METHOD AND SYSTEM FOR PARTICLE JET BORING

Abstract

The present invention provides a method and system for the generation of, the utilization of, the processing of, and the maintenance of a heterogeneous solid-particle impactor-laden fluidic-process circuit that incorporates a particle-injector system and a fluidic-amplifier jet head to produce a conical-shaped cutting jet of fluid and solid-particle impactors that perform functions during the boring, well-bore conditioning, and/or controlling the inclination and azimuth of deep subterranean well bores during their construction.

Description

FIELD OF THE INVENTION

The present invention relates to the oil, gas, and geothermal drilling industries, and more particularly, but not by way of limitation, to methods and systems of particle jet boring.

BACKGROUND OF THE INVENTION

In the oil, gas, and geothermal drilling industries, the resources easiest to access have been located in the relatively shallow reservoirs and the industry is now faced with the prospect of drilling a higher percentage of deeper and more expensive well bores in search of the remaining oil, gas, and high-energy-density geothermal reserves. The cost of drilling deeper well bores increases exponentially as a function of depth when utilizing rotary-mechanical drilling methods and equipment. It is common to drill the deepest 20% of the well bore at a cost of greater than 70% of the total well bore drilling cost. Reducing the cost of drilling deep well bores through methods of increasing the Rate of Penetration (ROP), conditioning the well bore to mitigate related problems, and drilling straight and vertical well bores is commercially important to the oil and gas and geothermal drilling industries. Reducing the cost of drilling well bores can maximize the value of energy developers' existing exploration and development drilling budgets.

Particle Jet Drilling (PJD) has been investigated for the past approximately 45 years as a potential method to reduce the cost of drilling deep large-diameter well bores. Practical and economical application of PJD methods have been sought throughout this time as a means to increase the ROP, reduce drill-bit rotary-mechanical wear on the down-hole drilling equipment, and assist in drilling as near vertical a well bore as possible when drilling oil, gas, and/or geothermal well bores.

PJD system investigations have focused mainly on increasing the ROP for drilling deep large-diameter well bores. This technology is best described as the use of a heterogeneous slurry comprised of solid particles entrained within a drilling fluid that is circulated into the well bore through the pipe string and accelerated through a fluid nozzle system at a distal end of the pipe string within the well bore to impact and disintegrate the subterranean formations being drilled through various energy transfer mechanisms that vary with the materials and operating conditions present.

The investigation of PJD methods and equipment for drilling well bores has fallen into two main categories of investigation. The first category is the use of angular, relatively low-density crystalline structured abrasive particles for Abrasive Jet Drilling (AJD) investigations which eventually migrated into the second area of investigation which is the use of the relatively higher density ferrous solid material impactors for Impact Jet Drilling (IJD) purposes. While both these processes have been investigated for decades and much progress has been made after spending many millions of dollars for their investigation, the process of PJD has not been practiced commercially for drilling deep, large-diameter well bores.

The investigation history can be seen starting with using crystalline sand particles as the abrasive in the early AJD drilling process. The AJD process migrated to the IJD process with the introduction of the relatively higher density ferrous solid particle impactors in the form of steel shot. The process includes providing a fluid circuit comprising a surface drilling fluid system, a drill-pipe system within a well bore, and a drill bit or nozzle system attached to the drill string which may accelerate the drilling fluid against the well bore bottom hole, circulating the drilled cuttings and drilling fluid to the surface for separation, and processing the drilling fluid for reuse.

Solid impactors are added to the drilling fluid by various means to create an impactor slurry. The impactor slurry is then pumped through the pipe string to the drill bit and/or nozzle system and impinged against the bottom hole formation to modify it. The drilled cuttings, impactors, and drilling fluid are circulated to the surface equipment through the well bore where the drilled cuttings are separated. The drilling fluid and impactors are separately processed by various means for recirculation and reuse. The physics of the impactor-earthen formation modification process is one whereby the jetted impactor's impulse force must exceed a Critical Formation Cutting Stress (CFCS) level within the earthen formation. Early PJD investigations conducted during the 1960's through the mid-1970's thoroughly investigated the basic physics of and application of the then-current drilling technology and equipment.

SUMMARY OF THE INVENTION

In accordance with the present invention, a particle jet boring method and system is provided which substantially eliminates or reduces disadvantages and problems associated with previous systems and methods.

Various embodiments of the present invention contemplate boring a well bore by providing a high-pressure flow line adapted for high-pressure fluid to flow therethrough; providing an impactor injector coupled to the high-pressure flow line and adapted to accelerate a plurality of impactors and to inject the accelerated impactors into the fluid to foiin an impactor slurry of entrained impactors and fluid; transporting the impactor slurry to a pipe string in fluid communication with the high-pressure flow line; transporting the impactor slurry through the pipe string to a jet head connected to a distal end thereof and in fluid communication therewith; accelerating the impactor slurry in a down-hole direction and in a tangential direction to create a swirling flow of impactor slurry; impinging a formation of a well bore with the accelerated impactor slurry for removing formation particles therefrom; transporting the impactor slurry and the formation particles to an above-ground separator; separating at least a portion of the formation particles from the impactor slurry using a hydrocyclone separator; and separating at least a portion of the impactors from the fluid using a magnetic separator.

Various embodiments may also include providing a plurality of nozzle ports disposed radially around a periphery of the jet head and adapted to allow at least a portion of the impactor slurry to flow therethrough to impinge a side of the well bore. And may further include using at least a portion of the plurality of nozzle ports to generate a vectored thrust on the jet head. Various embodiments may also include monitoring a plurality of conditions including one or more of the following: a volume of impactors entrained in the impactor slurry; a size mixture of impactors entrained in the impactor slurry; a rate of penetration on the well bore formation; a density of the impactor slurry; an impactor count returning to the surface; a pressure of the impactor slurry; and a drill-string weight on bottom. Various embodiments may also include modulating one or more of the plurality of conditions to modulate at least one of a well bore diameter and the rate of penetration. Various embodiments may also include using a bent sub to generate an angled position of the jet head to allow directional boring.

In some embodiments, the boring of a well bore may include providing a high-pressure motive fluid flow; establishing venturi flow conditions at an access port into the high-pressure motive fluid; accelerating a plurality of impactors, the plurality of impactors adapted to be entrained in the high-pressure motive fluid for creating an impactor slurry; injecting the accelerated impactors into the high-pressure motive fluid by passing the accelerated impactors through a low-pressure area created by the venturi flow conditions; transporting the impactor slurry through a pipe string to a jet head connected to a distal end thereof and in fluid communication therewith, the jet head adapted for flowing the impactor slurry therethrough; accelerating the impactor slurry flowing through the jet head for impinging a surface of a well bore therewith and removing formation particles therefrom.

Various embodiments may include accelerating the plurality of impactors with enough kinetic energy to prevent the venturi flow conditions from ceasing. And where at least one of a mechanical, a fluidic, and an electromotive force is used to accelerate the plurality of impactors. Various embodiments may include where the venturi flow conditions are established using a dual concentric orifice adapted to generate a low-pressure region at the access port. In some embodiments, the concentric orifice is adapted to swirl the motive fluid. In some embodiments, an impeller wheel is used to accelerate the plurality of impactors.

Some embodiments contemplate boring a well bore by providing a supply of impactors; entraining the impactors into a fluid to form an impactor slurry; transporting the impactor slurry through a pipe string to a jet head connected to a distal end thereof and in fluid communication therewith; passing the impactor slurry through a jet head housing, the jet head housing having a stator therein adapted to impart a swirling flow regime to the impactor slurry passing therethrough; passing the impactor slurry through a swirl intensifier adapted to accelerate the impactor slurry both in an axial reaction and in a tangential direction; and passing the impactor slurry through a conical shaped exit orifice adapted to centralize and stabilize the jet head while preserving a velocity of the impactor slurry flowing therefrom; and impinging a surface of a well bore to remove formation particles therefrom.

Various embodiments may also include modulating the impactor slurry to change a diameter of the well bore being impinged. And forming a reentrant toroidal flow regime for entraining the formation particles into the impactor slurry and adapted to further abrade the surface. Some embodiments may include where the jet head housing has a converging conically shaped section at an entrance thereof for accelerating the impactor slurry flowing therethrough. In some embodiments, the jet head housing has an expanding conically shaped section at an exit thereof adapted to generate a conically-shaped impactor-slurry jet form. In some embodiments, the impactor slurry exits the jet head as a dual jet form comprising an inner cylindrical shaped jet region and an outer flowing conical jet region, wherein a greater portion of the impactor slurry flows through the outer flowing conical jet region. In some embodiments, the impactors are solid particles on the order of 0.025 inches in diameter. Impactors, such as, solid particle impactors, may range in size from the largest solid particle impactor that can be processed throughout the circuit to the smallest solid particle impactor that can satisfy the minimum mass-momentum-impulse force required to exceed the minimum critical formation cutting stress force of the earthen formations being drilled. In some embodiments, the impactors impinge the well bore at a speed of at least 1,200 feet per second. In some embodiments, the impactors impinge the well bore at a speed sufficient to remove formation particles having a mass greater than a mass of the impactors. In some embodiments, seven grains of formation are removed for each impactor impinging the well bore. In some embodiments, the impactors impinge the well bore using a combination of shear forces, compression forces, and abrasion/erosion forces. In some embodiments, the stator has a plurality of stator vanes running axially along an exterior surface thereof and adapted to impart tangential-radial forces on the impactor slurry flowing thereby. In some embodiments, the stator is adapted to be removed from the jet head.

Some embodiments rotate the jet head while some do not rotate the jet head. Some embodiments utilize the jet head in conjunction with roller-cone drill bits while some use the jet head in conjunction with fixed-cutter drill bits. Some embodiments utilize impactors to modify the well bore wall to mitigate low-pressure formation-fluid losses during drilling and casing operations; to minimize formation hydration; to minimize high-pressure flow into the well bore; to minimize fluid invasion into producing formation; to increase its structural integrity; to mitigate mechanical or thermal spallation. Some embodiments utilize impactors to modify the well bore wall in combination with other methods of lost-circulation remedies. Some embodiments use impactors to work harden the surfaces of the well bore and/or form casing connections. Some embodiments may prevent or minimize spurt loss, lost circulation, and/or filter cake to minimize differential sticking.

Another component sub-system may be a jet head that incorporates a combination of one, some, or none of the following features including a) a fluidic amplifier for impactor acceleration dynamics; b) a jet form such that a bottom hole pattern is cut in a manner that allows the interior of the jet head to be centralized and stabilized by the jet head to produce a point-and-drill well bore that can be straight, vertical, or directional; c) a jet form that dynamically control the diameter of the well bore through modulation of the circuit to modulate the impactor slurry, impactor size, and impactor concentrations; d) perpendicular flowing jets that can be used to modify the well-bore wall while generating a neutral lateral thrust or a selectively vectored lateral thrust on the jet head; f) retrieval of the jet head's internal-stator system via a wire line or reverse circulation slurry flow pressure in order to change the configuration; and/or g) a jet head that does not require conventional pipe string tubulars to conduct operations. Other aspects of various embodiments may provide the ability of the particle injector sub-system to continuously generate and modulate the impactor slurry impactor size(s), proportions, and concentrations in concert with the operation of the jet head.

Various embodiments of the present invention may provide one, some, or none of the above listed benefits. The aspects described herein provide exemplary embodiments and it is noted that there are many and various embodiments that can be incorporated into the spirit and principles of the present invention and the description of the listed embodiments is not to be construed as the only embodiments that incorporate the spirit and principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features.

FIG. 1 illustrates a flow diagram of a circuit that provides an overview of some circuit components;

FIG. 2 illustrates the physical components of an embodiment of the circuit;

FIGS. 3 a-b further illustrate an injector of FIG. 2;

FIGS. 4 a-c illustrate various formation types, a pipe string, and a jet head;

FIGS. 5 a-f illustrate various views of an embodiment of a jet head;

FIGS. 6 a-d illustrate various views of a well bore and a jet head; and

FIG. 7 a-d illustrate various views of a jet head.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 provides an overview of various steps practiced in boring deep large-diameter well bores according to various embodiments. The process 100 begins at step 102 where impactors are supplied for the process, for example, solid material impactors such as steel shot particles. At step 104, the impactors are then stored within a portable impactor processing and storage system which may be in close proximity to a drilling rig. At step 106, the impactors are fluidized or processed through a particle injector system to produce a low volume, highly concentrated impactor slurry sufficiently pressurized to be discharged at step 108 into the high pressure drilling fluid being independently pumped by the drilling rig's slurry pumps. In some embodiments, the particle injector generates a highly concentrated, low volume, high pressure impactor slurry which may also be used to modulate the slurry concentration. A description of the particle injector and its functions will be described in greater detail below.

The addition of the concentrated impactor slurry into the rig's high pressure fluid flow line forms a heterogeneous impactor slurry working fluid. The impactor slurry is then flowed within the rig's high pressure flow line system and pipe string to the distal end of the pipe string, which may be suspended within the well bore, where a jet head may be attached. As used herein, the terms drill, drilling, drill pipe, drilling rig, drilling fluid, or any other use of the term drill is intended in its broadest sense to mean devices, apparatuses, systems, and methods related to boring a hole in general and not intended to be limited to those devices, apparatuses, systems, and methods related to mechanical drilling involving drill bits and/or rotation of drill bits. At step 110, the dilute impactor slurry is directed to the jet head to perform various functions. The jet head may be configured in various configurations and various surface operating parameters may be changed to effect optimization of boring, well bore hole conditioning, and well bore direction and inclination functions. Some embodiments of the fluidic circuit and the jet head provide for a continuous supply of the impactor slurry. A description of the jet head and its functions will be described in greater detail below.

At step 112, the drilling, formation conditioning, and well-bore directional operational information are observed. At step 114, the information from step 112 is used to determine whether the jet head functions are performing optimally. The observation data may come from surface command and control instrumentation and/or subsurface instrumentation for monitoring of drilling operations. If the jet head is not operating optimally, certain operating parameters can be changed at the surface at step 118 or the internal part, such as a stator housing, of the jet head can be retrieved by use of a wire line to bring the internal part of the jet head to the surface to physically change its configuration at step 116 and be returned to the jet head by sending the internal part back down the pipe string to be again seated in the jet head to effect optimization of the operation of the jet head at step 120 for the functions of boring, conditioning the well bore, and/or controlling the inclination and azimuth of the well bore.

Passing the impactor slurry through the jet head will, among other things, generate formation cuttings, such as formation particles. At step 122, the impactor slurry and formation cuttings are circulated to the surface equipment through the annulus region between the pipe string exterior and the interior well-bore wall. The impactor slurry and formation cuttings continue to be circulated through the drilling rig's surface equipment to a point where they are separated from the fluid by a separator, such as a vibrating separator, a hydro-cyclone separator, or a magnetic separator at step 124. The formation particles may be discarded. The impactors are transported at step 126 then separated at step 130 from the formation cuttings by a separator. As will be apparent to one skilled in the art, each of the separations described herein may be accomplished in one separator or in a plurality of separators and may be accomplished in a variety of different orders. The impactors may then be transported at step 134 to a separator where the impactors are separated at step 136 according to mass from the hydraulic transport fluid and discharged into a storage tank where the impactors can be further processed at step 138 for consistent mass and size and/or stored in the portable impactor processing and storage system impactor storage tank to be re-used in step 104. At step 128, the fluid separated from the impactors and formation cuttings passes into the drilling rig's fluid processing, conditioning, and storage system. The processed and stored fluid is subsequently pumped in step 132 by the drilling rig's pumps into the drilling rig's high-pressure flow line system where the fluid is again combined with the concentrated impactor stream at step 108 to generate the impactor slurry. This pressurized impactor slurry may be comprised of impactors that are both new and those that have been used, recovered, and re-injected into the high-pressure fluid for transportation to the jet head.

Now referring to FIG. 2, an embodiment of a system is shown. The rig's fluid processing, conditioning, and storage system 240 holds conditioned fluid 245. Drilling rig pump suction line 235 is connected to both the storage tank 240 and the pump 230. The stored fluid 245 is sucked into and pumped by drilling rig pump 230 into the drilling rig surface high pressure flow lines 220. High pressure flow line 455 is connected to the drilling rig's high pressure flow line 220 through which the concentrated impactor discharge flow from injector 300 is combined with the drilling fluid flow generated by the drilling rig pumps 230 to form impactor slurry.

The impactor slurry is transported through the drilling rig's swivel 210, through the pipe string 200 which is connected to jet head 800 within the well bore 700. The impactors and cuttings slurry 255 are initially circulated through the annulus region between the pipe string 200 and the well bore system 700 and subsequently in the annulus region between the pipe string 200 and progressively the well head 100, the well pressure control equipment (not shown) but illustrated by casing 110, the bell nipple 120 and finally into the flow line 130 and onto the separator 250 where the impactors and formation cuttings 255 are separated from the fluid 245. The fluid 245 is processed, conditioned, and stored in the processing, conditioning and storage system 240.

In some embodiments, the impactors may be formed of metal and may have magnetic properties. The impactors and formation cuttings slurry 255 may be separated from the fluid 245 by the means of a separator, such as a shaker 250 and discharged onto a magnetic separator system 600. The magnetic drum 610 of magnetic separation system 600 magnetically holds the impactors 335 while allowing gravity to separate the formation cuttings 259 into formation cuttings discharge pile 260. The impactors 335 are subsequently released by the action of the magnetic drum 610 into an impactor collector 620 where the impactors are fed into hydraulic eductor 630 driven by a motive fluid pumped through line 465 through eductor 630 into flow line 470 to transport the recovered impactors through a hydro-cyclone separator 450 where the recovered impactors are separated from the motive fluid which is discharged into holding tank 408. The separated impactors are discharged through the underflow orifice of the hydro-cyclone separator 450 into impactor storage tank 402. Fluid 245 is transferred to fluid holding tank 408 within portable impactor processing and holding tank skid assembly 400 by vertical impeller pump 505 through low pressure flow line 460. Fluid 410 from tank 408 is gravity fed into the suction of impeller pump 435 and discharged into eductors 440 and 630. Eductor 440 is circulated to periodically circulate the impactors in tank 402 to ensure the impactors will flow freely into injector system 300. Eductor system 440 receives impactors from holding tank 402 and circulates it to hydro-cyclone separator 445 where the impactors are separated from the motive fluid 410 and discharged back into tank 402. The motive fluid 410 is circulated through hydro-cyclone separator 445 and discharged back into tank 408. Fluid holding tank 408 is in flow communication with fluid holding tank 407. Fluid 410 equalizes into holding tank 407 where it is stored as fluid supply fluid 405 for centrifugal charge pump 420. Charge pump 420 pre-charges a high pressure and low volume plunger pump 425. The plunger pump 425 provides motive fluid to operate impactor injector assembly 300. Injector assembly 300 regulates a supply of impactors from impactor storage tank 402 and a high pressure, low volume fluid flow from pump 425 to provide the conditions necessary to generate and discharge a high pressure, low volume highly concentrated impactor slurry into high pressure flow line 455.

FIG. 3 b illustrates one embodiment of an injector assembly 300 which is comprised of a feed and metering component 345, an impactor accelerator pump component 320, a liquid entrainment venturi component 350 and a fluidic amplifier component 370. The components of injector assembly 300 work together sequentially to pass impactors into the system from an atmospheric condition and to discharge the impactors in the form of a high-pressure slurry. Impactors 335 are gravity fed from tank 402 of FIG. 2 through conduit 332 into conduit 331 which contains a screw type auger (not shown) to be passed through housing 330 into particle impeller pump 320. The screw auger (not shown) is rotated and its speed controlled by the modulated speed of electric motor 333 to meter the flow of impactors 335 into component 320 through housing 330.

A hydraulic venturi system may be used to convert pressure into velocity and the pressure. In the process, a venturi system generates a partial vacuum around a high velocity jet which can be used to entrain solid particles. The hydraulic system has a steady state that will accept solid particles which have to be accelerated into the fluid system. That process absorbs hydraulic energy until a certain threshold is achieved at which point the hydraulic system will collapse. To entrain a large ratio of solid particles into a venturi based eductor, it may be desirable to first accelerate the speed of the solid particles in order to establish an energy neutral or energy positive relationship with the hydraulic eductor.

In FIG. 3a an impeller wheel 323 is shown retained between housing 322 and cover plate 325 of FIG. 3b which has been removed for clarity purposes. Impeller wheel 323 is rotated in direction 327 by the action of an electric motor 326 of FIG. 3b. The rotating impeller-wheel vanes 324 collect impactors 335 flowing through housing 330 and accelerate the impactors 335 to a high speed and into tangential opening 328 in housing 322 in order to flow through tube 329. Flow tube 329 passes into venturi housing 352 to form a circumferential orifice 353 within the interior of venturi housing 352. Seal and adjustment plate 351 provide a pressure seal to contain internal high pressure and serves as an adjustment mechanism for controlling the circumferential orifice 353 standoff distance. High-pressure fluid is supplied by fluid pump 425 of FIG. 2 through line 426 to the interior cavity 334 of venturi housing 352. The high-pressure fluid is passed though the circumferential orifice 353 to create a venturi jetting effect that serves to generating a low pressure region in front of the distal end of the flow tube 329. The fluid passing through the venturi also serves to entrain the high velocity impactors flowing through flow tube 329 into throat 354, thus forming a slurry of impactors and fluid. The slurry passes through the venturi throat 354 and into the interior chamber of fluidic amplifier component 370. Fluidic amplifier 370 is comprised of a top cap 378 of FIG. 3b, a main body 371, a bottom cap 376 and discharge flow line 455. The slurry from flow line 354 is passed tangentially into interior chamber 372 where it is flowed in a swirling motion and according to the laws of conservation of angular momentum a very high rotational speed is produced at central orifice 373 as the slurry passes through it to chamber 374. Once the slurry has passed through orifice 373 and into chamber 374, the slurry operating according to conservation of angular momentum slows substantially as it passes to the outermost diameter of the chamber 374 where the slurry flows into discharge flow line 455 which is tangentially connected to the outermost diameter of chamber 374. Both end caps of fluidic amplifier 370 have a central vortex stabilizer comprised of stabilizers 377 and 379 to stabilize the vortex flow motion within chambers 372 and 374.

The entrainment of impactors in a high-pressure liquid may utilize hydraulic driven eductors that operate on the venturi principle of converting fluid pressure to fluid velocity and subsequently recovering some of the original fluid pressure as the fluid expands in a down stream diffuser section of the eductor at reduced velocity. The eductor system may generate a partial vacuum in close proximity around the periphery of the high-speed axially-flowing motive-fluid jet of the system. This low-pressure region sucks particulate material into the periphery around the jet stream and entrains the material into the motive fluid as it is carried along in the annulus region within the venturi throat and the diffuser wall regions of the eductor as the jet stream expands.

The injector may be operated by firstly establishing the venturi flow conditions necessary to operate swirl chamber component system against the pressure of the drilling rig's flow line pressure. Once a steady state flow condition has been established to counterbalance the drilling rig high pressure flow line pressure, the impeller pump is activated and begins to flow impactors into the center of the coaxial jet flow of the venturi section. The velocity imparted by the impeller to the impactors is balanced with the volume of the venturi flow to provide target entrainment ratios. The kinetic energy of the impactors leaving the impeller wheel are designed to allow high impactor ratio entrainment while maintaining the continuous operation of the venturi jet and may equal or exceed the kinetic energy of the venturi jet. Thus if the kinetic energy of the impactors is equal to or greater than the kinetic energy needed to drive the venturi jet under stable flowing conditions, the venturi jet will be able to maintain or increase its efficiency of operation while entraining an increasing ratio the impactors. At certain conditions the mass flow of the impactors may account for the greater portion of the mass flow through the venturi throat by supplying the greater amount of kinetic energy necessary to maintain the venturi and swirl chamber sections of the injector providing a mechanism to entraining a very high ratio of impactors to motive liquid, thus achieving the goal of a particle injector that can modulate entraining a broad range of impactor sizes, mixtures, and volumes to generate a highly concentrated, high pressure impactor slurry flow. Impactor entrainment ratios on the order of 60% or greater may be achievable. It can be seen that a very low hydraulic horsepower system can be utilized to entrain a highly concentrated volume of impactors providing the injector system flexibility to optimize the design and operation of the down-hole features of a jet head for boring, conditioning, and directional control of large diameter well bores during their construction.

FIG. 4 c illustrates an embodiment where a cross-section of a large diameter well bore 700 in which a jet head assembly 800 is situated. Subsurface formations 702 through 708 underlie the earth's surface 701. Each of said formations have unique characteristic that provide challenges when being bored. Formation 702 is illustrated as a siltstone formation, formation 703 is illustrated as a water bearing sandstone formation, formation 704 is illustrated as a shale formation, formation 705 is illustrated as a coal formation, formation 706 is illustrated as a second shale formation, formation 707 is illustrated as a limestone formation and formation 708 is illustrated as a natural gas producing sand stone formation. Pipe string 200 is suspended within the well bore 725 and attached to jet head assembly 800. Surface casing 714 is situated and cemented 715 into formation 702. Casing 716 is situated and cemented 718 in formation 704 as a means isolate water bearing formation 703. Casing 718 is situated and cemented 719 in formation 706 as a means of isolating coal formation 705. Casing 720 is situated and cemented 721 in formation 708 as a means to isolate limestone formation 707. Limestone formation 707 may have natural fractures 709 and 710 as illustrated. Sandstone formation 708 may have natural fractures 711, 712 and 713 as illustrated.

FIG. 4 a illustrates an enlarged view of the lower section of the well bore of FIG. 4c. Pipe string 200 is shown attached to jet head assembly 800. The conical shaped end jet 830 and side jets 860 are illustrated issuing from jet head assembly 800. FIG. 4b illustrates an isometric view of the pipe string 200 attached to jet head housing 801 with side jets 860 and conical end jet 830 issuing from the jet head housing 801.

Some embodiments of the jet head sub-system of FIGS. 4a-4c utilize a swirling flow fluidic amplifier to generate a conical liquid jet form to maximize the acceleration of the impactors to allow the optimization of impactor particle count, size, and mixture. Some embodiments of the jet head sub-system of the circuit have been designed to simultaneously perform the functions of increasing the velocity of the impactors sufficiently to sustain a high ROP, form a cutting jet that can be modulated by the slurry properties to change the drilled diameter of the well bore, centralize the jet head through interaction between the jet head and the bottom of the hole, stabilize the jet head through interaction between the jet head and the bottom of the hole, modify the well bore wall through the jetting action of the jet head, and control the direction of the jet head through changing various jetting actions of the jet head.

FIG. 5 f illustrates an isometric view of one embodiment of a jet head assembly 800. FIG. 5a illustrates an exploded view of the components of the jet head assembly 800. Jet head housing 801 houses stator housing 802 which houses stator 803. Stator 803 is formed with stator channels 820 running axially along the exterior surface of the stator. Swirling flow centralizer and stabilizer 814 extends from the distal end of stator 803. The stem of the stator 803 is built with a recessed profile 813 that allows a retrieval tool (not shown) to latch onto the stator assembly for removal. The stator 803 is permanently bonded to stator housing 802. Stator housing 802 is removably latched (latch not shown) to the jet head housing 801. Typical ports 804 and 805 are providing in stator housing 802 to allow fluid to circulate from the interior of the stator assembly through corresponding typical ports 806 and 807 in jet head housing 801. Nozzles 809 and nozzle retainer 808 are typical of the nozzles and retainers for radially spaced fluid ports typified by fluid ports 806 and 807 and are shown in their seated position in FIG. 5b.

FIG. 5 b illustrates a cross-sectional view along section lines AA of FIG. 5e. Nozzles typified by nozzle 809 and nozzle retainer 808 are shown in place within jet head housing 801. Stator 803 and stator housing 802 are in place within jet head housing 801. Surfaces 814 and 810 faun a first interior cavity for imparting a swirling motion to the fluid passing through this section of the stator assembly. Surfaces 812 and 814 form a second interior cylindrical swirl cavity for the stabilization of the swirling slurry mass. The interior surface of the stator housing 802 forms an exit orifice 811 where the fluid passing through the cylindrical swirl stabilization chamber discharges through the exit orifice 811. The exit orifice 811 region provides a region where the centrifugal force of the swirling slurry mass is released in straight tangential lines forming an expanding conical jet form. FIG. 5c illustrates a side elevation the jet head 801 and pipe string 200. FIG. 5d illustrates the end view of jet head 801. FIG. 5e illustrates end view of jet head 801 with section cutting line AA visible.

Some embodiments of the jet head comprise a housing adapted to accept a removable stator assembly and an array of nozzle ports arranged radially around the periphery of the jet head. The stator housing has a first cylindrical shaped internal passageway in which the stator ribs are bonded to its face. This cylindrical section transitions to a converging conically shaped section that in turn transitions to a small diameter cylindrical chamber which both the converging conical section and the small diameter cylindrical section form the swirl chamber of the stator assembly. The swirl chamber section of the stator assembly transitions to an expanding conical shaped exit orifice section. The relative dimensions of the stator assembly flow passages, chambers, and orifices may be optimized to generate a range of operational features that can be modulated by changing the slurry composition and flowing conditions.

In operation, the slurry is pumped from the pipe string through the passageways created by the stator ribs and the stator housing which imparts an angled swirling motion to the slurry. The angle and initial velocity of the slurry swirling motion is controlled by the exit angle and total flow area of the stator ribs. The slurry flows from the stator channels into the converging conical section of the swirl chamber which serves the functions of imparting an axial flow velocity component into the swirling slurry flow and a chamber to accelerate the swirling slurry flow speed to a substantially higher rotational speed as the slurry flows in ever decreasing diameter circles and finally into the cylindrical flow stabilization section of the swirl chamber. The slurry swirling in the swirl chamber operates according to the law of conversation of angular momentum as the swirling slurry flow progresses from largest swirl chamber diameter to the smaller diameter of the cylindrically shaped swirl chamber section where the slurry rotational flow is stabilized at its maximum speed and allowing the Impactors to maximize their speed prior to passing into the exit orifice region of the stator housing. The drilling fluid component of the slurry during the acceleration of the slurry will be swirling at a greater speed than the impactors. The slurry dwell time in flow stabilization section of the swirl chamber allows the drilling fluid to act on the impactors to maximize the energy transfer to the impactors prior to the swirling flow regime change as the slurry flow transitions into the exit orifice of the stator housing.

The high-speed swirling slurry flow transitions from the swirl chamber's flow stabilization section and enters into the exit orifice region of the stator. Due to tangential release fluid dynamics the slurry flow forms a radially flowing cutting jet comprised of relatively high momentum impactors and high velocity drilling fluid flow. The high velocity slurry forms a radially expanding conically shaped cutting jet within the confines of the exit orifice and then extends beyond the exit orifice to form a conically shaped cutting jet which eventually transitions into a reentrant toroidal flowing jet form once the energy of the impinging impactors has been reduced to a level where they cannot further increase the diameter of the well bore under the current operating conditions.

The conically shaped cutting jet is forced against the bottom of the well bore by the vertical action jet head as it is allowed to move deeper within the formation being drilled. The exit orifice's concave conical surface comes in close proximity to the matching earthen formation bottom-hole profile being cut by the jetting action of the jet head. The concave conical shape of the exit orifice concurrent with the hydraulic action of the high velocity slurry cutting jet which is further confined between the exit orifice wall and the formation being drilled by the vertical motion of the jet head tends to physically centralize and stabilize the jet head in conjunction to the bottom hole profile generated by the cutting action of the slurry jet. As there are no lateral forces acting on the jet head from the operation of the jet head system during the drilling process, the centralization and stabilization features of the operation of the jet head system will naturally cause it to drill a straight hole in a vertical direction. This is a very important well bore construction aspect for reducing the cost of drilling deep well bores.

The impactor momentum within the cutting jet generated by the effects of the slurry speed advantage generated in the swirl chamber sections of the stator assembly will maintain the impactor velocity, and therefore its kinetic energy, for a greater working distance than the drilling fluid contained within the slurry cutting jet. The expanding conical cutting jet formed within the exit orifice region of the stator assembly will eventually form a reentrant toroidal flow regime before the slurry flow is hydraulically released to flow upward within the well bore to carry the entrained impactors and formation cuttings out of the well bore. The slurry cutting jet velocity leveraging feature of the fluidic amplifier of the jet head leverages the slurry flow supply pressure available at the jet head to allow the use of very small impactors while satisfying the CFCS requirement for formation cutting purposes. Once the CFCS has been exceeded by the slurry impactor action, establishing a targeted well bore diameter and ROP is provided by the modulating the number of impactor impingements per unit time. The Injector of the circuit modulates the slurry composition in response to the dynamic requirements for establishing a targeted well bore diameter and then the targeted ROP by modulating the Impactor size, mixture, and volume of the slurry.

The ability to increase the impactor velocity in conjunction with the use of existing drilling fluid working pressures available on conventional drilling rigs during deep well bore construction allows the selection and use of smaller impactors that provide an increase in the Impactor impingement count per unit volume. Using a smaller impactor, for example, of a US Sieve Size 25 with a nominal diameter of 0.025 inches which can satisfy the CFCF when used with various embodiments at a flow rate of 12 GPM produces approximately 275 million impacts per minute.

Further, formation removal efficiencies are gamed by the use of smile impactors as the closer the impactor dimension are to the earthen formation grain size that is dislodged by the action of the impactors, the more efficient the removal of the earthen formations becomes. This is due to the smaller impactors impinging the formation in shear and imparting higher impulse force to the earthen formation due to a close match up between the depth of cut vs. the impactor diameter. The formation is more efficiently removed in shear than in compression when larger impactor particles are used that generate greater impact incidence angles due to the impactor vs. grain size mismatch. Thus, the use of impactors with a diameter larger than the formation grains will generate fewer impacts per unit of slurry flow and the impinging incidence angle would render a much less impactor impulse energy transfer to the formation. Further, utilizing the smallest practical impactor is desirable from the point of view that they are more easily entrained, circulated throughout high pressure flow line the fluid circuit, circulated out of the well bore, circulated throughout the low pressure flow line circuits, and more easily circulated through existing down hole tools.

The purposeful introduction of lateral forces acting on the jet head such as a vectored thrust generated as a result of employing the selective operation of peripheral jets provided within the jet head would serve to provide a point-and-drill direction control mechanism when constructing well bores. As there are not weight-on-drill-bit or rotary torque requirements for operation of the present invention, less expensive non-standard pipe string such as tubular casing and tubing can be utilized to reduce the parasitic pressure losses of the slurry circulated within the tubular string as well as the flow and pressure properties within the well bore annular region. The ability of the jet head to produce a well bore diameter larger than the physical outside dimensions of the jet head, the jet head can be used to drill and/or under-ream the well bore at high speeds to economically prepare it for the well bore construction savings that may be achieved through the use of monobore well geometry using solid expandable casing methods and/or close tolerance casing nesting practices.

FIG. 6 d illustrates a cross-section of lower section of a well bore showing one embodiment of well-bore casing 720 cemented into formation 708 by cement sheath 721. Modified well-bore wall surface 871 is shown next to unaffected formation 870 of formation 708. Well bore wall 874 is shown formed by the cutting action of cutting jet 830. Natural fracture 711 is shown adjacent modified well bore 871. A cross-sectional view of a portion of the pipe string 200 and the jet head assembly 800 is shown. Circulation of the pressurized drilling fluid 380 containing impactors 335 is shown flowing through the interior of pipe string 200, through the stator vanes 820 where a swirling motion is imparted to the pressurized drilling fluid 380. The pressurized drilling fluid 380 is shown flowing through lower stator housing 802 and subsequently through exit orifice 811 of FIG. 5b. Within exit orifice 811 of FIG. 5b the pressurized drilling fluid 380 forms an expanding conical shaped cutting jet 830 which cutting action cuts formation 708 forming a bottom hole pattern 732. The cutting action of conical jet 830 cuts the formation face 730 generating formation cuttings 259 that are entrained in the drilling fluid for transportation up the annular space between the jet head body 802, the exterior pipe string 200 and the well bore wall 874 and the interior wall 722 of casing 720 as a returning drilling fluid slurry 255. The return drilling fluid slurry 255 containing impactors and formation cuttings is shown in cross section flowing up only one side of the well bore annulus for clarity purposes.

FIG. 6 a illustrates the effect of the action of the expanding conical cutting jet 830 flowing into a reentry toroidal shaped flow regime 832. Fluid jet 830 containing impactors 335 cuts the formation face 730 of FIG. 6d and carries the formation cuttings 259 into the reentry toroidal flow 832 where the drilling fluid, impactors 335, and formation cuttings 259 and 733 continue to cut the formation forming face 832. The formation cuttings 259 and impactors 335 circulate in the toroidal flow 832 continuing to cut the formation and are eventually forced out of the toroidal flow 832 to be circulated upwards within the well bore annulus to the drilling rig's surface equipment for processing.

FIG. 6 b illustrates the circular shaped side jet 861 impacting well bore wall 874 where well bore wall 874 is modified by the jet action of impactors impacting the well bore wall. Modified well bore wall 871 forms a new well bore wall comprised of a thin layer of densified formation material 872. Formation region 870 is the unaffected near well bore region of formation 708.

FIG. 6 c illustrates natural formation fracture 711 which has been sealed by the action of the side jets 861 and modified formation material 872 to isolate internal pathway of fracture 711 from the well bore and the drilling fluid 255 within well bore 708.

FIG. 7 d illustrates the front elevation of jet head 801, with horizontal section lines EE, HH and II shown. FIG. 7a illustrates a cross section about horizontal section line EE that shows four side ports within the jet head 801 which two are blanked off with nozzle port plugs 866 and 867. Two ports contain nozzles with circular shaped orifices that provide the pressurized drilling fluid 380 of FIG. 6d to form horizontal jets 862 and 863 that impinge perpendicularly against the formation 708. FIG. 71) illustrates a cross section about horizontal section line HH that shows four side jet ports within the jet head 801 of which two are blanked off with nozzle port plugs 864 and 865. Two ports contain circular shapes nozzle orifice that provide the pressurized drilling fluid 380 of FIG. 6d to form horizontal jets 861 and 860 that impinge perpendicularly against the formation 708. FIG. 7c illustrates a cross section about horizontal section line II that illustrates an overlay of the 8 jets positioned in the jet head 801. Four of the jets have been selectively blanked 866, 864, 865 and 867 in this case. Four of the jets have been fitted with nozzles with orifice in them 862, 860, 863 and 861. This arrangement of jets produces a net thrust force vectored along thrust vector 820.

Although various embodiments of the methods and systems of the present invention have been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the spirit of the invention as set forth herein.

Claims

1. A method for boring a well bore, the method comprising: providing a high-pressure flow line adapted for high-pressure fluid to flow therethrough;providing an impactor injector system coupled to the high-pressure flow line to accelerate a plurality of impactors and inject the accelerated impactors into the high-pressure flow line to form an impactor slurry of entrained impactors and high-pressure fluid;transporting the impactor slurry through a pipe string in fluid communication with the high-pressure flow line to a jet head in fluid communication with a distal end of the pipe string;accelerating the impactor slurry in a down-hole direction and in a tangential direction to create a swirling flow of impactor slurry;impinging a formation of a well bore with the accelerated impactor slurry for removing formation particles therefrom;transporting the impactor slurry and the formation particles to a separator system;using a magnetic separator of the separator system to separate at least a portion of the impactors from the formation particles;using a hydro-cyclone separator of the separator system to separate at ea a portion of the impactors from the high-pressure fluid.

2. The method of claim 1 and further comprising: providing a plurality of nozzle ports disposed radially around a periphery of the jet head and adapted to allow at least a portion of the impactor slurry to flow therethrough to impinge a side of the well bore.

3. The method of claim 3 and further comprising: using at least a portion of the plurality of nozzle ports to generate a vectored thrust on the jet head.

4. The method of claim 1 and further comprising: monitoring a plurality of conditions including one or more of the following: a volume of impactors entrained in the impactor slurry;a size mixture of impactors entrained in the impactor slurry;a rate of penetration on the well bore formation;a density of the impactor slurry;an impactor count returning to the surface;a pressure of the impactor slurry; anda drill-string weight on bottom.

5. The method of claim 4 and further comprising: modulating one or more of the plurality of conditions to modulate at least one of a well bore diameter and the rate of penetration.

6. The method of claim 1 and further comprising: using a bent sub to generate an angled position of the jet head to allow directional boring.

7. A method of boring a well bore, the method comprising: providing a high-pressure fluid flow;accelerating a plurality of impactors;establishing venturi flow conditions at an access port into a motive fluid;injecting the accelerated impactors into the motive fluid by passing the accelerated impactors through a low-pressure area created by the venturi flow conditions;entraining the impactors and motive fluid into the high-pressure fluid flow to create an impactor slurry;transporting the impactor slurry through a pipe string to a jet head connected to a distal end thereof and in fluid communication therewith, the jet head adapted for the impactor slurry to flow therethrough;accelerating the impactor slurry flowing through the jet head for impinging a surface of a well bore therewith and removing formation particles therefrom.

8. The method of claim 7 wherein the accelerating the plurality of impactors imparts enough kinetic energy to the impactors to prevent the venturi flow conditions from ceasing.

9. The method of claim 7, wherein at least one of a mechanical, a fluidic, and an electromotive force is used to accelerate the plurality of impactors.

10. The method of claim 7, wherein the venturi flow conditions are established using a dual concentric orifice adapted to generate a low-pressure region at the access port.

11. The method of claim 10 wherein a concentric orifice of the dual concentric orifice is adapted to swirl the motive fluid.

12. The method of claim 7 wherein an impeller wheel is used to accelerate the plurality of impactors.

13. A method of boring a well bore, the method comprising: providing a supply of impactors;entraining the impactors into a fluid to form an impactor slurry;transporting the impactor slurry through a pipe string to a jet head connected to a distal end thereof and in fluid communication therewith;passing the impactor slurry through a jet head housing, the jet head housing having a stator therein adapted to impart a swirling flow regime to the impactor slurry passing therethrough;passing the impactor slurry through a swirl intensifier adapted to accelerate the impactor slurry both in an axial direction and in a tangential direction;passing the impactor slurry through a conical shaped exit orifice adapted to centralize and stabilize the jet head while preserving a velocity of the impactor slurry flowing therefrom; andimpinging a surface of a well bore with at least a portion of the impactor slurry to remove formation particles therefrom.

14. The method of claim 13 and further comprising: modulating the impactor slurry to change a diameter of the well bore being impinged.

15. The method of claim 13 and further comprising: forming a reentrant toroidal flow regime for entraining the formation particles into the impactor slurry and adapted to further abrade the surface.

16. The method of claim 13 wherein the jet head housing has a converging conically shaped section at an entrance thereof for accelerating the impactor slurry flowing therethrough.

17. The method of claim 13 wherein the jet head housing has an expanding conically shaped section at an exit thereof adapted to generate a conically-shaped impactor-slurry jet form.

18. The method of claim 13 wherein the impactors have a diameter of 0.025 inches.

19. The method of claim 13 wherein the impactors impinge the well bore at a speed of at least 1,200 feet per second.

20. The method of claim 13 wherein the impactors impinge the well bore at a speed sufficient to remove formation particles having a mass greater than a mass of the impactors.

21. The method of claim 13 wherein the impactors impinge the well bore using a combination of shear forces, compression forces, and abrasion/erosion forces.

22. The method of claim 13 wherein the stator has a plurality of stator vanes running axially along an exterior surface thereof and adapted to impart tangential-radial forces on the impactor slurry flowing thereby.

23. A system for boring a well bore, the system comprising: a high-pressure flow line adapted for high-pressure fluid to flow therethrough;a venturi system coupled to the high-pressure flow line and adapted to create an area of low pressure at an access port to a motive fluid;an impactor injector coupled to the venturi system and adapted to continuously accelerate a plurality of impactors through the area of low pressure and into the motive fluid,an amplifier adapted to inject the motive fluid and the impactors into the high-pressure flow line to form an impactor slurry therein;a pipe string in fluid communication with the high-pressure flow line and adapted to transport the impactor slurry from the high-pressure flow line to a region of a well bore;a jet head in fluid communication with a distal end of the pipe string and adapted to accelerate the impactor slurry in a down-hole direction and in a tangential direction to create a swirling flow of impactor slurry for impinging a formation of a well bore with the accelerated impactor slurry for removing foil cation particles therefrom.

24. The system of claim 23 wherein the impactor injector is an impeller wheel.

25. The system of claim 23 and further comprising a first separator adapted to separate at least a portion of the formation particles from the impactor slurry.

26. The system of claim 23 and further comprising a second separator adapted to separate at least a portion of the impactors from the high-pressure fluid.

27. The system of claim 23 wherein the jet head is adapted to impart a conical shaped jet flow of impactor slurry at an exit thereof.