CN104987682A - Biodegradable resin material applied to oil and gas fields and preparation method for biodegradable resin material - Google Patents

Abstract

The invention provides a degradable resin material used in oil and gas fields and a preparation method thereof. The preparation method of the degradable resin material applied in oil and gas fields is to melt and knead two or three kinds of polymers in polyglycolic acid, polycaprolactone and polylactic acid and a chain extender to prepare a resin alloy, namely It is the degradable resin material used in oil and gas fields. The degradable resin material used in oil and gas fields is prepared by the above method, and can be prepared in the shape of flakes, powders, granules, balls, etc., or made of one of polyglycolic acid, polycaprolactone and polylactic acid into flakes , powder, granules, balls and other shapes, used in various oil and gas well construction operations (drilling, well completion, well workover and acid fracturing) for temporary plugging and filtration protection of reservoirs, temporary plugging of blastholes and layers that have been constructed It has the advantages of complete degradability and zero damage to the formation.

Description

Degradable resin material used in oil and gas fields and preparation method thereof

technical field

The invention relates to a degradable resin material used in oil and gas fields and a preparation method thereof, belonging to the technical field of oil and gas exploitation.

Background technique

In various construction operations of oil and gas wells, such as drilling, well completion, well workover or stimulation operations, fluid loss control materials are widely used to reduce the intrusion of working fluid into the reservoir and reduce its damage to the reservoir. The fluid loss control agent used can block the fractures and pores of the reservoir, thereby reducing the intrusion of working fluid, and plugging the pore throats and fractures of the reservoir. After the operation is completed, these plugging materials also block the flow of oil and gas from the reservoir. Flow into the wellbore and cause damage to the reservoir.

In order to reduce the damage caused by the fluid loss control agent to the reservoir, temporary plugging materials are usually used. After the construction operation is completed, the temporary plugging fluid loss control agent will dissolve, degrade and disappear by itself. This is what oilfield engineers and technicians have been pursuing. Target.

The commonly used temporary plugging agents are mainly water-soluble, acid-soluble and oil-soluble. Water-soluble polymers, such as polyacrylamide, polyvinyl alcohol, etc., water-soluble inorganic salts are mainly used in saturated brine systems, such as potassium chloride, sodium chloride and other salt particles. The acid solubility is mainly calcium carbonate particles, and after the construction work is completed, use hydrochloric acid to remove it. The oil-soluble temporary plugging agent is mainly some resin materials, such as C6-C10 resin, asphalt and so on.

However, these temporary plugging materials have some shortcomings and deficiencies. For water-soluble temporary plugging materials, the carrier fluid needs to be organic hydrocarbons, and after the operation is completed, there needs to be a sufficient amount of water in the formation. During the subsequent liquid drainage process, The produced water in the formation dissolves it, removes its temporary blockage, and dredges the oil and gas channels. If there is not enough water in the formation, or the formation pressure is insufficient, and there is not enough water produced, it is necessary to squeeze water into the formation to dissolve these water solubles. Temporary plugging materials are often unable to be completely dissolved and removed, causing certain damage to the formation; acid-soluble temporary plugging materials, after completing the temporary plugging operation, need to inject acid to dissolve the temporary plugging materials and remove them. Clogging is not suitable for acid-sensitive reservoirs, even for non-acid-sensitive reservoirs, an additional operation is required, which increases operating costs. Since the acid solution cannot fully soak all the temporary blocking materials, it cannot be completely dissolved. Unblock the oil and gas channels; for oil-soluble temporary plugging materials, first of all, it is not suitable for gas wells, and second, it is oil wells. Since the formation crude oil only contacts the front edge of temporary plugging, when the dissolution reaches saturation, it is mainly achieved by diffusion and convection. Slow dissolution, which leads to long and insufficient contact time, and there is some damage to the formation.

Based on the above shortcomings of existing temporary plugging materials, it is necessary to invent materials that can be degraded in the formation only by formation temperature. Due to the different burial depths of oil and gas reservoirs, the bottom hole temperature of oil and gas wells is also different. For example, the burial depth of the main reservoir in Daqing Oilfield is only 1000-1600 meters, and the bottom hole temperature is only 50-60 ℃. For example, Tazhong, Tabei, Tarim Oilfield Kuche Piedmont and other oil and gas reservoirs are buried at a depth of 5,000-8,000 meters, and the bottom hole temperature is 130-180°C, which requires degradable materials to degrade under different temperature conditions.

Contents of the invention

In order to solve the above technical problems, the object of the present invention is to provide a degradable resin material used in oil and gas fields and a preparation method thereof. The degradable resin material is a new type of material that can be degraded at the formation temperature, and can play a role of temporary plugging in various construction operations of oil and gas wells, with zero damage to the formation.

In order to achieve the above object, the present invention provides a method for preparing a degradable resin material applied to oil and gas fields, which comprises the following steps: making the polymer and the chain extender carry out a melt mixing reaction (preferably carried out under nitrogen protection), preparing A resin alloy is obtained, which is the degradable resin material used in oil and gas fields, wherein the polymer includes two or three of polyglycolic acid (PGA), polycaprolactone (PCL) and polylactic acid (PLA). kind.

In the present invention, the polycaprolactone used has H-(O-(CH ₂ ) ₅ -CO) _n -OH in its structural formula, its glass transition temperature is -60°C, and its melting point is 60°C, so the It is difficult to use polymer as a temporary plugging agent for oil and gas well construction operations above 60 °C. The polyglycolic acid used is a homopolymer with glycolic acid repeating units represented by -(O-CH ₂ -CO)-, its glass transition temperature (Tg) is about 36°C, and its structure is The ester group in it can be completely degraded, the degradation speed is fast, the degradation intermediate product is glycolic acid, and the final product is carbon dioxide and water. The polylactic acid (crystallized polylactic acid) used has a melting point of 180-210°C, and the ester groups in its molecular structure can be completely degraded at the reservoir temperature, and the final products are carbon dioxide and water. It can be seen that the three polymers, polyglycolic acid (PGA), polycaprolactone (PCL) and polylactic acid (PLA), can degrade under reservoir conditions (formation temperature and formation water), and the final products of degradation are all water And carbon dioxide, friendly to the environment, does not pollute reservoir rocks and formation water.

In the above preparation method, preferably, based on the total mass of the polymer, the polymer is composed of 10-90% polyglycolic acid and 10-90% polycaprolactone (the sum of the two 100%); or by 10-90% polyglycolic acid and 10-90% polylactic acid (the sum of the two is 100%); or by 10-90% polycaprolactone and 10-90% The polylactic acid composition (the sum of the two is 100%); %).

In the present invention, the resin alloy formed by melting and kneading two or three of polyglycolic acid, polycaprolactone, and polylactic acid with a chain extender has a new structure, and its mechanical properties and chemical properties are uniform. changes happened. By adjusting the ratio of each polymer, a certain ratio of multi-segment mosaic structure can be formed to obtain materials with different strengths and different temperatures degraded to meet the requirements of temporary plugging materials for different construction purposes of oil and gas wells at different depths. Specifically, polycaprolactone can be completely decomposed into carbon dioxide and water at formation temperature, and has a low crystallization melting point, only 60°C. It is difficult to use this polymer as a temporary plugging agent for oil and gas well construction operations above 60°C. However, by mixing with one or two of the other two polymers and a chain extender, the obtained resin alloy can have new mechanical and chemical properties.

In the above preparation method, preferably, the weight average molecular weight of the polyglycolic acid is 10,000-120,000 (more preferably polyglycolic acid chips); the weight average molecular weight of the polycaprolactone is 10,000-15 Ten thousand (more preferably polycaprolactone slices); the weight average molecular weight of the polylactic acid is 10,000-150,000 (more preferably polylactic acid slices).

According to a specific embodiment of the present invention, preferably, the above-mentioned preparation method further includes the following steps: performing vacuum stirring and drying pretreatment on the polymer, so that the water content of polyglycolic acid, polycaprolactone and polylactic acid is lower than 0.1wt% (percentage by weight), more preferably, less than 0.01wt%; especially preferably, the previous vacuum stirring and drying of the polyglycolic acid is: at 90-105 ° C, the vacuum degree is 10-100 thousand Stir and dry for 2-8 hours (more preferably 4-6 hours) under Pascal; the vacuum stirring and drying of the polycaprolactone is: at 50-55 ° C, vacuum 10-100 kPa, stir and dry for 5 -16 hours; the vacuum stirring and drying of the polylactic acid is as follows: stirring and drying for 2-12 hours (more preferably 6-8 hours) at 80-95° C. and a vacuum degree of 10-100 kPa. After the pretreatment, the water content of the three polymers is lower than 0.1%, preferably lower than 0.01%, which is beneficial to the subsequent melt-kneading reaction.

According to a specific embodiment of the present invention, preferably, the above-mentioned preparation method further includes the following steps: when performing the melt-kneading reaction, adding inorganic nano-materials to prepare resin nano-alloys, which are used for the oil and gas field operations. Degradable resin material; wherein the inorganic nanomaterials include nano-silicon dioxide and/or nano-titanium dioxide, the particle diameter of which is 5-20nm, and the added amount of the inorganic nano-materials is 0.01-3% of the total mass of the polymer .

In the above-mentioned preparation method, preferably, the chain extender is a chain extender containing an active group epoxy group, preferably ADR-4300, ADR-4370 and ADR-4380 produced by BASF SE (BASF SE) one or a combination of several. More preferably, the chain extender is ADR-4370, which contains 9 reactive epoxy groups in each molecule.

In the above preparation method, preferably, the added amount of the chain extender is 0.05%-5.0% of the total mass of the polymer, preferably, the added amount of the chain extender is the total mass of the polymer of 0.1-0.3%.

The present invention selects the degradable polymers of polyglycolic acid, polycaprolactone and polylactic acid as the basic raw material prepolymer molecule, and its end groups are both hydroxyl and carboxyl groups, which can react with chain extenders containing active group epoxy groups For example, each molecule of ADR-4300, ADR-4370 and ADR-4380 produced by BASF AG contains different numbers of active group epoxy groups (3-9), which can react with PGA, PCL and PLA Groups (hydroxyl-terminated, carboxyl-terminated) undergo a link reaction to form a polymer alloy with a larger molecule, for example, as shown in the following reaction equation:

In the above preparation method, preferably, for the polymer composed of polycaprolactone, polyglycolic acid and polylactic acid, the temperature of the melt-kneading reaction is 200-230°C, more preferably 205-220°C, Most preferably 205-210°C; for polymers composed of polycaprolactone and polylactic acid, the temperature of the melt-kneading reaction is 180-230°C, more preferably 205-220°C, most preferably 205-210°C °C; for polymers composed of polycaprolactone and polyglycolic acid, the temperature of the melt mixing reaction is 180-220 °C, more preferably 190-210 °C, most preferably 200-205 °C; for poly For the polymer composed of glycolic acid and polylactic acid, the melting and mixing reaction temperature is 205-240°C, more preferably 205-220°C, most preferably 205-210°C. When the temperature is less than the above-mentioned lower limit, the polymerization tends not to proceed sufficiently. On the other hand, when the temperature exceeds the above-mentioned upper limit, the resulting resin tends to be thermally decomposed.

In the above preparation method, preferably, the melt-kneading reaction time is 3-20 minutes, more preferably 5-8 minutes. If the reaction time is less than the above-mentioned lower limit, the reaction will not proceed sufficiently, while on the other hand, if it exceeds the above-mentioned upper limit, the color of the produced resin will become dark.

In the above-mentioned preparation method, preferably, the temperature is raised to the temperature of the melt-kneading reaction at a rate of temperature increase of 5-20° C./min.

According to a specific embodiment of the present invention, preferably, the melt kneading is carried out by using a reciprocating single-screw kneading extruder.

According to a specific embodiment of the present invention, preferably, the above-mentioned preparation method further includes the following steps: using a wire drawing die (for example, a 3 mm wire drawing die) to slice the resin alloy or resin nano-alloy prepared by the melt mixing reaction, and then lower the temperature (for example, air-cooling and cooling), and the sliced resin alloy or resin nano-alloy is prepared, which is the degradable resin material used in oil and gas fields.

According to the specific embodiment of the present invention, preferably, the above-mentioned preparation method also includes the following steps: mixing two or three of polyglycolic acid, polycaprolactone and polylactic acid in a mixer, and the mixing temperature and time can be routinely adjusted by those skilled in the art, and can be carried out under vacuum conditions, and then added to a reciprocating single-screw mixing extruder to mix and react with a chain extender (or further with inorganic nanomaterials).

According to different reservoir conditions and purposes of use, the prepared resin alloy or resin nano-alloy can be processed into required shapes such as flakes, powders, granules, balls, fibers, etc., such as balls with a diameter of 20-80 mm, Φ0.8-5 mm particles with different particle sizes, 40-200 mesh powder, 0.1-0.3 mm thick, 5-10 mm diameter or side length flakes, Φ10-150 microns, 2-15 mm in length Millimeter filaments, etc., are degradable resin materials used in oil and gas fields. The specific preparation steps are as follows.

According to a specific embodiment of the present invention, preferably, the above-mentioned preparation method also includes the following steps: using a plastic mill to grind the resin alloy or resin nano-alloy or the polyglycolic acid, polycaprolactone and polylactic acid (which can be It is a mixture of one of the polyglycolic acid, polycaprolactone and polylactic acid (which can be treated before vacuum stirring and drying) and the inorganic nanomaterial Grind and cool with liquid nitrogen, control the temperature of the grinding disc at -10 to 0°C, and sieve with different mesh sieves to obtain the required mesh powder, such as 40 mesh-200 mesh (ie 74-420μm) of different specifications The powder is the degradable resin material used in oil and gas fields. The powdery degradable resin material can be used for temporary plugging of reservoir pores and micro-fractures in drilling fluid, well completion fluid, workover fluid, kill fluid, acid fluid, fracturing fluid, etc. to reduce fluid loss. Reduce the damage of the working fluid to the reservoir.

According to a specific embodiment of the present invention, preferably, the above-mentioned preparation method further includes the following steps: using a granulator (which can be used in conjunction with a wire drawing die) to mix the resin alloy or resin nano-alloy or the polyglycolic acid and polylactic acid ( It can be one of the ones after vacuum stirring and drying) or the mixture of one of the polyglycolic acid and polylactic acid (which can be vacuum stirring and drying before treatment) and the inorganic nanomaterial is heated to 160- 200°C for granulation; or the polycaprolactone (which can be pre-treated by vacuum stirring and drying) or the polycaprolactone (which can be pre-treated by vacuum stirring and drying) and the inorganic nanomaterial The mixture is heated to 50-60°C for granulation; then cooled to 15-35°C (preferably at a rate of 5-20°C/min) to obtain particle sizes of Φ0.8-1 mm, Φ1-1.5 mm, Φ1 .5-2 mm, Φ2-2.5 mm, Φ2.5-3 mm or Φ3-5 mm particles are the degradable resin materials used in oil and gas fields. The granular degradable resin material can be used for temporary plugging of fractures during drilling and well completion, and can also be used for plugging of fractures that have been opened during fracturing, implementing fracture diversion, or for temporary plugging of old fractures and repeated fracturing wait.

According to a specific embodiment of the present invention, preferably, the above-mentioned preparation method further includes the following steps: mixing the resin alloy or resin nano-alloy or the polyglycolic acid and polylactic acid (which may be pre-treated by vacuum stirring and drying) One or the mixture of one of the polyglycolic acid and polylactic acid (which can be pre-treated by vacuum stirring and drying) and the inorganic nanomaterial is rolled at 160-190°C (rolling machine can be used) into a thin sheet with a thickness of 0.1-0.3 mm; or the polycaprolactone (which can be treated before vacuum stirring and drying) or the polycaprolactone (which can be treated before vacuum stirring and drying) and the The mixture of inorganic nanomaterials is rolled at 50-55°C (rolling machine can be used) into thin sheets with a thickness of 0.1-0.3mm; then the temperature is lowered to 20-30°C (preferably at a rate of 5-20°C/min) , and then pulverized (a shredder can be used) into circular and/or similarly circular flakes with a diameter of 5-10 mm and/or square and/or similarly square and/or triangular pieces with a side length of 5-10 mm (If it is an irregular polygonal sheet, the diameter of the circle made with its center as the center is within the range of 5-10 mm), which is the degradable resin material used in oil and gas fields.

According to a specific embodiment of the present invention, preferably, the above-mentioned preparation method also includes the following steps: using a melt spinning machine to melt the resin alloy or resin nano-alloy or the polyglycolic acid and polylactic acid (which can be vacuum stirring and drying before After treatment) or the mixture of one of polyglycolic acid and polylactic acid (which can be treated before vacuum stirring and drying) and the inorganic nanomaterial is heated to 200-210 ° C, and then heated at 65 Stretching and setting at -90°C; or the polycaprolactone (which can be pre-treated by vacuum stirring and drying) or the polycaprolactone (which can be pre-treated by vacuum stirring and drying) and the inorganic nano The mixture of materials is heated to 60-65°C, and then stretched and set at 30-40°C; the fiber filaments of Φ10-150 microns are formed, and then cut into short fibers with a length of 2-15 mm, which is the described Degradable resin materials used in oil and gas fields. The fibrous degradable resin material can be used to temporarily plug natural fractures during drilling and well completion, carry proppant during fracturing construction, plug the cracks that have been opened, realize artificial fractures to turn to form new hydraulic fractures, and improve the performance of hydraulic fractures. Sweep range, increasing the stimulation volume of hydraulic fracturing.

According to a specific embodiment of the present invention, preferably, the above-mentioned preparation method also includes the following steps: using an injection molding machine to inject the resin alloy or resin nano-alloy or the polyglycolic acid and polylactic acid (which can be vacuum stirring and drying after pretreatment) ) or the mixture of one of the polyglycolic acid and polylactic acid (which can be pre-treated by vacuum stirring and drying) and the inorganic nanomaterial is heated to 160-200 ° C, and the balanced screw speed is 100-175 rpm, back pressure 300-700 kPa, feed port temperature 20-25°C, feed temperature 150-160°C, metering section temperature 190-210°C, injection port temperature 190- Under the conditions of 210°C and a mold temperature of 20-25°C (injection speed is appropriately faster), molds of different specifications are used to make balls of Φ4-15 mm; or the polycaprolactone (which can be vacuum stirring before drying) treated) or the mixture of the polycaprolactone (which may be treated before vacuum stirring and drying) and the inorganic nanomaterial is heated to 60-65°C, and the balanced screw speed is 100-175 rpm, back The pressure is 300-700 kPa, the temperature of the feeding port is 20-25°C, the feeding temperature is 55-60°C, the temperature of the metering section is 60-65°C, the temperature of the injection port is 58-62°C, and the mold temperature is 20- Under the condition of 25°C (injection speed should be faster), molds of different specifications are used to make balls of Φ4-15 mm, which are the degradable resin materials used in oil and gas fields. The spherical degradable resin material can be used to plug fractures, perforated blastholes, and screen pipes, meeting the temporary plugging construction requirements of long well sections or extremely thick span reservoirs.

According to a specific embodiment of the present invention, preferably, the above-mentioned preparation method further includes the following steps: mixing the resin alloy or resin nano-alloy or the polyglycolic acid and polylactic acid (which may be pre-treated by vacuum stirring and drying) One or the mixture of one of the polyglycolic acid and polylactic acid (which may be pre-treated by vacuum stirring and drying) and the inorganic nanomaterial is heated to 160-200 ° C; or the polycaprolactone (It can be pre-treated by vacuum stirring and drying) or the mixture of the polycaprolactone (which can be pre-treated by vacuum stirring and drying) and the inorganic nanomaterial is heated to 60-75 ° C; cast into a mold to make Obtain rods (moulds of different specifications can be used to obtain rods with a cross-sectional size of 100×100 mm), and then the rods are processed (machining milling machines or lathes, etc.) into balls of Φ20-80 mm , which is the degradable resin material used in oil and gas fields. The spherical degradable resin material can be used for throwing balls in staged fracturing.

In the above preparation method, the temperature at which one of the three polymers is mixed with the inorganic nanomaterial can be higher than the melting point of the polymer, for example, it can be 5-10° C. higher than the melting point. Preferably, the mixing temperature of polyglycolic acid and the inorganic nanomaterial is 220-235°C, the mixing temperature of polylactic acid and the inorganic nanomaterial is 180-220°C, and the mixing temperature of polycaprolactone and the inorganic nanomaterial The temperature is 60-70°C. The added amount of the inorganic nanometer material is 0.01-3% of the mass of the polymer. A reciprocating single-screw kneading extruder or mixer can be used to mix the above-mentioned one polymer with the inorganic nanomaterial, as long as the two form a uniform mixture. Afterwards, the mixture of the prepared polymer and inorganic nanomaterials can also be sliced by using a wire drawing die (for example, a 3 mm wire drawing die), and then cooled (for example, air-cooled and cooled) to prepare mixture slices for processing into the above-mentioned different shape.

According to the specific embodiment of the present invention, preferably, in the above-mentioned preparation method, for PGA/PCL/PLA three kinds of polymers and chain extender or with the resin alloy or the resin nanoalloy that the reaction of inorganic nanomaterial and chain extender obtains , or PGA/PCL, PGA/PLA, PCL/PLA two polymers and chain extenders or resin alloys or resin nanoalloys obtained by reacting with inorganic nanomaterials and chain extenders, and need to be made into filaments or sheet materials Yes, the chain extender is preferably ADR-4300 produced by BASF AG, which contains 3 active groups epoxy groups in each molecule, and its addition amount is 0.1-5.0% of the total mass of the polymer, preferably the addition amount It is 0.5-1.0% of the total mass of the polymer; for PGA/PCL/PLA three kinds of polymers and chain extenders or resin alloys or resin nano-alloys obtained by reacting with inorganic nanomaterials and chain extenders, or PGA/PCL, PGA /PLA, PCL/PLA two kinds of polymers and chain extender or with inorganic nanomaterials and chain extender reaction resin alloy or resin nanoalloy, and need to be made into particles or spherical materials, the chain extender is preferably BASF shares The company's ADR-4370, each molecule contains 9 reactive epoxy groups, the amount added is 0.05%-5.0% of the total mass of the polymer, preferably 0.1-0.3% of the total mass of the polymer %.

The present invention selects the degradable polymers of polyglycolic acid (PGA), polycaprolactone (PCL) and polylactic acid (PLA) as basic raw materials, which all contain hydroxyl and carboxyl groups, and can be combined with epoxy group-containing reactive groups. Chain agent reaction, select two of these prepolymers (PGA/PCL, PGA/PLA, PCL/PLA) or three (PGA/PCL/PLA) according to a certain ratio, and then add rings containing active groups The chain extender of oxygen group, as the combination of one or more in ADR-4300, ADR-4370 and ADR-4380 produced by BASF Co., Ltd., carries out melt mixing reaction under certain conditions, prepares resin alloy, Inorganic nanomaterials can also be further added to prepare resin nanoalloys.

According to different reservoir conditions and purposes of use, the prepared resin alloy or resin nano-alloy or one of polyglycolic acid, polycaprolactone and polylactic acid or polyglycolic acid, polycaprolactone and polylactic acid can be mixed A mixture with inorganic nanomaterials is processed into required shapes such as flakes, powders, granules, balls, fibers, etc., which are degradable resin materials used in oil and gas fields. Since the working fluid with surface temperature is injected into the bottom of the well during the construction operation, the surface temperature is lower than the formation temperature, and the formation is cooled. The degradable resin material used in oil and gas fields is stable at lower than low temperature conditions Degradation, sealing the formation, preventing the working fluid from invading the formation, reducing the damage of the working fluid to the formation, and also reducing the amount of working fluid, saving operating costs; when the operation is completed, the formation heat is transferred to the oil and gas field. The degradable resin material slowly reaches the formation temperature, and the degradable resin material slowly and completely degrades under the formation temperature within a certain period of time, thereby removing the blockage of the formation oil and gas channels and causing zero damage to the formation.

On the other hand, the present invention also provides a degradable resin material used in oil and gas fields, which is prepared by the above-mentioned preparation method of the degradable resin material used in oil and gas fields.

The degradable resin material used in oil and gas fields can be processed into the required shape according to the reservoir conditions and the purpose of use. It mainly has the following advantages: (1) In various construction operations of oil and gas wells, such as drilling, well completion , During workover or stimulation operations, the degradable resin material can be widely used to reduce the invasion of the operating fluid to the reservoir and reduce its damage to the reservoir; (2) To temporarily block the formation pore throats and prevent the intrusion of the operating fluid formation, reducing the damage of the working fluid to the formation, and also reducing the amount of working fluid, saving operating costs; (3) After the operation is completed, the heat of the formation is transferred to the degradable resin material, and the temperature of the formation is gradually reached. Under the formation temperature, it will slowly and completely degrade within a certain period of time, thereby removing the blockage of the oil and gas passages in the formation and causing zero damage to the formation.

Description of drawings

Fig. 1 is a flow chart of the preparation of the degradable resin material of the embodiment.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

Example 1

This embodiment provides a degradable resin material applied to oil and gas fields, as shown in Figure 1, which is prepared through the following steps:

(1) Stir and dry polycaprolactone slices with a weight average molecular weight (Mw) of 80,000 at 50-55°C and a vacuum of 90 kPa for 12 hours; The acetic acid slices were stirred and dried for 4 hours at 100-105°C and a vacuum of 90 kPa; hours, make its moisture content lower than 0.1wt%, the best lower than 0.01wt%;

(2) Take 100 kilograms of polycaprolactone slices, 750 kilograms of polyglycolic acid slices and 150 kilograms of polylactic acid slices after removing water and add them to a stainless steel mixer with a stirring device, heat up to 50 ° C, and At a temperature of 90 kPa, mix for 10 minutes;

(3) Add the mixture of polyglycolic acid, polycaprolactone and polylactic acid in the mixer to the reciprocating single-screw mixing extruder, add 3.5 kilograms of silicon dioxide with a particle diameter of 15-20nm, and Add 1 kg of chain extender ADR-4370 produced by BASF AG, and then under nitrogen protection, heat up to 202°C at a heating rate of 8°C/min, and then carry out melt mixing reaction for 7 minutes to prepare PGA/PCL /PLA resin nano alloy;

(4) Cooperate with the drawing die of 3 millimeters, the PGA/PCL/PLA resin nano-alloy that makes is sliced, then air-cooled cooling, makes PGA/PCL/PLA resin nano-alloy slice;

(5) Grind the prepared PGA/PCL/PLA resin nano-alloy slices with a plastic mill, cool with liquid nitrogen, control the temperature of the grinding disc at -10 to 0°C, and sieve with a 200-mesh (74 μm) sieve to obtain 200 mesh (74 μm) PGA/PCL/PLA resin nano-alloy powder to prepare powdery degradable resin material.

Temporary plugging experiment using the prepared 200 mesh (74 μm) powdery degradable resin material: core data: core length: 5.01 cm, core diameter φ2.51, under the temperature of 150 ° C, with standard brine (NaCl: 7wt%) , CaCl ₂ : 0.6wt%, MgCl ₂ 6H ₂ O: 0.4wt%), the brine permeability of the core was measured to be 40.18×10-3μm2, and the PGA/PCL/PLA with a thickness of 2cm and 200 mesh (74μm) was placed at room temperature The resin nano-alloy powder temporary plugging agent is installed in a steel mold and placed at the core injection end. The pressure bearing capacity of the temporary plugging agent with a thickness of 2cm at 150°C is measured with a constant flow rate of standard brine at 5mL/min when the temperature rises to 150°C. , when the pump injection pressure rises to 40MPa, it turns to constant pressure control, the permeability drops to 0.09×10 ^-3 μm ² , and the permeability drops by 99.77%. The plugging effect is better under the pressure difference of 40MPa; Close the valve at the outlet end, put it in an oven at 150°C for 20 hours, take it out and put it into the core flow system, measure its permeability with standard brine at 150°C to 39.12×10-3μm2, and the recovery value of the core permeability is 97.36%. The powdery degradable resin material degrades completely.

Example 2

The PGA/PCL/PLA resin nano-alloy slices prepared in Example 1 are granulated through a screw granulator at 200°C, the particle diameter is Φ1-1.5 mm, and the temperature is dropped to At 20°C, molded Φ1-1.5 mm particles are obtained, and a granular degradable resin material is obtained.

The Φ1-1.5 mm granular degradable resin material is used in Well C1 (in the well depth of 6513-6572m, the temperature of this well section is 152°C-153°C, two layers are opened, 6513-6524m and 6561-6572m) well temporarily For plugging and diverting fracturing operations, use guar gum jelly fracturing fluid to carry, and divide into one temporary plugging and diverting fracturing, use the Φ1-1.5 mm particle temporary plugging material 268 kg, after diverting, under the same pump injection displacement, the pressure rises The height is 15.2MPa, and the diversion effect of temporary plugging is obvious. The granular temporary plugging material is completely degraded at 150°C for 12 hours.

Example 3

This embodiment provides a degradable resin material applied to oil and gas fields, as shown in Figure 1, which is prepared through the following steps:

(1) Stir and dry polycaprolactone chips with a weight average molecular weight (Mw) of 20,000 at 50-55°C and a vacuum of 90 kPa for 11 hours; The acetic acid slices were stirred and dried for 4 hours at 95-100°C and a vacuum of 90 kPa; the moisture content was lower than 0.1wt%, preferably lower than 0.01wt%;

(2) Get 500 kilograms of polycaprolactone slices and 500 kilograms of polyglycolic acid slices after the above water removal and add them to a stainless steel mixer with a stirring device, heat up to 45 ° C, and under a vacuum of 90 kPa, Mix for 10 minutes;

(3) Add the mixture of polyglycolic acid and polycaprolactone in the mixer to the reciprocating single-screw mixing extruder, add 5 kg of silicon dioxide with a particle diameter of 10-20nm, and add 1.3 kg The chain extender ADR-4300 produced by BASF Co., Ltd. is then heated to 205°C at a heating rate of 10°C/min under nitrogen protection, and then melted and kneaded for 8 minutes to obtain a PGA/PCL resin nanoalloy ;

(4) Extrude the molten PGA/PCL resin nano-alloy through a reciprocating single-screw mixing extruder at 190°C, and use a rolling machine to roll the PGA/PCL resin nano-alloy into a thin sheet with a thickness of 0.3 mm , with a cooling rate of 10°C/min, the temperature is lowered to 25°C, and then crushed into flakes with a side length (square flake) of 5-10 mm to obtain a flake-like degradable resin material.

This sheet-like degradable resin material is used for drilling in the reservoir section of Well C2 (the well has serious leakage in the 4167-4171m section, and it is impossible to continue drilling. After plugging, the pressure at the wellhead was 12 MPa, and the pressure did not drop for 30 minutes. Drilling operations continued, and no leakage was found after drilling to 4190m, which proved that the plugging effect was good. After 12 days of production, the crude oil output was 53 cubic meters per day, which proved that the degradation performance was good.

Example 4

This embodiment provides a degradable resin material applied to oil and gas fields, as shown in Figure 1, which is prepared through the following steps:

(1) Stir and dry polyglycolic acid slices with a weight average molecular weight (Mw) of 15,000 at 100-105°C and a vacuum of 90 kPa for 4 hours; polylactic acid slices with a weight average molecular weight (Mw) of 10,000 Stir and dry for 6 hours at 90-95°C and a vacuum of 90 kPa to make the moisture content lower than 0.1wt%, preferably lower than 0.01wt%;

(2) Take 700 kg of polyglycolic acid slices and 300 kg of polylactic acid slices after dehydration and add them to a stainless steel mixer with a stirring device, heat up to 50 ° C, and mix the materials under a vacuum of 90 kPa. 10 minutes;

(3) Add the mixture of polyglycolic acid and polylactic acid in the mixer to the reciprocating single-screw mixing extruder, and add the chain extender ADR-4370 produced by 2 kilograms of BASF AG, then under nitrogen protection At a heating rate of 8°C/min, the temperature was raised to 200°C, and then melted and kneaded for 7 minutes to obtain a PGA/PLA resin alloy;

(4) Use a wire drawing die of 3 mm to slice the obtained PGA/PLA resin alloy, then air-cool and cool down to obtain a PGA/PLA resin alloy slice;

(5) Use an injection molding machine for injection molding. During injection molding, the temperature of the feed port is 25°C, the PGA/PLA resin alloy slice is heated to 170°C, the balanced screw speed is 150 rpm, and the back pressure is 500 kPa. The temperature of the material is 160°C, the temperature of the metering section is 200°C, the temperature of the injection port is 200°C, the temperature of the mold is 25°C, the injection speed is appropriately faster, and the mold of Φ6 mm is used to obtain a spherical degradable resin material of Φ6 mm, which can be used For perforating blastholes and screens, it meets the temporary plugging construction requirements for long well sections or extremely thick span reservoirs.

The Φ6 mm spherical degradable resin material is used as a perforation blasthole plugging ball to divert fracturing fractures. The Φ6 mm ball is used in well C3 (fracturing section 4235-6243m and 4277-6789m, phase angle 60°C helical Perforation, hole density 16 holes/m) implemented tool-free layered diversion fracturing, used a total of 50 balls of Φ6mm, and once the diversion ball was diverted to fracturing, the pressure increased by 11.3MPa after the diversion ball entered the blasthole, which proved that it has good performance. Interlayer steering performance. The degradation rate of the Φ6mm spherical degradable resin material is greater than 95% in 24 hours at 130°C.

Example 5

This embodiment provides a degradable resin material applied to oil and gas fields, as shown in Figure 1, which is prepared through the following steps:

(1) Stir and dry polycaprolactone chips with a weight average molecular weight (Mw) of 30,000 at 50-55°C and a vacuum of 90 kPa for 12 hours; polylactic acid with a weight average molecular weight (Mw) of 20,000 Stir and dry the slices at 90-95°C and a vacuum of 90 kPa for 6 hours, so that the moisture content is lower than 0.1wt%, preferably lower than 0.01wt%;

(2) Take 350 kg of polycaprolactone slices and 650 kg of polylactic acid slices after dehydration and add them to a stainless steel mixer with a stirring device, heat up to 50 ° C, and mix under a vacuum of 90 kPa. 10 minutes;

(3) Add the mixture of polycaprolactone and polylactic acid in the mixer to the reciprocating single-screw mixing extruder, add 1 kg of silica with a particle diameter of 10-20 nm, and add 1 kg of BASF The chain extender ADR-4300 produced by the joint-stock company was then heated to 202°C at a heating rate of 8°C/min under the protection of nitrogen, and then melted and kneaded for 7 minutes to obtain a PCL/PLA resin nano-alloy;

(4) Cooperate with the wire drawing die of 3 millimeters, the PCL/PLA resin nano-alloy that makes is sliced, then air-cooled cooling, makes PCL/PLA resin nano-alloy slice;

(5) Using a melt spinning machine to heat the resin nano-alloy slices to 200-210°C for melt spinning, then stretch and shape them at 80°C to form fiber filaments of Φ20-30 microns, and then cut them into lengths of 8 mm staple fiber to obtain resin nano-alloy staple fiber, which is the degradable resin material used in oil and gas fields.

The 1.5 grams of short fiber filaments of 8 mm are filled in the wedge-shaped seam of the aluminum core (the length of the aluminum rock core is 5.08 cm, the diameter of the rock core is 2.5 cm, the length of the wedge-shaped seam is 2 cm, the wide end seam is 2 mm wide, and the narrow end fracture width 0.5mm), fill the fractures with short fibers, connect the cores to the flow experiment, and use standard brine (NaCl: 7wt%, CaCl ₂ : 0.6wt%, MgCl ₂ ·6H ₂ O: 0.4wt%) was injected at a constant pressure of 20MPa, and the pumping pressure was stabilized for 20 minutes to stop the pumping. The plugging effect of short fiber filaments was better under a pressure difference of 20MPa; After 40 hours in an oven at 130°C, the aluminum core was taken out for observation, and the short fibers were completely degraded, indicating that the short fiber degradable resin material was completely degraded.

Claims (16)

1. The preparation method of the degradable resin material applied to oil and gas fields, which comprises the following steps: the polymer and the chain extender are melted and kneaded to prepare a resin alloy, which is the degradable resin material applied to oil and gas fields , wherein the polymer comprises two or three of polyglycolic acid, polycaprolactone and polylactic acid. 2. The preparation method according to claim 1, wherein, based on the total mass of the polymer, the polymer is composed of 10-90% polyglycolic acid and 10-90% polycaprolactone; Either composed of 10-90% polyglycolic acid and 10-90% polylactic acid; or composed of 10-90% polycaprolactone and 10-90% polylactic acid; or composed of 10-80% polyhydroxy Acetic acid, 10-60% polycaprolactone and 10-70% polylactic acid. 3. The preparation method according to claim 1, wherein, the weight average molecular weight of the polyglycolic acid is 10,000-120,000; the weight average molecular weight of the polycaprolactone is 10,000-150,000; The weight average molecular weight of lactic acid is 10,000-150,000. 4. according to the described preparation method of claim 1 or 3, it also comprises the following steps: described polymer is carried out pretreatment to vacuum stirring drying, makes the water content of polyglycolic acid, polycaprolactone and polylactic acid all lower than 0.1wt%, preferably less than 0.01wt%, and the molecular weight of the polymer after the pretreatment does not change; more preferably, the vacuum stirring and drying of the polyglycolic acid is: at 90-105°C, vacuum Stir and dry for 4-8 hours at a temperature of 10-100 kPa; the vacuum stirring and drying of the polycaprolactone is: at 50-55 ° C and a vacuum of 10-100 kPa, stir and dry for 5-16 hours; The vacuum stirring and drying of the polylactic acid is as follows: stirring and drying for 2-12 hours at 80-95° C. and a vacuum degree of 10-100 kPa. 5. The preparation method according to claim 1, further comprising the step of: when carrying out the melting and kneading reaction, adding inorganic nanomaterials to prepare resin nanoalloys, which is the degradable compound used in oil and gas fields. Resin material; wherein the inorganic nanomaterials include nano-silicon dioxide and/or nano-titanium dioxide with a particle diameter of 5-20nm, and the added amount of the inorganic nano-materials is 0.01-3% of the total mass of the polymer. 6. preparation method according to claim 1, wherein, described chain extender is the chain extender containing active group epoxy group, is preferably ADR-4300, ADR-4370 and ADR-4380 that BASF AG produces One or more combinations; the added amount of the chain extender is 0.05%-5.0% of the total mass of the polymer, preferably, the added amount of the chain extender is the total mass of the polymer 0.1-0.3%. 7. The preparation method according to claim 1, wherein, for the polymer composed of polycaprolactone, polyglycolic acid and polylactic acid, the temperature of the melt mixing reaction is 200-230°C, preferably 205- 220°C, more preferably 205-210°C; for polymers composed of polycaprolactone and polylactic acid, the temperature of the melt-kneading reaction is 180-230°C, preferably 205-220°C, more preferably 205°C -210°C; for polymers composed of polycaprolactone and polyglycolic acid, the temperature of the melt-kneading reaction is 180-220°C, preferably 190-210°C, more preferably 200-205°C; For the polymer composed of polyglycolic acid and polylactic acid, the melting and mixing reaction temperature is 205-240°C, preferably 205-220°C, more preferably 205-210°C. 8. The preparation method according to claim 1, wherein the time for the melt-kneading reaction is 3-20 minutes, more preferably 5-8 minutes. 9. The preparation method according to claim 1 or 5, wherein the melt mixing is carried out by a reciprocating single-screw mixing extruder; The resin alloy or resin nano-alloy prepared by refining reaction is sliced, and then the temperature is lowered to prepare the sliced resin alloy or resin nano-alloy, which is the degradable resin material used in oil and gas fields. 10. according to the described preparation method of claim 1,4,5 or 9, it also comprises the following steps: adopt plastic mill to make described resin alloy or resin nano-alloy or described polyglycolic acid, polycaprolactone and One of the polylactic acid or the mixture of one of the polyglycolic acid, polycaprolactone and polylactic acid and the inorganic nanomaterial is ground, and cooled with liquid nitrogen, and the temperature of the grinding disc is controlled to be -10 to 0°C, The 40-200-mesh powder obtained by sieving is the degradable resin material used in oil and gas fields. 11. The preparation method according to claim 1, 4, 5 or 9, further comprising the step of: using a granulator to mix said resin alloy or resin nano-alloy or said polyglycolic acid and polylactic acid Or the mixture of one of the polyglycolic acid and polylactic acid and the inorganic nanomaterial is heated to 160-200°C for granulation; or the polycaprolactone or the polycaprolactone and the inorganic The mixture of nanomaterials is heated to 50-60°C for granulation; then cooled to 15-35°C to obtain particle sizes of Φ0.8-1 mm, Φ1-1.5 mm, Φ1.5-2 mm, Φ2-2.5 mm , Φ2.5-3 mm or Φ3-5 mm particles are the degradable resin materials used in oil and gas fields. 12. The preparation method according to claim 1, 4, 5 or 9, further comprising the step of: mixing the resin alloy or resin nanoalloy or one of the polyglycolic acid and polylactic acid or the poly The mixture of one of glycolic acid and polylactic acid and the inorganic nanomaterial is rolled into a thin sheet with a thickness of 0.1-0.3 mm at 160-190 ° C; or the polycaprolactone or the polycaprolactone The mixture with the inorganic nanomaterials is rolled at 50-55°C into thin sheets with a thickness of 0.1-0.3 mm; then cooled to 20-30°C, and then pulverized into a circle with a diameter of 5-10 mm and/or similar circles Shaped sheets and/or square and/or similar square and/or triangular sheets with a side length of 5-10 mm are the degradable resin materials used in oil and gas fields. 13. The preparation method according to claim 1, 4, 5 or 9, further comprising the step of: using a melt spinning machine to spin the resin alloy or resin nanoalloy or one of the polyglycolic acid and polylactic acid One or the mixture of one of the polyglycolic acid and polylactic acid and the inorganic nanomaterial is heated to 200-210°C, and then stretched and set at 65-90°C; or the polycaprolactone or the The mixture of the polycaprolactone and the inorganic nanomaterials is heated to 60-65°C, and then stretched and set at 30-40°C; the fiber filaments of Φ10-150 microns are formed, and then cut into lengths of 2-15 mm The short fiber filaments are the degradable resin materials used in oil and gas fields. 14. The preparation method according to claim 1, 4, 5 or 9, further comprising the step of: using an injection molding machine to inject one or more of the resin alloy or resin nano-alloy or the polyglycolic acid and polylactic acid The mixture of one of the polyglycolic acid and the polylactic acid and the inorganic nanomaterial is heated to 160-200°C, at a balanced screw speed of 100-175 rpm, with a back pressure of 300-700 kPa, feeding Φ4- 15 mm balls; or the polycaprolactone or the mixture of polycaprolactone and the inorganic nanomaterials is heated to 60-65 ° C, at a balanced screw speed of 100-175 revolutions per minute and a back pressure of 300-700 kPa, feed port temperature is 20-25°C, feed temperature is 55-60°C, metering section temperature is 60-65°C, injection port temperature is 58-62°C, mold temperature is 20-25°C Under the condition of Φ4-15 mm, the ball is made, which is the degradable resin material used in oil and gas fields. 15. The preparation method according to claim 1, 4, 5 or 9, further comprising the step of: mixing the resin alloy or resin nanoalloy or one of the polyglycolic acid and polylactic acid or the poly The mixture of one of glycolic acid and polylactic acid and the inorganic nanomaterial is heated to 160-200°C; or the polycaprolactone is heated to 60-75°C; cast into a mold to obtain a rod, and then Process the bar into a ball of Φ20-80 mm, which is the degradable resin material used in oil and gas fields. 16. The degradable resin material used in oil and gas fields, which is prepared by the preparation method of the degradable resin material used in oil and gas fields according to any one of claims 1-15.