Synergistic bridge plug plugging agent as well as preparation method and application thereof

Abstract

The invention provides a synergistic bridge plug plugging agent as well as a preparation method and application thereof, and belongs to the field of oilfield chemistry. The bridge plug plugging agent comprises: 35-70 parts of an inert particle material; 5-10 parts of a fiber material; 5-10 parts of a sheet material; 15 to 40 parts of a solidifiable granular material; and 5-15 parts of a modified activator. The plugging layer is preliminarily formed through bridging and filling of the inert granular material, wedging of the flaky material and rib pulling of the fiber material; and the modified activator wrapping layer is melted at the leakage layer temperature, and the consolidated material is activated for consolidation, so that the pressure bearing capacity of the plugging layer is further improved, and backflow and re-leakage are prevented. The plugging and pressure-bearing effects are good, and the pressure-bearing capacity of a plugging layer is improved through the consolidation effect. The plugging agent is safe and simple to construct, a drilling tool assembly does not need to be replaced in the construction process, and time is saved; and filling and consolidation can be performed in a leakage layer without squeezing, so that the squeezing pressure is prevented from uncovering a new gap or a plugging layer of a weak stratum, and the problems of long open hole section and multi-point leakage of the weak stratum can be solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil field chemistry in oil drilling engineering, and relates to a synergistic bridge plug leak stoppage agent and a preparation method and application thereof. BACKGROUND

[0002] Lost circulation is a common problem in the process of oil and gas well drilling, which not only consumes a large amount of drilling fluid and plugging material, but also induces downhole complex conditions such as well collapse, pipe sticking, overflow, blowout and even wellbore abandonment, resulting in huge economic losses. Suitable plugging technology is the main method to deal with lost circulation. Current plugging technologies mainly include bridge plug plugging technology, cement-based consolidation plugging technology and polymer gel plugging technology.

[0003] In field construction, bridge plug plugging technology is the first choice due to its wide material sources, low cost and simple and safe process. However, the size of the downhole leakage layer cannot be accurately obtained, and the conventional bridge plug plugging agent is not easy to deform, which makes it difficult to match the size of the leakage layer crack, and cannot effectively bridge and stay. The bridge plug plugging technology relies on the physical accumulation of the sealing layer, and the materials are independent of each other and have weak interaction. Under the action of long-term alternating stress such as drilling tool collision, circulating flushing, tripping suction and the like, the sealing layer is easy to fail and cause re-leakage. The consolidation plugging material has moderate cost, can enter different size cracks, has high strength and is not easy to re-leak. However, before the consolidation of the plugging material, the residence capacity is insufficient, and the plugging material cannot effectively stay in the leakage layer, resulting in the flow of the plugging material with the plugging slurry and the failure of plugging. Moreover, the plugging material with coagulation properties is pumped into the downhole leakage layer from the ground by using the drilling tool, which has a high risk of flash coagulation. Usually, the drilling tool is replaced with a smooth drill pipe for plugging, and one trip of tripping cycle is as long as 3-5 days. Despite this, slight carelessness may also cause drilling tool accidents such as "sausage filling" or "flag pole insertion". Therefore, the industry is generally forced to choose to use the consolidation plugging technology under the condition of multiple bridge plug plugging failures. The polymer gel plugging material has deformation capacity and strong adaptability to cracks, but has high cost and low pressure-bearing capacity, which greatly limits its field application.

[0004] Due to the above reasons, in the case of long open hole section and multiple leakage points, the selection of plugging technology is limited. The bridge plug plugging method has a fast time efficiency, but is easy to re-leak, and as the well section increases, it is difficult to determine whether it is a new leakage point or a re-leakage of the upper leakage layer after drilling leakage occurs, further increasing the difficulty of plugging. The use of consolidation type plugging material for plugging has a long construction period and high operation risk, which does not meet the concept of drilling speed and efficiency improvement. SUMMARY

[0005] Therefore, the present application aims to provide a synergistic bridge plug and its preparation method and application.

[0006] The present application provides a synergistic bridge plug, which comprises the following components in mass fraction: 35-70 parts of inert particle material; 5-10 parts of fiber material; 5-10 parts of sheet material; 15-40 parts of solidifiable particle material; 5-15 parts of modified activator; the sum of the mass fraction of each component is 100.

[0007] The modified activator is an activated material in which alkaline substances are wrapped by thermoplastic substances; the thermoplastic substances are paraffin and / or petroleum resin.

[0008] In some embodiments of the present application, the alkaline substances wrapped in the modified activator are one or more of calcium oxide, hexamethylenetetramine, m-phenylenediamine and triethanolamine.

[0009] The size of the modified activator is 20-200 mesh of standard sieve.

[0010] In some embodiments of the present application, the solidifiable particle material is selected from inorganic cement powder and / or solid reactive resin powder.

[0011] The size of the solidifiable particle material is 20-300 mesh of standard sieve.

[0012] In some embodiments of the present application, the inorganic cement powder is fly ash and / or slag; the solid reactive resin powder is selected from one or more of phenolic resin, urea-formaldehyde resin, epoxy resin and melamine resin.

[0013] In some embodiments of the present application, the inert particle material is selected from one or more of calcium carbonate, shell slag, quartz sand, green stone powder, walnut shell and polymer plastic.

[0014] The size of the inert particle material is 8-20 mesh, 20-40 mesh and 40-120 mesh of standard sieve, respectively.

[0015] In some embodiments of the present application, the fiber material is selected from one or more of sugar cane residue, hemp fiber, silicate fiber, sepiolite fiber and synthetic fiber.

[0016] The length of the fiber material is 1-3 mm and / or 0.5-1 mm.

[0017] In some embodiments of the present application, the sheet material is selected from one or more of mica sheet, glass paper, fish scale, sheet resin, polyethylene film and polypropylene film.

[0018] The sheet material has a thickness of 0.005-0.05 mm and a side length of 0.5-3 mm.

[0019] The present application provides a preparation method of the bridge plug plugging agent as described above, comprising the following steps:

[0020] The alkaline substance and the thermoplastic substance are modified by wrapping to obtain a modified activator; the thermoplastic substance is paraffin and / or petroleum resin.

[0021] According to mass fraction, the inert particulate material, the fibrous material, the sheet material, the solidifiable particulate material and the modified activator are mixed to obtain the bridge plug plugging agent after stirring.

[0022] The present application provides an application of the bridge plug plugging agent as described above in drilling fluid plugging.

[0023] In some embodiments of the present application, the bridge plug plugging agent has an addition amount of 10%-40% in the drilling fluid according to mass volume percentage.

[0024] Compared with the prior art, the plugging agent provided by the present application is mainly composed of inert particulate material, fibrous material, sheet material, solidifiable particulate material and modified activator in a certain proportion. The key of the present application is that the modified activator cooperates with the solidifiable particulate material, etc. Among them, the modified activator can select a wrapping layer with a suitable melting point according to different leakage layer temperatures. The wrapping layer is stable during the ground preparation or pumping process. When it reaches the leakage layer, the wrapping layer is gradually destroyed, and the activated material is released to contact the solidifiable particulate material and generate a solidification reaction, so as to achieve the purpose of positioning and controlled release activation. The solidifiable particulate material used in the present application does not generate a solidification reaction without directly contacting the activator, and has stable performance at room temperature. When used with the modified activator, etc., it has good controllability and stability. Through the synergistic effect of the solidifiable particulate material and the modified activator, the present application can effectively control the position and timing of the solidification reaction during the plugging construction process, not only avoiding the flash freezing accident, but also facilitating storage and transportation. In addition, if equipment failure, drilling tool jamming and other special situations occur during the pumping process, the complex processing time is increased.

[0025] Furthermore, the present application adopts the concept of micro-solidification, that is, selecting appropriate proportion of solidifiable particulate material to control the solidification strength to meet the plugging demand, while further reducing the operation risk. In summary of the above points, the present application can solve the performance deficiency of the solidification plugging material with high drilling tool risk, which is beneficial to the popularization and application of the present application in field plugging. DETAILED DESCRIPTION

[0026] In order to make the technical features, objectives and effects of the present application more clearly understood, the technical solutions of the present application will be described in detail below in conjunction with specific embodiments. The described embodiments are only some of the embodiments of the present application, not all.

[0027] The present application provides a synergistic bridge plug leak sealing agent, which comprises the following components by mass fraction:

[0028] 35-70 parts of inert particle material;

[0029] 5-10 parts of fibrous material;

[0030] 5-10 parts of sheet material;

[0031] 15-40 parts of solidifiable particle material;

[0032] 5-15 parts of modified activator; the sum of the mass fractions of each component is 100;

[0033] The modified activator is an activated material of thermoplastic substance wrapped alkaline substance; the thermoplastic substance is paraffin and / or petroleum resin.

[0034] The bridge plug leak sealing agent provided by the present application has good leak sealing pressure bearing effect, excellent leak layer adaptability, safe and simple construction process, and is beneficial to solve the problems of long open hole section of weak formation and multiple point leakage, thereby providing technical support for long open hole section fast drilling.

[0035] According to the mass fraction, the bridge plug leak sealing agent described in the embodiments of the present application comprises: 35-70 parts of inert particle material, 5-10 parts of fibrous material, and 5-10 parts of sheet material. In the present application, the inert particle material is used to bridge and fill in a certain ratio, the sheet material is wedged, and the fibrous material is used as reinforcement, so as to form a preliminary sealing layer when applied.

[0036] The inert particle material is in the form of powder or particle, which can be a relatively stable inorganic material (such as containing carbonate, silicate, silicon oxide, etc.) or a polymer plastic (such as aromatic resin material), and the composition can be 35-60 parts, such as 35 parts, 40 parts, 50 parts, 55 parts, etc. Preferably, the inert particle material is selected from one or more of calcium carbonate, shell residue, quartz sand, green stone powder, walnut shell and polymer plastic, which are all commercially available materials known to those skilled in the art. The inert particle material is preferably a natural inorganic material, wherein the quartz sand is a quartz particle obtained by crushing quartzite; the quartzite is a non-metallic mineral, which is a hard, wear-resistant and chemically stable silicate mineral, and the main mineral component is SiO2. Green stone belongs to the limestone category, and the main component is calcium carbonate, which can be crushed into green stone powder. The walnut shell is a granular material processed by crushing, screening and other treatments, which is chemically stable; the shell powder is a powder made of shell by crushing and grinding, and the main component is calcium carbonate and a small amount of organic matter. Further preferably, the size of the inert particle material is 8-20 mesh, 20-40 mesh and 40-120 mesh, respectively; it can be different mesh of the same kind of material, and the ratio of the three is preferably 10-20:10-20:10-20.

[0037] The fiber material refers to a substance composed of continuous or discontinuous filaments, and the aspect ratio (length-diameter ratio) is usually large. The fiber material mainly includes natural fibers and chemical fibers (synthetic fibers), and the natural fibers are divided into plant fibers, animal fibers and mineral fibers, and the synthetic fibers are mainly high molecular components, such as polypropylene fibers and polyamide fibers; the fiber material used in the embodiments of the present application has a length of less than 5 mm. Preferably, the fiber material is selected from one or more of sugar cane residue, hemp fiber, silicate fiber, sepiolite fiber and synthetic fiber, and more preferably is silicate fiber, sepiolite fiber or polypropylene fiber, which are all commercially available materials (the length of the fiber material is 1-3 mm and / or 0.5-1 mm). For example, the sepiolite fiber is a fiber material mainly composed of sepiolite mineral, which belongs to natural mineral fiber; the sepiolite is a silicate mineral, which has good heat resistance and corrosion resistance. The length of the fiber material is 1-3 mm and / or 0.5-1 mm; the polypropylene fiber in some embodiments has a fineness range of 0.008-0.013 mm. In addition, the fiber fineness refers to the fineness degree of the fiber expressed by the diameter of the fiber. Specifically, the silicate fiber, sepiolite fiber or polypropylene fiber, etc. meet the length and diameter conditions, have certain toughness, and are cheap and easy to obtain.

[0038] In the embodiments of the present application, the sheet material is generally a two-dimensional size morphology, a stable inert filling material; the sheet material can effectively improve the residence capacity of the plugging material through its unique planarity. The sheet material can be rigid or ductile, such as mica sheet, glass paper, fish scale, sheet resin, etc.; it can also be flexible, such as polyethylene film and polypropylene film, etc. Preferably, the sheet material is selected from one or more of mica sheet, glass paper, fish scale, sheet resin, polyethylene film and polypropylene film, further being mica sheet or sheet resin, which can be commercially available or self-made sheet material (thickness of 0.005-0.05 mm, edge length of 0.5-3 mm). The mica sheet used in some embodiments is mainly mica flake (flake mica); the sheet resin used in some other embodiments is the polymeric film fragment material in patent No. 201811024931.X, or the resin-based sheet material prepared in patent No. 202211237504.6. Preferably, the thickness of the sheet material is 0.005-0.05 mm, and the edge length is 0.5-3 mm; for the self-made sheet resin in the laboratory (patent No. 202211237504.6, a resin-based sheet material for plugging and a preparation method), the thickness can be 0.005-0.05 mm, and the edge length is 1-3 mm.

[0039] As preferred, the embodiments of the present application use inert particle materials of different mesh numbers, 10 parts of silicate fibers with a length of lmm, and 10 parts of mica sheets with an edge length of 0.5-3 mm, which have good comprehensive performance.

[0040] In addition to the inert particle materials, fiber materials and sheet materials described above, the plugging agent of the embodiments of the present application includes: 15-40 parts of solidifiable particle materials; 5-15 parts of modified activators; the sum of the mass fractions of the components is 100.

[0041] In the preferred embodiments of the present application, the solidifiable particle materials are selected from one or more of inorganic cementitious powders (fly ash, slag, etc.), solid reactive resin powders (phenolic resin, urea-formaldehyde resin, epoxy resin, melamine resin, etc.), etc.; the size is 20-300 mesh of the standard sieve. The solidifiable particle materials have a powder particle morphology, and the amount can be 15 parts, 20 parts, 25 parts, 30 parts, 40 parts, which mainly plays a role in solidification and plugging.

[0042] For the inorganic cementing powder, the inorganic cementing material, i.e. inorganic consolidated material, can be consolidated under the action of the solidifying agent. The fly ash is fine ash collected from flue gas after coal combustion, and has a similar appearance to cement. Generally, the darker the color, the finer the fly ash particle size, and the higher the carbon content. The fly ash particles have a porous honeycomb structure, a large specific surface area, and high adsorption activity. The particle size range is 0.5-300 μm. The slag is the residue after ore dressing or smelting. The solid reactive resin is a reactive thermoplastic resin, which can be consolidated in the presence of an activator. Preferably, the solid reactive resin powder is selected from one or more of phenolic resin, urea-formaldehyde resin, epoxy resin and melamine resin. The molecular weight of the epoxy resin is preferably 400-7000.

[0043] The modified activator in the embodiment of the present application is an activated material in which a thermoplastic substance wraps an alkaline substance. The thermoplastic substance is paraffin and / or petroleum resin. Preferably, the alkaline substance wrapped in the modified activator is one or more of calcium oxide, hexamethylenetetramine, m-phenylenediamine and triethanolamine. The modified activator is selected from one or more of wrapped modified calcium oxide, wrapped modified hexamethylenetetramine, m-phenylenediamine and triethanolamine. The modified activator is adjusted according to the consolidated granular material. The modified activator generally uses one or more of thermoplastic substances such as paraffin and petroleum resin to wrap the alkaline substance, and the thermoplastic material is adjusted according to the temperature. Further, the size of the modified activator is 20-200 mesh of the standard sample sieve.

[0044] The consolidated granular material used in the embodiment of the present application is fly ash or slag, phenolic resin, urea-formaldehyde resin, epoxy resin, melamine resin, etc. Without direct contact with the activator, the consolidated granular material does not have a consolidation reaction and has stable performance at room temperature. When used with the modified activator, the consolidated granular material has good controllability and stability. Through the synergistic effect of the consolidated granular material and the modified activator, the position and timing of the consolidation reaction can be effectively controlled during the plugging construction process.

[0045] The modified activator is prepared in the embodiment of the present application, and specifically includes: modifying the alkaline substance and the thermoplastic substance to obtain the modified activator.

[0046] Further, the activator is wrapped with a thermoplastic material by a microcapsule wrapping method. The specific method is as follows: a certain amount of thermoplastic material is measured into a three-necked flask, constant temperature and constant speed stirring is carried out at a certain temperature (above the melting point of the thermoplastic material), a stabilizer can be optionally added, and the mixture is uniformly mixed to become a continuous phase medium; the activator powder is weighed and slowly added into the continuous phase medium; constant temperature water bath stirring is uniformly dispersed, and slow cooling is carried out for granulation.

[0047] The embodiment of the present application provides a preparation method of the bridge plug plugging agent as described in the foregoing, which includes:

[0048] a modified activator is provided;

[0049] The inert particle material, the fibrous material, the sheet material, the solidifiable particle material and the modified activator are mixed according to the mass fraction, and the synergistic bridge plug agent is obtained after stirring.

[0050] Furthermore, the application provides application of the bridge plug agent as described above in plugging of a drilling fluid. The synergistic bridge plug agent as described above is applied in plugging of a drilling fluid, and the amount of the bridge plug agent in the drilling fluid can be 10% to 40% according to the mass volume percentage, for example, 15%, 20%, 25%, 30%, etc. The drilling fluid can be a water-based drilling fluid, and a conventional composition can be used.

[0051] The embodiment of the application combines the respective advantages of the bridge plug plugging and the consolidation plugging, forms a bridge plug agent with simple process, high plugging strength, and can improve the efficiency of the plugging operation. The inert particle bridging, the sheet material wedging, the fibrous material reinforcing, and the preliminary formation of the plugging layer are achieved by the reasonable particle size grading. The modified activator with the delayed activation is obtained by the wrapping modification. After reaching the leakage layer, the wrapping layer is damaged under the action of the formation temperature and pressure, the activator is released, the consolidation reaction between the activator and the consolidation material is generated, the force between the plugging materials is increased, the pressure bearing capacity and the stability of the plugging layer are improved, the failure and the re-leakage are prevented, and the one-time success rate of the plugging is improved. The plugging agent described in the embodiment of the application is used to solve the problems of the long open hole section and the multi-point leakage in the complex formation, especially the weak formation, and provides technical support for the long open hole section and the fast drilling.

[0052] In order to further understand the present application, the synergistic bridge plug agent, the preparation method and the application thereof provided by the present application are specifically described in combination with the embodiments. In the embodiments, the experimental method without the specific experimental conditions is the conventional method and the condition known in the art.

[0053] Some embodiments of the application carry out the plugging of the bridge plug agent in the water-based drilling fluid. Specifically, 300 mL of the plugging base slurry is prepared according to the formula 4% bentonite + 0.5% anhydrous sodium carbonate, and different amounts of the plugging agent product are added to the plugging base slurry, and the plugging experiment is carried out on the crack module with different sizes. The amount of the plugging agent is added according to the mass volume percentage, and the amount can be 10% to 40%.

[0054] In the following examples, the slag used was purchased from Jinan Qingda Fengcheng Engineering Technology Co., Ltd., which is granulated blast furnace slag; the modified phenolic resin used for the diamond grinding wheel (WL-1501 resin, Weilin New Material Technology Co., Ltd.); and the inert particulate material is well known to those skilled in the art, wherein the calcium carbonate, quartz sand, walnut shell, and green stone powder are sourced from the Lingshou County Huashuo Mineral Product Processing Factory; the silicate fibers and sepiolite fiber materials used are sourced from the Lingshou County Huashuo Mineral Product Processing Factory, and the length is 1-3 mm. The mica sheets used are sourced from the Lingshou County Huashuo Mineral Product Processing Factory, with a thickness of 0.005-0.05 mm and a side length of 0.5-3 mm.

[0055] Preparation of the modified activator:

[0056] 6 g of paraffin wax was weighed into a three-necked flask, and was uniformly mixed by constant-speed stirring at 60°C to become a continuous phase medium; 10 g of calcium oxide was slowly added to the continuous phase medium; the mixture was uniformly dispersed by constant-speed stirring in a water bath, and was slowly cooled and granulated.

[0057] Example 1

[0058] 20 parts of quartz sand particles of standard sample sieve 8-20 mesh, 20 parts of quartz sand particles of standard sample sieve 20-40 mesh, 20 parts of quartz sand of standard sample sieve 40-120 mesh, 10 parts of silicate fibers of length 1 mm, 10 parts of mica sheets of side length 0.5-3 mm, 15 parts of slag, and 5 parts of paraffin wax-coated calcium oxide particles of standard sample sieve 40-100 mesh were added to a mixing device and uniformly mixed and stirred, to obtain the bridge plug plugging agent for drilling hole plugging.

[0059] Example 2

[0060] 20 parts of green stone powder particles of standard sample sieve 8-20 mesh, 20 parts of green stone powder particles of standard sample sieve 20-40 mesh, 15 parts of green stone powder of standard sample sieve 40-120 mesh, 10 parts of silicate fibers of length 1 mm, 10 parts of mica sheets of side length 0.5-3 mm, 20 parts of slag, and 5 parts of paraffin wax-coated calcium oxide particles of standard sample sieve 40-100 mesh were added to a mixing device and uniformly mixed and stirred, to obtain the bridge plug plugging agent for drilling hole plugging.

[0061] Example 3

[0062] 15 parts of walnut shell particles of standard sample sieve 8-20 mesh, 15 parts of walnut shell particles of standard sample sieve 20-40 mesh, 10 parts of walnut shell of standard sample sieve 40-120 mesh, 10 parts of silicate fibers of length 1 mm, 10 parts of mica sheets of side length 0.5-3 mm, 30 parts of slag, and 5 parts of paraffin wax-coated calcium oxide particles of standard sample sieve 40-100 mesh were added to a mixing device and uniformly mixed and stirred, to obtain the bridge plug plugging agent for drilling hole plugging.

[0063] Example 4

[0064] The standard sample sieve 8-20 mesh quartz sand particles 10 parts, the standard sample sieve 20-40 mesh quartz sand particles 10 parts, the standard sample sieve 40-120 mesh quartz sand 15 parts, length 1 mm silicate fiber 10 parts, mica sheet 10 parts with side length of 0.5-3 mm, slag 40 parts, standard sample sieve 40-100 mesh paraffin wrapped calcium oxide particles 5 parts are added into the mixing device and mixed and stirred uniformly, to obtain the bridge plug plugging agent for drilling.

[0065] Comparative Example 1

[0066] The standard sample sieve 8-20 mesh quartz sand particles 30 parts, the standard sample sieve 20-40 mesh quartz sand particles 30 parts, the standard sample sieve 40-120 mesh quartz sand 20 parts, length 1 mm silicate fiber 10 parts, mica sheet 10 parts with side length of 0.5-3 mm are added into the mixing device and mixed and stirred uniformly, to obtain the bridge plug plugging agent.

[0067] Comparative Example 2

[0068] The standard sample sieve 8-20 mesh walnut shell particles 20 parts, the standard sample sieve 20-40 mesh walnut shell particles 20 parts, the standard sample sieve 40-120 mesh walnut shell 20 parts, length 1 mm silicate fiber 20 parts are added into the mixing device and mixed and stirred uniformly, to obtain the bridge plug plugging agent.

[0069] Comparative Example 3

[0070] The standard sample sieve 8-20 mesh calcium carbonate particles 20 parts, the standard sample sieve 20-40 mesh calcium carbonate particles 20 parts, the standard sample sieve 40-120 mesh calcium carbonate 20 parts, mica sheet 20 parts with side length of 0.5-3 mm are added into the mixing device and mixed and stirred uniformly, to obtain the bridge plug plugging agent.

[0071] Compared with the conventional bridge plug plugging agent of the above comparative material, the synergistic bridge plug plugging agent of the present application can be consolidated, and the main advantages include: ① high bearing strength; ② not easy to return and re-leak. The evaluation results of the plugging product prepared by the example of the present application are as follows.

[0072] (1) Performance evaluation of consolidatable material

[0073] The consolidatable material and the modified activator are the key materials of the synergistic plugging agent of the present application, which have good controllability and stability. Through the consolidation reaction, the interaction between the plugging materials is increased, the bearing capacity and stability of the plugging layer are improved, the failure and re-leakage are prevented, and the one-time success rate of plugging is improved.

[0074] In 100ml water, respectively add different mass of solidifiable granular material (slag) and activator, and investigate the performance of solidifiable material at different temperature, and the result is shown in Table 1.

[0075] Table 1 Performance evaluation of solidifiable material in the embodiment of the present application

[0076]

[0077] Table 1 is the control condition of surface solidification reaction. From the comparison between Experiment 1 and Experiment 2, it can be seen that the solidifiable material in the composition of the present application does not have reaction ability in general, and must be under the action of activator to obtain reaction activity, which is beneficial to storage, transportation, and convenient for preparation of plugging slurry. From Experiment 2 and Experiment 3, it can be seen that the modified activator coating layer in the present application is stable at room temperature, and when it reaches the leakage layer, the coating layer is gradually destroyed under the action of temperature, and the activator is released to contact the solidifiable material and occur solidification reaction, so as to achieve the purpose of positioning and controlled release of activator. From Experiment 3 and Experiment 4, it can be seen that the reaction time of the solidifiable material can be controlled by the amount of modified activator in the present application, which is beneficial to adjusting the reaction time according to different leakage degree, for example, the solidification reaction time needs to be controlled at 3-5h in the case of larger leakage channel, so as to quickly establish high-strength plugging layer; in the case of smaller leakage channel or pressure plugging, it is necessary to continuously squeeze the plugging slurry into the leakage layer, and the solidification reaction time is preferably controlled at 6-8h.

[0078] From the above experiments, it can be seen that the solidifiable granular material in the present application has good controllability and stability when used with modified activator.

[0079] (2) Evaluation of plugging pressure-bearing capacity

[0080] A self-developed fracture plugging simulation device (which can be heated) in the laboratory is used to evaluate the plugging effect of the product of the present application. The simulation plugging device is convenient to operate and has high experimental efficiency; the device is pressurized by a displacement pump, the fracture module is 15cm long, which is milled from a cylinder with a diameter of 6.3cm, and the simulated fracture width is 1-5mm, the roughness of the fracture surface and the bending degree of the fracture surface are changed by smearing cement mortar or pasting quartz sand on the fracture surface, so that the fracture module is more in line with the actual situation.

[0081] Preparation of experimental base slurry 7 parts, each 300 mL, the formula is 4% bentonite + 0.5% anhydrous sodium carbonate, wherein the bentonite is from the Ling Shou County Huashuo mineral product processing plant, which is a common drilling industry slurry making soil. Different mass volume percentages of 15% product are added to the prepared 7 parts of base slurry, stirred uniformly, and simulated plugging tests are carried out on 3 mm wide crack modules (test temperature is 90℃), under 1 MPa pressure, after 8 hours of static state, pressure is applied, pressure bearing effect is tested, the crack is taken out, and the plugging layer state is observed, and the test results are shown in Table 2.

[0082] Table 2 Plugging effect of the plugging agent in the embodiment of the application

[0083]

[0084] Note: In the table, the pressure bearing value “≥6” means that when the pressure is increased to 6 MPa, the plugging layer formed by the plugging agent in the crack can still stably reside.

[0085] From the experimental results, it can be seen that the plugging agent of the application has strong pressure bearing capacity for crack size, and has excellent plugging and pressure bearing capacity.

[0086] (3) Evaluation of the anti-damage capacity of the plugging layer

[0087] Preparation of experimental base slurry 7 parts, each 300 mL, the formula is 4% bentonite + 0.5% anhydrous sodium carbonate, wherein the bentonite is from the Ling Shou County Huashuo mineral product processing plant, which is a common drilling industry slurry making soil. Different mass volume percentages of 15% product are added to the prepared 7 parts of base slurry, stirred uniformly, and simulated plugging tests are carried out on 3 mm wide crack modules (test temperature is 90℃), under 1 MPa pressure, after 8 hours of static state, pressure is applied, pressure bearing effect is tested, the crack is taken out, and the plugging layer state is observed, and the test results are shown in Table 2.

[0088] Table 3 Anti-damage capacity of the plugging layer in the embodiment of the application

[0089]

[0090] Note: In the table, the pressure bearing value “≥6” means that when the pressure is increased to 6 MPa, the plugging layer formed by the plugging agent in the crack can still stably reside.

[0091] From the experimental results, it can be seen that the plugging agent of the application has strong pressure bearing capacity for crack size, and has excellent plugging and pressure bearing capacity.

[0092] The particle size of the solidified material described in the application is much smaller than that of the bridge plug plugging material, the bridge plug material is more beneficial to bridging residence, and the residence capacity of the solidified material is not considered in the application, so the plugging experiments of different cracks are not compared. In the application, the solidified material accounts for 15% to 40%, which can not only have the strength of solidified plugging, but also reduce the risk of difficult control of the solidified plugging reaction rate.

[0093] From the above examples, it can be seen that the bridge plug plugging agent provided by the application can effectively control the position and timing of the solidification reaction during the plugging construction process through the synergistic effect of the solidifiable particle material and the modified activator, not only avoiding the flash condensation accident, but also facilitating storage and transportation. In addition, if equipment failure, drill pipe blockage and other special conditions occur during pumping, the complex processing time is increased. The application also selects an appropriate proportion of solidifiable particle material to control the solidification strength to meet the plugging demand, while further reducing the operation risk. It can be seen that the application can solve the performance deficiency of the solidified plugging material with high drill pipe risk, and is beneficial to the popularization and application of the plugging on site.

[0094] The above examples are only used to illustrate the technical features and implementation process of the application, and are not intended to limit the technical solutions of the application. It should be pointed out that for ordinary skilled persons in the art, the application can still be modified or replaced equivalently without departing from the principle of the application, and the modifications or replacements are all covered in the protection of the application.

Claims

1. A synergistic bridge plug sealing agent, characterized in that, It comprises the following components in parts by weight: 35-70 parts of inert particulate material; 5-10 parts of fibrous material; 5-10 parts of sheet material; 15-40 parts of bindable particulate material; 5-15 parts of modifier / activator; the sum of the parts by weight of each component is 100. The modified activator is an activating material in which an alkaline substance is encapsulated by a thermoplastic substance; the thermoplastic substance is paraffin and / or petroleum resin.

2. The bridge plug sealant according to claim 1, characterized in that, The alkaline substance encapsulated in the modified activator is one or more of calcium oxide, hexamethylenetetramine, m-phenylenediamine, and triethanolamine; the size of the modified activator is 20-200 mesh on a standard sieve.

3. The bridge plug sealant according to claim 1, characterized in that, The solidifiable particulate material is selected from inorganic cementitious powder and / or solid reactive resin powder; the size of the solidifiable particulate material is 20-300 mesh on a standard sieve.

4. The bridge plug sealant according to claim 3, characterized in that, The inorganic cementitious powder is fly ash and / or slag; the solid reactive resin powder is selected from one or more of phenolic resin, urea-formaldehyde resin, epoxy resin and melamine resin.

5. The bridge plug sealant according to claim 1, characterized in that, The inert particulate material is selected from one or more of calcium carbonate, shell residue, quartz sand, bluestone powder, walnut shells and polymer plastics; the size of the inert particulate material is 8-20 mesh, 20-40 mesh and 40-120 mesh respectively on standard sieves.

6. The bridge plug sealant according to claim 1, characterized in that, The fiber material is selected from one or more of sugarcane bagasse, hemp fiber, silicate fiber, sepiolite fiber and synthetic fiber; the length of the fiber material is 1-3 mm and / or 0.5-1 mm.

7. The bridge plug sealant according to claim 1, characterized in that, The sheet material is selected from one or more of mica sheets, cellophane, fish scales, sheet resin, polyethylene film, and polypropylene film; the sheet material has a thickness of 0.005 to 0.05 mm and a side length of 0.5 to 3 mm.

8. A method for preparing the bridge plug sealing agent according to any one of claims 1-7, comprising the following steps: A modified activator is obtained by encapsulating and modifying an alkaline substance and a thermoplastic substance; the thermoplastic substance is paraffin and / or petroleum resin. According to the mass fractions, inert particulate material, fibrous material, sheet material, bindable particulate material and the modified activator are mixed and stirred to obtain the bridge plug sealing agent.

9. The application of the bridge plug plugging agent as described in any one of claims 1-7 in drilling fluid plugging.

10. The application according to claim 9, characterized in that, The amount of the bridge plug plugging agent added to the drilling fluid is 10% to 40% by weight-volume percentage.

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