The present disclosure relates generally, to systems, methods, devices, and compositions usable within a wellbore, and more specifically, to systems and methods for fracturing a formation using materials that are ingestible by humans to stimulate production (e.g., of hydrocarbons) therefrom.
To stimulate and/or increase the production of hydrocarbons from a well, a process known as fracturing is performed. In brief summary, a pressurized fluid—often water—is pumped into a producing region of a formation at a pressure sufficient to create fractures in the formation, thereby enabling hydrocarbons to flow from the formation with less impedance. Solid matter, such as sand, ceramic beads, and/or similar particulate-type materials, can be mixed with the fracturing fluid, this material generally remaining within the fractures after the fractures are formed. The solid material, known as proppant, serves to prevent the fractures from closing and/or significantly reducing in size following the fracturing operation, e.g., by “propping” the fractures in an open position. Some types of proppant can also facilitate the formation of fractures when pumped into the formation under pressure. While the presence of proppant in the fractures can hinder the permeability of the formation, e.g., by impeding the flow of hydrocarbons toward the wellbore, the increased flow created by the propped fractures normally outweighs any impedance caused by the proppant. The materials being transported into a formation for the purposes of fracturing may be referred to as “fracturing material.” The fracturing material may comprise any material that is being transported into a formation for fracturing purposes, and may include fluids, gasses, solids, or combinations thereof.
Fracturing using aqueous fluids is often undesirable due to the negative effects of water on the formation. For example, clays and other formation components can swell when exposed to water, while salts and other formation components may dissolve, such that exposure to a significant quantity of water can destabilize a formation. Use of water and other aqueous fluids also generates issues regarding disposal. Specifically, aqueous fracturing fluid recovered from a well (e.g., subsequent to a fracturing operation) contains various wellbore fluids and other chemicals (e.g., additives to facilitate fracturing using the fluid), and as such, the recovered fracturing fluid must be collected and stored at the surface and disposed of in an environmentally acceptable manner, as required by numerous regulations. Such a process can add considerable time and expense to a fracturing operation.
Non-aqueous fracturing fluids have been used as an alternative, one such successful class including hydrocarbon-based fluids (e.g., crude/refined oils, methanol, diesel, condensate, liquid petroleum glass (LPG) and/or other aliphatic or aromatic compounds). Hydrocarbon-based fracturing fluids are inherently compatible with most reservoir formations, being generally non-damaging to formations while creating acceptable fracture geometry. However, due to the flammability of hydrocarbon-based fluids, enhanced safety preparations and equipment are necessary when using such fluids for wellbore operations. Additionally, many hydrocarbon-based fluids are volatile and/or otherwise unsuitable for use at wellbore temperatures and pressures, while lacking the density sufficient to carry many types of proppant. As such, it is common practice to use chemical additives (e.g., gelling agents, viscosifiers, etc.) to alter the characteristics of the fluids. An example a system describing use of liquid petroleum gas is described in U.S. Pat. No. 8,408,289, which is incorporated by reference herein in its entirety. Use of chemical additives generates waste and disposal issues similar to those encountered when performing fracturing operations using aqueous fluids.
Embodiments usable within the scope of the present disclosure include systems usable for stimulating a formation (e.g., by forming fractures therein), such as through the provision of pressurized fluid to the formation through a wellbore. A fluid supply system, adapted to provide a fluid (e.g., a fracturing fluid, such as propane, other alkanes, halogenated hydrocarbons, other hydrocarbons, or any other fracturing fluid, such as water) can be provided in fluid communication with the formation. A power subsystem that includes one or more pumps (e.g., high pressure pumps, usable for fracturing operations) in communication with the fluid can be used to pressurize the fluid to a pressure sufficient to stimulate the formation. In an embodiment, a proppant addition system can be used to provide solid material (e.g., proppant, such as sand, ceramic, beads, glass bubbles, crystalline materials, or any other solid and/or particulate matter usable to maintain fractures in a formation) into the fluid.
In addition to the one or more pumps, the power subsystem can include an electric-powered driver (e.g., an electric motor) communicating with and actuating the pump(s), and an electrical power source (e.g., a turbine-powered generator, a grid power source, and/or another source of AC or DC power), in communication with and powering the electric-powered driver. Alternatively or additionally, a generator can be powered using reciprocating engines (e.g., diesel engines) without departing from the scope of the present disclosure. A single pump can be actuated using a single electric-powered driver or multiple electric-powered drivers, and multiple pumps can be actuated using a single electric-powered driver or multiple electric-powered drivers. Similarly, a single power source can power one or multiple electric-powered drivers, or one or multiple electric-powered drivers can be powered by multiple power sources. In an embodiment, the power subsystem can be adapted for simultaneous or selective/alternative use of an on-site power source, such as a generator powered by a natural gas turbine, or a grid power source (e.g., power lines or similar conduits associated with a remote power source).
One or more transformers can be used to alter voltage from the power source to a voltage suitable for powering the electric-powered drivers. One or more variable frequency drives (“VFD(s)”) can be provided in communication with the transformer(s) and respective electric-powered drivers.
The novel features believed characteristic of the disclosed subject matter will be set forth in the claims portion of this document. The disclosed subject matter itself, however, as well as a further objectives and advantages thereof, will best be understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying FIGURES, wherein:
One or more embodiments are described below with reference to the listed Figures.
Reference now should be made to the FIGURES, in which the same reference numbers are used throughout the different FIGURES to designate the same components.
Before describing selected embodiments of the present subject matter in detail, it is to be understood that the present subject matter is not limited to the particular embodiments described herein. The disclosure and description herein is illustrative and explanatory of one or more presently preferred embodiments of the invention and variations thereof, and it will be appreciated by those skilled in the art that various changes in the design, organization, order of operation, means of operation, equipment structures and location, methodology, and use of mechanical equivalents may be made without departing from the spirit of the embodiments.
As well, it should be understood the drawings are intended illustrate and plainly disclose presently preferred embodiments of the invention to one of skill in the art, but are not intended to be manufacturing level drawings or renditions of final products and may include simplified conceptual views as desired for easier and quicker understanding or explanation of the subject matter. As well, the relative size and arrangement of the components may differ from that shown and still operate within the spirit of the invention as described throughout the present application.
Moreover, it will be understood that various directions such as “upper”, “lower”, “bottom”, “top”, “left”, “right”, and so forth are made only with respect to explanation in conjunction with the drawings, and that the components may be oriented differently, for instance, during transportation and manufacturing as well as operation. Because many varying and different embodiments may be made within the scope of the inventive concept(s) herein taught, and because many modifications may be made in the embodiments described herein, it is to be understood that the details herein are to be interpreted as illustrative and non-limiting.
The disclosure provides methods and systems including the use of human ingestible materials as forming a slurry used to fracture a hydrocarbon formation in a hydraulic fracturing stimulation process. Previous practices incorporate numerous chemicals and toxic products into the fracturing process which, although can be done safely, still pose a hazard to workers, communities, and the environment.
The art of fracturing since its inception has consisted of adding chemicals to the base fluid to viscosify the fluid along with adding a solid material to provide a bridging or propping method to keep the fracture open post treatment. Even as the science of fracturing has progressed, the use of chemicals and proppants not fit for human consumption still remains common and numerous.
Method 100 may include storing 110 fracturing fluid comprising HPF under pressure at the well location to maintain the HFP in a liquid state.
Method 100 may include transferring 120 HPF under pressure via boost pump to high pressure fracturing pumps. In an embodiment, fracturing fluid may consist of HFP without added chemical agents.
Method 100 may include storing 130 mesoporous silica proppant in a suitable container at the well location.
Method 100 may include feeding 140 mesoporous silica proppant from a storage vessel. In an embodiment, the proppant may be transferred into an auger which aids in transferring it into the fluid stream. In an embodiment, the feeding 140 may include gravity feeding.
Method 100 may include mixing 150 HFP fracturing fluid and mesoporous silica proppant to form a slurry. In an embodiment, the mixing 150 may be upstream of high pressure fracturing pumps.
Method 100 may include elevating 160 the pressure of the slurry, such as via operation of high pressure pumps, to a pressure sufficiently high to fracture the formation.
In an embodiment, a fracturing method 100 may satisfy requirements for preservation of the environment and human safety. Eliminating the use of water and chemicals may alleviate concerns associated with other processes for stimulating low permeability hydrocarbon reservoirs. Utilizing an approved human ingestible proppant material may eliminate or substantially reduce hazards associated with other proppant materials. For example, some proppant materials have been identified to cause silicosis when inhaled and thus require extensive use of personal breathing safety apparatuses. In an embodiment, the density of the proppant may be matched to the fracturing fluid to enable improved proppant transport by providing desired proppant buoyancy. In an embodiment, providing desired proppant buoyancy may substantially eliminate or abolish settling problems and enable or create long effective propped fractured lengths.
Embodiments may include using a non-toxic binary system utilizing both a fracturing fluid and proppant which are approved for human ingestion and use in the drug delivery field. Reducing the health, safety, and environmental risk can enable the safe and effective practice of fracturing in areas where previous techniques may pose unacceptable risks to community health or the environment or violating regulations. An advantage of embodiments may be delivering better well performance/economics while substantially eliminating health risks associated with previous practices.
The present disclosure provides a human ingestible proppant that may substantially eliminate or reduce the hazards associated with conventional sand or silica based proppants. In an embodiment, a human ingestible proppant may, when ingested, break down by endocytosis and/or enzymatic processes which may render the proppant harmless to a living being. In embodiments, such a human ingestible proppant may comprise a specific gravity of less than 1.50, which, in an embodiment, may be attributed to a mesoporous internal structure of the proppant. In embodiments, the proppants may vary in shape and size. In embodiments, use of a proppant material may substantially eliminate hazards associated with conventional sand or silica based proppants. As used herein, a human ingestible proppant material may include a material of such nature which when ingested into the human body will be broken down by endocytosis and/or enzymatic processes without harm to the person. In an embodiment, a human ingestible proppant may be inert to the conditions encountered when used as a propping material to stimulate a subterranean oil and/or gas reservoir. In an embodiment, a human ingestible proppant may have a density or specific gravity less than 1.50. In an embodiment, such a proppant may have a mesoporous internal structure of the proppant. It will be understandable that a proppant, as herein disclosed, may have various shapes and sizes.
Previous proppants used to stimulate subterranean oil and/or gas reservoirs include native mined crystalline sand grains and/or man-made ceramic products. Due to numerous factors in the transportation of the sand from the mine to the fracturing site, a meaningful percentage of the crystalline sand grains become damaged creating a hazardous crystalline dust. This crystalline dust is a known health hazard causing silicosis and is described as such by the US Occupational Safety and Health Administration in a fact sheet, as follows: “Crystalline silica dust can cause silicosis, which in severe cases can be disabling, or even fatal. The respirable silica dust enters the lungs and causes the formation of scar tissue, thus reducing the lungs' ability to take in oxygen. There is no cure for silicosis. Since silicosis affects lung function, it makes one more susceptible to lung infections like tuberculosis.”
Typical man-made ceramic proppants include materials such that their densities become even greater than that of conventional sand (2.65 g/cc). In low viscosity fracturing fluids this may be a detriment, at least in part because greater the difference in density between the fluid and the proppant results in proppant settling becoming more pronounced as defined by Stokes Law:
Vertical Settling Rate=(g(Density of Proppant−Density of the Frac Fluid)(Proppant Dia)
̂2)/(18(Fluid Viscosity))
This disclosure provides a human ingestible proppant material sufficient for transport of the proppant along a fracture to prop it open. Such a proppant material may have physical properties that may eliminate unacceptable environmental and health dangers. Embodiments may provide improved well performance/economics while also substantially eliminating health risks and environmental risks associated with previous practices.
The hydrocarbon well system 300 may comprise a wellbore 110 and formation fractures in a formation region 320 produced by stimulating the formation region with a human ingestible slurry comprising a fluid and a proppant. In embodiments, the fluid may be HFP. In embodiments, the proppant may be mesoporous silica.
Similar cellular mechanics are involved in “phagocytosis” (fag “o-si-to’ sis) which is the engulfing of microorganisms or other cells or larger foreign particles by phagocytes, sometimes call “scavenger cells” or “carrier cells” which are prevalent throughout the body.
Phagocytes ingest and kill microbes, present foreign body antigens to lymphocytes, scavenge degenerating material, and release mediators. Classes of phagocytes may include: 1) microphages, which are polymorphonuclear leukocytes that ingest chiefly bacteria; 2) macrophages, which are mononucleated cells (histiocytes and monocytes) that are largely scavengers, ingesting dead tissue and degenerated cells and particulate matter. In embodiments, the slurry and/or particles comprised in the slurry may be ingested and/or destroyed by phagocytes.
The first medium addition subsystem 510 will require the use of pressure vessels and pumps configured to receive pre-pressurized fluids.
The low vapor pressure hydrocarbon-based fracturing fluids being pumped through the second medium addition subsystem 540 will be capable of transporting proppant more effectively and with less damage to the system 500 than if the second medium addition subsystem 540 were dealing with high vapor pressure materials. This is due to the higher viscosities of the lower vapor pressure materials.
The proppant addition system 570 is configured to allow for an operator to vary the amount of proppant being added per unit volume of the carrier medium. Similarly, the medium mixing system 540 is configured to allow the operator to vary the amount of the first medium relative to the amount of the second medium that is introduced to the formation. These controls allow the operator to tailor the end fracturing fluid being pumped into the formation to the formation itself and the effects the operator desires inducing in the formation.
In an embodiment, a suitable fracturing fluid may include, or may consist of, a mixture of naturally occurring components of conventional and unconventional hydrocarbons. In an embodiment, a suitable fracturing fluid may include, or may consist of, a selected mixture of low molecular weight alkanes or light alkanes referred to as ‘baby oil” in common language as the stimulation or hydraulic fluid. In an embodiment, a suitable fracturing fluid may include a mixture of light alkanes suitable for use in LAS (Light Alkanes Stimulation), a subset of odorless, colorless technical grade organic oils described in the classifications and/or standards of U.S. Department of Agriculture, U.S. Occupational Safety and Health Administration, U.S. Food and Drug Administration, U.S. Pharmacopeial Convention, NF, BP, DAB, EuP, Japanese, and other pharmacopoeias.
In an embodiment, a suitable mixture of light alkanes usable in LAS excludes very low molecular weight alkanes such as natural gas, LPGs, and heavier alkanes. Such excluded heavier alkanes may be solids and may possess different chemical characteristics.
Because light alkanes already exist within a reservoir, using them as a stimulation fluid may not damage the reservoir rock and may therefore allow increased production from the well compared with traditional hydraulic fracturing. Light alkanes can also be self-supplied from the reservoir being stimulated. Additionally, light alkanes can be recycled through the reservoir and recovered for further use (in the same way as for propane and heptafluoropropane).
In an embodiment, a suitable fracturing fluid, as herein disclosed, may omit water and any chemical additives. In an embodiment, a fracturing fluid, as herein disclosed, may include a mixture of light alkanes that is supplied from stimulated reservoirs and recovered for reuse. In an embodiment, a suitable fracturing fluid, as herein disclosed, may be a nonflammable mixture of light alkanes having a low vapor pressure and a high flash point. In an embodiment, a suitable fracturing fluid, as herein disclosed, may be non-toxic and approved for use in food preparation, such as personal care products and cosmetics approved by appropriate regulatory agencies such as the FDA. In an embodiment, a suitable fracturing fluid, as herein disclosed, may not deplete atmospheric ozone or may not contribute to global warming. In an embodiment, a suitable fracturing fluid, as herein disclosed, may be used in light alkane stimulation (LAS) systems and methods.
In embodiments, routes of ingestion of the human ingestible materials may include, but are not limited to, inhalation with pulmonary placement, all alimentary routes, contact with the integument, and intravenous injection, such as is the case with meso-porous amorphous silica.
In embodiments, the human ingestible materials may be approved, or may have the possibility of being approved, for human ingestion by regulatory authorities and agencies such as, but not limited to, the U.S. Food and Drug Administration, the U.S. Pharmacopeial Convention, the U.S. Department of Agriculture, the U.S. Occupational Safety and Health Administration, NF, BP, DAB, EuP, Japanese, and other pharmacopoeias worldwide. Even though the human ingestible material may be approved by the aforementioned regulators, the human ingestible materials may include toxicity.
In embodiments, the human ingestible materials may be nearly absent toxicity of any kind.
In embodiments, the human ingestible materials may be ingested via inhalation with pulmonary placement, all alimentary routes, contact with the integument, and intravenous injection; may be approved for human ingestion by regulatory authorities and agencies (such as those listed above); and may be nearly absent toxicity of any kind.
In embodiments, the human ingestible materials may be handled and deployed by almost all existing hydraulic fracturing equipment. In embodiments, existing hydraulic fracturing equipment may be modified with specific gaskets and/or O-rings.
In embodiments, the human ingestible materials may be at least one mineral oil.
In embodiments, the human ingestible materials may comprise amorphous silica.
In embodiments, the human ingestible materials may comprise boron laced amorphous silica.
In embodiments, the human ingestible materials may comprise meso-porous amorphous silica.
In embodiments, the human ingestible materials may comprise boron laced meso-porous amorphous silica.
It is noted that any of the aforementioned proppants may be utilized in combination with HFP and/or light alkanes.
For the purposes of this disclosure, the term “low molecular weight alkanes” refers to the subset of odorless colorless technical grade organic oils as described in the classifications and/or standards of U.S. Department of Agriculture, U.S. Occupational Safety and Health Administration, U.S. Food and Drug Administration, U.S. Pharmacopeial Convention, NF, BP, DAB, EuP, Japanese, and other pharmacopoeias worldwide.
While various embodiments usable within the scope of the present disclosure have been described with emphasis, it should be understood that within the scope of the appended claims, the present invention can be practiced other than as specifically described herein.
This application is related to: U.S. Provisional Patent Application Ser. No. 62/010,302, filed Jun. 10, 2014; U.S. Provisional Patent Application Ser. No. 61/889,187, filed Oct. 10, 2013; U.S. Provisional Patent Application Ser. No. 62/036,284, filed Aug. 12, 2014; U.S. Provisional Patent Application Ser. No. 62/036,297, filed Aug. 12, 2014; U.S. patent application Ser. No. 14/199,461, filed Mar. 6, 2014; U.S. patent application Ser. No. 14/511,858, filed Oct. 10, 2014; U.S. Provisional Patent Application Ser. No. 61/774,237, filed Mar. 7, 2013; U.S. Provisional Patent Application Ser. No. 61/790,942, filed Mar. 15, 2013; U.S. Provisional Patent Application Ser. No. 61/807,699, filed Apr. 2, 2013; U.S. Provisional Patent Application Ser. No. 61/870,350, filed Aug. 27, 2013; U.S. Provisional Patent Application Ser. No. 61/915,093, filed Dec. 12, 2013; U.S. patent application Ser. No. 14/735,745, filed Jun. 10, 2015; U.S. patent application Ser. No. 14/511,858, filed Oct. 10, 2014; U.S. patent application Ser. No. 14/825,089, filed Aug. 12, 2015; U.S. patent application Ser. No. 15/179,616, filed Jun. 10, 2016; U.S. Patent Application Ser. No. 62/249,777, filed Nov. 2, 2015; U.S. Patent Application Ser. No. 62/347,708, filed Jun. 9, 2016; U.S. Patent Application Ser. No. 62/347,702, filed Jun. 9, 2016; and U.S. Patent Application Ser. No. 61/889,187, filed Oct. 10, 2013. The aforementioned applications are incorporated by reference in their entireties. The application claims priority to: U.S. Provisional Patent Application Ser. No. 62/010,302, filed Jun. 10, 2014; U.S. Provisional Patent Application Ser. No. 62/036,284, filed Aug. 12, 2014; U.S. Provisional Patent Application Ser. No. 62/036,297, filed Aug. 12, 2014; U.S. patent application Ser. No. 14/199,461, filed Mar. 6, 2014; U.S. patent application Ser. No. 14/511,858, filed Oct. 10, 2014; U.S. Provisional Patent Application Ser. No. 61/774,237, filed Mar. 7, 2013; U.S. Provisional Patent Application Ser. No. 61/790,942, filed Mar. 15, 2013; U.S. Provisional Patent Application Ser. No. 61/889,187, filed Oct. 10, 2013; U.S. Provisional Patent Application Ser. No. 61/915,093, filed Dec. 12, 2013; U.S. Provisional Patent Application Ser. No. 61/807,699, filed Apr. 2, 2013; U.S. Provisional Patent Application Ser. No. 61/870,350, filed Aug. 27, 2013; U.S. patent application Ser. No. 14/735,745, filed Jun. 10, 2015; U.S. patent application Ser. No. 14/511,858, filed Oct. 10, 2014; U.S. patent application Ser. No. 14/825,089, filed Aug. 12, 2015; U.S. patent application Ser. No. 15/179,616, filed Jun. 10, 2016; U.S. Patent Application Ser. No. 62/249,777, filed Nov. 2, 2015; U.S. Patent Application Ser. No. 62/347,708, filed Jun. 9, 2016; U.S. Patent Application Ser. No. 62/347,702, filed Jun. 9, 2016; and U.S. Patent Application Ser. No. 61/889,187, filed Oct. 10, 2013.
Number | Date | Country | |
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61774237 | Mar 2013 | US | |
61790942 | Mar 2013 | US | |
61915093 | Dec 2013 | US | |
61807699 | Apr 2013 | US | |
61870350 | Aug 2013 | US | |
62249777 | Nov 2015 | US | |
62347708 | Jun 2016 | US | |
62347702 | Jun 2016 | US | |
62036297 | Aug 2014 | US | |
61889187 | Oct 2013 | US |
Number | Date | Country | |
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Parent | 14199461 | Mar 2014 | US |
Child | 15186159 | US | |
Parent | 14825089 | Aug 2015 | US |
Child | 14199461 | US | |
Parent | 14511858 | Oct 2014 | US |
Child | 14825089 | US |