WO2014150431A1

WO2014150431A1 - Bridging material for treating lost circulation

Info

Publication number: WO2014150431A1
Application number: PCT/US2014/023244
Authority: WO
Inventors: Brent CAUBARREAUX
Original assignee: Ipmm, Llc
Priority date: 2013-03-15
Filing date: 2014-03-11
Publication date: 2014-09-25

Abstract

Embodiments of the present application include tools for treating lost circulation in subterranean formations. The tool includes a housing with a plurality of large bridging materials disposed therein. The large bridging materials are characterized as being sufficiently large to be unsuitable for pumping into the wellbore in a slurry. Also provided is a method for use of such tools, including positioning a tool in a wellbore at or above a lost circulation zone and releasing the large bridging materials from the housing. In another aspect, a bridging material for use in a subterranean formation is provided having a jack-shaped form.

Description

BRIDGING MATERIAL FOR TREATING LOST CIRCULATION

Cross-Reference to Related Applications

The present application claims priority to provisional applications U.S. Serial No. 61/920,525 filed on December 24, 2013, and. U.S. Serial No. 61/788,436, filed on March 15, 2013, the disclosures of which, are incorporated herein by reference.

Field of Use

The present application relates to tools that cart be used to treat lost circulation of subterranean formations. More particularly, the present application relates to use of large bridging materials in a tool that axe capable of bridging severely fractured or faulted formations, including boreholes formed using vertical drilling or horizontal directional drillin (HDD).

Background of the Description

A. natural resource such as oil or gas residing in a subterranean formation may be recovered by drilling a well into the formation, in vertically drilled boreholes, the subterranean formation is usually isolated from other formations using a technique known as well cementing, in particular, a weiibore is typically drilled down to the subterranean formation white circulating a drilling fluid through the weiibore. After the drilling is terminated, a siring of pipe, e.g., casing, is run in the weiibore. Subsequently, oil or gas residing in the subterranean formation may be recovered by driving the fluid into the well using, for example, a pressure gradient that exists between the formation, and. the weiibore, the .force of gravity, displacement of the .fluid using a pump or the force of another drilling fluid injected into the well or an adjacent well. Although drilling of HDD boreholes is similar in some respects, pipeline are generally installed without cementing the pipelines in place.

Drilling fluids, often referred to as drilling muds in the oil industry, are water-, oil-, or synthetic-based formulations. They circulate within ihe weiibore during -drilling operations, carrying cuttings to the surface, lubricating the drilling equipment, and acting as a cooling agent. Unfortunately, the drilling fluids may be "lost" if they enter into a porous or fractured subterranean formation rather than returning to the surface for recycling and reuse. This problem is described as "lost circulation", and can result in problems ranging from decreased productivity to complete well failure. The severity of the lost circulation is generally classified into several different categories: seeping or seepage losses (<I 0 barrels/hoar in oil-based fluids and <25 barrels per hour in water- based fluids), moderate losses (10 to 30 barrels/hour in oil-based fluids and 25 to 1 0 barrels per .hour in water-based fluids), severe losses (> 30 barrels hour in oil-based fluids and > 100 barrels/hour in water-based fluids), or total losses (no mud returns). Thus, lost circulation is a significant problem in the industry, and. is estimated to cost about S800 million per year in the United States alone.

in most cases of lost circulation, the operator or contractor can. pump either a conventional lost circulation material (LCM) in the form of a pill or a high concentration in the active system. These LCMs have included a variety of different materials and particle sizes depending on the degree of lost circulation. For example, conventional LCMs include fine, medium, or coarse celSulosic fibers, coarse nut shells, mica, cellulose derivatives, and calcium carbonate (.1-3 mm in diameter). For more severe or total lost circulation, "lost circulation squeeze pills^'' (e.g., PLAN B, DiaseaJ-Mi.? and E Z

Squeeze®) are commonly used to form a solid plug within the porous, faulted, depleted, or fmctared formation. Although most LCMs have a definite and constant volume (i.e., the material does not swell, or grow within the formation), some products are available which are s ellable (i.e. , increase in size or "grow" downhole).

Existing LCMs often fail to treat the most severe cases of lost circulation. For example, with LCMs that require shear thickening for activation, severely fractured formations are unable to provide sufficient resistance to shear and activate the .material. Other LCMs are simply too small to anchor in the severel fractured formations because the LCMs are pumped through the drill string into the formation using standard rig equipment As a result, the LCM is lost to the fractured formation without curing the lost circulation.

Thus, there remains a need to reduce or eliminate the loss in circulation of drilling fluids, particularly in severely fractured formations for which no viable alternative exists.

Summary of the Description

Embodiments of the present description include tools for treating lost circulation in subterranean formations and methods for their use. In a first aspect, a tool is provided including a housing with a plurality of large bridging materials disposed therein. The large bridging materials are characterized as being sufficiently large to be unsuitable for pumping into the weilbore in a slurry, in embodiments, the bousing further irickdes a bridle feature configured to connect the housing to one or more rigs for pulling and pushing the tool through HDD boreholes. in a second aspect, a bridging material for use in. a subterranean formation is provided having a jack-shaped form.

in a third aspect, methods are provided for treating lost circulation in a

subterranean fomuuion using the tool.

Brief Description of the Drawings

FIG- 1 shows a perspecti v e view of the jack-shaped bridgi ng materials.

FIG. 2 shows a cross-sectional illustration of a tool according to an. embodiment

FIG. 3 shows a cross-sectional illustration of a tool according to an embodiment

FIG, 4 shows a schematic cross-sectional illustration of a tool according to an embodiment that is positioned in a weilbore for release of large bridging materials.

FIG. S shows a schematic cross-sectional illustration of a tool according to another embodiment.

FIGS. 6 A and 6B show a partial side-view of a tool with a bridle feature according to two embodiments.

Detailed Description

Embodiments of the present application address the above-described needs by providing a oot designed to treat, lost, circulation of subterranean ormations and methods for its use. The tool generally comprises a housing pre-loaded with large bridging materials. The housing ma be configured for attachment to a drill string so that it may be positioned in a weilbore. Once the tool is positioned at or near the lost circulation zone, the large bridging materials can. be forced out of the housing and into the lost circulation zone of the subterranean formation, for example, using pressure created by the mud pumps. In embodiments, the large bridging materials are themselves sufficient to seal the lost circulation zone of the subterranean formation. In other embodiments, the large bridging materials partially seal the lost circulation zone of the subterranean formation by providing a sufficient backing for conventional lost circulation materials that are subsequently .introduced into the weilbore. As used herein, the "subterranean formation" encompasses both areas below exposed earth and areas below earth covered by water, such as ocean or fresh water. The "lost circulation zone" of the subterranean formation may include a void, vugular zone, or fracture of vary ing degrees of severity. In embodiments, the lost circulation zone is a severely fractured or faulted formation. Such formations commonly are associated with salt formations, faults, tectonic activity, earthquake activity, or combinations of these geological phenomena. Tile terms "wellbore" and "borehole" are used interchangeably and refer io both vertically drilled wells and HDD wells unless specified.

As used herein, the term "large bridging materials" is used generally to describe bridging materials that are too large to be introduced into the wellbore as a slurry usin mud pumps. The large bridging materials of the present application are capable of creating a bridge across severely fractured formations that prior art bridging materials and squeeze pills usually are ineffective at treating. In embodiments, the large bridgin materials ma comprise one or more of rags, rope, cardboard, plastic, paper, rubber, acid soluble materials (e.g., calcium carbonate), processed, drill cuttings, and the like.

Desirably, the large bridging materials will not swell (i.e., do not increase in size) when exposed to water. The type of large bridging materials that may be used depends in part oti the type of wellbore, as the large bridging materials used in HDD boreholes preferably comprise naturally-occurring materials (e.g., calcium carbonate or cellulose and fiber- based materials) in view of the HDD borehole's proximity to fresh water aquifers.

In embodiments, the large bridging materials are characterized as having an average largest dimension (e.g., length) (L) of greater than about 0.5 Inch (-1.25 cm). For example, the large bridging materials may have an average length from about 1. inch (-2.5 era) to about 18 inches (- 5 cm), from about 2 inches (-5 cm) to about 18 inches (-45 cm), from about 4 inches (-10 cm) to about 16 inches (-40.5 cm), or from about 6 inches (-15 cm) to about 12 inches (-30.5 cm).

in embodiments, the large bridging materials may be characterized as having an average surface area of greater than about 0.75 square inches (> -5 cm^'), greater than about 50 square inches (> -320 cm'), or greater than about 75 square inches (> -480 cm"). For example, the large bridging materials may be sections of rope having an average diameter of 2 inches and an a verage length of 4 inches, providing an average surface area of greater than approximately 25 square inches (-160 cm"), or may be 10 x 20 inch rags ha ving an average surface area of greater than approximately 2500 square inches (1.6 x 10^'' cm¹). Other non-limiting examples of surface areas of various types of large bridging materials are summarized in the following table:

Although the large bridging materials may be blended or layered with one or more types of conventional LCM (i.e. , those that can be pumped into a wellbore), tire average length and average surface area of the large bridging materials described herein excludes any such additional materials. Conventional LCM are commercially available from numerous manu facturers, non-limi ting examples of which include Bridgecarb-Ultra

System, Sluggit®, Bridgesal- Ultra® System, l¾sg-Sakt^!, Hysa -^! System, Hysal* Activator, Ilysal® C, Hysal® HD, Hysal® HT, Hysal® SF, OSS® Pill System,

Sohrhridge®, PBS PSug& System, Sanheal Pill® System, SolukleenS System, and

Soiubridge® (all available from TBC-Brinadd).

ID embodiments, the large bridging materials comprise a plurality of jack -shaped materials 10 (FIG. 1). As used herein, the term "jack-shaped" refers to materials having at least three points 12 protruding from a central point 14. As used herein, "points" refer to elongate members extending from a hub. For example, in embodiments the jack-shaped materials 10 may have four, five, six (illustrated in FIG. 1), seven, or eight points protruding from a central point. The points define the vertices of various polyhedrons (e.g. , a four-point structure defines the comers of a tetrahedron; a six-poin t structure defines the corners of an octahedron; etc.). The jack -shaped materials 10 desirably are effective at both anchoring the material within the fractures of the formation and

interlocking with each other.

These jack-shaped bridging materials 10 may be formed in various sizes using different types of materials. For example, the jack-shaped bridging materials 10 desirably have an average length (L of greater than about 0.5 inches (- i .25 cm). In embodiments, the jack-shaped bridging materials 10 may have an average length from about 0.5 inches (--J .25 cm) to about 6 inches (-- 15 cm), from about 1. inch -2.5 cm) to about 4 inches (-10 cm), or abou 2 indies -5 cm) or 3 inches (-7,6 cm). The interlocking nature of the smaller jack-shaped bridging materials 10 may enable them to function in the same manner as the other larger bridging materials provided herein,

In addition,, the materials may be specially engineered using various polymers, low melting point metals (e.g., aluminum and aluminum alloys, lead, magnesium and magnesium .alloys, and the like), and composite -materials having a desired melting point and density, thereby reducing or eliminating the potential for the material to migrate or "float" out of the loss zone and up the wellbore after its release from the tool. In embodiments, the jack-shaped bridging materials 10 are formed using a composite material formed from extruding a thermoplastic polymer (e.g.. high density polyethylene, low density polyethylene, polypropylene, and the like) with, a weighting agent (e.g.. a heavier weight material such as hematite, lead (it) sulfide (galena), barite, calcium carbonate, and the like), la embodiments, the jack-shaped bridging materials 10 are formed using low melting point metals. The jack-shaped bridging materials 1.0 formed using thermoplastic polymers and low melting point metals may be particularly suitable for use in treating lost circulation because the materials would effectively fuse together when exposed to increased hydrostatic pressure and temperatures downhole.

The large bridging materials are disposed inside of a housing defining the tool ^'body that may be any container suitable for use in a wellbore and suitable for transporting the large bridging materials into the wellbore. In an embodiment (FIG. 2), the tool 20 has a housing 22 in the form of a tubular structure that may be either open or closed, to the wellbore prior t the release of the large bridging materi als 24 therein. For example, the housing 22 may be a tubular structure having an openin at both proximal and distal ends. The "distal end" of the tool refers to the portion of the tool that is downstream or downhole in the borehole, while the "proximal end" of the tool refers to the portion of the tool that is upstream or uphole in the borehole.

The diameter (D_s) of the housing 22 should be smaller than the diameter of the wellbore. For example, the diameter of the tabular structure may be from about J .5 inches to about 48 inches, from about 6 inches to about 36 inches, or from about 12 inches to about 24 inches, in embodiments, the diameter of the housing is constant along its length (as shown in FIG, 2)„ while in other embodiments, the diameter of the housing is greater at its distal end than, its proximal end (not shown), thereby reducing the possibility of excessive pressure build-up or bursting while pumping to dispense the bridging materia! from the distal end.

The housing may be formed from any suitable material, non-limiting examples of which include metals (e.g., steel), polymers (e.g., plastic), and composite materials (e.g., fiberglass), in embodiments in which the housing is formed of a polymer or fiberglass, the housing may advantageously be later drilled or milled in the event that the tool is

inadvertently lost or stuck do v.nh.ole (e.g.. doe to differential sticking, etc). In addition, melting or softening points of soch materials may be modified so that the housing also may function as a bridging material along with the large bridging materials disposed therein. For example, the housing may be a frangible polymer that fractures upon application of a certain pressure by the drilling fluid or drill to the housing, allowing for the release of the large bridging materials t herein i f not already released from t he ^'housing.

In other embodiments, the housin is fomied of a water soluble or water degradable polymer that at least partially dissolves upon contact with fluid in the wellbore, thereby releasing the large bridging materials into the wellbore. Such polymers also may only partially degrade upon exposure to aqueous fluids under downhoie conditions, impairing the mechanical strength of the housing so that it may be more easily ruptured, in still other embodiments, only a portion of the housing is formed from a water soluble or water degradable polymer (e.g., an end cap attached to a bottom end of the housing).

in embodiments, the housing material and/or structure of the housing may be configured to counteract any poteiitial problems with buoyancy caused by displacement of the drilling fluid. For example, the weight of the housing may be increased by increasing the thickness of the sidewail or by other appropriate means known to those skilled in the art.

In embodiments, the tool includes an end cap attached to one or both ends of the housing. For example, an end cap attached to the ^'bottom of the housing in a vertical borehole (or distal end of the housing in an HDD borehole) insures that the large bridging material will be retained within the housing until the tool is positioned in the lost circulation zone and release of the large bridging materials is desired. To enable release of the large bridging materials through the end of the housing in such embodiments, the end- cap may be configured to be detached from the housing when a certain pressure is applied by the drilling fl uid, may be formed of a water soluble or water degradable polymer as described above, or may include a mechanical means (e.g.. a valve) to open and release the large bridging materials from the housing.

The too! may be placed into the wellbore using any suitable method, and may be used either when drilling a pilo hole or when the pilot hole is already drilled.

For example, the tool may be dropped in an empty wellbore, attached to a drill string using one or more tethers and. lowered into the wellbore, or lowered directly into the wellbore using one or more tethers. As used herein, a "tether" refers to a length of material that is suitable for holding the tool and thai, may be attached to the housing. The tether may be integral with the housing or separable, in embodiments, the tether may be cut to allow the housing io remain in the wellbore. Once the tether is severed, an operator could pull out of the hole, pick up a drilling assembly, trip back into the hole, and force the large bridging material further into the formation using the weight of ihe drill, string. Not wishing to be bound by any theory, it is believed that the pressure in the wellbore in vertical boreholes will facilitate placement of the tool do nhole in the lost circulation zone.

in HDD applications, the tool may include a bridle feature to facilitate placement of the too! in the borehole. As used herein, a "bridle feature' refers to a feature that enables the tool to be pulled in one direction by a first rig while being pushed from the other direction, using a second rig. in embodiments, the bridle feature may include a female- or male-threaded drill pipe connection (a "box end") secured to the housing by one or more metal straps. For example, the bridle feature may include two (2), three (3) or four (4) metal straps that are welded, bolted, or screwed onto or near an end of the tool. The bridle feature and straps should extend sufficiently away from the end of the tool to permit release of the large bridging materials f om the tool. For example, the straps may be from about .1 foot {--30.5 cm) to about 6 feet (- 182.9 cm) or about 3 feet. (-91 .4 cm) to about 6 feet in length.

The tool may include one or more elements to facilitate release of the large bridging materials- from the housing into the lost circulation zone. For example, the housing may include an insert formed by a longitudinal rod with one or more plates configured to be pushed disially when pressure from the drilling fluid is applied. The plates* distal motion also would push d e large bridging materials distaily, facilitating the release of the large bridging material out the distal end of the housing.

In embodiments, the tool may include an auger disposed in the housing. The auger may be operated by connecting it to a conventional mud motor or by an integral motor disposed in the housing. The integral motor may simplify the tool design in some respects by eliminating or simplifying any connecting means needed betwee the tool body and the mud motor (e.g.. to facilitate rotation of the anger).. Because less torque will be required to rotate the tool than is required to rotate a drilling bit daring operation of the well, fewer lobes would be required in the motor and. a shorter motor housing could be used. Thus, in an embodiment the tool may comprise both an auger section and an integral motor, the auger section being connected to the driveshaft assembly of the motor section in a manner similar to the wa a driveshaft is connected i.o the differential of a truck or car, thereby enabling the driving or rotating off he auger of the tool and the release of the large bridging materials into the wel!bore.

in an embodiment, the tool may furthe comprise hydraulic motor disposed between the integral motor and the auger. One or more small internal hydraulic fluid reservoir may be included to supply ihe hydraulic pump with the required hydraulic fluid. The hydraulic fluid may be cooled via heat exchanger which would be exposed to the drilling -fluid being expelled above the auger section, in embodiments, the hydraulic fluid may be conventional hydraulic fluid or an environmentally sa fe hydraulic fluid (e.g., mineral or vegetable oil-based hydraulic fluids). Be hydraulic drive assembly may be beneficial by reducing the auger speed of rotation while allowing a greater torque to be achieved.

Embodiments of the above-described tools desirably would be prepared at the manufacturing facility by pre-loading the tool body with the large bridging material and storing the tool until needed. The tool may be loaded, for example, via one or more removable doors in the tool body. The appropriate type of large bridging materials and size of large bridging materials {i.e., average length and average surface area) will depend on the type of formation being drill ed and the size of the fractures or faults in the formation. After identifying the appropriate type and. size of large bridging materials for use in a particular weilbore, a tool having the appropriate large bridging materials disposed therein for the particular situation could then be positioned at the lost circulation zone in ihe wellbore. Once positioned, {he large bridging .raateriai can. be released from the housing of the tool body. For example, the large bridging materials may be "pumped out" of die housing of the tool body by fee pressure applied from drill ing fluid pumped using the existing rig equipment. After being released from the tool body, the large bridging materials desirably would remain sufficiently concentrated together in a plug type form to create an instant bridge, or "plug", in and across the lost circulation zone of the subterranean formation (i.e., across a severely .fractured or faulted formation).

In embodiments, the large bridging materials are alone sufficient to seal the lost circulation zone of the subterranean formation. In other embodiments, the large bridging materials may form a backing or foundation to allow for subsequent addition of conventional lost circulation materials into the lost circulation zone, in such

embodiments, the large bridging materials desirably are sufficiently anchored i the lost circulation zone after being released from ihe housing to permit use of a hesitation squeeze procedure for introducing the conventional lost circulation materials. Such procedure are known by those skilled in the art. Generall described, during hesitation squeeze procedures, the pumps are intermittently shut down after introducing a volume of lost circulation materials downhole to the lost circulation zone. This allows for dewatering of the slurry with, the lost circulation materials so that the solid lost circulation materials can. be systematically deposited in the lost circulation zone.

The above-described tools also may be effective for use in various other drilling applications that would benefit from delivery of large bridging materials. For example, the tools may be used to facilitate placement of bridge plugs that enable the lower wellbore to be permanently sealed, from production or temporarily isolated from a treatment conducted on an upper zone. In such applications, the tool may be used to deliver the large bridging materials to a desired site downhole. either independently operating as the bridge plug or acting as a "bumper" to facilitate placement of cement plug. The large bridging materials in such applications also may advantageously reduce the volume of cement needed to form the cement plug.

Thus, also provided is a method for facilitating placement of a bridge ping in a subterranean formation. The method may comprise positioning a tool in a wellbore at or near a desired site for placement of the bridge plug, the tool comprising a housing with a plurality of large bridging materials disposed therein, and releasing the large bridging materials ^"from the housing. The large bridging materials being characterized as being sufficiently large to be unsuitable for pumping info the weiibore in slurry. The releasing of the large bridging materials from the housing in such applications may be effec tive to independently form a temporary bridge plug or may be effective to facilitate- subsequent pumping and placement of a cement bridge plug.

The present description may be further understood by reference to the foll wing prophetic examples.

Example 1 : Open-Bore Tool

As illustrated in FIG. 2, a tool 20 has an open-bore design formed from a tubular structure 22 with two open ends. The large bridging materials 24 disposed in the tubular structure 22 incl ude a mixture of one or more of rags, rope, cardboar d, plastic, paper, and rubber, having an average length of greater than 0.5 inches. The proximal end of the housing 22 is opened and attached to the drill string (not shown), so as to allow positioning of the tool 20 in the weiibore and use of pressure from the flow of the drilling fluid to release the large bridging material into the weiibore. The distal end of the housing 22 is at least partially closed by an end cap 26 attached to the housing 2-2 tha is configured to detach from the housing 22 when a certain pressure is applied. After the end cap 26 detaches from the housing 22, the large bridging materials 24 are dispersed .from the housing 22 into the weiibore.

Example 2: Piston-Type Tool

As illustrated in FIG.3, a tool has a piston-type design formed from a tubular structure 30 with two open ends and a piston assembly therein. The piston, assembly is a rod 34 positioned longitudinally in the tubular structure 30 with two or .more plates 36, 38 positioned longitudinally along the rod 34 (e.g., at the top and bottom of the housing). The plates 36, 38 may be aligned with each other or offset from each other to facilitate the exit of the large bridging materials 32 from the housing 30. When the drilling fluid is pumped into the weiibore, the drilling fluid exerts a pressure on the most proximal plate 36 of the piston assembly, pushing both the piston assembly and the large bridging material 32 distaily to release the large bridging material 32 from the distal end of the housing 30 into the weiibore. Example 3: Auger-Type Tool

As illustrated in FIG. 4, a tool 0 having an auger-type design has a housing 42 defined by a tubular structure. The housing 42 includes both an auger section 44 (similar io that used to convey grain or other types of materia!) and a motor section 46. The auger section 44 includes an auger 48 with the large bridging materials 50. The auger stem 52 is connected to the driveshaft. assembly 54 of the integral motor 46, The driveshaft. assembly 54 extends from the motor stem 56 which has a plurality of lobes 58. Drilling fluid bypass openings 60 disposed in the housing 42 between, the integral motor 46 and the auger section 44 allow excess flow of the drilling fluid to bypass the auger section 44, thereby reducing the risk that the pressure from the drilling fluid will pack or plug the large bridging materials 50 inside the housing 42 of the tool. The drilling fluid by-pass openings 60 may be configured to permit all or a portion of the drilling fluid to bypass the auger section 44, A bumper plate 62 disposed between the motor section 46 and the auger section 44 diverts the drilling fluid away from the auger section 44 and out the drilling fluid by-pass openings 60, The bumper plate 62 may be configured so that it rotates with the driveshaft assembly 54 and auger stem 52.

The tool 42 can be lowered into a wellbore 64 to a lost circulation zone 66 by attaching the tool 42 to the drill string by a tether 68. Once in position, drilling fluid ("mud") flows through the motor section 46 of the too! 42, causing the driveshaft assembly 54 and auger stem 52 to rotate. As the auger 52 stem rotates, the auger blades 48 move downward to release the large bridging materials 50 into the wellbore 64.

The auger-type tool optionall may include a hydraulic motor section (described in Example 4 below) disposed between the motor section 46 and the auger section 44. The hydraulic drive assembly may be beneficial by reducin the auger speed of rotation while allowing a greater torque to be achieved, thereby allowing use of a smaller mud motor (i.e., having fewer lobes).

Example 4: Hydraulic Motor-Powered Tool

As illustrated in FIG, 5, a tool 140 having an auger-type design has a housing 1.42 defined by a Iubular structure. The housing J 42 includes both an auger section 1.44 and a motor section 146. The auger section 144 includes an auger 148 with, the large bridging materials 15Θ, The auger stem 152 is connected to the driveshaft assembly 54 of the integral hydraulic motor 170. The driveshaft assembly 154 extends from the motor stem 1 6 which has a plurality of lobes 158. Drilling fluid bypass openings 160 disposed in the housing 142 above the motor section 146 allow excess flow of the drilling fluid to bypass the auger section 144, thereb reducing the risk that the pressure from the drilling fluid will pack or plug the large bridging materials 150 inside the housing 142 of the tool The drilling fluid by-pass openings 160 may be configured to permit ail or a portion of the drilling fluid io bypass the auger section 144. A bumper plate 162 above the motor section 146 and the auger section 144 di verts the drilling fluid out the drilling fluid by-pass openings 160. The bumper plate 1 2 may be configured so that it rotates with the driveshaft assembly 154 and auger stem 152.

Two or more removable doors 174 in the auger section 144 of the housing 142 enable the large bridging materials 150 to be loaded into the housing 142. The doors 174 may be secured closed, for example, by means of recessed, hex. bolts (not shown).

The tool 146 can be lowered into a we!!bore to a lost circulation zone by attaching the tool 140 to the drill siring b a tether 168, Once in position, drilling fluid ("rand") flows through the motor section 146 of the tool 140, causing the driveshaft assembly 154 and auger stem 152 to rotate. As the auger 152 stem rotates, the auger blades 148 move downward to release the large bridging materials 150 into the wellbore. The integral hydraulic motor 170 is connected to one or more hydraulic oil reservoirs 172, A hydraulic oil overflow line connecting two or more hydraulic oil reservoirs 172 allows the hydraulic oil pressure to stabilize. The integral hydraulic motor may be beneficial by reducing the auger speed of rotation while allowing a greater torque to be achieved, thereby allowing use of a smaller mud motor

Example 5: Hydraulic-Type Tool

A tool also is pro vided that may be used in well control using any of the above- described loots. For example, the tool ma be appropriate for use in a blowout by lowering the tool inside the blowout preventer, riser pipe, casing, or open hole. The housin desirably is smooth on the outside surface of the housing and/or is beveled in shape to facilitate sealing-off the inside diameter of a blowout preventer, riser pipe, casing, or open hole. Preferably, the housing has as large an outside diameter as possible.

Once the tool is positioned, the rams of the blowout preventer may be closed about the device or the tool may be wedged inside the blowout pre ventor, riser, casing or open hole using the bevel-shaped section and rubber seals. The large bridging materials disposed inside the housing then can be dispensed hydraulic-ally using a hydraulic line connecting the tool to a hydraulic pump on the surface or at a safe, remote location. The large bridging materials desirably are heavier materials (e.g., steel, rubber, plastic, etc.) that are capable of effectively packing-off or plugging the blowout preventer, riser, casing, or open hole.

Example 6: HDD-Type Tool

As illustrated in FIGS. 6A and 6B, the tool may include a bridle feature 72 to facilitate use of the tool in HDD boreholes. The bridle feature 72 may include two or three straps 74 (FIGS. 6 A and 6B, respectively) connecting the tubular structure 74 at one or both ends to a section of drill pipe 76 and a box-end 78 comprising a male or female threaded drill pipe connection. The bridle feature 72 optionally may include one or more bracing features 80. as shown in FIG. 6A, to provide additional support to the straps 74 (particularly for connecting to the rig pulling the too! through an HDD borehole).

While the present invention has been described in detail with respect to specific embodiments thereof it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily conceive of alterations to, variations of, and equivalents to those embodiments. Accordingly, the scope of the present invention should be assessed as thai of the appended claims and any equivalents thereof.

Claims

I claim;

A fool for treating lost circulation comprising a plurality of large bridging materials disposed a housing, wherein the large bridging materials are characterized as being sufficiently large to be unsuitable for pumping into a wellbore in a shiny.

The too) of claim. I, wherein die large bridging materials are effecti ve for treating a severely fractured or severely faulted subterranean formation.

The tool of claim. 1 or 2, wherein, the large bridging materials comprise one or more of rags, rope, cardboard, plastic, paper, rubber, and calcium carbonate.

The tool of any one of claims 1 to 3, wherein the large bridging materials are non- swellable.

The too) of any one of claims 1 to 4, wherein die large bri dging materi als have an average length of greater than about 0.5 inches.

The tool of any one of claims I to 4, wherein the large bridging materials have art average length of greater than, about 4 inches.

The tool of any one of clai ms I to 6, wherein the large bridging materials have an average surface area of greater than, about 0.75 square inches.

The tool of any one of claims 1 to 7, wherein the large bridging maiersais comprise a jack -shaped material ,

The tool of claim 8, wherein the jack-shaped material has at least three points protruding from a central point.

The tool of claim. 8 or 9, wherei the jack-shaped materials comprise a composite material of a polymer and a weighting agent.

1 1. The tool, of claim .10, wherein the polymer comprises a thermoplastic poly mer and the weighting agent is selected from the group consisting of hematite, lead (1!) sulfide (galena), barite, calcium carbonate, mid combinations thereof.

12. The tool of claim i 1, wherein the thermoplastic poiymer is a high density

polyethylene, low density polyethylene, polypropylene, or a combination thereof.

13. The tool of any one of claims I to 12, wherein the housing comprises a tubular

structure in which the large bridging materials are disposed.

14. The tool of claim 13, wherein the tubular structure comprises a metal, polymer, fiberglass, or a combination thereof,

1.5, The tool of claim 13 or 1 , wherein the tubular structure comprises a frangible

material.

16. The tool of any one of claims 13 to 15, wherein the tabular structure compri ses a material suitable for use as a bridging material in the weitbore.

17. The tool of any one of claims I 3 to 1 , wherein at least one of a proximal or a distal end of the tubular structure is open to the weilbore.

18. The tool of any one of claims 17, wherein the housing further comprises a cap

disposed a t the distal end of the tubular structure, at least partially closing the distal end of the tabular structure,

1 . The tool of any one of claims 1 to 18, wherein the housing further comprises a piston assembly disposed therein.

20. The tool of any one of claims 13 to. 1 , wherein the tool further comprises an auger, an integral motor, or a combination thereof

21. The tool of any one of claims 13 to 20, further comprising at least one bridle feature configured to connect the housing to one or more rigs for pulling and/or pushing the tool through a horizontal directional drilling borehole to treat a formation with lost circulation.

22. A bridging material for treating lost circulation o f a fractured formation comprising a jack -shaped material,

23. The bridging material of claim 22, wherein the jack- shaped material has at least three points protruding from a central point.

24. The bridging material of claim 22 or 23, wherein the jack-shaped material comprises a composite material including a polymer and a weighting agent.

25. The bridging material of claim. 24, wherein the polymer comprises a thermoplastic polymer and the weighting agent is selected from the group consisting of hematite, lead (H) sulfide (galena)., bariie, calcium carbonate,, and combinations thereof.

26. The bridging material of claim 25, wherein the thermoplastic polymer is a high

density polyethylene, low density polyethylene, polypropylene, or a combination thereof.

27. A method fo treating lost circulation in a subterranean formation comprising:

positioning a tool in a welibore at or near a lost circulation zone, wherein the tool comprises a housing with a plurality of large bridging materials disposed therein, the large bridging materials being characterized as being sufficiently large to be unsuitable for pumping into the welibore in a slurr '; and

releasing the large bridging materials from die housing,

28. The method of claim 27, wherein, the subterranean formation is a severely fractured or severely faulted formation.

29. The method of claim 27 or 28, wherein the large bridging materials comprise one or more of rags, rope, cardboard, plastic, paper, rubber, or calcium carbonate. The method of any one of claims 27 to 29, wherein the large bridging materials are noii-s ellabSe.

The method of any one of claims 2? to 30, wherein, the large bridging materials have an average length of greater than about 0.5 inches.

The method of any one of claims 27 to 30, wherein the large bridging materials have an average length of greater than about 4 inches.

The method of any one of claims 27 to 32, wherein the large bridgi ng materials ha ve an average surface area of greater than about 0.75 square inches.

The method of any one of claims 27 to 33, wherein the large bridging materials comprise a jack-shaped material.

The method of any one of claims 27 to 34. wherein releasing the large bridging materials comprises dissolving at least a portion of the housing, puncturing the housing, bursting the housing with pressure in the weilbore, forcing the large bridging materials from an end of the housing with pressure, or combinations thereof.

The method of any one of claims 27 to 34, wherein releasing the large bridging materials comprises rotating an auger disposed within the housing.

The method of any one of claims 27 to 36, wherein positioning the tool comprises attaching the housing onto a drill string and lowering the tool into the weilbore.

The method of claim 37, wherein the housing is attached to the drill string by a tether.

The method of any one of claims 27 to 36, wherein positioning the tool comprises pulling and/or poshing the too! using one or more rigs connected to a bridle feature of the housing in a horizontal directional drilling (HDD} weilbore.

The method of any one of claims 27 to 39, further comprising removing the tool from the weilbore after releasing of the large bridging materials from the housing. The method of claim 39 or 40, wherein, the tool is connected to a reamer or a swab.

The method of laim 38, further comprising cutting the tether to release the tool i n. ellbore.