MX2011003784A - Additives to suppress silica scale build-up. - Google Patents

Abstract

Treatments and compounds useful in subterranean formations are discussed, with particular attention to those where particulates and/or surfaces may be subject to silica scale build-up. Certain embodiments pertain to utilizing silica scale control additives with particulate packs. Of these, certain methods may treat particulate packs in a subterranean formation with silica scale control additives, certain methods may combine silica scale control additives with particulates prior to formation of a particulate pack, and certain compounds may provide the features of both silica scale control additives and particulates.

Description

ADDITIVES TO DELETE THE ACCUMULATION OF SILICA INCUSES FIELD OF THE INVENTION The present disclosure relates to treatments and compounds useful in underground formations, and, at least in some embodiments, with treatments and compounds where the particles and / or surfaces can be subjected to the accumulation of silica scale.

BACKGROUND OF THE INVENTION In the production of fluids, such as hydrocarbons or water, from an underground formation, the underground formation must be sufficiently conductive to allow the convenient flow of secretion to a well bore for sounding that penetrates the formation. Among others, hydraulic fracturing can be a useful treatment to increase the conductivity of an underground formation. Hydraulic fracturing operations in general may involve pumping a treatment fluid (eg, a fracturing fluid or a "filler fluid") into a bore hole for sounding that penetrates an underground formation at a hydraulic pressure sufficient to create or improve one or more trajectories, or "fractures", in the underground formation. Improving a fracture generally involves extending or lengthening a natural or pre-existing fracture in the formation. These fractures generally increase the permeability of that portion of the formation. The treatment fluid may comprise particles, among which are included consolidation particles that deposit in the resulting fractures. It is believed that the particles help to prevent fractures from fully closing with the release of hydraulic pressure, forming conductive channels through which fluid can emanate between the formation and the drill hole for sounding.

In general, it is believed that the particle surfaces generally comprise minerals, which can react with other substances (eg, water, minerals, treatment fluids, and the like) that reside in the underground formation in chemical reactions provoked, at least partly, by the conditions created by the mechanical stresses on those minerals (for example, the fracturing of the mineral surfaces or the compaction of the particles). These reactions in the present are referred to as "voltage activated reactions" or "voltage activated reactivity". One type of these stress-activated reactions may be the reactions of diagenesis. In the sense in which it is used herein, the terms "diagenesis reactions", "diagenesis reactivity", and "diagenesis" include chemical and / or physical processes which, in the presence of water, move a portion of the mineral in a particle and / or convert a portion of the mineral into a particle in some other form. A mineral that has been moved or converted into the present is referred to as a "diagenesis product" or "diagenic product". Any particle comprising a mineral may be susceptible to these reactions of diagenesis, including natural silicate minerals (eg, quartz), synthetic silicates and vitreous materials, metal oxide minerals (both natural and synthetic), and the like.

Two of the main mechanisms that are believed that the reactions of diagenesis involve "pressure dissolution" and "precipitation processes". When two mineral surfaces impregnated with water come into contact with each other at a low point of formation, the mineral solubility located near that point can increase, causing the minerals to dissolve. The minerals in solution can diffuse through the water film outside the region where the mineral surfaces are in contact (for example, the pore spaces of a packet of particles), where they can precipitate out of the solution. The dissolution and precipitation of minerals in the course of these reactions can reduce the conductivity of a packet of particles, inter alia, by clogging the pore spaces in the parcel of particles with a mineral precipitate and / or by collapsing the pore spaces by dissolving the solid mineral in the "walls" of those pore spaces. In other cases, minerals on the surface of a particle may exhibit a tendency to react with substances in the reservoir, formation, and / or treatment fluids that are in contact with the particles, such as, water, gelling agents (eg, example, polysaccharides, biopolymers, etc.), and other substances commonly found in these fluids. The molecules coming from these substances can be anchored to the mineral surface of the particle. These types of reactivity can also decrease the conductivity of an underground formation, inter alia, through the obstruction of conductive fractures in the formation by any molecules that have been anchored to the resident particles within those fractures. Both types of reactions in general require the presence of a fluid, such as water, to be present at any significant degree.

Silica (silicon dioxide) appears naturally in a variety of crystalline and amorphous forms, all are sparingly soluble in water; thus leading to the formation of undesirable deposits. The silicates can be salts derived from silica or silicic acids, especially orthosilicates and metasilicates, which can be combined to form polysilicates. The solubility of silica depends, although not exclusively, on several factors such as pH, temperature, and ionic composition. Most silicates, except alkali silicates, are sparingly soluble in water. Several different forms of silica and silicate salt deposits are possible and the formation of deposits depends, among other factors, on the temperature and pH of the water.

SUMMARY OF THE INVENTION The present disclosure relates to treatments and compounds useful in underground formations, and, at least in some embodiments, with treatments and compounds where the particles and / or surfaces can be subjected to the accumulation of silica scale.

One embodiment of the present invention provides a method. The method comprises providing an additive for controlling silica scale in an underground formation. The method further comprises providing a package of particles in the underground formation. The method further comprises allowing the silica scale control additive to suppress the accumulation of silica scale next to the particle package.

Another embodiment of the invention provides another method. The method comprises providing a fluid comprising a carrier fluid, a plurality of particles, and an additive for the control of silica scale. The method further comprises introducing the fluid into an underground formation. The method further comprises allowing at least one of the particles to form a packet of particles in the underground formation. The method further comprises allowing the silica scale control additive to suppress the accumulation of silica scale next to the particle package.

Still another embodiment of the invention provides a composition. The composition comprises a plurality of particles of the silica scale control additive, wherein the silica scale control additive is capable of suppressing the build-up of silica scale next to the particle package.

The features and advantages of the present invention will be apparent to those skilled in the art. While many changes can be made by those skilled in the art, these changes are left from the spirit of the invention.

DETAILED DESCRIPTION OF THE INVENTION The present disclosure relates to treatments and compounds useful in underground formations, and, at least in some embodiments, with treatments and compounds where the particles and / or surfaces can be subjected to the accumulation of silica scale.

The term "coating" in the sense in which it is used herein, refers to at least a partial coating of some or all of the particles. The term "coating" does not imply a complete or substantial coverage of the particles or mixture of particles. Instead, a particle can be coated if it has, for example, at least a partial coating.

The term "derivative", herein is defined to include any compound that is prepared from one of the listed compounds, for example, by replacing one atom in the listed compound with another atom or group of atoms, at arranging two or more atoms in the listed compound, by ionizing one of the listed compounds, or by creating a salt of one of the listed compounds. A derivative of a material can include, but is not limited to, a composition of a compound based on a plurality of base materials, a composite material, or an aggregate material of various compositions.

In the sense in which it is used herein, the terms "diagenesis reactions" "diagenesis reactivity" and "diagenesis" include chemical and physical processes which, in the presence of water, move a mineral and / or convert a mineral in some other way. Examples of these minerals include, but are not limited to, oxides or hydroxides of zirconium, magnesium, aluminum, titanium, calcium, strontium, barium, radium, zinc, cadmium, boron, gallium, iron, or any other suitable element to form a product. diagenic These minerals can be found in a particle, in a formation, and / or introduced into a formation as "source material of diagenesis". A mineral that has been moved or converted into the present is referred to as a "diagenesis product" or "diagenic product." As used herein, the term "aqueous fluid interaction" includes a variety of possible interactions between an aqueous fluid and a particle. These interactions may include the infiltration of the aqueous fluid into the particle, for example, through pores, voids, fissures, cracks, and / or channels at or near the surface of the particle. These interactions may also include diagenesis.

As used herein, the term "diffusion barrier" includes any classification of materials, including a coating, on or near a particle that prevents and / or prevents the interaction of the aqueous fluid with the particle. For example, some diffusion barriers fill or cover pores, voids, fissures, cracks, or channels at or near the surface of the particle to prevent and / or prevent infiltration by the aqueous fluid. As another example, some diffusion barriers prevent and / or prevent diagenesis.

As used herein, the term "diagenic protective materials" refers to one or more diagenic products that can be selectively stimulated to form a diffusion barrier.

As used herein, the term "filler material" or "filler material" means a particulate material that is capable of being filled into a pore, void, crack, crack, or channel in or near the surface of a particle or on the surfaces within the porous matrix of the individual particles.

As used herein, the term "relatively low molecular weight" refers to a molecular weight that could encompass short chain monomers and polymers having physical dimensions from a few Angstroms to several hundred manometers.

In the sense in which it is used herein, a "monolayer" refers to a coating of a material approximately one unit thick. For chemical products, this can mean a coating as fine as a molecule, and for particle compositions, it can mean a coating of a depth of particle grain.

In the sense in which it is used in the present, the terms "pores", "holes", "cracks", "cracks" and "channels" refer to the characteristics at or near the surface of a particle. Any given particle may have one or more pores, voids, fissures, cracks, or channels, or it may be free of these characteristics. One or more of these characteristics in general can be referred to as "surface features". The use of the terms with in no way intended to indicate that all three must be present simultaneously, or totally, for the teachings of the present exposition to apply.

In the sense in which it is used herein, the terms "particle", "macroparticle", "consolidation particle" and "gravel" are all used to refer to either an individual particle or a plurality of particles that they can be used to support a fracture in an underground formation, to form a consolidation package, or to be used in the formation of a gravel pack. These particles can be placed in an underground formation, including in spaces in the rock itself, fractures within the rock, and / or drilling the well for sounding that penetrates the underground formation.

As used herein, the term "package" or "package of particles" refers to a collection of particles within an enclosed volume, wherein the particles can be juxtaposed and / or in contact with each other. Yes, and where the pore spaces can be placed between the particles. Examples of "packages" may include "consolidation packages", which may refer to a collection of consolidation particles within a fracture, and / or "gravel packs", which may refer to a grouping of particles that are packaged Close enough to prevent the passage of certain materials through the package.

The term "on the fly", in the sense in which it is used herein, indicates that a flow stream comprising particles is introduced into another flow stream comprising a hydrophobic coating agent in such a way that the streams combine and they are mixed so that they flow as a single current, in some cases, the currents can be combined to flow as a single current as part of a progressive treatment at the work site. This mixing can also be described as mixed "in real time".

As used herein, the term "silica scale control additives" can be any product capable of suppressing the build-up of silica scale by increasing the solubility of the silica in solution, inhibiting propagation of polymeric silica chain, and / or by decreasing the size or amount of any silica scale created in a solution.

The term "gel", in the sense in which it is used herein, and its derivatives refer to a viscoelastic or semi-solid state, similar to gelatin assumed by some colloidal dispersions.

If there is any conflict in the uses of a word or term in this specification and one or more of the patent or other documents that may be incorporated herein by reference, definitions that are consistent with this specification shall be adopted for the purposes of understanding of this invention.

There are many advantages of the present invention, only some of which are mentioned here. An advantage of the methods discussed herein may be the suppression of the build-up of silica scale within a packet of particles in an underground formation, including the rock itself, fractures within the rock, and / or a well for sounding. that penetrates the underground formation. Without limiting the invention to a particular theory or mechanism, it is currently believed that, when placed within a formation, a packet of particles may experience an accumulation of silica scale due to the dissolution of silica from either the particles or the formation. Silicon can be dissolved in fluids, such as fluids for formation or fluids for treatment. The dissolved silica can then be precipitated in various ways to create a silica scale in, upstream, or downstream of the particle package. This silica inlay may have a tendency to form or collect in the interstitial spaces of the particle package, which may reduce the permeability of the package over time. As such, the suppression or inhibition of silicon dissolution and the accumulation of silica scale may be able to reduce the loss of permeability in the particle package, thereby increasing the final well productivity.

The protection of the particles from this damage can be achieved in several ways. In one embodiment, an additive for control of silica scale can be used to treat a package of particles. Silica scale control additives can suppress the buildup of silica scale by increasing the solubility of silicon within the particle package while simultaneously avoiding large accumulations of silica scale. Various additives can be used for control of silica scale to limit the formation of silica scale, as will be discussed in more detail below.

The protection of the particles from harmful interactions with aqueous fluids can be achieved in several days. In accordance with the embodiments of the present invention, these may generally include the treatment of a particle with a diffusion barrier that acts to prevent the interaction of the particles with the aqueous fluids during and / or after placement in the formation. The diffusion barrier may comprise one of various types of materials, including hydrophobic materials, diagenic protective materials, and various polymer compositions. Some embodiments of the present invention may use a filler material to fill the pores, voids, cracks, crevices, or channels that may be present on a particulate surface. Alternatively, a filler material can be used to generate and / or place the diffusion barrier. For example, a hydrophobic material may be used to coat a filler material, and the filler material may then generate a diffusion barrier (eg, comprising a diagenesis product) on the particles. The filler material can fill pores, voids, fissures, cracks, or channels on the surfaces of the particle, resulting in a surface that may be more hydrophobic than the original particle surface. Each of these materials and methods will be described in greater detail below.

The particles that can be used in the embodiments of the present invention include any consolidation particles or gravel that can be used in an underground application. Suitable particles can include sand, sintered bauxite, silica alumina, glass beads, etc. Other suitable particles include, but are not limited to, sand, bauxite, garnets, fumed silica, ceramic materials, glass materials, polymeric materials, polytetrafluoroethylene materials, pieces of nutshell, pieces of seed husk, pieces of fruit bone, wood, composite particles, consolidation particles, degradable particles, coated particles, gravel, and combinations thereof. Suitable composites may comprise a binder and a particulate material in which suitable particulate materials may include, silica, alumina, garnets, smoked coal, carbon black, graphite, mica, titanium dioxide, meta-silicate, silicate calcium, kaolin, talc, zirconia, boron, fly ash, hollow glass microspheres, solid glass, and combinations thereof, in certain embodiments, the particles may comprise common sand. In some embodiments, a derivative of one or more of the particulate materials may also be used. The derivatives may include materials such as compounds, composite materials, and aggregate materials of various compositions. In some embodiments of the present invention, some or all of the particles may consist of a material with a source of diagenesis. In this embodiment, the particles may comprise oxides or hydroxides of zirconium, magnesium, aluminum, titanium, calcium, strontium, barium, radium, zinc, cadmium, boron, gallium, iron, or any other suitable element to form a diagenic product. Suitable particles can take any form including, but not limited to, the physical form of platelets, chips, flakes, ribbons, bars, strips, spheres, spheroids, ellipsoids, toroids, granules, or tablets. Although a variety of particle sizes may be useful in the present invention, in certain embodiments, the particle sizes may vary from about 200 mesh to about 8 mesh.

The particle embodiments of the present invention may contain pores, voids, cracks, crevices, or channels at or near the surface. For example, SEM micrographs at high magnification can show that the surfaces of the particles, such as the particles made of bauxite, can be loaded with pores, voids, fissures, cracks, and channels. Without being limited by theory, it is believed that these pores, voids, fissures, cracks, or channels at or near the surface of the particle can provide a direct path to allow harmful interaction between aqueous fluids and particles that can lead to the degradation of the particles under formation pressure and temperature.

In some embodiments, the particles may be treated or coated with one or more suitable substances. In general, the particles can be treated or coated with any substance that is suitable for traditional particle treatments. In certain embodiments, the particles are coated to prevent the injection of water into the particles. For example, the particles can be coated and / or used as discussed in "Prevention of Water Intrusion Into Particulates" by Nguyen et al., U.S. Patent Application Serial Number, Geochemical Control of Fracturing Fluids "by Reyes et al. al., United States patent application No. , and / or "Ceramic Coated Particulates" by Reyes et al., United States patent application No. , each presented on the same day, and the total exposures thereof are incorporated herein by reference in their entirety. In one embodiment, a portion of the particles may be coated to limit their diagenic reactivity while others may remain uncoated to provide a reaction site for the source material of diagenesis.

In one embodiment, an additive for controlling silica scale with a packet of particles (eg, a consolidation pack or gravel) can be used to suppress the buildup of silica scale by mitigating, inhibiting, or suppressing formation and accumulation. of silica (also known as silica inlay). The formation of silica scale on the surface of the formation fracture or in a solution within a particle pack can occur on the particles. Silica scale control additives can increase the amount of soluble silica in a solution. Without intending to be limited by theory, it is believed that the silica scale control additives inhibit the polymerization and accumulation of silica and colloidal silica by breaking down the chain propagation. In one embodiment, an additive for control of silica scale can be any compound that controls the formation of scale to some degree and does not react negatively with the particles, the formation, a treatment fluid, a forming fluid, or any other aspect of the underground environment. In one embodiment, suitable silica scale control additives can include polyaminoamide and polyethyleneimine dendrimers, which can be combined with carboxymethylinulin and polyacrylates. In an alternative embodiment, the polyallylamines, the polyacrylamide copolymers, and the polyallydiamethylammonium chloride can also be used as additives for control of silica scale. "Examples of suitable silica scale control additives include Acumer ™ 5000, commercially available from Rohm and Hass of Philadelphia, PA; and Cla-Sta® XP and Cla-Sta® FS available from Halliburton Energy Services, Inc. of Duncan, OKAY.

In some embodiments, an additive for control of silica scale can be added to a treatment fluid (eg, a fracture fluid, a carrier fluid, a stimulation fluid, etc.) in an amount sufficient to suppress the accumulation of silica inlays by inhibiting the formation of silica scale. The treatment fluid may be aqueous, non-aqueous, or a combination of fluid types. In general, the treatment fluid may comprise a carrier fluid, particles, such as a proppant agent, and one or more additives, such as additives for control of silica scale. In some embodiments, the amount of silica scale control additive may be any amount necessary to control the deposition of silica and silicate in the system to be treated. In one embodiment, the amount may be any amount sufficient to obtain a conserved permeability in a packet a proppant agent of at least about 40%, the measurement of which is described in more detail later. In one embodiment, the amount of the silica scale control additive can vary from about 1 to about 1000 parts per million (ppm) by weight of the carrier fluid. In an alternative embodiment, the amount may vary from about 1 to about 100 ppm by weight of the carrier fluid. The pH of the carrier fluid can also have an impact on the effectiveness of the additive for control of silica scale. In some embodiments, the pH of the carrier fluid can be maintained between about 4.0 and about 8.0. In one embodiment, the pH of the carrier fluid can be maintained between about 6.5 and about 7.5.

Silica scale control additives can be added to a well for sounding before, after, or during the placement of a particle pack. In one embodiment, the additive for controlling silica scale can be added to a fracture fluid and can be carried with the fracture fluid during fracture formation. In some embodiment, the additive for control of silica scale may be in the fracturing fluid in the formation during placement and adjustment of a packet of particles.

Alternatively, the silica scale control additive can be mixed with a carrier fluid used to carry and adjust the particle package in the formation. In yet another embodiment, the additive for silica scale control can be used after the particle pack has been placed in the well for sounding. In these embodiments, a carrier fluid can be used to carry the additive for control of silica scale in the borehole and through the particle pack. By way of example, a packet of particles can be contacted by an additive for control of silica scale. This technique can also be used as a post-treatment method to periodically treat the particle package over time, among other purposes, to maintain permeability in the particle package.

One embodiment of the present invention provides a method. The method comprises providing additives for control of silica scale in an underground formation. The method further comprises providing a package of particles in the underground formation. The method further comprises allowing the silica scale control additive to suppress the build-up of silica scale next to the particle package.

In some modalities, this method can be used in the recovery of fluids from the underground formation. The fluids that are recovered can be a fluid introduced previously in the underground formation, an aqueous deposit and / or a fluid for formation, a hydrocarbon fluid, or a combination thereof.

Another embodiment of the invention provides another method. The method comprises providing a fluid comprising a carrier fluid, a plurality of particles, and an additive for control of silica scale. The method further comprises introducing the fluid into an underground formation. The method further comprises allowing at least one of the particles to form a packet of particles in the underground formation. The method further comprises allowing the silica scale control additive to suppress the accumulation of silica scale next to the particle package. In some modalities, this method can be useful in the recovery of fluids from the underground formation. The fluids that will be recovered can be a fluid introduced previously into the underground formation, an aqueous deposit and / or a fluid for formation, a hydrocarbon fluid, or a combination thereof.

Still another embodiment of the invention provides a composition. The composition comprises a plurality of particles, an additive for control of silica scale, wherein the additive for control of silica scale is capable of suppressing the accumulation of silica scale next to the package of particles. In some embodiments, this method may be useful in the preparation of particles for underground treatments and / or the use of the particles in underground treatments.

In order to quantify the mechanical strength of the particles and the permeability of the particle package, both before and after exposure to formation conditions and fluids, various test procedures can be used to determine various properties of the particles. the particles. The first test method studies the temperature-stimulated diagenesis of a package of particles by exposing a packet of particles to a flowing solution of simulated formation fluid at an approximate formation temperature. The second procedure studies the diagénico growth stimulated by the tension / temperature through the exhibition of a package of particles to a static flow environment under pressures and temperatures of simulated formation. The mechanical strength of the individual particles can be measured before and after the test procedures to determine the percentage of loss of particle resistance due to exposure to the formation temperature or pressure. Alternatively, the permeability of the particle package can be measured before and after the temperature-stimulated diagenesis test to determine a conserved permeability value for the particle package. As would be understood by one of ordinary skill in the art with the benefit of this exposure, the conditions of the expected underground formation (eg, temperature, pressure, formation fluid composition) for a selected underground formation will determine the training conditions suitable for testing procedures.

In the temperature-stimulated diagenesis test procedure, deionized water can first be heated to a test temperature between approximately 93.33 ° C (200 degrees Fahrenheit (° F)) and approximately 315.56 ° C (600 ° F) by passing it to through a heat exchange coil. The simulated formation fluid can be formed by passing the deionized water through multiple packages of crushed formation material arranged in series. The number of training packages required for the test may vary such that the simulated training fluid leaving the last packet may be in equilibrium with the crushed formation material. Through experimentation, the typical number of training packages in general can be between about 1 and about 10. The crushed formation material can be sifted to remove the fines and a mesh fraction of about 8/35 can be used in the training packages.

In one embodiment, once a simulated formation fluid is obtained in equilibrium with the crushed formation material, the simulated formation fluid can be directed to a column containing a packet of particles. The temperature in the particle package can be maintained at an approximate formation temperature between approximately 93.33 ° C (200 ° F) and approximately 315.56 ° C (600 ° F), which corresponds approximately to the temperature of the deionized water entering first To the system. A simulated formation secretion flow quantity can be maintained at approximately 1 milliliter per minute during the test.

The flow test can be maintained for between about 10 to about 200 days, and in one embodiment, for at least about 20 days. After this time, the particle package can be disassembled to test the mechanical properties of the individual particles, as will be discussed in more detail below. For example, a surface and compositional analysis can be performed after disassembly to determine what types of materials are being formed under simulated formation conditions. At this time a permeability test can also be performed. In this test, the permeability of the particle packets can be measured at room temperature before the particle pack dismantling. The measured permeability of the package can then be compared to an initial permeability measurement performed of the package at room temperature before the package is placed in the test apparatus. The comparison of the initial permeability measurement with the permeability measurement obtained after the package is subjected to the test conditions can allow a preserved permeability to be calculated.

The test method for voltage / temperature stimulated diagenesis may involve testing the particle package under static flow conditions at approximate formation pressures and temperatures. In this method, a packet of particles can be loaded into a test cell and filled with a saline solution. The test cell can be loaded between approximately 2.44 kg / m2 (0.5 pounds per square foot (lb / ft2)) of particles up to approximately 14.64 kg / m2 (3.0 lb / ft2) of particles. In one embodiment, as the fluid medium, a solution of KC1 at about 2% can be used. Formation wafers, whether manufactured from the core material of formation or from the rock outcrop material, can be placed above and below the particle pack in the test column. The system can then be closed and placed under simulated formation pressure and heated to approximate formation temperatures. In one embodiment of this method, the temperature can be maintained between approximately 37.77 ° C (100 ° F) and approximately 287.78 ° C (550 ° F). In another embodiment, the temperature can be maintained between about 37.77 ° C (100 ° F) and up to about 176.67 ° C (350 ° F). The pressure can be maintained between approximately 140.62 kg / cm2 (2, 000 psi) and approximately 703.1 kg / cm2 (10,000 psi). In another embodiment, the pressure can be maintained between about 351.55 kg / cm2 (5,000 psi) and about 562.48 kg / cm2 (8,000 psi). In one embodiment, the test may be conducted between about 1 to about 50 weeks, and in another embodiment, the test may be conducted for at least about 4 weeks (approximately 28 days).

With the term of the voltage / temperature stimulated diagenesis test, the test cell can be disassembled and the particle packet can be removed for testing. As with the flow test method, additional tests can also be performed at this time. For example, a surface and compositional analysis can be performed after disassembly to determine what types of materials are being formed under simulated training conditions. Alternatively, the resulting interstitial fluid can be analyzed to determine the relative solubility of the particles under the formation conditions.

Changes in the mechanical properties of the particles obtained from either the voltage-stimulated diagenesis or the temperature-stimulated diagenesis test can be determined using a crushing resistance analysis of individual grains. The analysis can utilize a Weibull statistical analysis procedure based on a plurality of crushed particle samples. The crushing test can be based on a point load of uni-axial understanding of a particle. Under compression load in the uni-axial direction, a spherical particle may be under tension in directions perpendicular to the load with a tensile strength, s, calculated by 2. 8 F s = p? 1 where d is the diameter of each particle and F is the load.

A Weibull analysis may include a statistically significant number of samples to be shredded, which may vary from about 10 to about 50 samples to shred individual, or between about 20 to about 40 samples to shred individual. In one embodiment, a sample size between about 25 and about 30 samples for individual particle grinding can be used in the analysis. All the resistance data points can then be classified from low to high as s? < s2 < s3 < ... < s ?, where N represents the total number of samples. A break probability can be calculated from the equation: N where, as before, N is the total number of samples, for example approximately 30 samples, and # is the index number for the rated resistance values (for example, 1 to N). by graphing a linear graph can be obtained An eibull distribution can be found by linear adjustment and by generating an equation; where m is the Weibull module and s is the characteristic resistance. The resistance will tend to increase along with the reliability of the resistance calculation when the values s0 and m increase. Then the characteristic resistance changes in the particles can be determined. By comparing the characteristic resistance of the particles before exposure to the simulated formation fluid with the characteristic resistance of the particles after exposure to the simulated formation fluid, a conserved resistance can be calculated from the equation: (Conserved where s? exposed is the characteristic resistance of the particles after exposure to the simulated formation fluid, and s? Sir exposing is the characteristic resistance of the particles before exposure. Similarly, a conserved permeability can be calculated by dividing the permeability measured at the end of the temperature-stimulated diagenesis test with the permeability measured at the beginning.

In one embodiment, a single set of test conditions can be used for the comparison of different sets of particles comprising diffusion barriers and / or filling materials. It is defined that the conserved resistance value will be measured by the stress / temperature stimulated diagenesis test. In this method, a packet of particles is loaded into a test column and filled with a saline solution comprising a KC1 solution of approximately 2%. The test cell is charged with approximately 9.76 kg / m2 (2 lb / ft2) of particles. Training wafers are placed above and below the particles in the test cell. The system is then closed and placed under a pressure that will be approximately equal to the expected pressure in the formation in which the particles are expected to be placed. The temperature can be maintained at a temperature that is approximately equal to the formation temperature where the particles are expected to be placed. For example, the system can be placed under simulated formation pressure of approximately 632.79 kg / cm2 (9000 psi) and a temperature of approximately 121.11 ° C (250 ° F). These conditions are then maintained for approximately 28 days.

With the term of the voltage / temperature stimulated diagenesis test, the test cell is dismantled and the particle matrix is removed for testing. Changes in the mechanical properties of the particles are obtained using tested particles using the voltage / temperature stimulated diagenesis test. The analysis uses a Weibull statistical analysis procedure based on a plurality of samples for particle grinding, as discussed above. An individual analysis includes a statistically significant number of samples, which may be between about 20 and about 40 samples, for example, about 30 shredded samples of individual particles. However, in some cases, the sample size may vary so that the actual number of samples is smaller or larger to obtain a statistically significant number of samples. Then the characteristic resistance changes in the particles can be determined. By comparing the characteristic resistance of the particles before exposure to the simulated formation fluid with the characteristic resistance of the particles after exposure to the simulated formation fluid, a preserved resistance value is calculated from the equation. where s0 exposed is the characteristic resistance of the particles after exposure to the simulated formation fluid, and s0 Not exposed is the characteristic resistance of the particles before exposure.

Similarly, it is defined that the conserved permeability value of the particle package will be measured by the temperature-stimulated diagenesis test. In the temperature-stimulated diagenesis test procedure, an initial permeability measurement of a particle packet is performed while the particle packet is at room temperature. Then, deionized water is heated to a test temperature of approximately 260 ° C (500 ° F) by passing it through a heat exchange coil. Lower test temperatures may also be used depending on the specific particulate material and the coating used. For example, one of ordinary skill in the art can determine that a lower test temperature is required to avoid thermal decomposition of the particles, diffusion barrier, or filler material. The simulated formation fluid is formed by passing deionized water through multiple packages of crushed formation material arranged in series. The number of training packages required for the test may vary such that the simulated formation fluid allows the last package to be in equilibrium with the crushed formation material at the flow magnitude used during the test of approximately 1 milliliter per minute. . The typical number of training packages in general is between about 2 and about 5. The crushed formation material is sifted and an 8/35 mesh fraction is used in the training packages. The formation material is obtained by grinding a core removed from a specific well during drilling or from the drilling chips obtained while drilling the well for drilling through a zone of interest.

The simulated formation fluid is then directed to a column containing a packet of particles. The temperature in the particle pack is maintained at a temperature of approximately 260 ° C (500 ° F). A lower test temperature can be used depending on the specific particulate material and the coating material used. For example, one of ordinary skill in the art can determine that a lower test temperature is required to avoid thermal decomposition of the particles, diffusion barrier, or filler material. A simulated formation secretion flow quantity is maintained approximately 1 milliliter per minute during the test. The flow test is maintained for approximately 30 days. After this time, the permeability of the parcel of particles is measured before disassembly and after the parcel of particles has been allowed to cool to room temperature, allowing a conserved permeability to be calculated from the equation: Permeability 'comJa b l d d where Permeabilidadexpuesta is the permeability of the particles after exposure to the simulated formation fluid, and Permeability Without exposing is the permeability of the particles before exposure.

The particles prepared and tested according to the methods of the present invention using the modality characteristic conditions can exhibit a conserved strength value of greater than about 20%. Alternatively, the particles can exhibit a conserved strength value greater than about 60%. In yet another embodiment, the particles may exhibit a conserved strength value greater than about 80%. In yet another embodiment, the particles can exhibit a conserved strength value greater than about 90%. In one embodiment, the particles used to form a package can be characterized by a conserved permeability value of at least about 40%. In another embodiment, the particles can be characterized by a conserved permeability of at least about 60%. In yet another embodiment, the particles can be characterized by a retained permeability of at least about 80%. In some embodiments, the conserved permeability can be at least about 99%.

Therefore, the present invention will be adapted to obtain the ends and advantages mentioned as well as those that are inherent in the present. The particular embodiments discussed above are illustrative only, since the present invention can be modified and practiced in different but equivalent ways, which is evident to those skilled in the art having the benefit of the teachings herein. In addition, no limitations are intended to the details of construction or design herein shown, other than those described in the claims below. Therefore, it will be apparent that the particular illustrative embodiments set forth above can be altered or modified and all these variations are considered to be within the scope and spirit of the present invention. While the compositions and methods are described in terms of "comprising", "containing", or "including" various components or steps, the compositions and methods may also be "consisting essentially of" or "consisting of" the various components and steps. All numbers and variations discussed above may vary by some amount. Wherever a numerical variation with a lower limit and an upper limit is exposed, any number and any included variations that lie within the variation are exposed. In particular, each variation of values (of the form, "from about a to about b" or, equivalently, "between about a to b" or, equivalently, "from about ab") set forth herein, shall be understood to mean that They establish each number and variation encompassed within the broadest variation of values. Also, the terms in the claims have their clear, normal meaning unless explicitly and clearly defined otherwise by the owner. In addition, the indefinite articles "one" or "one", in the sense in which they are used in the claims, are defined herein to mean one or more of one of the elements that are presented. If there is any conflict in the uses of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, definitions that are consistent with this specification shall be adopted.

Claims (20)

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as property CLAIMS:

1. A method characterized in that it comprises: provide an additive for control of silica scale in an underground formation; provide a package of particles in the underground formation; Y allow the silica scale control additive to suppress the buildup of silica scale next to the particle package.

2. The method according to claim 1, characterized in that the additive for control of silica scale comprises at least one substance selected from the group consisting of: a polyaminoamide dendrimer, a polyethyleneimine, a carboxymethylinulin, a polyacrylate, a polyallylamine, a copolymer of polyacrylamide, a polyallydiamethylammonium chloride, any combination thereof, and any derivative thereof.

3. The method according to claim 1, characterized in that the additive for control of silica scale is present in a fluid in a concentration between about 1 and about 1000 parts per million by weight of the fluid.

4. The method according to claim 3, characterized in that the fluid has a pH greater than or equal to about 4.0 and less than or equal to about 8.0.

5. The method according to claim 1, characterized in that the package of particles has a conserved permeability of about 40% or more as determined using a temperature-stimulated diagenesis test, using the formation conditions expected for the underground formation.

6. The method according to claim 1, characterized in that: the package of particles comprises a plurality of particles; Y at least one of the plurality of the particles is coated with a hydrophobic coating material.

7. A method characterized in that it comprises: provide a fluid comprising: a carrier fluid; a plurality of particles; Y an additive for controlling silica inlays; introduce the fluid in an underground formation; allow at least one of the particles to form a packet of particles in the underground formation; Y allow the silica scale control additive to suppress the buildup of silica scale next to the particle package.

8. The method according to claim 7, characterized in that the additive for control of silica scale comprises at least one substance selected from the group consisting of: a polyaminoamide dendrimer, a polyethyleneimine, a carboxymethylinulin, a polyacrylate, a polyallylamine, a copolymer of polyacrylamide, a polyallydiamethylammonium chloride, any combination thereof, and any derivative thereof.

9. The method according to claim 7, characterized in that the plurality of particles comprises at least one substance selected from the group consisting of: a sand, a sintered bauxite, a silica alumina, a glass bead, a bauxite, a fumed silica, a ceramic material, a glassy material, a polymeric material, a polytetrafluoroethylene material, a composite particle, a coated particle, a degradable particle, a proppant, a gravel, any combination thereof, and any derivative thereof

10. The method according to claim 7, characterized in that the carrier fluid comprises at least one substance selected from the group consisting of: an aqueous fluid, a hydrocarbon fluid, a gel, and a derivative thereof.

11. The method according to claim 7, characterized in that the additive for control of silica scale is present in the fluid in a concentration between about 1 and about 1000 parts per million by weight of the carrier fluid.

12. The method according to claim 7, characterized in that the carrier fluid has a pH greater than or equal to about 4.0 and less than or equal to about 8.0.

13. The method according to claim 7, characterized in that the package of particles is a pack of proppant agent placed in one or more fractures in the underground formation.

14. The method according to claim 7, characterized in that the package of particles has a conserved permeability of about 40% or more as determined using a temperature-stimulated diagenesis test using the formation conditions expected for the underground formation.

15. The method according to claim 7, characterized in that at least one of the plurality of particles is coated with hydrophobic coating material.

16. a composition characterized in that it comprises: a plurality of particles; Y an additive for controlling silica scale, wherein the additive for control of silica scale is capable of suppressing the accumulation of silica scale close to the plurality of particles.

17. The composition of claim 16, characterized in that the additive for controlling silica scale comprises at least one substance selected from the group consisting of: a polyaminoamide dendrimer, a polyethylene imine, a carboxymethylinulin, a polyacrylate, a polyallylamine, a polyacrylamide copolymer , a polyallydiamethylammonium chloride, any combination thereof, and any derivative thereof.

18. The composition according to claim 16, characterized in that the plurality of proppant agent particles comprise at least one substance selected from the group consisting of: a sand, a sintered bauxite, a silica alumina, a glass bead, a bauxite, a smoked silica, a ceramic material, a vitreous material, a polymeric material, a polytetrafluoroethylene material, a composite particle, a coated particle, a degradable particle, a proppant, a gravel, any combination thereof, and any derivative of the same.

19. The composition according to claim 16, characterized in that at least some of the plurality of particles are coated with a hydrophobic coating material.

20. The composition according to claim 16, characterized in that: at least some of the plurality of particles are placed in a packet of particles in an underground formation; Y the package of particles has a conserved permeability of about 40% or more as determined using a temperature-stimulated diagenesis test using the formation conditions expected for the underground formation.