Adsorption type flushing agent, adsorption type prepad fluid, preparation method and application

Abstract

The invention belongs to the technical field of oilfield exploitation, and relates to an adsorption type flushing agent, an adsorption type prepad fluid, a preparation method and application. The adsorption type flushing agent comprises one or more of processed wood fibers, natural wood fibers and mineral fibers. The adsorption type flushing agent is mainly composed of wood fibers and mineral fibers. Wherein a large number of tiny pores and gaps are formed in the surface of the wood fiber, the gaps have good adsorbability, and when the gaps make contact with oil stains, strong adsorption force is formed around the oil stains, and the oil stains are adsorbed and fixed; the mineral fiber is composed of a fiber structure with polyhedral pore walls and pore channels extending alternately, a three-dimensional structure with a large specific surface area is formed, and due to the special structure, the mineral fiber has extremely high adsorption capacity and can rapidly adsorb and fix oil substances. When the adsorption type flushing agent is combined with oil-based flushing fluid, the dual effects of adsorbing and removing oil stains and efficiently and chemically dissolving and flushing can be effectively achieved.

Description

Technical Field

[0001] This invention belongs to the field of oilfield development technology, and relates to an adsorption-type flushing agent, an adsorption-type pre-fluid, a preparation method and application thereof, and particularly to an adsorption-type flushing agent suitable for efficient cleaning of non-water-based drilling fluid filter cake, an adsorption-type pre-fluid containing the same, and a preparation method thereof. Background Technology

[0002] With increasingly stringent marine environmental protection requirements, the proportion of recyclable non-water-based drilling fluids used in offshore oilfield exploration and development is gradually increasing. my country's energy exploration and development is continuously advancing into deepwater and ultra-deepwater areas. Deepwater resources account for more than two-thirds of the oil and gas resources in the South China Sea, making it an important energy replacement area. In recent years, during deepwater exploration, special and complex well conditions such as ultra-deepwater, extremely high temperature differences, and ultra-shallow layers have emerged, as seen in wells like Baiyun 5-2 and Lingshui 36-1. Under these conditions, effectively removing the filter cake formed by non-water-based drilling fluids on the wellbore has become a key technical challenge in ensuring cementing quality.

[0003] Currently, there is considerable research both domestically and internationally on the flushing of non-aqueous drilling fluid filter cake. Foreign companies such as Halliburton, Baker Hughes, and Schlumberger typically employ a technology that uses surfactant-based phase-inverting agents in conjunction with a separator fluid. This aims to transform the non-aqueous drilling fluid and separator fluid mixture from an oil-in-water to a water-in-oil state, thereby flushing the casing interface mud cake and emphasizing its compatibility with non-aqueous drilling fluids and cement slurries. Domestic research primarily focuses on surfactant-based flushing fluids, mainly simulating the flushing process of non-aqueous mud cake on the rotor using rotational viscometers. Among these, CNOOC's research emphasizes the efficient flushing of non-aqueous filter cake prepared under high-temperature and high-pressure conditions (e.g., 90℃, 3.5MPa, 30min). These conditions require a high degree of simulation but present significant flushing challenges.

[0004] Existing technologies already include various pre-fluid or flushing fluid solutions for drilling fluid filter cake flushing. For example: Patent CN117511526A discloses an active fiber flushing fluid for removing filter cake in cementing. It uses cellulose fibers loaded with nano-ferric oxide as the active material and uses an oxidant to decompose the polymer in the filter cake of water-based drilling fluid. It is suitable for water-based systems and can be flushed at a high rotation speed (800 rpm).

[0005] Patent CN107603576A provides an oil-based mud flushing fluid for cementing, which uses hydrocarbon solvents as the main components and has a certain flushing effect on non-water-based drilling fluid mud cake. It uses a sandpaper wall-building method to simulate mud cake and closely resembles the actual well wall adhesion.

[0006] Patents CN120209807A, CN103642476A, CN114605975A, CN117777973A, etc., have proposed flushing or pre-fluid systems for oil-based drilling fluids from different perspectives. Most of them are mainly based on surfactant compounding, taking into account the functions of cleaning, isolation or interface enhancement.

[0007] Patent CN119286489A discloses a mud cake destroying flushing agent containing glass fibers, which uses a high rotation speed for flushing and uses a chemical destroyer. However, this solution does not fully demonstrate its compatibility with cement slurry, and the fibers are prone to settling in a system without a suspending agent.

[0008] In summary, most existing flushing solutions for non-water-based drilling fluid filter cake rely on surfactants, employing chemical cleaning or physical scouring. However, they still have the following shortcomings in efficiently removing filter cake while simulating real well conditions: most flushing experiments are conducted at high speeds above 200 rpm, making the filter cake prone to detachment due to centrifugal force, failing to accurately simulate the actual flushing conditions in the field or with the flushing fluid; for thick and dense filter cakes formed by non-water-based drilling fluids at low temperatures of 20-50℃ and in high-permeability formations, the cleaning effect of existing flushing fluids is limited, resulting in unsatisfactory cementing interface quality; in some fiber-reinforced flushing solutions, the physical scouring effect is not significant after the fiber materials, such as PP fiber and glass fiber, are evenly dispersed in the suspension system, and there are risks of easy agglomeration, sedimentation, or incompatibility with cement slurry.

[0009] Current technologies do not address the synergistic effect of natural or mineral fibers with porous adsorption structures and oil-based flushing fluids to achieve dual cleaning functions of adsorption and chemical dissolution. Therefore, there is still a need to develop a pre-fluid system that can efficiently clean non-water-based drilling fluid filter cake under low-shear conditions, and has good compatibility with drilling fluids and cement slurries, especially suitable for complex well conditions in low-temperature, high-permeability formations. Summary of the Invention

[0010] The purpose of this invention is to address the shortcomings of existing technologies by providing an adsorbent flushing agent, an adsorbent pretreatment solution, its preparation method, and its application.

[0011] The adsorbent flushing agent provided by the present invention includes one or more of processed wood fiber, natural wood fiber, and mineral fiber.

[0012] The above-mentioned adsorbent flushing agent, by weight, includes: 1-10 parts processed wood fiber, 0-10 parts natural wood fiber, and 1-10 parts mineral fiber.

[0013] The aforementioned adsorbent flushing agent contains processed wood fibers that are scraps or chips from wood processing plants and engineered wood processing plants; the natural wood fibers include one or more of the following: pine, poplar, camphor, eucalyptus, fruit wood, and nutshells; and the mineral fibers include one or more of the following: sepiolite fiber, magnesia fiber, and asbestos fiber.

[0014] In the above-mentioned adsorbent rinsing agent, the particle size of the processed wood fiber, the natural wood fiber, and the mineral fiber is 20 mesh to 80 mesh.

[0015] The method for preparing the adsorbent flushing agent provided by the present invention includes: mixing processed wood fiber, natural wood fiber and mineral fiber evenly.

[0016] The adsorption-type pretreatment solution provided by the present invention includes the above-mentioned adsorption-type flushing agent.

[0017] The above-mentioned adsorption-type pretreatment solution, by weight, includes: 100 parts of slurry preparation water, 0.5 to 3 parts of release agent, 3 to 15 parts of adsorption-type flushing agent, 15 to 50 parts of oil-based flushing solution, 0.3 to 1 part of defoamer, and 0 to 400 parts of barite.

[0018] The aforementioned adsorption-type pretreatment solution includes one or more of fresh water, seawater, or salt water.

[0019] The aforementioned adsorption-type pre-flushing liquid contains a separating agent comprising one or more of the following materials: bentonite, attapulgite, sepiolite, xanthan gum, wenlun gum, guar gum, polyanionic cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, and polymers.

[0020] The aforementioned adsorption-type pretreatment liquid is composed of a polymer formed by polymerization of one or more monomers selected from N,N-dimethylacrylamide, acrylic acid, acrylonitrile, 2-acrylamido-2-methylpropanesulfonic acid, and acrylamide.

[0021] The aforementioned adsorption-type pretreatment solution, wherein the oil-based rinsing solution is composed of a solvent, a nonionic surfactant, an amphoteric surfactant, a polymer, and water.

[0022] In the above-mentioned adsorption-type pre-fluid, the defoamer is tributyl phosphate.

[0023] The method for preparing the adsorption-type pretreatment solution provided by the present invention includes: (1) Weigh the slurry water into the mixing cup and add the defoamer; (2) Add the release agent to the mixing cup at 500-4000 rpm and hydrate for 3-30 minutes; (3) Add oil-based rinsing solution at 500-4000 rpm and stir for 0.5-3 min; (4) Add barite at 500-4000 rpm and stir for 0.5-3 min; (5) Add the adsorbent rinsing agent at 500-2000 rpm and stir for 0.5-3 min.

[0024] The present invention also provides the application of the above-mentioned adsorbent flushing agent or the above-mentioned adsorbent pre-fluid in the efficient cleaning of non-water-based drilling fluid filter cake.

[0025] In the above applications, the efficient cleaning time is 3-10 minutes, and the rotational viscometer speed is 60-100 rpm.

[0026] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: (1) The adsorption-type flushing agent provided by this invention is mainly composed of wood fiber and mineral fiber. The surface of the wood fiber has a large number of tiny pores and voids, which have good adsorption properties. When in contact with oil stains, it forms a strong adsorption force around the oil stains, adsorbing and fixing the oil stains. The mineral fiber is composed of a fiber structure with alternating polyhedral pore walls and channels, forming a three-dimensional structure with a large specific surface area. This special structure gives the mineral fiber a very strong adsorption capacity, which can quickly adsorb and fix oily substances. When used in combination with oil-based flushing liquid, it plays a dual role of oil stain adsorption and removal and efficient chemical dissolution and flushing.

[0027] (2) The adsorption-type pre-fluid provided by the present invention can achieve efficient cleaning of non-water-based drilling fluid filter cake at room temperature to high temperature. At the same time, it has good compatibility with cement slurry and non-water-based drilling fluid. Field application verification shows that it is convenient for field construction.

[0028] (3) The present invention sets the flushing rate to 100 rpm according to international practice, which can effectively simulate the actual flushing situation on site or in the flushing fluid.

[0029] (4) Through field application practice, this invention has successfully overcome the technical challenge of cleaning the thick non-water-based drilling fluid filter cake in deep-water operation blocks such as Lingshui. According to calculations, implementing this technology can generate indirect economic benefits of over ten million yuan in just two months, demonstrating significant social and economic benefits. Attached Figure Description

[0030] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention.

[0031] Figure 1 Electron micrograph of poplar wood; Figure 2 Electron micrograph of sepiolite; Figure 3 The images show the effect of using the adsorption-type pre-fluid prepared in Example 5 to flush the non-water-based drilling fluid filter cake in the Wushi Block of Beibu Gulf at 20°C; where A is a photo before flushing, B is a photo after 7 minutes of flushing, C is a photo after 9 minutes of flushing, and D is a photo of the interfacial water wettability test. Figure 4 The images show the effect of using the pre-fluid prepared in Comparative Example 1 to flush non-water-based drilling fluid filter cake in the Wushi Block of Beibu Gulf at 20°C; where A is a photo before flushing, B is a photo after 7 minutes of flushing, and C is a photo after 10 minutes of flushing. Figure 5 The images show the effect of using the pre-fluid prepared in Comparative Example 2 to flush non-water-based drilling fluid filter cake in the Wushi Block of Beibu Gulf at 20°C; where A is a photo before flushing, B is a photo after 7 minutes of flushing, and C is a photo after 10 minutes of flushing. Figure 6 The images show the effect of using the pre-fluid prepared in Comparative Example 3 to flush non-water-based drilling fluid filter cake in the Wushi Block of Beibu Gulf at 20°C; where A is a photo before flushing, B is a photo after 7 minutes of flushing, and C is a photo after 10 minutes of flushing. Figure 7 The images show the effect of using the adsorption-type pre-fluid prepared in Example 5 to flush the non-water-based drilling fluid filter cake in the Wushi Block of Beibu Gulf at 90°C; where A is a photo before flushing, B is a photo after 3 minutes of flushing, C is a photo after 4 minutes of flushing, and D is a photo of the interfacial water wettability test. Figure 8 The images show the effect of using the pre-fluid prepared in Comparative Example 1 to flush the non-water-based drilling fluid filter cake in the Wushi Block of Beibu Gulf at 90°C. Among them, A is a photo before flushing, B is a photo after 7 minutes of flushing, C is a photo after 15 minutes of flushing, and D is a photo of the interfacial water wettability test. Figure 9 The images show the effect of using the adsorption-type pre-fluid prepared in Example 4 to flush the non-water-based drilling fluid filter cake in the Wushi block of Beibu Gulf at 90°C; where A is a photo before flushing, B is a photo after 3 minutes of flushing, C is a photo after 4 minutes of flushing, and D is a photo of the interfacial water wettability test. Figure 10 The image shows the effect of using the adsorption-type pre-fluid prepared in Example 6 to rinse the non-water-based drilling fluid filter cake in the Wushi Block of Beibu Gulf at 90°C; where A is a photo before rinsing, B is a photo after rinsing for 3 minutes, and C is a photo of the interfacial water wettability test. Detailed Implementation

[0032] To fully understand the purpose, features, and effects of this invention, the following detailed embodiments are provided. Except as described below, the process methods of this invention employ conventional methods or apparatus in the art. Unless otherwise specified, the terms and expressions used below have the meanings commonly understood by those skilled in the art.

[0033] According to a first aspect of the present invention, an adsorbent flushing agent is provided, comprising one or more of processed wood fibers, natural wood fibers, and mineral fibers.

[0034] The adsorbent flushing agent provided by this invention is mainly composed of wood fiber and mineral fiber. For example... Figure 1 As shown, the surface of wood fibers has numerous tiny pores and voids. These voids have excellent adsorption properties, and when they come into contact with oil stains, they form a strong adsorption force around the oil stains, adsorbing and fixing the oil stains. For example... Figure 2 As shown, the mineral fiber is composed of a fiber structure with alternating polyhedral pore walls and channels, forming a three-dimensional structure with a large specific surface area. This special structure gives the mineral fiber a strong adsorption capacity, enabling it to quickly adsorb and fix oily substances.

[0035] In some preferred embodiments, the adsorbent rinsing agent comprises, by weight, 1-10 parts processed wood fiber, 0-10 parts natural wood fiber, and 1-10 parts mineral fiber. For example, the weight of the processed wood fiber is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts, or any value between any two of the above; the weight of the natural wood fiber is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts, or any value between any two of the above; and the weight of the mineral fiber is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts, or any value between any two of the above.

[0036] In some preferred embodiments, the processed wood fibers are scraps from wood processing plants and engineered wood processing plants, with a particle size of 20-80 mesh, more preferably 20-40 mesh. The natural wood fibers include scraps of one or more of pine, poplar, camphor, eucalyptus, fruit wood, and nutshells, with a particle size of 20-80 mesh, more preferably 40-60 mesh. The mineral fibers include one or more of sepiolite fiber, brucite fiber, and asbestos fiber, with a particle size of 20-80 mesh, more preferably 20-60 mesh. This invention achieves the transformation of waste into valuable resources through the resource utilization of factory waste.

[0037] In some preferred embodiments, the particle size of the processed wood fiber, the natural wood fiber, and the mineral fiber is 20 mesh to 80 mesh.

[0038] The term "mesh" refers to the number of sieve openings per inch (25.4 mm) of length.

[0039] According to a second aspect of the present invention, the present invention also provides a method for preparing an adsorbent flushing agent, comprising: mixing processed wood fiber, natural wood fiber and mineral fiber in a specified ratio until uniform.

[0040] The types, proportions, particle sizes, and other information of the processed wood fiber, natural wood fiber, and mineral fiber are the same as those described in the first aspect of the present invention regarding the adsorption-type rinsing agent, and the present invention will not repeat the limitation here.

[0041] According to a third aspect of the invention, the invention also provides an adsorbent pretreatment solution comprising the adsorbent flushing agent described in the first aspect of the invention.

[0042] In practice, for medium- and low-temperature, high-permeability formations, existing flushing fluid and pre-flush fluid systems have no significant flushing effect on non-water-based drilling fluid filter cake. However, adding the adsorbent-type flushing agent described in this application can significantly improve the flushing effect of the adsorbent-type pre-flush fluid.

[0043] In some preferred embodiments, the adsorbent pretreatment solution comprises, by weight: 100 parts of slurry water, 0.5 to 3 parts of release agent, 3 to 15 parts of adsorbent rinsing agent, 15 to 50 parts of oil-based rinsing solution, 0.3 to 1 part of defoamer, and 0 to 400 parts of barite.

[0044] In some preferred embodiments, the slurry water includes one or more of fresh water, seawater, or salt water.

[0045] In some preferred embodiments, the release agent comprises one or more of the following materials: bentonite, attapulgite, sepiolite, xanthan gum, wenlun gum, guar gum, polyanionic cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, and polymers.

[0046] More preferably, the polymer is polymerized from one or more monomers selected from N,N-dimethylacrylamide, acrylic acid, acrylonitrile, 2-acrylamide-2-methylpropanesulfonic acid, and acrylamide.

[0047] Optionally, the release agent can be obtained commercially, for example, it can be purchased from Blue Ocean Boda Technology Co., Ltd., brand name: C-S32S.

[0048] In some preferred embodiments, the oil-based rinsing solution is composed of a solvent, a nonionic surfactant, an amphoteric surfactant, a polymer, and water.

[0049] Optionally, the oil-based rinsing solution can be obtained commercially, for example, it can be purchased from LanHaiBoda Technology Co., Ltd., with the brand name: C-W24L / C-W23L. Optionally, the oil-based rinsing solution can be formulated according to the method disclosed in CN107603576A.

[0050] In some preferred embodiments, the defoamer is tributyl phosphate.

[0051] In this invention, the density of the adsorption-type pretreatment solution is controlled between 1.00-2.30 g / cm³ by varying the amount of barite added. 3 between.

[0052] According to a third aspect of the present invention, the present invention also provides a method for preparing an adsorbent pretreatment solution, comprising: (1) Weigh the slurry water into the mixing cup and add the defoamer; (2) Add the release agent to the mixing cup at 500-4000 rpm and hydrate for 3-30 minutes; (3) Add oil-based rinsing solution at 500-4000 rpm and stir for 0.5-3 min; (4) Add barite at 500-4000 rpm and stir for 0.5-3 min; (5) Add the adsorbent rinsing agent at 500-2000 rpm and stir for 0.5-3 min.

[0053] More preferably, the preparation method of the adsorption-type pretreatment solution of the present invention includes: (1) Weigh the slurry water into the mixing cup and add the defoamer; (2) Add the release agent to the mixing cup at 2000 rpm and hydrate for 10 min; (3) Add oil-based rinsing solution at 2000 rpm and stir for 1 min; (4) Add barite at 2000 rpm and stir for 1 min; (5) Add the adsorbent rinsing agent at 1500 rpm and stir for 1 min.

[0054] The adsorption-type pre-fluid prepared according to the method of the present invention has good filter cake washing ability and good compatibility with non-water-based drilling fluids and cement slurries. Under the condition of rotational viscometer of 60~100 rpm, it can achieve efficient cleaning of non-water-based drilling fluid filter cake in 3~10 minutes.

[0055] Example The present invention is further illustrated below by way of examples, but the invention is not limited to the scope of the examples described herein. Experimental methods not specifically described in the following examples were performed according to conventional methods and conditions. The separating agents and oil-based rinsing solutions used in the following examples and comparative examples were all commercially available, as detailed below: Release agent: Purchased from Blue Ocean Boda Technology Co., Ltd., brand name: C-S32S; Oil-based flushing fluid: purchased from Blue Ocean Boda Technology Co., Ltd., brand name: C-W24L / C-W23L.

[0056] Example 1: Preparation of an adsorbent rinsing agent Weigh 200g of processed wood fiber with a particle size of 20-40 mesh and weigh 100g of sepiolite fiber with a particle size of 20-60 mesh. Mix the two samples evenly to prepare an adsorbent rinsing agent.

[0057] Example 2: Preparation of an adsorbent rinsing agent Weigh 100g of processed wood fiber with a particle size of 20-40 mesh, weigh 100g of poplar fiber with a particle size of 40-60 mesh, weigh 100g of sepiolite fiber with a particle size of 20-60 mesh, and mix the three samples evenly to prepare an adsorbent rinsing agent.

[0058] Example 3: Preparation of Adsorbent Rinse Agent Weigh 100g of processed wood fiber with a particle size of 20-40 mesh, weigh 50g of poplar fiber with a particle size of 40-60 mesh, and weigh 150g of sepiolite fiber with a particle size of 20-60 mesh. Mix the three samples evenly to prepare an adsorbent rinsing agent.

[0059] Example 4: Preparation of Adsorption-type Pretreatment Solution Weigh 300 g of fresh water into a mixing cup and add 0.9 g of defoamer tributyl phosphate; add 6 g of release agent at 2000 rpm and hydrate for 10 min; then add 100 g of oil-based rinsing solution at 2000 rpm and stir for 1 min; finally add 30 g of the adsorbent rinsing agent prepared in Example 1 at 1500 rpm and stir for 1 min.

[0060] Example 5: Preparation of Adsorption-type Pretreatment Solution Weigh 300 g of fresh water into a mixing cup and add 0.9 g of defoamer tributyl phosphate; add 6 g of release agent and hydrate for 10 min at 2000 rpm; then add 100 g of oil-based rinsing solution and stir for 1 min at 2000 rpm; next, add 200 g of barite and stir for 1 min at 2000 rpm; finally, add 30 g of the adsorbent rinsing agent prepared in Example 1 and stir for 1 min at 1500 rpm.

[0061] Example 6: Preparation of Adsorption-type Pretreatment Solution Weigh 300 g of fresh water into a mixing cup and add 0.9 g of defoamer tributyl phosphate; add 3 g of release agent and hydrate for 10 min at 2000 rpm; then add 100 g of oil-based rinsing solution and stir for 1 min at 2000 rpm; next, add 1200 g of barite and stir for 1 min at 2000 rpm; finally, add 30 g of the adsorbent rinsing agent prepared in Example 1 and stir for 1 min at 1500 rpm.

[0062] Comparative Example 1 Weigh 300 g of fresh water into a mixing cup and add 0.9 g of defoamer tributyl phosphate; add 6 g of release agent and hydrate for 10 min at 2000 rpm; then add 100 g of oil-based rinsing solution and stir for 1 min at 2000 rpm; then add 200 g of barite and stir for 1 min at 2000 rpm.

[0063] Comparative Example 2 Weigh 300 g of fresh water into a mixing cup and add 0.9 g of defoamer tributyl phosphate; add 6 g of release agent and hydrate for 10 min at 2000 rpm; then add 100 g of oil-based rinsing solution and stir for 1 min at 2000 rpm; next, add 200 g of barite and stir for 1 min at 2000 rpm; finally, add 1.8 g of PP fiber (6 mm) and stir for 1 min at 1500 rpm.

[0064] Comparative Example 3 Weigh 300 g of fresh water into a mixing cup and add 0.9 g of defoamer tributyl phosphate; add 6 g of release agent and hydrate for 10 min at 2000 rpm; then add 100 g of oil-based rinsing solution and stir for 1 min at 2000 rpm; next, add 200 g of barite and stir for 1 min at 2000 rpm; finally, add 9 g of glass fiber (3 mm) and stir for 1 min at 1500 rpm.

[0065] Performance testing 1. Evaluation of rinsing effect and interfacial wettability 1.1 The rinsing effect and interfacial wettability of Example 5, Comparative Examples 1, 2, and 3 at 20°C were evaluated. The specific evaluation methods for rinsing effect and interfacial wettability are as follows: The non-water-based drilling fluid was poured into a high-temperature and high-pressure fluid loss tester. The pressure was set to 3.5 MPa, the temperature to 90°C, and the fluid loss time to 30 min. After the experiment, the filter paper containing the non-water-based drilling fluid filter cake was removed and fixed to the rotating cylinder of the rotary viscometer with a rubber band. A photograph was taken.

[0066] According to Example 5, Comparative Example 1, Comparative Example 2, and Comparative Example 3, the pretreatment solution was prepared and placed in an atmospheric pressure thickener and cured at 20°C for 20 minutes. The solution was then poured into a flow beaker and placed on the measuring stage of a rotary viscometer. The beaker was slowly raised until it completely submerged the filter cake and was about 1 cm above the top edge of the filter cake.

[0067] Turn on the motor and rinse at a speed of 100 rpm for 3 to 10 minutes.

[0068] After the rinsing experiment, lower the measuring platform, remove the beaker, observe the rinsing effect, and take photos.

[0069] Remove the rinsed filter paper, lay it flat, and test the interface wettability using the water droplet method, then take a picture. If the water droplets spread out quickly, it indicates that the rinsed interface is water-wetted; if the water droplets shrink into a spherical shape or do not spread, it indicates that the rinsed interface is oil-wetted.

[0070] Figure 3 , Figure 4 , Figure 5 and Figure 6 The flushing effect and interfacial wettability evaluation results of the pre-flush fluids of Examples 5, 1, 2, and 3 on the non-water-based drilling fluid filter cake in the Wushi block of the Beibu Gulf at 20°C are shown respectively.

[0071] Through analysis Figure 3-6 It can be seen that at 20℃, Comparative Example 1, using only oil-based rinsing solution without adsorbent rinsing agent, showed a thinning of the filter cake, but the filter cake was still not completely rinsed. In Example 5, the rinsing effect of the adsorbent pre-flushing solution after adding adsorbent rinsing agent was significantly improved; the filter cake was rinsed clean at 100 rpm for 9 minutes, and the interface was water-wetted. Comparative Example 2, with added PP fiber, showed no significant rinsing effect; Comparative Example 3, with added glass fiber, showed no significant rinsing effect. This is because the adsorbent rinsing agent has a porous and polyhedral structure with alternating pore walls. When in contact with oil, these pores form a strong adsorption force around the oil, thus accelerating the collapse of the non-aqueous filter cake structure. When used in combination with oil-based rinsing solution, it achieves a dual effect of oil adsorption and removal, as well as efficient chemical dissolution and rinsing.

[0072] 1.2 Evaluation of the rinsing effect and interfacial wettability of Example 5 and Comparative Example 1 at 90°C.

[0073] Figure 7 and Figure 8 The flushing effect and interfacial wettability evaluation results of non-water-based drilling fluid filter cake in the Beibu Gulf Wushi Block of Example 5 and Comparative Example 1 at 90°C are shown respectively.

[0074] from Figure 7-8It can be seen that at 90℃, the pre-flushing solution with only oil-based rinsing fluid and no adsorbent rinsing agent is basically clean after rinsing at 100 rpm for 15 minutes; the rinsing efficiency of the pre-flushing solution with adsorbent rinsing agent is significantly improved, and it is completely cleaned after rinsing at 100 rpm for 3~4 minutes, and the interface is wetted by water.

[0075] The experimental data above show that adding an adsorbent-type flushing agent to the pre-flushing solution can significantly improve the flushing timeliness, increasing efficiency by more than 80%.

[0076] 1.3 Evaluation of the rinsing effect and interfacial wettability of Examples 4 and 6 at 90°C.

[0077] Figure 9 and Figure 10 Examples 4 and 6 respectively show the flushing effect and interfacial water wettability evaluation results of non-water-based drilling fluid filter cake in the Wushi block of Beibu Gulf at 90°C.

[0078] The experimental results from Examples 4 and 6 show that the adsorption-type pre-solvent does not increase in weight and increases in weight to 2.30 g / cm³. 3 At any time, the filter cake can be rinsed clean within 3-4 minutes at 90℃, and the interface is wetted with water.

[0079] 2. Compatibility testing The compatibility of Example 5 with non-water-based drilling fluids and cement slurries in the Beibu Gulf Wushi Block was evaluated, and the tests were conducted in accordance with GB / T19139-2012 "Test Methods for Cement in Oil Wells".

[0080] Cement slurry was prepared according to the following formula: "327g fresh water + 24g C-FL80L (purchased from LanHai Boda Technology Co., Ltd.) + 3g C-R21L (purchased from LanHai Boda Technology Co., Ltd.) + 2g C-DF60L (purchased from LanHai Boda Technology Co., Ltd.) + 800g Shandong Zhongchang G cement".

[0081] At 90℃, the rheological compatibility of Example 5 with the non-water-based drilling fluid of the Beibu Gulf Wushi Block is shown in the table below. There is no abnormal increase in viscosity, indicating good compatibility.

[0082]

[0083] At 90°C, the rheological compatibility of Example 5 with cement slurry is shown in the table below. There is no increase in viscosity, indicating good compatibility.

[0084]

[0085] At 90℃, the effect of Example 5 on the thickening time and compressive strength of cement paste was tested. The thickening test conditions were: 90℃, 45 min, 40 MPa; the compressive strength test conditions were: 90℃, 24 h, 21 MPa. The test results are shown in the table below. There was no abnormal shortening of the thickening time, and the compressive strength met the requirements.

[0086]

[0087] This invention has been tested in the South China Sea operating block, and the test results show that the cementing quality has been significantly improved, achieving good application results.

[0088] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0089] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0090] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. An adsorptive rinse agent characterized in that, The method comprises the following steps: The method comprises the following steps:

2. The adsorptive flush according to claim 1, characterized in that The method comprises the following steps:

3. The adsorptive flush of claim 1, wherein, The method comprises the following steps:

4. The adsorptive flush of claim 1, wherein, The method comprises the following steps:

5. A method of preparing an adsorptive rinse according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: The method comprises the following steps:

6. An adsorptive front fluid, characterized by The method comprises the following steps:

7. The adsorptive front seal of claim 6, wherein, The method comprises the following steps:

8. The adsorptive front seal of claim 7, wherein, The method comprises the following steps:

9. The adsorptive front seal of claim 7, wherein, The method comprises the following steps:

10. The adsorptive front seal of claim 9, wherein, The method comprises the following steps:

11. The adsorptive front seal of claim 7, wherein, The method comprises the following steps:

12. The adsorptive front seal of claim 7, wherein, The method comprises the following steps:

13. A method of preparing an adsorptive front fluid as claimed in any one of claims 6 to 12, characterized in that The method comprises the following steps: The method comprises the following steps: The method comprises the following steps: The method comprises the following steps: The method comprises the following steps: The method comprises the following steps: The method comprises the following steps:

15. 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