geological formations of various sophistication are known.
From the state of the art we shall describe only the most promising technologies or those that have already been examined.
Overview of Present Technologies:
The technologies may be evaluated also according to such properties as specific energy necessary for an extracted cubic centimeter, the maximum possible performance at the borehole bottom, and maximum available drilling speed.
From this point of view, the most important role is played by mechanical principles such as electro-spark discharges in water and water beam cutting.
Among available solutions, which are not yet completely viable for deep geothermal conditions, there may be included the following examples:
Considerable progress in drilling technology is represented by the U.S. Pat. No. 5,771,984 of the authors Jefferson Tester et al., titled “Continuous Drilling of Vertical Boreholes by Thermal Processes: Rock Spallation And Fusion”, where the energy to power the drilling rig at the bottom is delivered by power water, which flushes the borehole, drives the turbine, and produces electric energy for the actual process of drilling by thermal spallation or fusion of the rock. The invention of U.S. Pat. No. 5,771,984 is also the basis for the subject matter of the firm Potter Drilling LLC, the technologies of which are already in the state of prototype testing.
Related technologies are described in the U.S. Pat. No. 5,107,936 titled “Rock Melting Excavation Process”. The author Werner Foppe describes a process by rock fusion on the circumference of the borehole, pressing the melt into the core and breaking of the core. The same author describes in the U.S. Pat. No. 6,591,920 fusion of the rock and its pressing into the surrounding rock.
Cutting the rock by a plasma beam is described in the U.S. Pat. No. 3,788,703 by Thorpe. Nevertheless, it does not solve removal of the crushed rock.
At the University in Tel Aviv, the authors Jerby et al.: JOURNAL OF APPLIED PHYSICS 97 (2004) solve the process of rock spallation by local overheating using microwaves.
The largest group of patents covers technology of cutting the rock by a water beam.
Described are variants of different modifications, for example utilization of cavitation, turbulent processes, combinations with other mechanical principles and the like. For example the U.S. Pat. No. 5,291,957 describes the process of using a water beam in combination with a turbulent and mechanical process.
In the last decade, intensive research of utilization of high-energy laser beams for rock disintegration is in progress. It concerns especially the conversion of military devices for disintegrating rock. The laser energy is used for the process of thermal spallation, fusion and evaporation of the rock.
The patent of Japanese authors Kobayashi et al., U.S. Pat. No. 6,870,128 titled “Laser Boring Method And System”, describes laser drilling, where the light beam is fed from the surface through optical cable to the borehole bottom. This system evaporates the rock, which requires high consumption of energy.
The authors Zhiyue Xu et al. describe in the paper LASER SPALLATION OF ROCKS FOR OIL WELL DRILLING, published in the Proceedings of the 23rd International Congress on Applications of Lasers and Electro-Optics 2004, a method of thermal spallation, which is energetically more favorable, but removal of the crushed material is performed by classical flushing.
Methods of using electric discharge are based on long-term experience in other application areas. The method described in the U.S. Pat. No. 5,425,570 of the author G. Wilkinson is based on a combination of electric discharge with subsequent explosion of a small amount of an explosive or of an induced aluthermic process.
U.S. Pat. No. 4,741,405 and U.S. Pat. No. 6,761,416 of the author W. Moeny describe usage of multiple electrodes with high-voltage discharge in an aqueous environment, while removal of the crushed rock is performed by classical flushing.
An analogous method is described also in the U.S. Pat. No. 6,935,702 of the authors Okazaki et al. titled “Crushing Apparatus Electrode And Crushing Apparatus” with the usage of classical flushing.
The author A. F. Usov describes the use of electric discharge for drilling large diameters of over 1 m with the speed of up to several m/h, realized in the Scientific center Kola of Russian Academy of Sciences.
In the patent RU 2059436 C1 the author V. V. Maslov describes generating high voltage pulses for material destruction.
The authors Hirotoshi et al. describe in the paper Pulsed Electric Breakdown and Destruction of Granite, published in Jpn. J. Appl. Phys. Vol. 38 (1999) 6502-6505, successful usage of electric discharge on the typical geothermal rock-granite.
Rising of heavy undersea loads is described in the U.S. Pat. No. 4,422,801 titled “Buoyancy System For Large Scale Underwater Risers” of the authors Hale et al., where effective manipulations with large loads to over 3000 m depth are reached by variable buoyancy of ballast tanks.
In the U.S. Pat. No. 5,286,462 of the author J. Olson, there is described a system of quick gas generation for quick emptying ballast tanks for utilizing buoyancy for manipulating loads.
The problem of fast moving of an object in aqueous environment, which is a determining factor for transport effectiveness, is solved for military purposes in the U.S. Pat. No. 6,962,121 titled “Boiling Heat Transfer Torpedo” of the author R. Kuklinski and the U.S. Pat. No. 6,684,801 titled “Supercavitation Ventilation Control System”. These describe the method of artificial supercavitation, in which it is possible with a properly shaped object to achieve a speed of several hundred meters per second in water.
An apparatus for deep stimulating at the borehole bottom is described in the U.S. Pat. No. 4,254,828 titled “Apparatus For Producing Fractures And Gaps In Geological Formations For Utilizing The Heat Of The Earth” of the authors Sowa et al., in which the importance of pressure generation at the borehole bottom by an autonomous energy system is described. Similarly, also in the U.S. Pat. No. 7,017,681 of the authors Ivannikov et al. is described an autonomous system of stimulation by hydrodynamic effects at the borehole bottom.
At present, the state of techniques for forming casings is represented by expandable casings of various kinds. For example, technology described by the authors R. Cook et al. in the U.S. Pat. No. 6,739,392 titled “Forming A Wellbore Casing While Simultaneously Drilling A Bore” uses a sequence of steps, where special piping lowered down without casing is expanded by a pressure medium.
From the point of view of continuous casing production, the present state of the art provides a convenient starting point, because there have already been developed and put in practice cement composite mixtures, which quickly set under water and form high-strength concrete, especially for military purposes. Such cement composite mixtures have been developed also for storing hazardous wastes.
Substantial progress compared to the current state of the art is represented by a solution in which the system of interlocking pipes has been removed and is now replaced by freely moving containers in a water environment of continuously constructed casing. This is described below.
In the patent application 5087-2007 titled “Device For Excavation Of Deep Holes In A Geological Formation And Method Of Energy And Material Transport In These Holes” of the authors I. Koci{hacek over (s)} et al., there is described an innovative solution of a drilling device, wherein the main innovations are the transportation of rock, the material for casing production, and the transfer of energy through openings in the casing. The casing is filled with water by means of autonomous transport modules or containers by utilizing gas buoyancy. With negative buoyancy the containers move downwards. Casing is continuously formed from a part of the extracted rock and material supplied from the surface. The device includes an underground base, a transport module, a surface base, and the borehole in the geological formation and filled with water. Nevertheless, this device does not sufficiently solve the movement of transport modules, continuous preparation of the casing profile, manipulation with transport modules in the underground base and in the surface base, and control of and communication with the components. The device as a whole creates conditions for nearly linear dependence of the price of the created borehole (well) on its depth/length.
Summary of Recent Technologies
However, most of these methods have not reached the goal of substantial cost reduction in performing a deep drilling, as there have been several factors acting simultaneously against it:
Also the presence of a fluid (water, viscous transport fluid) in the borehole acts against the efficiency of these technologies. Energy supply has been solved, for example, by pressure water supply, electric energy supply via an electric cable, composite flushing line, or optical-fibre cables for high energy laser power supply. All mentioned technologies presume a certain steady, continually extended connection between the drilled ground and the surface. Similarly, also transport of the crushed rock still depends on the extending piping for transport media.
An equally important part of the borehole is the borehole wall casing made of gradually inserted pipes, which, moreover, narrow down with the borehole depth and so reduce the overall throughput and contribute to excessively rising price in dependence on the borehole depth. Recently, expandable casing with the same diameter in the whole borehole has been developed, but this only partially solves the problem of exponential price of the borehole.
None of the drilling technologies described so far has brought any innovation, which would substantially change the efficiency of the whole drilling process and the efficiency of the crushed rock transport to the surface, and which would guarantee drilling to large depths (over 5 km) and, simultaneously, guarantee approximately linear price dependence. From this, it follows the need of such technology, which substantially solves disadvantages of the current state of the art in the following aspects:
The above disadvantages are eliminated to a large extent by a system for performing deep drillings, the system containing a surface base, a borehole in geological formation filled with fluid, and a robotic multi-functional underground drilling platform, which contains the following schematic blocks or steps: mechanism (2) for crushing rock (1), continuous formation of the casing profile so as to form a transfer and transport infrastructure, transport container(s) (16), control and communication subsystem (39), energy subsystem (4), transport container operation, removing and loading rock (1) from the place of rock crushing, and a method of performing deep drillings, especially for performing geothermal deep drillings according to the present invention, the system and method characterized (as illustrated in
To increase the system efficiency, the robotic multi-functional underground drilling platform can be further enhanced with at least one of the following schematic subsystems or steps:
Continuous formation of a casing profile preferably comprises a formwork bottom, a formwork curved piece, a flexible connection, bottom of formwork cement composite mixture, space for casing forming, connection with the container of cement composite mixture, and an elastic connection of curved pieces.
Transfer and transport infrastructure preferably comprises transport piping, casing of cement composite mixture, service piping, a channel for transmitting service signals, energy, and service water, fuel supply piping, moving formwork of the fuel supply, labyrinth sealing, a moving elastic seal, a fuel inlet leading into the fuel supply piping, a fuel supply system at the surface, and an underground fuel supply system connection. The casing is in a part, preferably in a lower, deeper part, made of cement composite mixture with considerably higher thermal conductivity than in the upper part, and the formwork for moving the fuel supply contains a sealing between the fuel supply formwork and the formed casing.
Operating transport containers preferably comprises a braking and manipulation platform, a rotary actuator, a braking device, a braking cylinder, a braking piston, and a rotary platform.
Removing and loading the rock from the place of rock crushing preferably comprises circulating water for loading the rock, a flushing path, a system of flaps for flushing the rock out, a flushing channel, a flushing space, and a space for loading the rock.
The transport container is equipped with a braking device for braking the container at the borehole bottom for braking the container in the transport piping. A cyclone separator separates the crushed rock from the water for loading the crushed rock into the transport container. A hydraulic piston, pressure hydraulic medium, energy carrier and/or interface node is included for connection with the platform for transportation of the cement composite mixture or mixture of water with the rock.
The control and communication subsystem is preferably protected by a hermetic box resistant against high-pressure water. The box surface is able to dissipate heat from the control and communication subsystem into the environment such as into the surrounding circulating cooling water.
Sealing against the surrounding rock preferably includes an elastic torus, made of a textile based on metal fibers, Kevlar, carbon fibers, or a mixture thereof. The elastic torus is water pressurized.
Protection against vibrations and pressure waves is preferably formed by a covering containing granulate, a covering of a perforated metal plate, suitably shaped baffle areas, channels for leading away a pressure wave, partially open gas containers and the like, or any combination thereof.
The connection to the container of cement composite mixture preferably includes or contains at least one connection to a high-pressure hydraulic medium.
Container injection at the surface preferably includes a source of water such as from a decanting plant, a water pump, a flap system for container injection, a surge chamber for container injection, a flap system for releasing a container, and a water path over the container.
Exit (ejecting) of containers at the surface preferably includes an exit to a decanting plant, a system of grids, a damping structure, a flap system for catching a container, a surge chamber for container exit (ejection), a number of containers and/or material transporters.
The method of performing deep drillings, in particular geothermal deep drillings in geological formations, according to the present invention may include the following features:
To increase the effect of the method of performing deep drillings, the following procedures may be utilized:
The nature of the invention consists mainly in an innovative method of drilling deep boreholes with high economic efficiency at nearly the same price per unit of the borehole depth up to 10 km with preservation of the same constant borehole diameter. The stated technical result is achieved via a robotic multi-functional platform working at the depth of the borehole at the place of rock crushing. The above subsystems and subcomponents cooperatively ensure necessary activities for effective rock crushing, flushing out and removing the rock from the place/depth of drilling, loading the rock into the transport container, transporting the rock to the surface, continuous forming of the casing, transport of the cement composition downward from the surface, manipulation of containers, shifting and directing the platform, control of the process of drilling and communication with the surface, feeding electric energy by means of a cable from the surface, transformation of this energy to the required energy form, as well as auxiliary functions of sealing against surrounding rock, connecting with the container of cement composite mixture transport, and protection against pressure waves during detonation crushing of the rock.
The underground robotic platform, realizing the above features and activities, eliminates disadvantages of the prior state of the art and enables continuous drilling process without the shortcomings of classical methods of drilling.
Innovation in the Technical Solution
Innovation in the technical solution is formed by modular robotic platform with the following functionalities:
a is a top down cross section of a casing profile of the present invention;
b is an elevational cutaway view of the robotic drilling platform of
c is an elevational cutaway view of the robotic drilling platform of
a is a top down cross section view of a service subsystem;
b is another top down cross section view of the service subsystem of
c is another top down cross section view of the service subsystem of
a is another top down cross section view of the service subsystem of
b is an elevational cutaway view of the service subsystem of
a is another top down cross section view of the service subsystem of
b is an elevational cutaway view of the service subsystem of
a is a top down cross section view of a transport infrastructure;
b is an elevational cutaway view of the transport infrastructure of
a is a top down view of a control and communication device;
b is an elevational cutaway view of the control and communication device of
c is an elevational view of another control and communication device;
a is a top down cross section view of the service system of
b is an elevational view of the service system of
The mechanism (2) for crushing rock (1) can be modified in a modular way for various crushing technologies (electrical discharge, spallation and the like). The rock crushing mechanism (2) includes rock crushing component (3) having moving action members (5), which crush the rock. The rock crushing component (3) may also have electrodes or jets and the like, an energy subsystem (4) or a part of an energy subsystem, a part of the control electronics (68), and actuators and sensors (23). The rock crushing mechanism (2) is moved relative to the basic jacket (6) by a shifting mechanism (12) which imparts fine movement of the rock crushing mechanism (2). This whole process takes place under water, which fills in the whole borehole.
The whole underground platform (22) moves, the base of the platform (22) being formed by the basic jacket (6). The underground platform (22) shifts relative to rock (1) by means of movement mechanism (7) which moves and directs the platform. The movement mechanism (7) includes a movement actuator (9) and a support spacer (10) as a support mechanism for shifting the whole system. The movement mechanism (7) shifts the device by alternating activation of the movement actuators (9), support spacers (10) and auxiliary spacers (11). The whole unit may also be moved by various values of shift of the movement actuators (9).
The movement mechanism (7) moves and directs the platform by activating auxiliary spacers (11) and movement actuators (9), and gets to its starting position for repeatedly shifting the basic jacket (6) relative to rock (1). The outer protecting sheath (8) forms protection of the rock crushing mechanism (2) against pollution and crushed rock.
The third substantial function of the underground platform (22) is continuous formation of casing from cement composite mixture, which is reinforced by steel, carbon, Kevlar fibers, and the like of various lengths.
Forming the casing is separated from the space of the rock crushing mechanism (2) of rock crushing and movement mechanism (7) by the bottom (18) of the casing formwork. Forming of the casing comprises steel curve pieces (19) of various shapes mutually connected by a flexible joint (21). These parts determine the shape of casing (20) of cement composite mixture. The casing thus creates a system of transport pipes (32).
An important part of forming the casing is the sealing step (17). That is, a sealing must be formed against the surrounding rock, with the cement composite mixture filled against the rock (1). This sealing against the surrounding rock is done via an expandable torus made of composite of metal (carbon, Kevlar) textiles pressurized by power water with controlled pressure through a power water inlet (27).
The fourth function of the underground robotic platform (22) is the braking and manipulation platform (15), the base of which includes a rotary actuator (13) and a braking device (14) of the transport container (16), which is transported through transport piping (32) via circulating water (46) from the surface. The protection against vibrations and pressure waves is realized by a partially open space in which is present gas forming an elastic absorption medium.
a-c show in detail manipulation of transport containers (16).
b shows a preferred embodiment of the invention in more detail from the point of view of manipulation of the transport containers (16). A transport container (16) has come by means of transport pipe (32) from the surface into the space of underground robotic platform (22). The braking device (14) of the transport container (16) brakes the transport container (16) to rest from the original speed of circulating water (46) in transport pipe (32).
The braking effect is achieved by braking piston (24) entering into the braking cylinder (33), which is a part of the transport container (16), and by a narrow profile of forcing water out of the braking cylinder (33). Braking piston (24) is located on the rotary platform (50) and driven by the rotary actuator (13).
c shows a preferred embodiment of the invention in more detail from the point of view of manipulation with the transport container (16), which is being rotated by 180° into the position of re-injecting the transport container (16) into circulating water (46) that is headed to the surface through transport pipe (32) after loading crushed rock (1) in rock loading space (31) through flushing path (54).
Circulating water (46) coming through the transport pipe (32) from the surface is directed by a system of flaps (30) for flushing the rock into channel (26) and through the flushing space (28). The circulating water (46) is mixed with crushed rock (1) and conveyed to the rock loading space (29), where a cyclone separation effect in which the tangential movement of the mixture of circulating water (46) with rock (1) is utilized. The coarse fractions of rock (1) settle in the transport container (16) and circulating water (46) with the smallest fractions of rock (1) leaving through the transport pipe (32) to the surface.
After completing the flushing and loading, the transport container (16) is injected into the water circuit in transport pipe (32) by means of injecting power water into the space between the braking piston (24) and the braking cylinder (33). Due to the hydraulic press effect, the transport container (16) starts to move until it is caught by circulating water (46) in the transport pipe (32).
a-c show in more detail phases of manipulating the transport container (16) into different positions in the opening (35) in the rock. In the first position concentric with transport pipe (32), the incoming circulating water (46) brakes the transport container (16) and settles it down on the rotary platform (50), while connections to pressure media are established.
In the second position, the transport container (16) is rotated 90° and is connected with the inlet (25) of connecting module (36) for transporting cement composite mixture. The valve (37) of connecting module (36) is opened for distributing the cement composite mixture into the transport container (16). The cement composite mixture is then injected into the space (47) for formation of the casing. After emptying the transport container (16) of cement composite mixture, the transport container (16) is conveyed to departure position 180° from the starting position.
a,b describe the service system for providing for and for performing functions of underground robotic platform (22) in more detail.
Water, which is used for cooling of aggregates, for production of electric, hydraulic energy and the like, flows through a pair of service pipes (34). In the profile which follows after service pipes (34) is where aggregates such as a box of the control and communication block (39), miniature turbine (41), generator (42) of electric energy, and hydraulic pump (43) for high-pressure media for controlling and driving hydraulic elements are located. A part of the service system also includes channel (40) for service signals and energy and for passage of some of the service water (71). The system of service functions is connected also to block (2) of rock crushing, which is interconnected with boxes of the control and communication block (39) and also with service water (71).
a shows a top down view through casing (20) of cement composite mixture with two transport pipes (32) and two service pipes (34) and with a section through transport container (16) shown in the profile of transport pipe (32).
a shows a section through the continuous casing (20) of cement composite mixture containing four openings, two for transport pipes (32) and two for service pipes (34). In section 7b-7b in
System of flaps (51) may redirect water from the decanting plant (49) to transport containers (16) for injecting containers.
The surge chamber (53) for injecting containers serves for isolating the high-pressure environment from the outer environment. Simultaneously with redirecting the system of flaps (51) for injecting containers and system of flaps (52) for releasing a container in the cycle of transport containers (16), most of the water volume moves through water route (79) over the container and pushes it into the transport pipe (32). This action is repeated with the next transport container. It is obvious that acting of system of flaps (51) for injecting containers and system of flaps (52) for releasing a container must be synchronized to maintain the total water volume flowing into the transport pipe (32) constant.
a-c shows a preferred embodiment of the control and communication box (39). The control and communication box (39) is resistant against high pressure of more than 1000 bar, having an optimum shape (sphere) for the ratio volume/surface/pressure, and being intensively cooled by service water (71) from the outside and by an inner cooling system (70) from the inside.
a shows a particular embodiment of the control and communication box (39), where box (61) is resistant against water and pressure is equipped from the outside of spherical surface by ribbing (66), to which cooling water (62) is fed. Further, electric energy is fed through an electric energy supply (63) in special high-pressure transition pieces (64), hydraulic energy is fed through a hydraulic energy supply (65), and signals are carried through special high-pressure transition pieces (64).
b shows section 10b-10b from
c shows a preferred embodiment of the control and communication box (39) of a larger volume in the form of several spherical parts mutually interconnected in one hermetic unit. This multi-box (82) is received in a packing forming a service channel (72) through which flows service water (71) and exits return water (73).
a,b show a preferred embodiment of the invention, where the method of continuous forming of casing (20) of cement composite mixture simultaneously forms openings in casing (20) of cement composite mixture, thereby expanding the openings automatically with the drilling process, as described below.
This advantageous property can be utilized for example in the case of rock crushing mechanism (2) based on the supply of liquid or gaseous fuels (for example hydrothermal cleavage-spallation).
a shows a section through casing (20) of cement composite mixture, where several pipes (74) of fuel supply are realized besides transport pipe (32) and service pipe (34). There may be several pipes (74) of fuel supply for various fuel components and also reserve pipes for the case of failure or clogging.
b shows a part of the moving formwork (75) of fuel supply in the form of a metal tube terminating with several seals, for example by a labyrinth seal (77), sliding elastic seal (76), such that an opening in the casing pipe (74) of fuel supply is realized.
b further shows inlet (83) of fuel into the fuel piping in the casing by firm attachment of the fuel supply system (78) at the surface. The fuel piping is also firmly attached to the rock crushing device (2) at the borehole bottom at the underground robotic platform (22).
The present invention may be utilized in the field of geothermal drillings, oil wells and gassers, mining wells, ore veins, and tunneling. The invention is profitable mainly in rock crushing in aqueous environment at high pressures and temperatures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 5011-2009 | Feb 2009 | SK | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/SK2010/050002 | 2/3/2010 | WO | 00 | 8/4/2011 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2010/090609 | 8/12/2010 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3788703 | Thorpe | Jan 1974 | A |
| 4254828 | Sowa et al. | Mar 1981 | A |
| 4422801 | Hale et al. | Dec 1983 | A |
| 4741405 | Moeny et al. | May 1988 | A |
| 5107936 | Foppe | Apr 1992 | A |
| 5168940 | Foppe | Dec 1992 | A |
| 5286462 | Olson | Feb 1994 | A |
| 5291957 | Curlett | Mar 1994 | A |
| 5425570 | Wilkinson | Jun 1995 | A |
| 5771984 | Potter et al. | Jun 1998 | A |
| 6591920 | Foppe | Jul 2003 | B1 |
| 6684801 | Kuklinski | Feb 2004 | B1 |
| 6739392 | Cook et al. | May 2004 | B2 |
| 6761416 | Moeny | Jul 2004 | B2 |
| 6870128 | Kobayashi et al. | Mar 2005 | B2 |
| 6935702 | Okazaki et al. | Aug 2005 | B2 |
| 6962121 | Kuklinski | Nov 2005 | B1 |
| 7017681 | Ivannikov et al. | Mar 2006 | B2 |
| 7416258 | Reed et al. | Aug 2008 | B2 |
| 7487834 | Reed et al. | Feb 2009 | B2 |
| 20100031653 | Foppe | Feb 2010 | A1 |
| Number | Date | Country |
|---|---|---|
| 9603566 | Feb 1996 | WO |
| 03069110 | Aug 2003 | WO |
| 2007122003 | Nov 2007 | WO |
| 2008144096 | Nov 2008 | WO |
| 2009005479 | Jan 2009 | WO |
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| John Kennedy, Anaconda drilling system nears commercial rollout (Halliburton Energy Services), Drilling Contractor, Jul./Aug. 2000 (2 pages). |
| Tesco Corporation, Bulletin 3000e, Tesco Casing Drilling—Reach your reservoir with more efficiency and flexibility—Better Ways to the Bottom, © Apr. 2008 Tesco Corporation (12 pages). |
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| Number | Date | Country | |
|---|---|---|---|
| 20110290563 A1 | Dec 2011 | US |
