EA011152B1 - Composition for obtaining geosynthetic composite for borehole strengthening - Google Patents

Abstract

The invention relates to a position useful for creating geosynthetic composites in-situ, said composition comprising: at least one melamine-formaldehyde resin; and a non-aqueous drilling fluid, wherein the melamine-formaldehyde is soluble in nonaqueous drilling fluids and invert emulsion drilling fluids containing Cto Colefins, esters, paraffinic oils and blends thereof, and also soluble in diesel and mineral oils and blends thereof with Cto Colefins, esters, and paraffinic oils.

Description

The present invention relates to the technology of fixing the wall of boreholes. More specifically, the invention relates to chemical compositions for the production of geosynthetic composite materials for strengthening and strengthening of wells. Even more specifically, the invention relates to chemical compositions for producing ίη δίΐιι geosynthetic composites that are soluble in one or more non-aqueous drilling fluids or drilling fluids based on either inverse emulsions or drilling fluids derived from diesel and mineral oils, and mixtures of any of these drilling fluids with olefins C7-C20, esters and paraffin oils. The properties of the compositions can be changed by simply changing the concentration of the monomeric cross-linking agent and / or solvent.

The level of technology

Boreholes created to extract minerals, such as oil and natural gas, pass through geological strata that are numerous and differing from one another. These geological formations have different chemical composition, permeability, porosity, pore fluids, internal pressure in the pores and material properties. Important material properties that significantly affect well construction include compressive strength, tensile strength, crack initiation pressure, crack propagation pressure, porosity, Young's modulus (elasticity), Poisson's ratio, and volume compression ratio.

Large differences in reservoir pressure, reservoir material properties and types of reservoir fluids often require isolation and processing of some geological formations. Insulation and treatment may be required to treat a weak formation, to increase the pressure of formation of cracks near the wellbore, to strengthen weak zones, to eliminate mud absorption, to reduce formation permeability, to seal flow zones, to isolate high / low pressure zones, to eliminate unwanted water or gas intake, for direction to pipeline damage caused by the collapse of the reservoir and the subsequent destruction of pipes, or as a plug for wells that need shut off permanently or temporarily, or as a so-called preliminary plug for preparing the site for drilling a new well from the remaining upper part of the former well. In addition, when drilling highly branched wells, there is often a need to strengthen and seal the intermediate zones surrounding the formation. These intermediate zones are subject to considerable mechanical stresses. In addition, wells may have weak formations, which, when drilled, cause significant deviations from the vertical direction, or where part of the well is horizontal.

Weak formations may appear, for example, where the pressure at the beginning of the formation of cracks in one formation may be lower than the internal pressure in the pores of another formation. Increased wellbore pressure due to the permeability of a single formation can lead to the appearance of cracks in a weaker formation. Similarly, the fluid pressure gradient in the well, necessary to maintain the pressure in the pores of the formation during drilling, may exceed the hydraulic fracturing pressure in another weaker formation that goes into the well.

Attempts were made to isolate individual layers, reinforcing them with steel casing strings or cement, or any other methods known from the prior art. In the case of cementing steel casing in a borehole to isolate geological formations with significantly different properties, each such casing string is expensive and installing it reduces the diameter of the borehole in subsequent sections as the borehole deepens. Therefore, it is desirable to minimize the number of casing required to achieve the desired depth.

The use of cementing for drilling wells is known in the art, however, cement deficiency is that the cement hardening stage may take up to 24 hours, which is an unacceptably long period, especially in areas of very expensive offshore drilling. Another disadvantage of using cement is that, due to its granular structure, the material has a low ability to penetrate the formation, which can lead to a reduced sealing effect.

References to the use of resin-based cementing materials for sealing boreholes are known from the literature. In the book Νον, Νονοί \ Us11-Stsp1shd Ro1etg Soapsgs1s Sotrokys, Atspsap Sopgsgs1s [pkShgNs (AC1), 8rss1a1 RiYiuyop 69: ArrBsayop Ro1utsg Sopsgsyss,. 73-92, 2с1бшд Α.Ν. et al. described a resin-based system with an initiator and inhibitor, in which the final curing of the resin depends on the presence of water in the system. The main component of the resin are organic siloxanes.

Document \ ¥ O 94/12445 discloses an alternative material to cement and water suspensions, which is designed to complete the primary and secondary cementing of deep hot oil wells with a constant background temperature in the range of 120-200 ° C (248-392 ° E). The basis of the bonding agent is diallyl phthalate resin, for which the setting / curing time is controlled by the addition of a temperature-sensitive peroxide initiator and a suitable inhibitor.

- 1,011,152

The prior art various sealants for lining and hardening of boreholes. When using sealants, a resin or monomer should be selected for each well, based on compatibility with the drilling fluid or mud to complete the drilling of the well. Epoxy resins provide the best indicators of compressive strength, tensile strength and adhesive properties. However, epoxy resins and / or their curing agents have poor compatibility and unsatisfactory performance in combination with olefinic esters and paraffin hydrocarbon fluids.

HUO 94/12445 discloses a composition for sealing various types of zones in oil wells, which includes monomer, initiator and optionally filler, as well as other additives.

Patent I8 No. 4556109 describes a system based on curing by the condensation mechanism, and not by the free radical polymerization mechanism.

Acrylate or methacrylate resins / monomers that are soluble in olefinic, ester and paraffinic hydrocarbon fluids are commercially available. However, when used individually, such monomers and resins cannot provide such material characteristics as are necessary for a geosynthetic composite lining. Typically, these resins are characterized by poor tensile strength, low crack resistance and low compressive strength. Mixtures of acrylate monomers containing prepolymers have improved tensile strength, compressive strength and resistance to cracking. However, the prepolymers used in these mixtures are often insoluble in the hydrocarbon fluids mentioned above.

In engineering there is a definite need for chemical compositions that can create ίη δίΐη geosynthetic composites that are completely soluble in non-aqueous drilling fluids, drilling muds based on reverse emulsions, drilling fluids derived from diesel and mineral oils, and their compositions, and mixtures of any of the above drilling fluids with olefins С ₇ С ₂₀ , esters and paraffin oils. In addition, there is a need for the obtained η δίΐιι geosynthetic composites that provide good radial permeability and quickly set.

A definite achievement in this field of technology would be the development of a composition for the formation of a смесьη δίΐιι composite, which contains a mixture of components and which can be adjusted to obtain optimal material properties, depending on the properties and conditions arising in the reservoir, by simply applying the type and concentration of crosslinking monomer and / or solvent and by varying the amount of each component. In addition, it would be beneficial if the composition had improved compatibility with any combination of non-aqueous drilling fluids, drilling fluids based on reverse emulsions, or drilling fluids derived from diesel and mineral oils, and mixtures of any such drilling fluids with one or more esters , olefins and paraffin oils, or combinations thereof.

DISCLOSURE OF INVENTION

The present invention is a composition used to obtain ίη δίίη geosynthetic composites, this composition comprising a melamine formaldehyde resin, or a mixture of suitable melamine formaldehyde resins; optionally mixed with a polyol and / or poly (hydroxy) ether, or a combination thereof, and a non-aqueous drilling fluid. In some embodiments, the drilling fluid is a reverse emulsion drilling fluid containing C7-C20 olefins, esters, paraffin oils and their mixtures, as well as diesel and mineral oils and their mixtures with C7-C20 olefins, esters and paraffin oils. In addition, the composition may contain additives in order to initiate the polymerization and to regulate the polymerization time, which are selected from acidic, or acid-releasing additives, to initiate the polymerization. Optionally, a retarder or polymerization inhibitor is added in order to delay the onset of polymerization until injection into the formation is completed. In addition, the composition may contain other additives selected, for example, from one or more: a) binding agents, b) suspending agents; c) dyes; b) weighting; e) materials to combat absorption; and 1) other additives known from the prior art. The composition, including the amounts of each component, the type of acrylate / methacrylate monomer, if it is used, and the chemical composition and material properties of the thermoplastic elastomer, if used, is changed to ensure the required properties of the geosynthetic mineral-plastic composite formed by η δίΐιι as a result of chemical processing.

Brief Description of the Drawings

FIG. 1 shows a schematic of a device for mixing and injecting compositions of the present invention for chemical treatment of a well.

FIG. 2 shows an alternative arrangement of piping for components.

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Detailed Description of the Invention

The present invention has developed a chemical composition for producing ίη δίιι geosynthetic composite-plastic composites. This composition is compatible, or mixed, and is completely soluble in non-aqueous drilling fluids and solutions based on inverse emulsions containing C7-C20 olefins, esters, paraffin oils and their mixtures, as well as diesel and mineral oils and their mixtures with C ₇ olefins - C ₂₀ , esters and paraffin oils. This composition cures in the pores of the reservoir, binds together the particles of the reservoir and forms a rock-plastic composite. This treatment is suitable for use in order to increase the pressure that initiates cracks near the wellbore, in depleted zones, in ultrahigh pressure zones, flow zones, brown mud absorption zones and in other cases that will be obvious to those skilled in the art.

The melamine-formaldehyde component of the composition is a melamine-formaldehyde resin, which is soluble in any hydrocarbon mixture selected from one or more non-aqueous drilling muds, drilling muds based on reverse emulsions, diesel fuels and mineral oils, and any mixtures of them with C ₇ -C ₂₀ olefins, esters and paraffin oils and their combinations. Suitable melamine formaldehyde resins are amine crosslinking agents intended for the thermal setting of surface coatings. Suitable resins should have the ability to crosslink the molecules of the primary film former in the coating in order for a spatial thermally cured polymer network to form; This process involves the interaction of functional amino groups with the corresponding reactive groups of the primary film former. Suitable resins are soluble in solvents and contain melamine capable of expanding in water. Suitable resins have a flexible ability to catalytic setting in the temperature range from approximately 37.8 to 315.5 ° C and higher (100-600 ° D), more often between approximately 65.5 and 176.7 ° C (150-350 ° P), and provide a film with good flexibility and toughness. Resins for the composition are selected based on a combination of performance and curing parameters, depending on the properties of the formation to be processed.

Melamine formaldehyde resins can be used individually, can be mixtures of suitable melamine formaldehyde resins, or can also be mixed with a polyol or a mixture of polyols. Suitable polyols should be soluble in melamine-formaldehyde resin or in a mixture of melamine-formaldehyde resins, and also have solubility in the hydrocarbon phase of the drilling / finishing solution. Suitable polyols include, for example, but not limited to, ethylene glycol, propylene glycol, glycerin, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, and poly (ethylene propylene) glycol. A suitable amount of polyol is from 0 to 50%, more preferably from 5 to 35%, and most preferably from 10 to 30% of the reservoir volume. Polyols suitable for use in the present invention are commercially available under the trademark Wogapo1 Watasu ™ polypoly from Ωο \ ν Syesh1sa1 Sotrupa.

In addition, melamine formaldehyde resin or mixtures of melamine formaldehyde resins can optionally be mixed with poly (hydroxy) ether. The scope of protection of the invention also includes compositions of melamine formaldehyde resins or mixtures of resins with a mixture of polyol and poly (hydroxy) ether. A suitable poly (hydroxy) ether material should be soluble in melamine formaldehyde resin or in a mixture of melamine formaldehyde resins, as well as in the hydrocarbon phase of drilling and drilling completion solutions. Suitable poly (hydroxy) ethers include those with a high molecular weight with a preferred linear structure, which usually provides a combination of toughness and flexibility and is characterized by the presence of an ether functional group and a side hydroxyl group, which facilitates wetting and binding to polar substrates and fillers . Suitable poly (hydroxy) ethers include essentially linear polymers having the general formula - [Ό-Θ-Ε-Θ] _η , in which Ό is a radical residue of a dibasic phenol, Ε is a hydroxyl-containing radical epoxide residue and n equal to at least 30, means the degree of polymerization (see US Patent 4,355,122, incorporated herein by reference).

These poly (hydroxy) ethers can be prepared by mixing from about 0.985 to 1.015 mol of epihalohydrin with 1 mol of dibasic phenol, together with from about 0.6 to 1.5 mol of alkali metal hydroxide, such as sodium hydroxide or potassium hydroxide, usually in solution, at a temperature of from about 10 to 50 ° C, until at least 60 mol.% of epihalohydrin is converted.

Phenolic radical residue Ό containing dibasic phenol may be dibasic mononuclear phenol, dibasic polynuclear phenol or their mixtures. Preferred dibasic polynuclear phenols include bis (hydroxyphenyl) alkanes, di (hydroxyphenyl) sulfones, di (hydroxyphenyl) ethers, and the like.

The hydroxyl-containing radical residue Ε providing the epoxide may be a monoepoxide or diepoxide. The term "epoxide" means a compound containing an oxirane group, i.e. an oxygen atom bound to two vicinal aliphatic carbon atoms. Suitable

- 3,011,152 epoxides include monoepoxides, diepoxides, saturated epoxides, and the like, and mixtures thereof.

In addition, mixtures of suitable poly (hydroxy) ethers can be used. A suitable amount of poly (hydroxy) simple ether is in the range from 0 to 50%, more preferably from 5 to 35% and most preferably from 10 to 30% by volume of the composition. Suitable poly (hydroxy) ethers are commercially available under the trademark ΡΑΡΗΕΝ® Ryeiohu K.e8Sh8 from the company ΙΝΟΗΕΜ Sogr. They are available in the solid state, in the form of solutions, aqueous dispersions, mixtures of resins and micron powders (see also US Pat. No. 6,034,160 from ŠCHNEM, which is entirely incorporated into the description by reference).

To dilute the mixture of the selected composition can be used a solvent that improves the wettability of the surface of the reservoir and improves resistance to water pollution. This solvent must be miscible with water and hydrocarbons, and it can be selected from any conventional type known to those skilled in the art. Suitable solvents include (but are not limited to) low molecular weight anhydrous alcohols, such as methanol, ethanol, propanol; ethers and polyethers, such as tetrahydrofuran, dioxane, ethylene glycol monoalkyl ethers, polyethylene glycol monoalkyl ethers, or glycol esters; ether alcohols such as 2-butoxyethanol or mixtures thereof. Preferred solvents include ethylene glycol monobutyl ether, propylene glycol methyl ether acetate, and other solvents that are effective for dissolving thermoplastic elastomers or mixtures thereof. A suitable concentration of solvent can be selected in the range from 0 to 50 wt.%, More preferably from 1 to 35 wt.% And most preferably from 5 to 25 wt.%.

When using the present invention, a catalyst or initiator is used. The use of a catalyst or initiator is known in the art and it is not intended that the invention be limited to any particular type of catalyst. A suitable catalyst for the condensation polymerization of melamine formaldehyde resins is an acid catalyst or an acidic catalyst. Suitable catalysts may include, for example, (but not limited to) strong acid catalysts, such as mineral acids, including, for example, hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid; strong organic acids, including sulfonic or para-toluenesulfonic acid, benzenesulfonic acid, xylene sulfonic acid, dinonylnaphthalene disulfonic acid, dinonylnaphthalenesulfonic acid and dodecylbenzenesulfonic acid; weak organic acids, including (but not limited to) formic, boric, phosphorous, oxalic acid, and acid salts of hexamethylenetetramine, acetic acid, fumaric acid and formic acid; esters of weak organic acids, including (but not limited to) butyl acetate, isopropyl acetate and methyl formate; latent acid catalysts such as ammonium chloride, alkyl phosphoric esters and phenyl phosphate esters; and acid releasing catalysts, such as acid esters or blocked acid catalysts, including (but not limited to) the amine salts of dinonylnaphthalene disulfonic acid, dinonylnaphthalenesulfonic acid and dodecylbenzenesulfonic acid, or mixtures thereof.

Suitable free radical initiation catalysts or catalyst systems may include, for example, (but not limited to) azo compounds, alkyl or acyl peroxides or hydroperoxides, ketoperoxides, peroxide esters, peroxycarbonates and peroxyketals or mixtures thereof. Such compounds have different activation temperatures and half-lives, or in other words, the temperature at which their interactions are initiated, and the reaction becomes extensive. Examples of suitable alkyl peroxides, dialkyl peroxides, peroxides methyl ethyl ketone peroxide, cyclohexane dibutyl peroxide, di (2,4-dichlorobenzoyl) peroxide, diisobutyl peroxide, tert-butyl perbenzoate and tert-butyl peroacetate, or mixtures thereof. The catalyst can be used in a total amount from about 0.001 to 20% by weight, based on the weight of the polymerizable monomer.

Blocked catalysts can be used at elevated temperatures in order to slow down the polymerization process. Blocked catalysts are the amine salts of aromatic sulfonic acids. Examples include the amine salts of dinonylnaphthalenedisulfonic acid, dinonylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid and para-toluenesulfonic acid, and mixtures thereof. These blocked catalysts do not exhibit catalytic activity until they turn into acid form under the action of temperature. For example, para-toluenesulfonic acid may cure the resin at room temperature. Amine salts of para-toluenesulfonic acid cannot cure resin below 65-90 ° C.

Other additives may be incorporated, which include (but are not limited to) binding agents; suspending agents; colorants; weighting; materials to combat absorption.

Numerous binding agents are known in the art, and it is not intended to limit this invention to specific agents. Preferred binding agents include silane bonds.

- 4 011152 agents. Suitable binders may be selected from the group consisting vinyltrimethoxysilane, vinyltriethoxysilane, vinyl-tris (a-methoxyethoxy) silane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, δ-glycidoxypropyltrimethoxysilane, δ-glycidoxypropylmethyldimethoxysilane, δmetakriloksipropiltrimetoksisilan, δ-metakriloksipropilmetildimetoksisilan, akriloksipropiltrimetoksisilan, akriloksipropilmetildimetoksisilan, N-into- (Aminoethyl) ^ - aminopropyltrimethoxysilane, N-in- (Aminoethyl) ^ - Aminopropyltriethoxysilane, N-in- (Aminoethyl) ^ - Aminopropylmethyldi etoksisilan and N-B- (aminoethyl) ^ - aminopropilmetildietoksisilan and mixtures thereof. In addition, bifunctional sulfur-containing organic silanes are suitable, such as, for example, bis- (3triethoxysilylpropyl) tetrasulfide, bis- (3-trimethoxysilylpropyl) tetrasulfide, and bis- (3-trimethoxysilylpropyl) tetrasulfide grafted onto silicon dioxide commercially available from Osch.155a speakers. A suitable concentration of combining agent is in the range from 0 to 10 wt.%.

Suspending agents known in the art may be added to the formulation to prevent precipitation of a solid. However, this invention is not intended to limit any specific agents. Suitable suspending agents include, for example, organophilic clays, amines treated clays, oil-soluble polymers, quaternary ammonium compounds, polyamide resins, polycarboxylic acids, and soaps.

In addition, the composition may contain other conventional ingredients of the treatment fluids, such as additives to control fluid loss, colorants, antifoaming agents, if necessary, etc., used in conventional amounts that are known to those skilled in the art. Of course, one should refrain from adding such other ingredients if they adversely affect the basic desired properties of the treating fluids.

Weighting agents or density control materials may be added to the formulation. Suitable materials include, for example, galena, hematite, magnetite, iron oxides, ilmenite, barite, siderite, celestine, dolomite, calcite, manganese oxides, magnesium oxide, zinc oxide, zirconium oxides, spinels, and the like. If added, the amount of such material depends on the desired density of the chemical composition for processing. Typically, weighting material is added in order to obtain a mud density of up to about 1.1 kg / L (9 lb / gallon). Preferably, the weighting material is added up to 2.3 kg (5 pounds) per barrel (159 liters) and most preferably up to 225 kg (500 pounds) per barrel (159 liters) of the resin composition.

Materials to combat absorption can also be incorporated. Typically, these materials are distributed in categories such as fibers, flocs, granules, and blends. Specific examples include (but are not limited to) crushed mica, mica flakes, silica slag, diatomaceous earth, hydrated borates, fractionated sand, gilsonite, crushed coal, charcoal, cellophane flakes or ribbons, cellulose fiber, expanded perlite, paper scraps pulp and the like, walnut shells or other nuts, crushed to various sizes, cotton seed husks or cotton bolls, sugar cane fiber or crushed sugar cane fibers a, flax straw, shredded hemp, shredded fir bark, shredded bark and mahogany fibers, grape marc, crystalline silica, amorphous silica, clay, calcium carbonate and barite. Suitable amounts of additional solids used in combination with the copolymer (s) and / or ionomer (s) may be apparent to those skilled in the art.

The composition, chemical components and properties of the material - a thermoplastic elastomer - may vary in order to obtain a material with specified properties for the geosynthetic composite formed by η δίΐιι.

The method and apparatus for applying the composition of the present invention is described in more detail in the simultaneously filed application for US patent No. 60/576645, which is incorporated here by reference. The advantages of certain embodiments of the invention include reducing the number of casing strings that are required to create a borehole of a certain depth, eliminating the reduction of the borehole diameter, which is caused by the need to isolate geological formations with significantly different properties using steel columns cemented in the soil at regular intervals, ensuring the creation of a drilling rig wells of the same diameter or “mono-well”, lined with one body, or no more than two casing holes olonnami, after reaching the required depth. Simultaneously filed US patent application number 60/576440, which is used here as a reference, also applies to the problem at hand.

In the first stage of the method of applying the composition of the present invention, the material properties of the exposed geological formation are determined or evaluated. Certain properties are considered to select the appropriate treatment. These properties include, for example, cracking pressure, tensile strength, Young's modulus, Poisson's ratio, temperature, porosity, and permeability. Methods for determining such data are known to those skilled in the art and this invention is not intended to be limited to any specific test methods for determining

- 5,011,152 divisions of these properties.

After determining the properties of the reservoir, data can be obtained and analyzed in order to identify the necessary changes in the material properties of the open geological formation, which would be desirable in order to eliminate the need to install additional casing strings. Having identified the desired changes, you can select the appropriate chemical composition for processing, and you can also determine the value of the required minimum radial permeability distance and the amount of chemical treatment.

During processing, a cylindrical shell of a geosynthetic composite material is created, which radially propagates from the drilled well. For this geosynthetic composite, the values of the modulus of elasticity, tensile strength, compressive strength, tensile strength, fracture toughness and permeability are different from those for the surrounding formation. These properties allow the chemically treated area of the reservoir to withstand the increased stress (pressure) in the drilled well compared to the untreated formation, without fractures. The pressure of formation of cracks in the chemically treated area is higher than in the untreated formation. The permeability of the chemically treated area is usually lower than in the untreated formation.

The increase in cracking pressure depends on the material properties of the geosynthetic composite and the thickness of the treated area. The change in the pressure of the occurrence of cracks can be estimated using equations known from mechanics, specifically from rock mechanics, to calculate the pressure for the occurrence of cracks. The lack of permeability of the geosynthetic composite is an important factor in the change in the pressure of the occurrence of cracks. The impermeable treated area of the reservoir plays the role of an elastic layer that redistributes pressure applied to the well and the surrounding formation, allowing the application of increased stress (pressure) before cracking and destruction of the drilled well occurs. For an impermeable geosynthetic composite layer created by treating the formation, three types of destruction are possible: a) cracking of the geosynthetic composite, b) cracking in the untreated formation beyond the thickness of the geosynthetic composite, or c) plastic fracture of the geosynthetic composite. For some types of fracture, the impermeability of the layer is crucial, and the thickness of the layer is of little importance, with the exception of the thickness needed to obtain a completely impermeable layer. For other types of damage, layer thickness is important. The increase in cracking pressure depends on the material properties of the geosynthetic composite and the thickness of the treated area. The change in the pressure of the occurrence of cracks can be estimated using equations known from mechanics, specifically from mining mechanics, which allow one to calculate the strength of the seams for a fracture. The lack of permeability of the geosynthetic composite is an important factor in the change in pressure of the occurrence of cracks. The impermeable treated area of the reservoir acts as an elastic layer that redistributes pressure applied to the well towards the surrounding formation, which allows higher stresses (pressures) to be applied before the well bore breaks and collapses. For an impermeable geosynthetic composite layer created by treating the formation, three types of fracture are possible: a) rupture of the geosynthetic composite, b) cracking in the untreated formation beyond the geosynthetic composite, or c) plastic fracture of the geosynthetic composite. For some three types of fracture, the impermeability of the layer is crucial, and the thickness of the layer is of little importance, with the exception of the thickness necessary to obtain a completely impermeable layer. For other types of damage, the thickness of the layer is practically significant. Experts in the field of engineering geomechanics can use the principles of resistance of materials in order to calculate the most likely type of fracture and the required layer thickness in order to increase the pressure of the beginning of the formation of cracks.

The volume of the treated area is determined by the magnitude of the radial penetration from the borehole, the length of the interval, the diameter of the well and the porosity of the formation. The volume of the cylindrical shell, which is multiplied by the porosity of the reservoir, is calculated in order to estimate the volume of pore space that will be filled during chemical processing. Excess volume may be added to compensate for the uncertainty of the estimate. The borehole volume in excess of the processed interval must be filled with reagent for treatment prior to injection or during the injection process. In addition, this volume is added to the treatment volume of the formation with some excess in order to obtain the necessary volume for processing.

The permeability of the geological formation to be treated is an important factor. The reservoir must have sufficient permeability to ensure the flow of the chemical reagent into the pores, the replacement of the pore fluid and the stronger formation of particles together. It is desirable to treat formations having a matrix permeability between 1 and 50,000 millDarcy (MD). The penetration depth usually increases with permeability at constant injection pressure. Typically, the pressure required to inject the treatment reagent decreases with increasing permeability at a constant flow rate. Formations having a permeability of less than about 0.1 mD are difficult to process. For low permeability formations, treating fluids with very low viscosity, high injection pressures and a long treatment period are required. Practical

- 6 011152 solution for reservoirs with low permeability is the use of plastic material with high strength, which requires a small radial penetration distance from the drilled well in order to achieve the desired increase in the pressure of formation of cracks.

When creating the composition of a chemical treatment, it is necessary to consider the period of time that is required for the implementation of the treatment. The polymerization process should proceed after the completion of injection of the volume of reagent for treatment into the reservoir. However, the polymerization process should not take too long after completion of the injection, since dilution, or reverse flow, or interlayer fluid flow inside the well is possible. The processing time is estimated by the sum of the period required to inject the reagent for treatment inside the well, adjacent to the geological formation being treated, the time required for injection of the reagent for processing inside the formation, time to raise or remove any processing tool or pipelines from the processing interval, plus a factor security. The time required to inject the reagent for treatment inside the well, adjacent to the geological formation being treated, is calculated using the volume of the chemical reagent, the volume of the trigger column and the transfer rate. The time required to inject the volume of reagent for treatment inside the reservoir can be calculated using the volume of chemical reagent to be injected and the filtration rate.

The quasistationary filtration rate can be determined by filtering testing or fluid loss using a formation core or a synthetic core having filtration properties representing the geological formation being treated. This time required for the injection of a chemical reagent should be less than the curing time of the composition used. Typically, a well is filled with a composition in excess of the volume that is needed for processing, and then it is not necessary to increase the pressure to the desired degree in order to send the composition into the formation at a rate calculated from the filtration rate, taking into account the tolerance for errors and irreproducibility. Thus, the desired volume of the composition is sent to the reservoir near the interval to be processed.

The treatment agent can be selected based on a number of considerations, of which compatibility with well fluids (i.e. drilling fluids, final fluids and formation fluids) is important. The treatment reagent must be compatible or mixed with the well fluids, and most preferably, the treatment reagent must be completely dissolved in the well fluids. In addition, any catalyst or initiator must be compatible with well fluids. For example, in a fluid containing a large amount of acid soluble or neutralizing acid components, an acid catalyzed reagent should not be used to treat the fluid. In addition, the selected treatment agent must be able to penetrate the sediment of drilling fluid on the filter or through damage to the formation near the well, which is usually called the shell.

Additional significant factors when considering the choice of treatment reagent are the strength and material properties for chemical processing, the viscosity of a chemical reagent, the initiating or catalytic type of chemical reagent for processing, the well temperature, the required time of placement of the chemical reagent in the geological formation and the permeability, porosity and lithology of the geological reservoir.

In practice, the thickness of the treated reservoir (geosynthetic composite) exceeds the minimum thickness necessary to achieve the desired increase in pressure of the occurrence of cracks in the reservoir. This is due to the heterogeneity of the reservoir and any changes in the injection process. As a result, the geological formation is processed in order to improve / enhance the properties of the material to the required level by injecting a chemical processing agent into the formation to create a geosynthetic composite extending in the radial direction from the well from 0.05 to 5 m, preferably from 0, 1 to 3 m, most preferably from 0.25 to 2 m. The type of reagent for chemical treatment and the depth of penetration are mutually related and should be determined taking into account the type of geological formation, permeability and porosity of the nera otannoy portion of the formation, the presence of natural and induced fractures, cracks, voids or defects; and the required material properties of the geosynthetic composite, which is formed by 8η 8jp as a result of chemical processing. In sturdy formations or when using very strong reagents for treatment, a smaller radial penetration depth may be required. A deeper radial penetration depth may be required for weak or non-reinforced formations, and / or when using less powerful reagents for processing.

In the first stage of the method of applying the composition of the present invention, the material properties of the opened geological formation can be determined or assessed. These properties may include, for example, the type of geologic formation, the permeability and porosity of the raw part of the formation, and the presence of natural and induced fractures, cracks, defects or voids. In some embodiments of the present invention, at the next stage, the necessary changes in the material properties of the exposed geological formation can be identified in order to eliminate the need to install casing before the drilling process can be continued.

Taking into account the changes in material properties required to continue the process

- 7 011152 rhenium and eliminating the need to install casing, you can choose the composition for treatment, taking into account compatibility with well fluids (ie drilling fluids, final solutions and formation fluids), strength and material properties for chemical processing, the viscosity of the chemical solution for processing , initiating or catalytic type of chemical reagent, well temperature, required time of placement of the chemical reagent in the geological formation and permeability, porosity and lithology of the formation.

The treatment chemical should be at least compatible with the fluids of the well and preferably completely dissolved in the fluids of the well. The catalyst or initiator must also be compatible with well fluids. For example, it is impractical to use an acid catalyzed reagent to treat a fluid containing a large number of acid soluble or neutralizing acid components. In addition, the selected treatment chemical must be able to penetrate the sediment of drilling fluid on the filter or through damage to the formation near the well. In sturdy formations or when using very strong chemicals for treatment, a smaller radial penetration depth may be required, and a deeper radial depth of penetration may be required for weak or non-reinforced formations and / or for less powerful chemical agents for processing.

The reservoir is treated in order to improve / enhance the properties of the material to the required level, choosing the appropriate composition of the reagent for processing, and then injecting this reagent into the reservoir to create a geosynthetic composite extending in the radial direction from the borehole wall from 0.05 to 5 m, preferably from 0.1 to 3 m and most preferably from 0.25 to 2 m.

The composition of the chemical treatment reagent according to the invention can be introduced into the well through the drill string (layout at the bottom of the column) by open treatment if a large amount of plugging agent (material for anti-absorption) is used in the drilling mud by injection with time lag or by injection in time without reverse circulation (especially in the zone with high filtration losses). Preferably, the composite extends in the radial direction from the well from 0.25 to 2 m. The monomer / resin composition solidifies in the pores of the formation and binds the formation particles together to form a rock-plastic composite.

After processing, the material properties of the geosynthetic composite are improved compared with the properties of the untreated geological formation. This increases the pressure of the occurrence of cracks, respectively, the tensile strength, the Young's modulus and the Poisson's ratio change, the ductility, crack resistance, compressive strength and permeability improve.

After the zone has been processed, it is subjected to a pressure tightness test and the drilling can be continued. At this point, it may be advisable to use a drilling fluid with a higher or lower density, which is within the competence of a specialist in this field of technology.

The following examples are provided to illustrate the invention described here. These examples are intended for illustration purposes only and should not be construed in any way to limit the scope of the invention. Specialists in this field of technology can recognize that many variations of the invention are possible within the scope of its scope disclosed in the description.

Examples 1-3 demonstrated the use of a composition with at least one melamine formaldehyde resin or a mixture of melamine formaldehyde resins, optionally mixed with polyol and / or poly (hydroxy) ether, soluble in non-aqueous drilling fluids and drilling muds based on reverse emulsions containing olefins C _7- C ₂₀ , esters, paraffin oils and their mixtures, as well as soluble in diesel and mineral oils and their mixtures with C ₇ C ₂₀ olefins, esters and paraffin oils; and optionally with other additives, one or more of which are selected from the group: binding agents; suspending agents; colorants; weighting; materials to combat absorption and other additives known from the prior art.

Example 1

Many treatments have been carried out in seven wells that have open hole intervals at a depth of approximately between 9,000 and 18,000 feet (2,743-5,486 m) at a gas field in South Texas. In this depth range, static geothermal temperatures occur between approximately 235 and 320 ° E (113-160 ° C). In these wells, many geological formations are discovered in this depth interval. Typically, fractured formations in a wellbore are described as a sequence of permeable sandstone layers separated by shale intervals and silt. Hydrocarbons, mainly gaseous, are extracted from some of the exposed layers of sandstone from other wells in the field. When mining, the pressure in the pores of these layers decreases and the pressure of initiation and propagation of cracks decreases. In other opened, permeable sands containing hydrocarbons, mining is not performed, and they retain the initial pressure in the pores of the formation and the corresponding elevated values of the initiation pressure and the propagation of cracks. In some cases, the mass of the drilling fluid required to balance the pressure in the pores of non-productive formations exceeds the values of the pressure of initiation and propagation

- 8,011,152 fractures in previously productive formations. Typically, casing is cemented and cemented in the wellbore in order to isolate geological formations with such differences in pressure and strength.

Failure to isolate formations with such differences in pressure and properties usually results in cracking of a weaker formation, which causes absorption of the drilling fluid. If mud absorption cannot be prevented or suppressed, an uncontrolled flow of hydrocarbons (or other fluids under pressure) between the formations or to the surface may occur. Such uncontrolled flow from the wellbore is called spouting in the prior art. In well No. 1 of this study, a weaker reservoir cracks under the action of a larger mass of drilling mud needed to control the pressure in the pores from a previously unproductive formation. The depth of the mud absorption zone is approximately 12,000 feet (3,658 m), which is 3,000 feet (914 m) deeper than the preliminary casing shoe. Strong and difficult controlled absorption of the drilling fluid was observed. To repair the destroyed reservoir and restore circulation, the resin is treated with a resin. In this treatment, the following composition is used, based on the final amount of 159 liters (1 barrel, 42 gallons) of fluid:

50.7 L (13.4 gal) reverse emulsion of drilling fluid in diesel oil 2.0 kg / l (16.7 lb / gallon) 63.8 liters (16.8 gallons) melamine formaldehyde resin kezpepe 755 16.0 liters (4.2 gallons) ethylene glycol monobutyl ether 145.6 kg (323.6 pounds) hematite 1.4 kg (3.06 pounds) catalyst - para-toluenesulfonic acid (solution in isopropyl alcohol, 40 wt.%) 4.54 kg (10 pounds) Madta Plieber K. Edward (coarse fibrous material to combat absorption) 2.27 kg (5 lb) Madsha RPeg Rte (fine fibrous material to combat absorption)

The density of the original drilling fluid is 2.0 kg / l (16.7 lb / gallon). Adding melamine formaldehyde resin, ethylene glycol monobutyl ether and catalyst reduces the solution density. Hematite (iron oxide) is added as a weighting agent in order to increase the density of the final mixture to an initial value of 2.0 kg / l (16.7 lb / gallon).

The treatment is carried out as follows.

Extrude the end of the drill string to 2,740 m (9,000 feet), directly inside the casing shoe with a diameter of 24.5 cm (9-5 / 8 inch).

50 barrels (7950 l) of the resin mixture (composition above) are pumped below the drill pipe to a depth where the front of the mixture is 10 barrels (1590 l) above the end of the drill string.

Note. No separating fluids are required before or after the resin mixture in order to separate the treatment fluid from the drilling fluid in the wellbore. This is because the resin is completely soluble in the mud and combines with the mud to form the treatment mixture. It contains a mutual solvent in order to ensure complete compatibility between the mud and the resin mixture. However, the solvent is excluded from the subsequent technological operations, due to the full compatibility of the resin with the drilling mud and the absence of water in most of the treated formations.

Close the ring blowout fuse to stop fluid circulation from the well and prepare resin injection to treat the mud absorption zone.

50 barrels (7950 l) of a resin mixture containing material to combat absorption are pumped into the loss zone using a mud pump, down the drill pipe to force the resin mixture out of the pipe into the formation.

When the entire resin mixture is displaced from the drill pipe, an additional 10 barrels (1,590 liters) of fluid is pumped down the drill pipe to displace the rear front of the resin mixture to a depth below the end of the drill pipe, but above the top of the mud absorption zone.

An additional 10 barrels (1590 L) of the displacer is pumped below the annulus to completely displace the back front of the resin mixture to a level just above the top of the mud absorption zone.

Maintain the well in the closed state for 8 hours before the resumption of drilling operations.

This treatment does not completely eliminate the absorption of the drilling fluid. However, this opens sealed high-pressure zones, from which the gas passed into the wellbore. Consequently, the risk of loss of control over the well is eliminated by reducing losses and sealing

- 9 011152 of the fountain zones. No other handling of this problem interval is required. Example 2

In well No. 2 of this study, the exposed depleted formation (with reduced pressure) cracks under the action of a larger mass of drilling mud needed to regulate in the exposed high-pressure zone. This causes the absorption of the drilling fluid and prevents further drilling process in order to deepen the wellbore. To repair the destroyed reservoir and restore circulation, the resin is treated with a resin. In this treatment, the following composition is used, based on the final amount of 159 liters (1 barrel, 42 gallons) of fluid:

50.7 L (13.4 gallons) Inverse Emulsion Drilling Fluid in Diesel Oil 2.0 kg / L (16.8 lb / gallon) Melamine-Formaldehyde Gum Kespepe 755 Ethylene Glycol Monobutyl Ether

63.8 liters (16.8 gallons)

16.0 liters (4.2 gallons)

148.9 kg (328.3 pounds)

3.47 kg (7.65 lb)

2.27 kg (5 lb)

2.27 kg (5 lb) hematite catalyst - formic acid (88%)

Macau Fiber Core (coarse fibrous material to combat absorption)

Maga Rayeg Rte (a fine fibrous material to combat absorption)

The density of the original drilling fluid is 2.0 kg / l (16.8 lb / gallon). Adding melamine formaldehyde resin, ethylene glycol monobutyl ether and catalyst reduces the solution density. Hematite (iron oxide) is added as a weighting agent in order to increase the density of the final mixture to an initial value of 2.0 kg / l (16.8 lb / gallon).

The treatment is carried out according to the following method.

Extrude the end of the drill string to 91 m (300 feet) above the mud absorption zone.

35 barrels (5565 l) of the resin mixture (composition shown above) are pumped below the drill pipe to a depth where the leading front of the mixture is 10 barrels (1590 l) above the end of the drill string.

Note. No separating fluids are required before or after the resin mixture in order to separate the treatment fluid from the drilling fluid in the wellbore.

Close the ring blowout fuse to stop fluid circulation from the well and prepare resin injection to treat the mud absorption zone.

35 barrels (5565 l) of a resin mixture containing material to combat absorption are pumped into the loss zone using a mud pump, down the drill pipe to force the resin mixture out of the pipe into the formation.

The back of the resin mixture is displaced to a level of 30.8 m (100 feet) above the top of the mud absorption zone.

Maintain the well in the closed state for 8 hours before the resumption of drilling operations.

After this treatment, the density of the drilling fluid is increased to 2.06 kg / l (17.2 lb / gallon) and the wellbore is deepened to a total predetermined depth without absorption of the drilling mud.

Example 3

Well 3 uses resin treatment to strengthen the formation until the absorption of drilling mud occurs. A processing resin is pumped into this well to cure the mud absorption zone and the high pressure spout is sealed at a shallower depth. Sealing the spouting area reduces the density of the drilling mud, which will be used for deep drilling. The reduced density of the drilling fluid provides for drilling the weakened formation to a greater depth without cracking the formation and absorbing the drilling fluid.

After drilling the weakened formation to a greater depth, the weak formation is treated with a mixture of resin in order to strengthen the formation and increase the pressure for the occurrence of cracks near the wellbore. The following mixture was used, based on the final quantity of 159 liters (1 barrel, 42 gallons) of fluid:

- 10 011152

77.6 liters (20.5 gallons)

63.8 liters (16.8 gallons) kg (161 lbs)

3.4 kg (7.65 pounds) of invert emulsion of drilling mud in diesel oil

1.92 kg / l (16.0 lb / gallon) melamine formaldehyde resin Kestepe 755 hematite catalyst - para-toluenesulfonic acid (solution in isopropyl alcohol, 40% by weight).

For this treatment using the technology of injection under pressure. The technique includes the following operations.

Descend the drill string and mark the overall depth. The total depth of the wellbore is approximately 30.8 m (100 ft) below the bottom of the weak interval that will be processed. The weak bed is about 46 m (150 feet) thick.

Extrude the drill string 15.4 m (50 ft) above the total depth.

Fill 30 barrels (4770 l) of the resin mixture from edge to edge and above the top of a weak reservoir. The height of the resin blend column is approximately 120 m (400 ft). An excess amount of resin is poured in, allowing the resin to be injected into the formation matrix.

The fluid is poured by pumping the resin mixture into the drill string, injecting fluid (usually drilling mud) after the resin blend so that the resin blend moves from the end of the drill string to the annular gap between the wellbore and the drill string. This annular gap is open to the surface to allow fluid to circulate from the wellbore when the resin blend is placed.

After pouring the resin mixture into the wellbore, the drill string is pulled up to the pre-casing shoe.

Ring blowout fuse close.

Fluid is pumped down the drill string to feed the resin into a weak formation.

Radial penetration of the resin into the wellbore can be calculated from the amount of fluid injected into the reservoir, the porosity of the reservoir, the thickness (height) of the reservoir and the diameter of the wellbore. With this treatment, the calculated radial penetration length of the resin is 0.6 m (1.9 feet).

After the resin is poured into the reservoir, the well is closed for 6 hours before cleaning the cured resin from the wellbore and resuming drilling operations to deepen the well.

The density of the drilling fluid is increased to over 2.04 kg / l (17.2 lb / gallon) during drilling operations to full depth, without absorbing the drilling mud. Resin treatment effectively strengthens the formation near the wellbore.

The method described above in this experimental study of well No. 3 is repeated in four more wells with similar successful results.

Claims (19)

CLAIM 1. Composition used to obtain зη zyi geosynthetic composites containing at least one melamine-formaldehyde resin and non-aqueous drilling fluid, and melamine-formaldehyde resin is soluble in non-aqueous drilling fluids and drilling fluids based on reverse emulsions containing С ₇ -С ₂₀ olefins, esters , paraffinic oils and their mixtures, and also soluble in diesel and mineral oils and their mixtures with C ₇ -C ₂₀ olefins, esters and paraffin oils. 2. The composition according to claim 1, which further comprises at least one polyol and / or poly (hydroxy) ether. 3. The composition according to claim 1, in which the melamine formaldehyde resin is a mixture of melamine formaldehyde resins. 4. The composition according to claim 1, which additionally contains other additives selected from one or more binding agents, suspending agents, dyes, weighting agents, materials for controlling absorption, or combinations thereof. 5. The composition according to claim 1, which further comprises one or more additives selected from catalysts and inhibitors, or any combination thereof, to initiate the polymerization and to regulate the polymerization time. 6. The composition according to claim 1, which further comprises a saturated thermoplastic elastomer. 7. The composition according to claim 1, in which the melamine-formaldehyde resin is a solvent soluble amine cross-linking agent intended for the thermal setting of surface coatings. 8. The composition according to claim 7, in which the melamine formaldehyde resin has the ability to catalytic setting in the temperature range from approximately 37.8 to 315.5 ° C (100-600 ° E). 9. The composition according to claim 1, which additionally contains a polyol that is soluble in melamine 10. The composition according to claim 9, in which the polyol is selected from the group consisting of ethylene glycol, propylene glycol, glycerol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol and poly (ethylene propylene) glycol. 11. The composition according to claim 1, in which the melamine formaldehyde resin is mixed with poly (hydroxy) ether, which is soluble in the melamine formaldehyde resin or a mixture of tar, as well as in the hydrocarbon phase of the drilling / finishing solution. - 11 011152 formaldehyde resin, as well as in the hydrocarbon phase of the drilling / finishing solution. 12. The composition according to claim 11, in which the poly (hydroxy) ether is a high molecular weight poly (hydroxy) ether. 13. The composition according to claim 11, in which the poly (hydroxy) ether is a poly (hydroxy) ether with a predominantly linear structure. 14. The composition according to claim 11, in which the poly (hydroxy) ether is characterized by ether functional groups and pendant hydroxyl groups, which facilitate wetting and binding to polar substrates and fillers. 15. The composition according to claim 1, which additionally includes a solvent that is miscible with water and hydrocarbons, to dilute the mixture. 16. The composition according to claim 15, in which the miscible solvent contains low molecular weight anhydrous alcohol. 17. The composition according to claim 4, in which the additives are selected from acidic or acid-releasing catalysts; free radical generating additives to initiate polymerization; and a retarder or inhibitor of the polymerization reaction in order to delay the onset of polymerization until the injection is completed. 18. The composition according to claim 17, wherein the acidic or acidic catalyst is selected from the group consisting of acids, strong organic acid catalysts and weak organic acids and their salts and esters, and mixtures thereof, for example from the group consisting of butyl acetate, isopropyl acetate and methyl formate and their combinations. 19. The composition according to claim 17, which contains a catalyst in a total amount from about 0.001 to about 20% by weight, based on the weight of the monomer to be polymerized.