Patent Application
20190316459
To perform hydraulic fracturing operations, frac-balls are deployed into an oil well and pumped downhole to seal into frac-valves for zonal isolation so that a target zone can be fractured by pressure pumping appropriate fracking fluids from surface pumps alongside proppants to prevent fracture closure. Conventional frac-balls can be damaged as they are pumped downhole due to the pumped fluid's high velocity in transporting the ball downhole and the ball's own momentum. The damage can cause water hammer effects as the ball impacts onto the valve to abruptly block the flow of the fracking fluid being pumped from the surface. Water hammer effects can produce damaging high-pressure spikes above the hydraulic fracturing valve or the zonal isolation device and falling pressure spikes below the valve. These pressure spikes and abrupt changes in fluid momentum may cause hydraulic and mechanical shock waves to travel along the tubing string resulting in kinking of the tubing, unsetting of a previously set packer, or other types of damage or malfunctions to the well's apparatus, the well's integrity, or damage to the formation itself. Although there have been developments in valve and plug apparatus, unfortunately, they have not adequately addressed the risks from uncontrolled impact of the ball onto the valve, including risks from mechanical shocks or water hammer effects. Consequently, the risks and costs, both in terms of time and money, of such accidents can be considerable.
Various features of the present disclosure are described herein. To solve the problem of removing the frac-ball to restore flow after the frac operation is completed, various degradable or disintegrable frac-ball materials and their combinations have been used in the prior art; however, the prior art does not address the novel approach disclosed by the present disclosure that achieves the useful mechanical properties and functions required to (1) perform zonal isolation while minimizing mechanical damage due to water hammer effects, (2) measure pressure and temperature data during wellbore stimulation, (3) post stimulation allowing near full bore opening by having the outer water reactive shell dissolve (4) superior predictability of dissolution compared with other offerings (5) release gauge carrier and sensor package, and (6) flow-back of sensor package to surface, enabling retrieval of pressure and temperature data during hydraulic fracturing and analysis to provide valuable information to client.
Embodiments of the present disclosure are directed to a gauge carrier, comprising a ball having an interior volume, an aperture, and a sensor positioned in the interior volume of the ball. The sensor has a sensing surface positioned in the aperture with the sensing surface exposed through the aperture. The gauge carrier also includes a shell configured to substantially surround the ball and to permit fluid to pass through the shell and reach the ball such that the sensor is in physical contact with fluid when the gauge carrier is submerged in the fluid. The shell is made of a dissolvable material, the ball and sensor together are buoyant in water at atmospheric pressure, and the gauge carrier is capable of withstanding hydrostatic pressure of greater than 10,000 psi.
Further embodiments of the present disclosure are directed to a method of obtaining a pressure and temperature profile in a well, including pumping a gauge carrier downhole, the gauge carrier having a sensor and a memory positioned within a ball, wherein the ball and sensor are together buoyant in water at atmospheric pressure, the gauge carrier also having a dissolvable shell. The method also includes upon reaching a desired depth in the well, triggering the dissolvable shell to dissolve, leaving the ball and sensor to float back to surface, and recording data for at least a portion of the time the gauge carrier is in the well.
Still further embodiments of the present disclosure are directed to a method of forming a material comprising forming an alloy from a major constituent and a minor constituent wherein the minor constituent is a rare earth material, adding powder elements to lower stacking fault energy to promote twinning, adding hardeners to promote precipitation to promote strain hardening, and performing post-processing to introduce basal plane surface faults and to homogenize strain hardening.
Below is a detailed description according to various embodiments of the present disclosure. Embodiments of the present disclosure are directed to the design methodology for a sensor pressure housing to cradle a pressure gauge and memory. In some embodiments, the present disclosure is directed to intelligent material selection and fabrication processes that enable deployment into a wellbore to close a prepositioned frac-plug with a diminished water hammer effect that can damage the frac-valve, damage the tubing string, or unintentionally unset packers or other equipment in the well. The hollow frac-ball is comprised of special alloy materials in a geometry that achieves high strength and ductility with tailorable specific gravity so that the ball's movement downhole and its gentler impact onto the frac-valve can be controlled by surface pumping. In addition, the frac-ball's properties include not only activating, or closing, the valve but also being dissolvable or water reactive to achieve timed and controlled disintegration after completion of the fracking or other downhole operation for which the frac-ball was instrumental, for example as in activating a frac-plug, bridge plug, packer, or flow control device.
The apparatuses, systems, and methods of the present disclosure can be designed using novel alloys which can last in a target environment from days to months and even years, as needed. They are able to successfully work in environments which can include fresh water, complex brines with varying anions and cations to up to point of saturation, inhibited acid or linear, crosslinked gels/fiber containing stimulation fluids, wherein pH of fluid can be very acidic (<1) to very alkaline (>11). The alloy is created using one or more of (1) ingot metallurgy (cast and extrusion), (2) metal matrix composite (ceramic dispersoids of various form factors in monolithic to solid solution or multi-phase metal matrix), and (3) power metallurgy (severe plastic deformation, such as cryogenic milling of powder, equal channel angular processing (ECAP) of solid, high pressure torsion of plates, gradient torsion of tubes, general forging machine operations to cold work alloys, flow-forming and pilgering of tubulars to refine grains, etc.)
At 16 hardeners can be added to promote precipitation which will further strain hardening. The hardeners can include Zr or other suitable hardeners which will promote precipitation. The hardeners can be between 0.1-10% by weight. At 18 post processing can be performed, including hot rolling, extrusion, hot forging, or any other suitable hot or cold process. The post processing procedures introduce basal plane surface faults and helps to homogenize strain hardening. Post-processing can include casting a billet to greater than 50% reduction via extrusion. The reduction ratio can be between 25-100,000% or more. Surface faults on basal planes are expected to impede dislocation movement and augment strength and ductility of HCP Mg alloy similar to twinning of FCC metals and alloys. To be noted that as dislocations slip and encounter SF boundaries, they can either (1) cut or interact with SFs' and facilitate plastic deformation or (2) accumulate around SF boundaries and accommodate strain hardening. At 20 the material can be machined using a lathe, mill, or other suitable machining techniques. The resulting material will have sufficient hardness and is sufficiently lightweight to be remarkably pressure-resistant and yet still buoyant in water at standard well pressure values.
Another route to produce a material with the desired properties is the metal matrix composite route in which initially the material is in a powder form before adding rare earth powders. Any rare earth material can be used, including Gd, Y, Sc, La, Ce, Ne, or others. The rare earth fraction can be between 5-25% by weight. The metal matrix composite route can include bulk metallic glass powder(s) (BMGs) routes, including ceramic and BMG dispersoids of various form factors in monolithic to solid solution or multiphase metal matrix. From this point forward the process can be similar to that described in the ingot metallurgy route. At 12 powder elements can be added to lower stacking fault (SF) energy of the alloy. One possible powder element is Ag which lowers the SF energy of the alloy. This material can be referred to as the SF-reducing element or the powder element. In some embodiments the SF-reducing constituent can be between 1-25% by weight. In some embodiments the powder element can be added during degassing. This process may promote twinning of the material.
At 16 hardeners can be added to promote precipitation which will further strain hardening. The hardeners can include Zr or other suitable hardeners which will promote precipitation. The hardeners can be between 0.1-10% by weight. At 18 post processing can be performed, including hot rolling, extrusion, hot forging, or any other suitable hot or cold process. The post processing procedures introduce basal plane surface faults and helps to homogenize strain hardening. Post processing can include casting a billet to greater than 50% reduction via extrusion. The reduction ratio can be between 25-100,000% or more. Surface faults on basal planes are expected to impede dislocation movement and augment strength and ductility of HCP Mg alloy similar to twinning of FCC metals and alloys. To be noted that as dislocations slip and encounter SF boundaries, they can either (1) cut or interact with SFs' and facilitate plastic deformation or (2) accumulate around SF boundaries and accommodate strain hardening. At 20 the material can be machined using a lathe, mill, or other suitable machining techniques. The resulting material will have sufficient hardness and is sufficiently lightweight to be remarkably pressure-resistant and yet still buoyant in water at standard well pressure values.
Yet another route to achieve acceptable properties in the material is a powder metallurgy route in which a metal powder is subjected to severe plastic deformation such as by combustion or another suitable method of combining the powder metals with other constituents. The powder metals are combined with rare earth materials in a way similar to what is described above with reference to the ingot metallurgy route and the metal matrix composite route. For example, At 12 powder elements can be added to lower stacking fault (SF) energy of the alloy. One possible powder element is Ag which lowers the SF energy of the alloy. This material can be referred to as the SF-reducing element or the powder element. In some embodiments the SF-reducing constituent can be between 1-25% by weight. In some embodiments the powder element can be added during degassing. This process may promote twinning of the material.
At 16 hardeners can be added to promote precipitation which will further strain hardening. The hardeners can include Zr or other suitable hardeners which will promote precipitation. The hardeners can be between 0.1-10% by weight. At 18 post processing can be performed, including hot rolling, extrusion, hot forging, or any other suitable hot or cold process. The post processing procedures introduce basal plane surface faults and helps to homogenize strain hardening. Post processing can include casting a billet to greater than 50% reduction via extrusion. The reduction ratio can be between 25-100,000% or more. Surface faults on basal planes are expected to impede dislocation movement and augment strength and ductility of HCP Mg alloy similar to twinning of FCC metals and alloys. To be noted that as dislocations slip and encounter SF boundaries, they can either (1) cut or interact with SFs' and facilitate plastic deformation or (2) accumulate around SF boundaries and accommodate strain hardening. At 20 the material can be machined using a lathe, mill, or other suitable machining techniques. The resulting material will have sufficient hardness and is sufficiently lightweight to be remarkably pressure-resistant and yet still buoyant in water at standard well pressure values.
In some embodiments the material can be created to be dissolvable when subjected to certain conditions. In some embodiments this is achieved by introducing noble granules to the material. This can be done at several different stages of the process. The noble granules render the material dissolvable by introducing failure vectors in the material. When the material is exposed to an environment having the right salinity, pressure, and other chemical properties, the material will dissolve. Accordingly the material can be selectively made to dissolve or not to dissolve as desired. The environment in which the material dissolves can be chosen by altering certain properties of the material and the noble granules. For example, a material with high rate of corrosion (ROC) designed via tailoring the amount of noble particles in metal matrix can be triggered at room temperature in tap water or water with 2500 ppm dissolved salts. On the other hand, materials with low ROC needs elevated temperature in combination with salinity equivalent to sea water or as high as 22% (near saturated or saturated brine) salts to trigger dissolution.
The foregoing disclosure hereby enables a person of ordinary skill in the art to make and use the disclosed systems without undue experimentation. Certain examples are given to for purposes of explanation and are not given in a limiting manner.
