MX2009013251A - Method of making proppants used in gas or oil extraction. - Google Patents

Abstract

A method of making frac sand having a selected grade from a naturally occurring, mined sand having a SiO2 content of at least about 80 percent and having a particle size range where the maximum particle size is less than about 8.0 mm, comprising: crushing the mined sand into an intermediate particulate material; screening the particulate material into a feedstock with particles having a particle size coarser than about 350 mesh and initial values for roundness and sphericity of the particles; passing the particles of the feedstock through a blast tube with an outlet to pneumatically abrade the particles and propel the feedstock in a stream under a given pressure from the outlet; directing the pressurized stream against a fixed target located at a given distance from said outlet to physically abrade the particles to form an output mass containing abraded particles: and, repeating operations (c) and (d) a number of times or process stages until the particles resulting from the repeatedl y abraded output mass is a final output mass having both processed roundness and sphericity values of at least 0.6 and wherein the values are greater than the initial values of the feedstock by at least about 0.10 to 0.50.

Description

METHOD FOR MANUFACTURING CONSOLIDATORS USED IN THE EXTRACTION OF GAS AND PETROLEUM BACKGROUND OF THE INVENTION A consolidator is a mass of spherical particles to be forced under pressure into lateral cracks in a well or borehole for the extraction of a gas or oil well. The consolidator must be able to flow into the fissure to form a "package" that maintains the outflow to the exit of the gas or oil extraction drilling. Consequently, it requires particles with a relatively uniform spherical shape characteristic, as well as the ability to absorb a compressive force that often exceeds a pressure of 281.24 kg / cm2 (4000 psi). The fracturing sand that occurs naturally is a silica sand that conforms to those requirements. This has a compression parameter known as "k-value", which value is usually 1 to 12, that is, from 703.1 kg / cm2 (1000 psi) to 843.72 kg / cm2 (12,000 psi). Only a limited number of silica sand deposits provide a fracturing sand by having a high degree of roundness and a high degree of sphericity, as well as a high compressive strength. Consequently, only the sand from those mines, or specific areas acceptable to be used as a consolidator for the extraction of oil or gas. With the current demand for the production of more oil and gas, that single natural silica sand applicable as a consolidator is becoming an insufficient supply. In this way, this sand has a very high price when bought in the open market. That special sand known as "fracturing sand" has a high roundness and high sphericity (which measures the curvature of individual particles and how the particles compare to a perfect sphere). Those values are generally greater than 0.6, where 1.0 is perfection. This "natural fracturing sand" of limited availability forms the basis and objective of the present invention. The invention is the creation of a "man-made" or synthetic fracturing sand from common and inexpensive silica sand. However, it has been determined that this invention can be used to process other hard materials in an appropriate consolidator. In addition, the invention has also been converted into a method for processing other granular natural minerals, such as olivine, as used in foundries.

SUMMARY OF THE INVENTION The preferred embodiment of the present invention is a method for converting somewhat common natural silica sand having a roundness and / or sphericity as low as 0.2-0.4 into a "fracturing sand" having a roundness and sphericity of more than 0.6 and greater preferably than 0.7. Natural sand, a little common, has a particle form "as obtained from the mine" classified as "round" to "angular". In other words, the silica sand to be converted does not have a high degree of roundness and sphericity and often does not have the compressive strength needed to be used as a fracturing sand. The "round" classification is used in the sand particle technique; but it does not mean that the particles have a high roundness or a high sphericity. The preferred embodiment of the invention involves the method of converting that natural sand into acceptable fracturing sand having a selected grade, which is commonly 20/40, 16/30, 30/50, and 40/70. As is known, the degree of sand is determined by the size of the maximum sieve through which the particles pass and the minimum sieve size through which the particles do not pass. Consequently, the degree of fracturing sand is defined by the maximum sieve size and the minimum sieve size of the particles. The grade is selected to determine the function of the fracturing sand and its permeability. In the grading of the fracturing sand, the maximum sieve size is 6-35 and the minimum sieve is 30-140 mesh.

The strength of the fracturing sand is measured by applying a pressure to a mass of the sand and determining how much pressure sand can absorb without losing 10% of its weight due to the compression action. Fracking sand needs to have a k value of 1-12, which indicates that the pressure absorbed by a sand mass without a loss of more than 10% of the weight is between 703.1 kg / cm2 (1000 psi) and 843.72 kg / cm2 (12,000 psi). This is the strength of the standard consolidator for natural fracturing sand and is doubled by the present invention. The k value of the acceptable consolidator is a characteristic set by the American Petroleum Institute (API) and ISO, the organization that defines the requirements for a consolidator used in the extraction of gas and oil. Another parameter of a consolidator according to what is established by API / ISO is the permeability which is measured by the flow of fluid through a mass of consolidators when compressed by a specific pressure of between 703.1 - 843.72 kg / cm2 (1 -12 kpsi). The permeability of the consolidator package that decreases with the pressure should have a permeability of at least about 25 Darcy to a maximum of 421 kg / cm2 (6000 psi).

The invention converts natural silica sand into fracturing sand to be used as a consolidator having the physical properties fixed by API / ISO. Thus, the invention involves a method of conveying the natural silica sand into an acceptable fracturing sand having a grade as selected by the end user. The grade selected is for the desired function in a specific type of oil or gas extraction well. Even though the invention was developed to produce sand of fracturing from common silica sand, it has been determined that the invention is more universal in its implementation by simply changing the hard material used as feed in the practice of the novel process. The invention improves the characteristics of certain man-made consolidators, even though the invention was developed to process natural silica sand. It has been found that the invention also converts natural olivine into olivine having particles with a roundness and sphericity exceeding 0.6 preferably 0.7. It has been found that olivine is more advantageous and improves in properties when used as foundry sand. This is the general statement of the method that constitutes the present invention and its specific use to convert silica sand into a consolidator and certain auxiliary uses as determined by additional research and development after discovery of the invention.

DESCRIPTION OF THE INVENTION The main aspect of the present invention is the discovery of a method for manufacturing a made version by the sand man of natural fracturing. The fracture sand created has a selected grade and is made of naturally extracted silica sand having an S1O2 content of at least about 80%. According to the invention, the somewhat common silica sand is ground into an intermediate particulate material and then sieved into a feedstock containing particles of a particle size that is larger than about 350 mesh with an initial value of roundness and sphericity not acceptable for a fracturing sand to be used as a consolidator. The feed material is then passed through a launch tube having an outlet to subject it to pneumatic abrasion and to propel the particles towards a flow under given pressure from a launch tube outlet. The pressurized flow of the feed material is directed to strike a fixed target located at a given distance from the outlet of the launch tube. The particles of the feed material are subjected to physical abrasion by particle-to-particle contact and collision with the target to form an exit mass containing particles subjected to abrasion with greater roundness and sphericity. This two-step abrasion of the feed material is carried out in a single step and repeated a number of times until the particles resulting from the repeated abrasive action create an acceptable output mass. The product is an exit mass having the roundness and sphericity of at least 0.6 and preferably at least 0.8. As a general aspect, the roundness and sphericity values of the final output mass are greater than the initial values of the feed material by at least 0.10. An improved roundness improvement at 0.10 is considered significant in the creation of the fracturing sand since the values of roundness and resulting sphericity are at least 0.6 in this way, the original roundness of 0.5 is processed to give a roundness of minus 0.6 If the original roundness is 0.2 then the process is carried out until the roundness of the final output mass is at least 0.6. After the abrasion process to create the necessary roundness, the final output mass is sifted to extract the desired degree, "selected", for the consolidator. The fracturing sand is then measured at its k value and is marketed as fracturing sand in competition with natural fracturing sand located only in a few specific areas of the world.

When the invention is carried out, the repeated pneumatic abrasion of the particles takes a total process time, which time is a combination of the time of the individual stages of the abrasion action. In practice, this residence time is in the range of 1-25 minutes for each stage of the abrasion action using the embodiment of the launch tube and target of the invention. The process also involves removing dust or small particles from the mass of particles as the mass is repeatedly passed through double abrasion operations. In the preferred embodiment of the invention, the values of roundness and sphericity for the final output mass is greater than about 0.8. The small particles are removed from the sand mass that is being processed by cyclone sorting apparatus for the mesh range of about 100-350. According to one embodiment of the invention, the method is carried out as an online process. In another mode, the process is a batch operation. Preferably the process is an in-line operation for two stages which are then repeated as a batch process.

The distance between the outlet of the launch tube and the fixed target varies between 5.08 - 60.96 cm (2- 24 inches). The outlet of the launch tube has a diameter of 10.16 - 20.32 cm (4-8 inches). In practice, the fixed target is a frustoconical structure with a flat steel plate, generally orthogonal to the outlet of the launch tube used in the action of double abrasion. The particles are subjected to abrasion by contact with each other in a launch tube as by collision with a mass joint with the fixed target.

According to another aspect of the invention, the process of the invention is carried out by means of a system involving a device for grinding silica sand mined into an intermediate particulate material. This particulate material is then sieved into a feedstock with particles having a coarser mesh size of about 350 and having an initial roundness and sphericity not acceptable for consolidators according to the API. The system involves a launch tube with an outlet for pneumatically abrading the intermediate particulate material and driving the particles in an air flow under a given pressure from the launch tube to collide with a fixed target located at a given distance of the exit of the launch tube. Consequently, the feed material is subjected to abrasion by contact with the individual particles in the launch tube and then by the action of the collision of the particles with each other and with the fixed target to form an output mass containing subject particles to abrasion of the feeding material. The action on the target is the particle to particle abrasion, as in the tube, and the collision with the target and with other particles in the target. The system involves a controller to repeat the passage of the feeding material through the tube and against the target a number of times or process steps until the resultant particles of the output mass repeatedly subjected to abrasion is a final output mass having processed roundness and sphericity values of at least 0.6. The roundness and sphericity values are greater than the initial value of the feed material by at least 0.10. After the feed material has been converted to the particle output mass that can be used as fracturing sand, the particles are then graded by a sieving network to obtain the desired selected grade, demanded by the final consumer. This degree can be of any value as defined above, but is normally 20/40, 16/30, 30/50 or 40/70. The system uses a Simpson Pro-Claim sand reclaimer as the launch tube and fixed target. This device has been used until now to clean foundry sand by removing the used binder and other impurities in the used foundry sand. However, the commercial device has never been suggested to carry out the method of the invention or to constitute the inventive system.

The method and system of the present invention utilizes the concept of pneumatic abrasion of the particles of the pressurized grain-to-grain abrasion feed material of the particles, as well as the abrasion of the particles by crushing the particles against the target. fixed at high speed and under high pressure. These processes are carried out by the combination of the launch tube, in which particle-to-particle abrasion takes place, as well as the fixed target in which the particles are subjected to abrasion are bombarded with each other and the target to increase the sphericity of the particles. individual particles. Combined operations are repeated a number of times or steps until the resulting particles of the output mass repeatedly subjected to abrasion is a final output mass having the desired increased roundness and sphericity.

According to another aspect of the present invention the method and system are used to increase the roundness of various mined granular minerals having a hardness of more than 6 Mohs and can be used as a consolidator.

Yet another aspect of the invention, the method for producing spherical consolidators is used for a man-made consolidator, such as the agglutinated particle compound. Each of these particles is produced in a general spherical manner but they often clump together, in which their ability to be used as a consolidator is distracted. Accordingly, those agglomerated particle compounds are passed through a throwing tube with an outlet to be subjected to pneumatic abrasion and then be driven in a low flow. pressure given from the outlet of the tube against a fixed target located at a given distance from the outlet of the tube. This action subjects the particles to physical abrasion, so that they are not already agglomerated or grouped and are individualized and in this way, their acceptability is improved as a man-made consolidator. The method of the present invention can be used to improve the characteristics of man-made ceramic particles, which usually have larger k values than the natural silica fracturing sand. This aspect of the method still involves the concept of particle-to-particle abrasion and collision with a fixed target until the individual particles are formed, so that they are optimized to be used as a consolidator in a gas or oil well.

The invention contemplates the use of a fixed target against which the particles are bombarded, it has been found in a broad sense, the particles that are being modified are simply impacted at high speed against the metal member if it is fixed or not technically fixed. According to the invention, the metal is a "fixed" target; however, a procedure would be equivalent to employing a moving metal target on which the feed material will be impacted since it is also subjected to abrasion to change the shape of the individual particles.

According to the different aspects of the present invention, the "selected" grade of the fracturing sand has a maximum mesh size of 6-35 mesh and a minimum mesh size of 30-140 mesh. Preferably, the grade for the fracturing sand has a maximum size in the mesh range of about 12-20 and a minimum size in the mesh range of about 40-70. The resultant consolidator produced by the method or system of the present invention has a value k in the range of 1 k to 12 k and has a permeability of at least 25 Darcy at 6 k.

According to another aspect of the present invention there is provided a method for producing a material with spherical particles of a mined granular material having a hardness of more than 6 Mohs and having a particle size where the maximum particle size is less than about 8.0 mm. This method comprises grinding the mined material into an intermediate particulate material. The particulate material is then screened to remove larger particles of approximately 350 mesh. Those particles have an initial value of roundness and sphericity that is substantially less than about 0.6. The particles are then subjected to abrasion by particle to particle contact at high speed and are also made to strike at high speed against the metal member. The abrasion and shock actions continue until the particles constitute an output mass having processed roundness and sphericity values greater than 0.6 and preferably greater than 0.8. As a further aspect of this definition of the invention, the metal member is a fixed target against which the feed material is struck at high speed. According to an alternative aspect of the invention, the mineral is natural olivine.

These and other aspects of the present invention are defined by the original appended claims of this application.

The main objective of the present invention is the production of a method and system for converting natural silica sand into a fracturing sand to be used as a consolidator in oil and gas wells. Man-made synthetic fracturing sand meets API criteria. .

Another object of the present invention is to provide a method and system, as defined above, method and system which employ the interaction of surface to particle abrasion and the impact of the particles against a metal member until the particle has an increase in roundness and sphericity of at least 0.10 so that the roundness and sphericity is greater than 0.6 and preferably 0.8.

A further object of the present invention is the provision of a method and system, as defined above, method and system which use a launch tube and a fixed tube for abrasion and collision particle to particle combined, actions which are performed simultaneously to increase the roundness and sphericity of sand of natural silica so that it can be used as fracturing sand.

A further object of the present invention is the provision of a method that can be used to improve the capabilities of a man-made consolidator, such as ceramic particles, and the roundness and sphericity of olivine to improve its use in the automotive industry. foundry.

These and other objects and advantages will become apparent from the following description taken together with the accompanying figures.

BRIEF DESCRIPTION OF THE FIGURES In the figures, FIGS. 1A-1D are schematic views showing the progress of the particle shapes when the method and system of the present invention are implemented; FIGURE 2 is a schematic figure of the selection process achieved in obtaining a "selected" grade for the consolidator produced using the present invention; FIGURE 3 is a schematic illustration of a consolidator pack employing fracturing sand produced in accordance with the present invention; FIGURE 4 is a block diagram of the preferred embodiment of the method that constitutes the present invention; FIGURE 5 is a side elevational view of the Simpson Pro-Claim sand reclaimer that is used to effect the preferred embodiment of the present invention; Y FIGURE 5A is an enlarged schematic view of the launch tube and the fixed target used to detect the preferred embodiment of the present invention with the presented dimensional and operating parameters.

PREFERRED MODALITIES OF THE INVENTION The preferred embodiment of the invention is described using the different figures; however, the invention is not limited to the described modality and is broader according to what is defined in the appended claims.

ABRASION PROCESS (FIGURES 1A-1D) The invention involves the concept of taking natural, somewhat common silica sand with a different particle shape and size and rheumatically abrading the individual particles by pressurized stirring together to abrasion grain by grain and then crash the particles with a mass against a fixed target T, as schematically illustrated in FIGS. 1A-1B. A mass of particles 10 is a feedstock formed from particles of silica sand that has been sieved to remove particles of a small size, such as a size less than about 50 microns. Optionally, the feed material can be sieved to remove large particles of a size greater than about a 5-6 mesh screen. Thus, the particles 10 have a size greater than about 50 micrometers to a large size of 8.0 mm, but preferably less than about 5 mm. The particles 10 are driven at a high velocity by a fluid flow represented as arrows in FIGURE 1A so that they are violently agitated against each other as they move towards the fixed target T. They then collide as a mass against the target, so that the combined pneumatic abrasion caused by the contact of the particles 10 with each other as they move towards the target T and the actual collision of the particles against the target T and the particles in the target to form a processed particle 10a. The particles 10a have an increase in the uniformity of the surface of the natural shape of the particles of the feed material 10. The only stage of pneumatic abrasion and collision with the target is repeats as shown in FIGURE IB where the particles 10a are reprocessed by abrasion and collision together with the blank T to form additionally processed particles 10b. That step of the process is repeated as shown in FIGURE 1C, where the processed particles 10b are converted to further processed particles 10c. As indicated by the step or function 20, the step of subjecting to pneumatic abrasion and crashing the particles against the fixed target is repeated several times to produce the lOx particles. A mass of these lOx particles is passed through the last operation or process step as schematically illustrated in FIGURE ID, so that the particles form a final processed mass of individual particles 100, which have a diameter of t, diameter which will vary from a small size, such as approximately 50 micrometers, to the largest size of the incoming feedstock 10 in FIGURE 1A. The abrasion process of the grain-to-grain contact and shock against the particle mass event is repeated many times or stages, each of which has a controlled residence time. This time for each stage is in the range of 5-25 minutes. The processing for a total residence time of successive stages is carried out on the feed material 10. The time is selected so that the individual particles have an increase in roundness and sphericities that improve dramatically with respect to the values of initial roundness and sphericity of the particles of the feedstock 10. The values are increased by a substantial amount, such as from 0.1 to 0.40. In fact, an improvement in the roundness of 0.10 is drastic, so that improving the roundness and sphericity of a value of 0.5 to a value of 0.6 is significant to produce fracturing sand. The pneumatic agitation of the grain-to-grain contact and shock or crushing on a fixed or white surface is repeated again and again in successive stages until the roundness and sphericity of the individual particles, according to what is measured in the laboratory, approaches values useful for consolidators according to what is determined by the API / ISO, value which is greater than 0.6 and preferably greater than 0.7 or 0.8. When the particles undergo a standard compression test for consolidators they involve a mass of particles that are compressed with a given pressure as 281.24-703.1 kgf / cm2 '(4,000 - 10,000 psi). The amount of fines produced by the particle grinding process is measured. A 5k consolidator is one where the crushing pressure is 351.55 kgf / cm2 (5k psi) resulting in less than 10% fines through a small or recording screen, as will be discussed with respect to FIGURE 2. In this way, a successful crushing test results in less than 10% fines that fall through the minimum sieve at a given crushing pressure. In practice, the present invention produces values of ka generally in the range of 4-6k. Since the value of k is somewhat indicative of the crystal structure, the smallest particles in a selected degree of consolidators help to ensure that the value of k is greater than about 4k. The silica of a single crystal produces a value of k generally greater than 6k. Thus, the "selected" grade for a fracturing sand produced by the invention is a degree that produces the desired value of k demanded by the fracturing sand customer. The k value of the crushing or compression test is a specification assigned to the extent of the fracturing sand by the end user. In this way the value of k is used by the manufacturer of the fracturing sand produced by the present invention to satisfy the requirement of the customer.

Selection of the Degree (Figure 2) The invention involves producing fracturing sand with a "selected" grade which is: usually 12-20 mesh up to 30-50 mesh. The common grades are 20/40, 16/30, 30/50 and 40/70. However, the fracturing sand can be graded with the maximum mesh size of 6-35 mesh and a minimum mesh size of 30-140 mesh. The grade of the sand of fracture produced is number where the first value is the maximum particle size and the second value is the minimum particle size and 90% of the fracture sand particles.

One aspect of the present invention involves selecting the desired degree of fracture sand produced in the stages illustrated schematically in FIGS. 1A-1D. To grade the fracturing sand, the final produced particles 100 having various diameters t were directed through a maximum size sieve 110 shown in FIGURE 2. The particles 100 have a variety of diameters, schematically illustrated as the size particles different a, b, c and d in decreasing values. The particles 100 having different diameters are passed through the maximum screen 100, which has a mesh size of 6-35 mesh. The particles a are too large to pass the sieve 100 so that they do not progress towards the P area. Those larger particles are removed from the upper part of the sieve 100. In the P area the particles progress towards the minimum sieve 120 which has a value in the range of 30-140 mesh. In this way, the small particles d are removed from the area P. The particles remaining in the area P constitute the product created by the present invention. This product is directed through conduit 130 to a vehicle of transport, which can be a bag or other container. The product in the conduit 130 has a degree which is 90% of the maximum size determined by the sieve 110 and the minimum size determined by the sieve 120. Accordingly, the method of the present invention involves directing the mass of sand particles processed 100 through a sieve of maximum size 110 which retains large particles and then through the lower sieve 120 which determines the minimum particle size for the product. Sieve 120 removes small particles d. Consequently, the sand with a selected grade is the material removed from between the two graduation sieves. This concept is known in the art and is used in the present invention to determine the "selected" degree of fracturing sand.

Consolider package (Figure 3) In practice, the fracturing sand created has a maximum particle size of just over 1.0 rare and a minimum size of about 0.5 mm. In this way, the fracturing sand is a mass of particles which are very large, so that they can allow a high permeability when the fracturing sand is in a PP consolidator package, as shown in FIGURE 3. The mass of the fracturing sand particles of the PP package are forced into a fissure where the package keeps the fissure open when there is high pressure in a vertical direction against the consolidator. This high pressure attempts to close the crack and can approach several thousand psi. The consolidator particles in the PP package have a high rouns and high sphericity, so that the high pressure in the crack in an oil or gas well keeps the crack open and does not prevent the passage of gas or oil through the fissure There is a permeability of at least 25 Darcy at 6 k due to the high individual rouns of the fracturing sand particles. In this way, oil or gas can be extracted when circumstances are irrecoverable.

The Method 200 (Figure 4) The preferred embodiment of the present invention is method 200 illustrated in the solid line portion of FIGURE 4. A natural, somewhat common silica sand is mined according to that indicated in step 202. Silica sand has a silica content greater than 80% and a hars of more than 6 Mohs. In the condition as it is extracted from the mine, the silica sand has a large agglomeration of particles and therefore it is crushed, cleaned and washed according to what is indicated in step 203. This operation is carried out in accordance with standard practice in a mining operation of silica sand. After that the silica sand extracted from the mine is crushed, this is a mass of smaller particles in a suspension that is sifted according to that indicated in step 206. The screened silica sand particles are then dried to produce a feed directed to station 300 where the feed material is subjected to abrasion by individual particles colliding with each other and then subjected to abrasion by the mass of particles colliding in a crushed mass against a fixed target. Station 300 is a device shown in FIGURE 5, which is a two-stage Simpson Pro-Claim 400 device. This particular commercial device is used to recover foundry sand and includes two separate stages for in-line processing. The feed material of the inlet line 302 is directed to the station 300 to effect a concurrent abrasion action and abrasion by collision with the white, double, on the dryer feed material 208. Each step of the abrasion operation in the station 300 is effected during a residence time which is generally in the range of 5-25 minutes. In this way, the feed material entering station 300 of line 302 is processed in line by two successive stages, where the processed mass of particles is subjected to abrasion in the same way for both processing steps. In a preferred embodiment, screening in Wet in the step or operation 206 removes particles of less than about 350 mesh. According to an option as indicated by the step or operation of the dotted line 210, the larger particles are removed from the feed material. In this way, the particle size will be smaller than a given screen size, such as a 6 mesh screen or about 5 mm. Consequently, the mass of particles enters the wet sieve 206 where the small particles are removed. The large particles have been removed by the optimum step 210. Accordingly, a feed material on line 302 is dried and has a particle size of less than 5 mm and a mesh of more than 350 or about 50 microns.

Station 300 includes a mechanism, such as an exhaust fan, to remove dust or fine products as indicated in step 30. A cyclone separator is set at a value between 100-350 mesh to remove particles of less than a selected sieve size as described by step 306. Fine powders are collected by accumulator 304a and small particles from the cyclone separator 306 are collected by collector 306a. The operation of steps 304 and 306 uses the structures shown in FIGURE 5 and FIGURE 5A. The feeding material is processed in two stages, each of which is carried out during a 5-25 minutes period. The total process time for station 300 is the so-called "residence time" for the device or machine 400. The total residual time is the accumulated time for the number of steps determined in step 308. Two steps are performed by the machine 400 and this is repeated until the feed material produces its final output mass in the product 310. In practice, the feed material is passed through the machine 400, as shown in FIGURE 5. Step The operation of the two-step machine is performed a number of times to give between 2 and 20 processing steps, so that the feed material is converted to the desired roundness and sphericity of the final output mass in the duct 310 The two stage machine illustrated in FIGURE 5 for the successive processing of the feed material or several of those machines can be connected successively for on-line processing. As an alternative, several series-operated machines operated in series will produce the desired residence time. When the preferred embodiment is used, 2 to 20 separate processing steps are used on the feed material to produce an output mass in. the conduit 310.

After the feed material has been repeatedly subjected to grain-to-grain contact and mass collision with the fixed target, the final product in the duct 310 is then passed through a screening process selected as shown in FIGURE 2. This aspect of method 200 is indicated by step 312 to produce a product in duct 130, such as the product graduated by the screens in FIGURE 2. The product in conduit 130 is then transported by means of bags and other containers for use in gas or oil wells. In summary, method 200 converts the feed material to line 302 by several passes through station 300. In this process, dust is removed as indicated by step 304 and cyclone sorter 306 is used for remove very small particles from the mass of particles that is being processed. The cyclone sorter is calibrated to remove the minimum particle size from the selected grade for the fracturing line. The product of the cyclone is classified by air at a size generally in the 100-350 mesh range. The equipment now used to perform the operation of station 300 is a Simpson Pro-Claim 400 machine, as shown in FIGURES 5 and 5A. The sand is subjected to abrasion is removed from the conduit or passage 310, which constitutes the final exit mass. As indicated in step 308, after removing the exit mass from the two-stage station 300, the two-stage abrasion procedure of the station 300 is repeated several times. The two-stage procedure of the station 300 is effected several times. Each "time" is referred to as a stage in the two-stage machine as shown in FIGURE 5. In practice, the process is repeated more than four times with the residence time of each stage being controlled a value of 5- 25 minutes. The number of repeated operations in step 308 determines the controlled residence time of the referred implementation. The residence time and the repeated use number of station 300 to obtain the acceptable final product is not a limitation for the invention. Actually, station 300 could be "operated" for longer times and used only in two stages to achieve the desired total residence time, after a feed material has been repeatedly processed during the total controlled residence time to produce the final exit mass in the duct 130, the final exit dough is graded by the screening method set forth in FIGURE 2 to produce the sand of the selected grade constituting the product FS.

System and Machine 400 (Figures 5 and 5A) The method 200 illustrated in FIGURE 4 is performed by the equipment to perform the different steps that constitute the preferred embodiment of the method. These different steps are combined to constitute the method 200. The invention is also a system for effecting a method 200 for converting common natural silica sand into highly desired fracturing sand equivalent to the natural fracturing sand hitherto available on a limited number of natural sources. The system of the invention incorporates a machine to perform the steps of method 200. The machine for performing station 300 in the preferred embodiment is machine 400 shown in FIGS. 5 and 5A; however, the system is broader than the illustrated machines and equipment in particular used in the preferred embodiment. The system is more broadly defined in the original claims of this application, which constitute the additional description of a system that forms an aspect of the present invention.

In practice, the preferred embodiment of the present invention, station 300 is a Simpson Pro-Claim device or machine. This machine is illustrated schematically in FIGURE 5 and FIGURE 5A, the latter of which contains the parameters used to adjust certain aspects of the machine 400 to effect the function of station 300 in method 200. The Simpson Pro-Claim machine 400 includes two duplicate stages 402 and 404 operated in sequence to process the feed material of the inlet conduit 302. The machine 400 has a common bell 406 with the inlet hopper 410 that receives the material of feed and passes the feed material through the gate 412 to the first stage 402. The two successive stages are divided by the central wall 412 and each includes an inclined collector plate 420, 422 which directs the processed particles to the recycling gates 423, 426, respectively. The gates are adjusted to determine the percentage of recycled particles per stage before the particles exit through the outlet gate 428 in the vertical outlet wall 429. The feed material of the conduit 302 is directed to the table 410 and then through the gate 412 to the first processing stage 402. After the feed material has been processed it falls on the inclined plate 420 which deposits the processed material on the adjustable gate 424. Some of the material is recycled through from step 402 and the remainder is taken to the second stage 404. After being processed in this second stage, the material falls on the inclined collecting plate 422 to pass over the gate 426 and then to the side gate 428. Accordingly, the feed material is processed twice by the machine 400 using consecutive processing steps 402, 404. The two-stage machine it is supported on the base 430, base which includes a chamber 440 having a high pressure bellows 442 for forcing pressurized air towards the chamber impellent at a controlled pressure c. The pressure c may vary between 50-15 k psi (3515.5-1054.65 kgf / cm2) preferably from about 50-100 psi (3.5-7.03 kgf / cm2) for the present invention. The stage 402 is communicated with the plenum chamber 440 by the vertical pressure tube 450 and the stage 404 is communicated by the plenum chamber by the vertical pressure tube 452. These pressure tubes create the energy for the processing of the feed material in the successive steps 402, 404. The first step 402 will be described in detail using the partial structure of FIGURE 5A. The same description is applied to the second stage 404 operated by the high pressure air of the pressure tube 452.

Referring now to FIGS. 5 and 5A, the first processing step 402 includes a vertical tube 500 and a conical collecting hopper 502. The material in the hopper 502 is driven through the launch tube 500 from an annular opening 512 defined by the outer cylindrical shield 514. The outlet 510 in the upper portion of the launch tube 500 has a diameter a, with the selectable valve listed in FIGURE 5A. The mass of particles M shown in FIGURE 5A is directed through the annular opening 512 towards the lower portion of the launch tube 500 and is driven upwards by the high pressure produced by the air flow A of the pressure tube. 450. The particles in the launch tube 500 are subjected to contact abrasion between the rapidly moving particles as they are propelled by the launch tube 500 towards the target T. The fixed metal target T includes the wall 520 orthogonal to the tube 500 and is separated from the exit 510 at a distance b that can change according to that indicated in FIGURE 5A. The flat wall 520 is surrounded by the conical skirt 522 and the cylindrical outlet deflector 524 for guiding the processed particle mass M 'of the blank T down the sloping collector plate 420, as best shown in FIGURE 5. The tube 500 launch and white produce the abrasion of the particles in the mass M by particle to particle abrasion and the abrasive action and collision against the wall 520 of the white T made of hardened steel. In this way, the incoming feedstock of the hopper 410 is processed first by the launch tube 500 and then by the blank T to change the roundness and sphericity of the modified particles M 'as the mass leaves the blank T towards the inclined plate 420 and then to the gate 424. Some of the particles are recirculated to be combined with the incoming feed material by the launch tube 500. A larger portion of the processed particles of mass M 'are directed to the second stage 404 for further reprocessing. Subsequently, the mass of processed particle twice is directed through the gate 428 to the outlet bell 600. This hood includes a dust outlet duct 304 connected with an appropriate exhaust fan to remove small dust particles from the material in the hood 600. bell 600 also includes an inclined outlet wall 602 having a portion of a first passage 604 and a portion 606 that removes large particles to be discharged through opening 608. Smaller particles pass through portion of sieve 606 to the collection vessel 610 which is connected to the outlet conduit 310 for the exit of the mass of particles. This mass is formed at the end of the two-stage processing machine to produce the final exit mass in the duct 310 to be transferred to the screening operation 312 shown in FIGURE 4. The two stages of the machine 400 are repeated several times so that the final output of the collection vessel 610 is the final output mass. The different stages can be added in series to produce an online operation. In accordance with the practical implementation of the present invention, the processed dough is repeatedly directed through the two-stage machine 400 to finally produce a final dough having the desired roundness and sphericity for a fracturing sand.

GENERAL VIEW The invention involves the concept of abrading the particles by particle to particle contact at high speed and also by striking the particles as a mass and at a high speed against a metal member. These two processes are performed using the incoming feed material until it is converted to a desirable roundness and sphericity, acceptable by the API for the "fracturing sand." The fracturing sand is graded according to that indicated by step 312 of the method. 200 and then it is tested for its value of K. It has been found that using the material 200 of the system to effect this method produces silica sand fracturing sand having more than 80% SiO2, fracture sand which has a roundness and sphericity greater than 0.7 and a value of k greater than 4 k, this created fracturing sand is equivalent to the natural fracturing sand and can be produced at a value lower than the normal market value of the natural fracturing sand.

PROOF OF PRODUCT SHREDDING For . obtaining the value of k, a crushing test is carried out where the processed fracturing sand of the present invention is crushed by a selected pressure, such as 421 kg / cm2 (6000 psi). Then the percentage of fines passing through the lower sieve of a double sifting system as shown in Figure 2. If the grade is 16/30, then the amount of fines passing through a 30 mesh sieve after the sand of processed fracturing has been crushed by 421 kg / cm2 (6000 psi) must be less than 10% of that particular degree to be acceptable for a fracturing sand requiring that high value of k. In this way, the crushing test of the fracturing sand is a specification that defines the crushing portion of the fracturing sand that has been produced by the method illustrated in Figure 4.

EXAMPLES In one embodiment of the present invention, four processing steps were performed using station 300. Each stage had a residence time of 18 minutes to give a total processing time of approximately 80 minutes. The incoming natural mineral was silica sand from the Uttica mines. The parameters for the Simpson Pro-Claim 400 machine were fixed with a = 10.16 centimeters (4 inches) b = 12.7 centimeters (5 inches) and c = 5.62 kgf / cm2 (80 psi). The product grade was 16/30. Another test was conducted on a similar extracted mineral with a residence time per stage of 6 minutes. The distance b was increased to 15.24 centimeters (6 inches). The final results were similar. Each test gave a dynamic reduction in turbidity, that is, reduction in the elements in undesirable traces. The value of k was 6000. Turbidity decreased from 400 to 160. These tests produced acceptable fracturing sand with a k value of 6 and a degree of 16/30. The turbidity was drastically lower than the acceptable value of the American Petroleum Institute. Other trials in different silica sands entered and produced a fracturing sand that has acceptable characteristics to be used as a commercial fracturing sand.

FOOD MATERIALS The feed material for practicing the invention described herein is mineral silica extracted from a mine having an SiO2 of more than 80%. The sand is "round" to "angular". Those are the shapes of the individual particles and they are found in the natural silica sand. The preferred feedstock has a very low roundness and sphericity. That natural silica sand can not be used as fracturing sand. In practice, the initial silica sand has a maximum grain size of less than 8.0 mm. Actually, the feed material now used comes from the mine with a particle size between 20 micrometers and approximately 6.0 - 8.0 mm. That Feeding material has been converted into fracturing sand by the invention. It has been found that the other "hard materials" can be extracted and ground for conversion by the invention into an acceptable consolidator. The hardness as defined by the Mohs scale is at least 6. In this way, the process used to produce sand from fracturing from silica sand can also be used to produce a consolidator from other hard minerals by changing the Feeding material. The process can also be used to process a material for feeding ceramic particles. The invention improves the physical characteristics of that man made consolidator. It has also been determined after the invention was made that it can be used to process an olivine feed material used in the foundry industry. By drastically increasing the roundness and sphericity of olivine particles, a smaller amount of binder is required to produce molds for metal casting and olivine improves in other circumstances.

MODIFICATIONS Although the preferred embodiment of the invention involves the collision of rapidly moving particles against a fixed metal target T, it has been found that the invention is broader since it simply requires collision with a metal object that is fixed or not. However, the invention involves the use of the Simpson Pro-Claim 400 machine which constitutes the invention. However, the invention is thus defined in broader terms since it is related to equivalent structures.

The different adjustments to the Simpson Pro-Claim machine and the order and magnitude of the steps of the method 200 can be changed without departing from the spirit and scope of the present invention, as defined by the appended claims.

Claims (50)

1. A method for manufacturing fracturing sand having a selected grade of natural sand, extracted from the mine, having an SiO2 content of at least about 80 percent and having a range of particle size, where the particle size maximum is less than about 8.0 mm, the method is characterized because it comprises: (a) crushing the extruded sand from the mine in an intermediate particulate material; (b) screening the particulate material in a feedstock with particles having a particle size larger than about 350 mesh and initial values of roundness and sphericity of the particles; (c) passing the particles of the feedstock through a launch tube with an outlet for pneumatically abrading the particles and driving the feedstock in a flow under a given pressure from the outlet; (d) directing the pressurized flue against a fixed target located at a given distance from the outlet to subject the particles to physical abrasion to form an exit mass containing particles subjected to abrasion: (e) repeat operations (c) and (d) a number of times or process steps until the particles resulting from repeated abrasion produce a mass that is a final output mass having processed roundness and sphericity values of less than 0.6 and where the values are greater than the initial values by at least about 0.10; Y, (f) sift the final exit mass to obtain a fracture sand with the selected grade.

2. The method in accordance with the claim 1, characterized in that operations (c) and (d) are performed concurrently to give a given residence time.

3. The method in accordance with the claim 2, characterized in that the residence time is in the range of 1-25 minutes.

4. The method according to claim 2, characterized in that the total processing time is generally the sum of the residence time of each processing step.

5. The method according to claim 1, characterized in that it includes removing dust and small particles from the output mass as if they were subjected to abrasion repeatedly.

6. The method according to claim 1, characterized in that the values of initial roundness and sphericity are less than about 0.6.

7. The method according to claim 6, characterized in that the roundness and sphericity values processed are greater than about 0.6.

8. The method according to claim 6, characterized in that the roundness and sphericity values processed are greater than about 0.8.

9. The method according to claim 1, characterized in that the roundness and sphericity values processed are greater than about 0.6.

10. The method according to claim 1, characterized in that the roundness and sphericity values processed are greater than about 0.8.

11. The method according to claim 5, characterized in that the small particles have a particle size in the range of less than about 100-350 mesh.

12. The method according to claim 1, characterized in that the method is carried out as an online process.

13. The method according to claim 1, characterized in that the given distance is between 5-60.96 centimeters (2-24 inches).

14. The method according to claim 13, characterized in that the given distance is between 15.24 and 30.48 centimeters (6 and 12 inches).

15. The method according to claim 1, characterized in that the given pressure is in the range of 3515.5-1054.65 kgf / cm2 (50-15k psi).

16. The method according to claim 15, characterized in that the given pressure is less than about 703.1 kgf / cm2 (10K psi).

17. The method according to claim 1, characterized in that the number of times is in the range of 2-20.

18. The method of compliance with claim 17, characterized in that the number of times is more than 4-8 times.

19. The method according to claim 1, characterized in that the outlet of the launch tube has a diameter in the range of 10.16-20.32 centimeters (4-8 inches).

20. The method according to claim 1, characterized in that the given distance is in the range of 5-10 centimeters (2-4 inches) and the diameter is in the range of 15.24-20.32 centimeters (6-8 inches).

21. The method according to claim 1, characterized in that the given distance is in the range of 15.24-30.48 centimeters (6-12 inches) and the diameter is in the range of 10.16-20.32 centimeters (4-8 inches).

22. The method according to claim 1, characterized in that the fixed target is frustoconical with a flat plate generally orthogonal to the exit of the launch tube.

23. The method according to claim 22, characterized in that the launch tube is generally vertical.

24. The method according to claim 1, characterized in that the selected degree is a degree with a maximum mesh value of 6 to 35 and a minimum mesh value of 3-140.

25. The method according to claim 1, characterized in that it uses a Simpson Pro-Claim sand recuperator as the launch tube and the fixed target.

26. A system for making fracturing sand having a selected grade of a natural sand, extracted from the mine, having an SiO2 content of at least about 80% and having a range of particle size, where the maximum particle size is less than about 8.0 mm, the system is characterized because it comprises: (a) a device for grinding the sand extracted from the mine in an intermediate particulate material; (b) a device for sifting the material particulate in a feedstock with particles having a particle size larger than about 350 mesh and initial values of roundness and sphericity of the particles; (c) a launching tube with an outlet for pneumatically abrading the particles and driving the feed material in a flow under a given pressure from the outlet; (d) a fixed target located at a given distance from the outlet to subject the particles to physical abrasion to form an exit mass containing particles subjected to abrasion: (e) a controller for repeatedly passing the feed material through the tube and against the target a number of times or process steps until the resulting particles of the output mass subject to repeated abrasion is a mass having values of processed roundness and sphericity of less than 0.6 and where the values are greater than the initial values by at least about 0.10; Y, (f) a graduation sieve network to sift the final output mass to obtain a fracturing sand with the selected grade.

27. The system according to claim 26, characterized in that it uses a recuperator of Simpson Pro-Claim arena as a launch tube and fixed target.

28. A method for manufacturing fracturing sand having a selected grade and better crushing strength than a natural sand, extracted from the mine, having an SiO2 content of at least about 80 percent and with a general particle shape classified among round and angular and having a range of particle size, where the maximum particle size is less than about 8.0 mm, the method is characterized in that it comprises: (a) grind the sand extracted from the mine in an intermediate particulate material; (b) screening the particulate material in a feedstock with particles having a particle size larger than about 350 mesh and initial values of roundness and sphericity of the particles; (c) subjecting the particles to pneumatic abrasion by pressurized grain-to-grain agitation of the particles; (d) subjecting the particles to abrasion by grinding the particles against a fixed target under high speed and / or high pressure; (e) repeating operations (c) and (d) a number of times or steps until the particles resulting from the output mass subjected to repeated abrasion are a mass of final output having processed roundness and sphericity values of less than 0.6 and where the values are greater than the initial values by at least about 0.10; Y, (f) sift the final exit mass to obtain a fracturing sand with the selected grade.

29. The method in accordance with the claim 28, characterized in that the operations (c) and (d) are carried out during a given residence time.

30. The method in accordance with the claim 29, characterized in that the given residence time is in the range of 5-25 minutes.

31. A method for manufacturing a spherical consolidator having a selected grade of a natural granular mineral, mined from the mine, having a hardness of more than 6 Mohs and having a range of particle size, where the maximum particle size is less than about 8.0 mm, the method is characterized in that it comprises: (a) crush the ore extracted from the mine in an intermediate particulate material; (b) screening the particulate material in a feedstock with particles having a particle size larger than about 350 mesh and initial values of roundness and sphericity of the particles; (c) passing the particles of the material from feeding through a launch tube with an outlet for subjecting the particles to airtight abrasion and driving the feed material in a flow under a given pressure from the outlet; (d) directing the pressurized flow against a fixed target located at a given distance from the outlet to subject the particles to physical abrasion to form an exit mass containing particles subjected to abrasion; (e) repeating operations (c) and (d) a number of times or 'process steps until the particles resulting from the output mass subjected to repeated abrasion is a final output mass having roundness and sphericity values processed of less than 0.6 and where the values are greater than the initial values by at least about 0.10; Y, (f) Sifting the final output mass to obtain a spherical consolidator with the selected grade.

32. The method in accordance with the claim 31, characterized in that the operations (c) and (d) are carried out during a given residence time.

33. The method in accordance with the claim 32, characterized in that the residence time is in the range of 5-25 minutes.

34. The method according to claim 31, characterized in that the mineral is natural sand that it has an SiO2 content of at least about 80%.

35. A method for manufacturing spherical consolidator having a selected grade of a mass of composite or bonded particles, each of which has a generally spherical shape, but which are bonded together, the method is characterized in that it comprises: (a) sieving the mass of a feedstock; (b) passing the particles of the feedstock through a throwing tube with an outlet for pneumatically abrading the particles and driving the feedstock in a flow under a given pressure from the outlet; (c) directing the pressurized flow against a fixed target located at a given distance from the outlet to subject the particles to physical abrasion to form an exit mass containing particles subjected to abrasion; (d) repeating steps (b) and (c) a number of times or process steps until the resulting particles of the output mass subjected to repeated abrasion is a final output mass having processed roundness and sphericity values of less than 0.6; Y, (e) sift the final output mass to obtain a spherical consolidator with the selected degree.

36. A method for manufacturing a spherical consolidator that has a selected grade of a mineral natural granular, extracted from the mine, having a hardness of more than 6 Mohs and having a range of particle size, where the maximum particle size is less than about 8.0 mm, the method is characterized in that it comprises: (a) crush the ore extracted from the mine in an intermediate particulate material; (b) screening the particulate material in a feedstock with particles having a particle size larger than about 350 mesh and initial values of roundness and sphericity of the particles; (c) subjecting the particles to particle-to-particle contact at high velocity and also striking the particles at high velocity against a metal member; (d) effecting the abrasion and shock actions until the particles constitute a final output mass having processed roundness and sphericity values greater than about 0.6; Y; (e) Sifting the final output mass to obtain a spherical consolidator with the selected grade.

37. The method according to claim 36, characterized in that the mineral is natural sand with an SiO2 content of at least about 80%.

38. The method according to claim 36, characterized in that the metal member is a white fixed against which the feed material collides at high speed.

39. The method according to claim 36, characterized in that the selected grade has a maximum mesh size of 6-34 and a minimum mesh size of 20-140.

40. The method according to claim 36, characterized in that the selected grade has a maximum size in the range of about 12-20 mesh and a minimum size in the range of about 30-50 mesh.

41. The method according to claim 36, characterized in that the consolidator has a value of k in the range of approximately 2 k to 15 k.

42. The method of compliance 'with the claim 39, characterized in that the consolidator has a value of k in the range of about 2 k to 15 k.

43. The method in accordance with the claim 40, characterized in that the consolidator has a value of k in the range of approximately 2 k to 15 k.

44. The method according to claim 36, characterized in that the consolidator has a permeability of at least 25 Darcy at 6 k.

45. A method for manufacturing a mineral with spherical particles from a natural granular mineral, extracted from the mine, having a hardness of more than 6 ohs and having a range of particle size, where the maximum particle size is less than about 8.0 mm, the method is characterized in that it comprises: (a) crush the ore extracted from the mine in an intermediate particulate material; (b) sieving the particulate material into a feedstock with particles having a particle size larger than about 350 mesh and initial values of roundness and sphericity of the particles substantially less than 0.6; (c) subjecting the particles to particle-to-particle contact at high velocity and also striking the particles at high velocity against a metal member; Y (d) effecting the abrasion and shock actions until the particles constitute a final output mass having processed roundness and sphericity values greater than about 0.6.

46. The method in accordance with the claim 45, characterized in that it includes: (e) Sifting the final exit mass to obtain a spherical consolidator with a selected grade.

47. The method in accordance with the claim 46, characterized in that the mineral is natural sand with an SiO2 content of at least about 80%.

48. The method according to claim 45, characterized in that the metal member is a fixed target against which the feed material is hit at high speed.

49. The method according to claim 48, characterized in that the mineral is natural olivine. .fifty. The method according to claim 45, characterized in that the mineral is natural olivine.