Patent Description:
During the drilling of subterranean wells, such as subterranean wells used in hydrocarbon development operations, drilling mud and other fluids can be pumped into the well. In certain drilling operations, the wellbore of the subterranean well can pass through a zone that has induced or natural fractures, are cavernous, or otherwise have an increased permeability, which is known as a lost circulation zone. In such a case, the drilling mud and other fluids that are pumped into the well can flow into the lost circulation zone and become irretrievable.

Lost circulation can be encountered during any stage of hydrocarbon development operations. Lost circulation can be identified when drilling fluid that is pumped into the subterranean well returns partially or does not return to the surface. While some fluid loss is expected, excessive fluid loss is not desirable from a safety, an economical, or an environmental point of view. Lost circulation can result in difficulties with well control, borehole instability, pipe sticking, unsuccessful production tests, poor hydrocarbon production after well completion, and formation damage due to plugging of pores and pore throats by mud particles. In extreme cases, lost circulation problems may force abandonment of a well.

<CIT> describes a fluid used in a borehole containing suspended solid objects made by an additive manufacturing process. An additive process of solidifying a liquid composition at a succession of selected locations within a workspace, in accordance with a digital design allows a wide variety of shapes to be made. The fluid described may be a drilling fluid or a borehole treatment fluid used prior to cementing and the objects may act, possibly in conjunction with other solids, to block loss of fluid into fractures in the formation around the borehole.

When unacceptable drilling fluid losses are encountered, conventional lost circulation materials are deployed with the drilling fluid from the surface. The revised fluid that includes the conventional lost circulation materials is pumped downhole as part of the standard well circulation system. The revised fluid passes through a circulation port to plug and pressure seal the exposed formation at the point where losses are occurring. Once sealing has occurred and acceptable fluid loss control is established, drilling operations can resume. Conventional currently available lost circulation material is most effective at sealing regularly shaped formation voids with widths up to approximately <NUM>-<NUM> millimeters (mm). In voids with larger widths, effective sealing is often both challenging and costly.

Embodiments of this disclosure provide a lost circulation shape that operates as a complimentary addition to conventional lost circulation material as described in this disclosure. The lost circulation shape can be deployed with the conventional lost circulation material. The lost circulation shape is a hollow perforated geometric shape that can fill with drilling fluid and have a generally neutral buoyancy in the drilling fluid. Due to this generally neutral buoyancy the lost circulation shape can move downhole freely with the drilling fluid and exit the drill string through the circulation port with the conventional lost circulation material. The lost circulation shape would be drawn into thief zone cavities or vugulars. The lost circulation shape can act as a trap for the conventional lost circulation material and allow for accumulation and bridging of the lost circulation material onto the lost circulation shape. This will result in eventual plugging of the formation.

In an embodiment of this disclosure, a system for sealing a lost circulation zone associated with a subterranean well includes a lost circulation material and a lost circulation shape. The lost circulation shape is a hollow body having an outer skin and an open interior chamber. The outer skin includes a plurality of perforations that extend through the outer skin, providing fluid communication between an exterior of the lost circulation shape and the open interior chamber. The plurality of perforations are sized to prohibit a passage of lost circulation material between the exterior of the lost circulation shape and the open interior chamber.

The lost circulation shape has a minimum size and a maximum size. The minimum size of the lost circulation shape is such that a smallest minimum sphere in which the lost circulation shape having the minimum size could fit has a diameter of <NUM>. The maximum size of the lost circulation shape is such that a smallest maximum sphere in which the lost circulation shape having the maximum size could fit has a diameter of <NUM>. The lost circulation shape includes a filling hole, the filling hole extending through the outer skin and having a diameter in a range of <NUM> to <NUM>. Filling the open interior chamber with drilling fluid can include applying a vacuum or applying a pressure to the lost circulation shape before circulating the lost circulation material through the drill string.

In other alternate embodiments, the open interior chamber can include a drilling fluid with a drilling fluid density. The lost circulation shape can have an average lost circulation shape density. A difference between the average lost circulation shape density and the drilling fluid density can be <NUM>% or less of the drilling fluid density. Alternately, the difference between the average lost circulation shape density and the drilling fluid density can be <NUM>% or less of the drilling fluid density.

In yet other alternate embodiments, the system can further include a circulating sub and a circulating port that extends through a sidewall of the circulating sub. The lost circulation shape can be sized to flow through the circulating sub port with a drilling fluid. The plurality of perforations can be sized to trap the lost circulation material within the lost circulation zone for forming a seal within the lost circulation zone.

In still other alternate embodiments the system can further include a drill string having a circulating port. The drill string can be located within a wellbore of the subterranean well and defines an annular space between an outer diameter surface of the drill string and an inner diameter surface of the wellbore. The lost circulation material can be located within a drilling fluid traveling downhole within the drill string, through the circulating port, and into the annular space. The lost circulation shape can be located within the drilling fluid travelling downhole within the drill string, through the circulating port, and into the annular space.

In yet another embodiment of this disclosure, a method for sealing a lost circulation zone associated with a subterranean well includes providing a drill string with a circulating port in the subterranean well. A lost circulation shape is circulated through the drill string. The lost circulation shape is a hollow body having an outer skin and an open interior chamber. The outer skin includes a plurality of perforations that extend through the outer skin, providing fluid communication between an exterior of the lost circulation shape and the open interior chamber. The plurality of perforations are sized to prohibit a passage of a lost circulation material between the exterior of the lost circulation shape and the open interior chamber. The lost circulation shape has a minimum size and a maximum size, where the minimum size of the lost circulation shape is such that a smallest minimum sphere in which the lost circulation shape having the minimum size could fit has a diameter of <NUM> and the maximum size of the lost circulation shape is such that a smallest maximum sphere in which the lost circulation shape having the maximum size could fit has a diameter of <NUM>. The lost circulation material can be circulated through the drill string.

In other embodiments, the lost circulation shape can be sized to be introduced into cavities of the lost circulation zone, forming a wedged lost circulation shape. The method can further include trapping lost circulation material with the wedged lost circulation shape to seal the lost circulation zone. The lost circulation shape includes a filling hole that extends through the outer skin and has a diameter in a range of <NUM> to <NUM>. The method further includes filling the open interior chamber with drilling fluid that travels through the filling hole.

In other alternate embodiments, the lost circulation shape can have an average lost circulation shape density. A difference between the average lost circulation shape density and a drilling fluid density can be <NUM>% or less of the drilling fluid density. Alternately, a difference between the average lost circulation shape density and a drilling fluid density can be <NUM>% or less of the drilling fluid density. The drill string can further include a circulating sub and the circulating port can be a circulating sub port that extends through a sidewall of the circulating sub. The lost circulation shape can be sized to flow through the circulating sub port with a drilling fluid.

In yet other alternate embodiments, an annular space can be defined between an outer diameter surface of the drill string and an inner diameter surface of the wellbore. Circulating a lost circulation shape through the drill string can include circulating the lost circulation material within a drilling fluid traveling downhole within the drill string, through the circulating port, and into the annular space. Circulating the lost circulation material through the drill string can include circulating the lost circulation shape within the drilling fluid travelling downhole within the drill string, through the circulating port, and into the annular space.

So that the manner in which the features, aspects and advantages of the embodiments of this disclosure, as well as others that will become apparent, are attained and can be understood in detail, a more particular description of the disclosure may be had by reference to the embodiments that are illustrated in the drawings that form a part of this specification. It is to be noted, however, that the appended drawings illustrate only certain embodiments of the disclosure and are not to be considered limiting of the disclosure's scope, for the disclosure may admit to other equally effective embodiments.

The disclosure refers to particular features, including process or method steps. Those of skill in the art understand that the disclosure is not limited to or by the description of embodiments given in the specification.

Those of skill in the art also understand that the terminology used for describing particular embodiments does not limit the scope or breadth of the embodiments of the disclosure. In interpreting the specification and appended Claims, all terms should be interpreted in the broadest possible manner consistent with the context of each term. All technical and scientific terms used in the specification and appended Claims have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs unless defined otherwise.

As used in the Specification and appended Claims, the singular forms "a", "an", and "the" include plural references unless the context clearly indicates otherwise.

As used, the words "comprise," "has," "includes", and all other grammatical variations are each intended to have an open, non-limiting meaning that does not exclude additional elements, components or steps. Embodiments of the present disclosure may suitably "comprise", "consist" or "consist essentially of' the limiting features disclosed, and may be practiced in the absence of a limiting feature not disclosed. For example, it can be recognized by those skilled in the art that certain steps can be combined into a single step.

Where a range of values is provided in the Specification or in the appended Claims, it is understood that the interval encompasses each intervening value between the upper limit and the lower limit as well as the upper limit and the lower limit. The disclosure encompasses and bounds smaller ranges of the interval subject to any specific exclusion provided.

Where reference is made in the specification and appended Claims to a method comprising two or more defined steps, the defined steps can be carried out in any order or simultaneously except where the context excludes that possibility.

Looking at <FIG>, subterranean well <NUM> can have wellbore <NUM> that extends to an earth's surface <NUM>. Subterranean well <NUM> can be an offshore well or a land based well, and can be used for producing hydrocarbons from subterranean hydrocarbon reservoirs. Drill string <NUM> can be delivered into and located within wellbore <NUM>. Drill string <NUM> can include tubular member <NUM> and bottom hole assembly <NUM>. Tubular member <NUM> can extend from surface <NUM> into subterranean well <NUM>. Bottom hole assembly <NUM> can include, for example, drill collars, stabilizers, reamers, shocks, a bit sub and the drill bit. Drill string <NUM> can be used to drill wellbore <NUM>. In certain embodiments, tubular member <NUM> is rotated to rotate the bit to drill wellbore <NUM>.

Wellbore <NUM> can be drilled through lost circulation zone <NUM>. In embodiments lost circulation zone <NUM> is a layer of a subterranean formation that is located uphole of a hydrocarbon formation, downhole of a hydrocarbon formation, or between separate hydrocarbon formations. In certain embodiments, drill string <NUM> can pass through a cased section of wellbore <NUM> of subterranean well <NUM> in order to reach uncased open hole portion of wellbore <NUM>.

A system for sealing lost circulation zone <NUM> associated with subterranean well <NUM> includes a circulating port to provide downhole fluid circulation. The circulating port provides fluid communication between an inner bore of drill string <NUM> and annular space <NUM>.

Annular space <NUM> is the elongated annular shaped space that extends a length of drill string <NUM> and is defined between an outer diameter surface of drill string <NUM> and an inner diameter surface wellbore <NUM>. During downhole fluid circulation, fluids can flow downhole through the inner bore of drill string <NUM> and uphole through annular space <NUM>. In reverse circulation, fluids can flow downhole through annular space <NUM> and uphole through the inner bore of drill string <NUM>.

In the example embodiment, drill string <NUM> can include circulating sub <NUM>. Circulating sub <NUM> can be a circulating sub known and commonly available in the industry for circulating fluids downhole. Circulating sub <NUM> can include circulating sub port <NUM>, which is a circulating port. Circulating sub port <NUM> extends through a sidewall of circulating sub <NUM> and provides fluid communication between the inner bore of drill string <NUM> and annular space <NUM>. In alternate embodiments, bottom hole assembly <NUM> can include the circulating port.

The system for sealing lost circulation zone <NUM> can be used to seal the entry of cavity <NUM> of lost circulation zone that has a cross sectional dimension X up to <NUM> which cannot be sealed with some currently available lost circulation material. Cavity <NUM> can be, for example, vugular or cavernous faults. Looking at <FIG>, after bottom hole assembly <NUM> has reached or passed through lost circulation zone <NUM>, a combination of lost circulation shape <NUM> and lost circulation material <NUM> can be used to seal cavities <NUM> of lost circulation zone <NUM>.

In the example embodiment of <FIG>, lost circulation shape <NUM> and lost circulation material <NUM> is pumped in a direction downhole through drill string <NUM>, and exits circulating sub port <NUM> to reach annular space <NUM> for delivery to lost circulation zone <NUM>.

Looking at <FIG>, lost circulation shape <NUM> is a hollow body having an outer skin <NUM> that defines the shape of lost circulation shape <NUM> and an open interior chamber. Outer skin <NUM> can have a thickness in a range of <NUM> to <NUM>. Lost circulation shape <NUM> can have a variety of diameters. In general, a smaller diameter lost circulation shape <NUM> can have a smaller thickness of outer skin <NUM> and a larger diameter lost circulation shape <NUM> can have a larger thickness of outer skin <NUM>. In certain embodiments, the thickness of outer skin <NUM> can be directly proportional to the diameter of lost circulation shape <NUM>. In alternate embodiments, when lost circulation shape <NUM> has a larger diameter, lost circulation shape <NUM> can include an internal support structure, such as a web type structure, to provide internal support to outer skin <NUM>.

In the example embodiments shown, lost circulation shape <NUM> is a sphere. In alternate embodiments, lost circulation shape <NUM> can have other three dimensional geometric shapes. As an example, lost circulation shape <NUM> can generally have the shape of a cube, ovoid, egg, hyper rectangle, triangular prism, pyramid, cone, or cylinder.

Lost circulation shape <NUM> can have a sufficient size to seal lost circulation zone <NUM>, without being so large in size that lost circulation shape <NUM> cannot fit through the circulation port. Lost circulation shape <NUM> is sized to flow through the circulation port with a drilling fluid in an unrestricted manner. In certain embodiments, a mix of various sizes of lost circulation shapes <NUM> can be used for sealing cavities <NUM> of various sizes.

In certain embodiments, lost circulation shape <NUM> can be formed in a variety of sizes. The minimum size of lost circulation shape <NUM> is such that the smallest minimum hypothetical sphere in which lost circulation shape <NUM> having the minimum size could fit has a diameter of <NUM>, regardless of the geometric shape of lost circulation shape <NUM>. The maximum size of lost circulation shape <NUM> is such that a smallest maximum hypothetical sphere in which lost circulation shape <NUM> having the maximum size could fit has a diameter of <NUM> regardless of the geometric shape of lost circulation shape <NUM>.

Lost circulation shape <NUM> can be formed of a metal, ceramic, or polymeric material. As an example, lost circulation shape <NUM> could be formed of any of a variety of suitable metallic materials, such as, for example, aluminum, titanium, copper, or nickel. Alternately, lost circulation shape <NUM> could be formed of any of a variety of suitable ceramic materials, such as, for example, gypsum, alumina, zircon, silicon nitride, glass, or silicate. Alternately, lost circulation shape <NUM> could be formed of any of a variety of suitable polymeric materials including plastic, thermoplastic and elastomers, such as, for example, acrylonitrile butadiene styrene (ABS), high-impact polystyrene (HIPS), polypropylene, polyethylene, nylon, acrylic, polyethylene terephthalate (PET), poly carbonate, or polyurethane.

Alternately, lost circulation shape <NUM> can be formed of other materials that are suitable for additive manufacturing, 3D printing, or other appropriate fabrication techniques.

The material used to form lost circulation shape <NUM> can be determined by the drilling application, the selected drilling fluid, and the lost circulation material <NUM> that is to be used for a particular application. In embodiments of this disclosure, lost circulation material <NUM> and lost circulation shape <NUM> can be used to solve a total loss situation where there is no need for removal of lost circulation material <NUM> and lost circulation shape <NUM>. In other embodiments, lost circulation material <NUM> and lost circulation shape <NUM> could be formed of a removable material. As an example, lost circulation material <NUM> and lost circulation shape <NUM> could be formed of aluminum that could be dissolved and removed with an acid treatment.

Outer skin <NUM> of lost circulation shape <NUM> includes a plurality of perforations <NUM> that extend through outer skin <NUM>. Perforations <NUM> provide fluid communication between an exterior of lost circulation shape <NUM> and the open interior chamber of lost circulation shape <NUM>. Perforations <NUM> allow for drilling fluid to enter the open interior chamber of lost circulation shape <NUM>. Because the drilling fluid can pass into and through lost circulation shape <NUM>, minimal hydrostatic forces are applied to lost circulation shape <NUM> downhole. Larger perforations <NUM> will minimize the hydrostatic forces. However, if perforations <NUM> are too large, then lost circulation shape <NUM> will not trap lost circulation material <NUM>. The size, shape, and number of perforations <NUM> can be optimized for each individual application. Alternately, a generic layout of perforations <NUM> can be developed with the size, shape, and number of perforations selected to function in a variety of subterranean wells <NUM>.

Perforations <NUM> are sized to prohibit the passage of lost circulation material <NUM> between the exterior of lost circulation shape <NUM> and the open interior chamber of lost circulation shape <NUM>. Perforations <NUM> are sized to trap lost circulation material <NUM> within lost circulation zone <NUM>, forming a seal within lost circulation zone <NUM>. As an example, perforations <NUM> can have dimensions that are smaller in size than lost circulation material <NUM> (<FIG>). Alternately some commonly available lost circulation material <NUM> is capable of sealing cavities <NUM> that have a dimension larger than the size of lost circulation material <NUM>. In certain embodiments the maximum size of perforations <NUM> will be smaller than the maximum bridging limitation of lost circulation material <NUM>. In such embodiments the maximum size of perforations <NUM> can be larger than the size of lost circulation material <NUM> so that some lost circulation material <NUM> pass through perforations <NUM> before lost circulation material <NUM> bridges across lost circulation shape <NUM>. Performance data can be obtained relating to the capabilities of currently available lost circulation material <NUM>. Such performance data can include the size of cavities that can be sealed with such lost circulation material. The performance data for a selected lost circulation material can be referenced for determining a suitable size of perforations <NUM>.

In the example of <FIG> perforations <NUM> through outer skin <NUM> of lost circulation shape <NUM> are diamond shaped. In the Example of <FIG>, perforations <NUM> through outer skin <NUM> of lost circulation shape <NUM> are circular. When perforations <NUM> are circular perforations <NUM> can have, for example, a size in a range of <NUM> to <NUM> in diameter. In alternate embodiments perforations <NUM> can have other shapes. For example purposes only, perforations <NUM> can be shaped as squares, hexagons, pentagons, triangles, rectangles, diamonds, circles or combinations of any of these shapes. The size, shape, and spacing of perforations <NUM> can be selected for optimized performance with a selected lost circulation material <NUM> (<FIG>). If the number of perforations <NUM> is large enough that the structural integrity of lost circulation shape <NUM> is compromised, then structural members may be added within the open interior chamber of lost circulation shape <NUM>.

Looking at <FIG>, lost circulation shape <NUM> further includes filling hole <NUM>. Filling hole <NUM> extends through outer skin <NUM>. Filling hole <NUM> has a diameter in a range of <NUM> to <NUM>. Filling hole <NUM> facilitates the filling of the open interior chamber with drilling fluid. In certain embodiments, the filling of lost circulation shape <NUM> could be assisted by holding the lost circulation shape under vacuum and then introducing drilling fluid. Alternately, a pressure can be applied instead of a vacuum for filling the open interior chamber with drilling fluid. Using a vacuum or pressure would be most useful when perforations <NUM> are sufficiently small that drilling fluid does not travel easily into the open interior chamber. Using a vacuum or pressure can overcome surface tension that could prevent the open interior chamber from filling with drilling fluid before lost circulation shape <NUM> is circulated downhole through drill string <NUM>.

The density of lost circulation shape <NUM> together with the presence of drilling fluid within the open interior chamber of lost circulation shape <NUM> allow lost circulation shape <NUM> to have generally neutral buoyancy within the drilling fluid. As used in this disclosure, a generally neutral buoyancy means that the lost circulation shapes will flow with the drilling fluid and will not tend to sink or rise relative to the movement of the drilling fluid.

Because of the drilling fluid located within the open interior chamber of lost circulation shape <NUM>, the average lost circulation shape density does not need to be absolutely equal to the drilling fluid density that is carrying lost circulation shape <NUM>. The lost circulation shape <NUM> can be carried by the drilling fluid free of excessive sinking or rising of lost circulation shape <NUM> relative to the movement of the drilling fluid if an average lost circulation shape density is near to the density of the drilling fluid. As an example, in certain embodiments the difference between the average lost circulation shape density and the drilling fluid density is <NUM>% or less of the drilling fluid density. In alternate example embodiments, the difference between the average lost circulation shape density and the drilling fluid density is <NUM>% or less of the drilling fluid density.

For the sake of clarity, as an example, a drilling fluid density of some currently available drilling fluid can range from <NUM>/m<NUM> to <NUM>/m<NUM> (<NUM> pounds per gallon (ppg) to <NUM> ppg). If a drilling fluid with a density of <NUM>/m<NUM> (<NUM> ppg) is used, then <NUM>% of <NUM>/m<NUM> (<NUM> ppg) is <NUM>/m<NUM> (<NUM> ppg). In this example embodiment, if the difference between the average lost circulation shape density and the drilling fluid density is <NUM>% or less of the drilling fluid density, then the average lost circulation shape density can be in a range of <NUM>/m<NUM> to <NUM>/m<NUM> (<NUM> ppg to <NUM> ppg).

A mixture of both lost circulation shape <NUM> and lost circulation material <NUM> is used to seal lost circulation zone <NUM>. If some currently available lost circulation material only was used (with no lost circulation shape <NUM>), the lost circulation material could flow into and out of cavities <NUM> without forming a seal. Some commonly used currently available lost circulation material would be too small relative to the cross sectional dimension X of cavity <NUM> for such lost circulation material to effectively and dependably seal lost circulation zone <NUM>. If lost circulations shapes <NUM> were used alone, it is possible that with a sufficient number of lost circulations shapes <NUM> that eventually lost circulation zone <NUM> could be sealed. However, because perforations <NUM> through outer skin <NUM> could continue to allow for the flow of fluids into and out of the open interior chamber of lost circulation shapes <NUM>, lost circulation would therefore only be somewhat restricted.

Looking at <FIG>, lost circulation material <NUM>, and lost circulation shape <NUM> are used together and pumped into cavity <NUM>. Looking at <FIG>, by using both lost circulation shape <NUM> and lost circulation material <NUM>, lost circulation shape <NUM> can be sized to be wedged into cavities <NUM> of lost circulation zone <NUM>, forming a wedged lost circulation shape. With lost circulation shape <NUM> constrained within lost circulation zone, loss flow will continue through perforations <NUM>. Due to the small size of perforations <NUM>, lost circulation material <NUM> will collect and within and on the outer surfaces of lost circulation shape <NUM>. Lost circulation material <NUM> can be trapped by the wedged lost circulation shape to seal lost circulation zone <NUM>. Lost circulation material <NUM> will collect and bridge and cause a total plug and consequent pressure seal. During such process, lost circulation shape <NUM> may be deformed, collapse, or be crushed due to well bore pressure acting on the formation. Such pressure will force lost circulation shape <NUM> and lost circulation material <NUM> further into cavities <NUM>, thereby giving a fully anchored seal. In alternate embodiments, lost circulation shape <NUM> may not be deformed, collapse or be crushed, but maintain its original <NUM>-dimensional structure.

In an example of operation and looking at <FIG>, lost circulation shape <NUM> and lost circulation material <NUM> are circulated downhole through drill string <NUM> with drilling fluid. The drilling fluid can be formulated for the particular conditions of wellbore <NUM>. The drilling fluid can be, for example, a water based mud, an oil based mud, or a synthetic based mud.

Lost circulation shape <NUM> and lost circulation material <NUM> can be introduced into drill string <NUM> at surface <NUM> and can exit drill string <NUM> through circulating sub port <NUM>. Because lost circulation shape <NUM> is generally neutrally buoyant in the drilling fluid, the pumping time required for delivering lost circulation material <NUM> to lost circulation zone <NUM> can be calculated by volume displacement methods, which is well understood in the art of circulating fluids in wellbores.

During the process of delivering lost circulation shape <NUM> and lost circulation material <NUM> downhole, if drilling operations could continue for a process that used only the lost circulation material <NUM>, this process would not change with the addition of lost circulation shape <NUM>. Therefore, embodiments for delivering the lost circulation shape <NUM> and lost circulation material <NUM> downhole could be undertaken while drilling operations continue and without having to remove drill string <NUM> from wellbore <NUM>. The addition of lost circulation shape <NUM> may not otherwise change the lost circulation sealing procedure.

Looking at <FIG> and <FIG>, lost circulation shape <NUM> and lost circulation material <NUM> enter cavity <NUM>. Looking at <FIG> and <FIG>, lost circulation shape <NUM> can become wedged within cavity <NUM>. Looking at <FIG> and <FIG>, as drilling fluid continues to pass through lost circulation shape <NUM>, lost circulation material <NUM> can become lodged in or against lost circulation shape <NUM> until a complete formation fault pressure seal is obtained. As lost circulation shape <NUM> is trapped and lost circulation zone <NUM> becomes blocked this will result in a pressure differential creation across the blockage formed by lost circulation shape <NUM> due to the drilling overbalance hydrostatic pressure.

In the example embodiments of <FIG> and <FIG>, lost circulation shape <NUM> has deformed, collapsed or been crushed within cavity <NUM>. A crushed lost circulation shape <NUM> could potentially trap lost circulation material more quickly than uncrushed lost circulation shape <NUM>. In addition, a crushed lost circulation shape <NUM> could potentially become lodged deeper into cavity <NUM>, providing a more secure seal of lost circulation zone <NUM> (<FIG>).

Lost circulation shape <NUM> is sized to be wedged into cavities <NUM> of lost circulation zone <NUM>, forming a wedged lost circulation shape. Lost circulation material <NUM> is then trapped by the wedged lost circulation shape to seal lost circulation zone <NUM>.

Claim 1:
A system for sealing a lost circulation zone (<NUM>) associated with a subterranean well (<NUM>), the system including:
a lost circulation material (<NUM>); and
a lost circulation shape (<NUM>), the lost circulation shape (<NUM>) being a hollow body having an outer skin (<NUM>) and an open interior chamber, where the outer skin (<NUM>) includes a plurality of perforations (<NUM>) that extend through the outer skin (<NUM>), providing fluid communication between an exterior of the lost circulation shape (<NUM>) and the open interior chamber;
the lost circulation shape (<NUM>) has a minimum size and a maximum size, where:
the minimum size of the lost circulation shape (<NUM>) is such that a smallest minimum sphere in which the lost circulation shape (<NUM>) having the minimum size could fit has a diameter of <NUM>; and
the maximum size of the lost circulation shape (<NUM>) is such that a smallest maximum sphere in which the lost circulation shape (<NUM>) having the maximum size could fit has a diameter of <NUM>;
characterized in that:
the plurality of perforations (<NUM>) are sized to prohibit a passage of lost circulation material (<NUM>) between the exterior of the lost circulation shape (<NUM>) and the open interior chamber; and
the lost circulation shape (<NUM>) includes a filling hole (<NUM>), the filling hole (<NUM>) extending through the outer skin (<NUM>) and having a diameter in a range of <NUM> to <NUM>.