Resource recycling device for water-based drilling waste

Abstract

The invention relates to the technical field of well drilling, and discloses a water-based well drilling waste resource recycling device which comprises a slurry buffer tank, a gel breaking tank, a filter press, a deionization tank, a settling tank, a modification tank and a storage tank which are connected in sequence. The mud buffering tank is used for buffering drilling waste, and the gel breaking tank is used for achieving gel breaking and destabilizing treatment of the drilling waste; carrying out solid-liquid separation on the gel-broken material by the filter press, and filtering out primary filtrate; the deionization tank is used for removing metal ions in the filtrate and forming precipitates; secondary filtrate is discharged after precipitates are precipitated and separated in the settling tank; the modification tank recovers the colloidal stability of the filtrate to form reused filtrate; the storage tank stores available filtrate. Based on the scheme, efficient resource recycling and harmless treatment in the well drilling waste treatment process can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling, and in particular to a resource recycling device for water-based drilling waste. Background Art

[0002] During oil and gas field drilling operations, water-based drilling fluids generate large amounts of drilling waste containing clay particles, high-molecular polymers, and metal ions. Currently, two methods are commonly used to treat water-based drilling waste. The first involves separating the waste into solids and liquids through gel crushing, filtration, and separation. The resulting filtrate, due to its damaged properties, cannot be recycled and must be transported for disposal. The resulting filter cake can be handled differently depending on the specific circumstances. The second method involves segmenting the drilling waste, with general solid waste (for non-polysulfone systems, drill footage above 4,000 meters) being landfilled and hazardous waste (for polysulfone systems, drill footage below 4,000 meters) being transported for disposal without solid-liquid separation.

[0003] The filtrate separated by water-based drilling waste treatment technology contains not only a variety of inorganic salt ions but also a variety of water-soluble organic substances. Furthermore, due to the varying composition of different drilling fluid systems and the different types and dosages of breaker agents, the filtrate is extremely complex, dark in color, and has a high COD value, which is difficult to remove. Improper treatment can seriously pollute the environment. Currently, the filtrate separated from drilling waste during drilling and completion is primarily sent to sewage treatment plants for centralized treatment. However, this treatment model carries high transportation and disposal costs and poses safety and environmental risks. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a resource recycling device for water-based drilling waste.

[0005] The present invention provides a resource recycling device for water-based drilling waste, comprising a mud buffer tank, a gel breaking tank, a filter press, a deionization tank, a sedimentation tank, a modification tank and a storage tank. The drilling waste passes through the mud buffer tank, the gel breaking tank, the filter press, the deionization tank, the sedimentation tank, the modification tank and the storage tank in sequence. Among them, the mud buffer tank is used to buffer drilling waste, the gel breaking tank is used to break the gel and destabilize, the filter press is used to filter out the primary filtrate, part of the primary filtrate is returned to the mud buffer tank, and the other part enters the deionization tank, the deionization tank is used to remove at least part of the metal ions in the primary filtrate and form a precipitate, the sedimentation tank is used to precipitate the precipitate and discharge the secondary filtrate, the modification tank is used to restore the colloidal stability of the secondary filtrate to form a reused filtrate, and the storage tank is used to store the reused filtrate.

[0006] Optionally: A double-layer filter bed is provided in the deionization tank, wherein the double-layer filter bed is composed of an upper coarse filter layer composed of modified sponge iron and a lower fine filter layer composed of a magnetic response chelating resin, wherein the outlet end of the upper coarse filter layer is connected to the inlet end of the lower fine filter layer, and the primary filtrate passes through the upper coarse filter layer and the lower fine filter layer in sequence; A porous support plate is provided at the bottom of the double-layer filter bed.

[0007] Optionally: The bottom of the deionization tank is provided with an anti-gradient assembly, which is located below the double-layer filter bed. The anti-gradient assembly includes: A spiral guide plate with a through hole in the center, wherein the plate surface of the spiral guide plate spirals and rises from the tank wall toward the center; The collecting and voltage-stabilizing tube vertically passes through the through hole, a water outlet hole group is arranged around the top of the collecting and voltage-stabilizing tube, and the bottom of the collecting and voltage-stabilizing tube is externally connected to the inlet of the sedimentation tank.

[0008] Optionally: At least one set of oblique vibration plates is obliquely arranged in the sedimentation tank.

[0009] Optionally: The inlet of the sedimentation tank is provided with a buoyancy diffuser.

[0010] Optionally: An ultraviolet lamp is installed in the sedimentation tank.

[0011] Optionally: A stirrer is installed in the modification tank.

[0012] Optionally: An anti-eddy current cross baffle is fixed on the top of the stirring shaft of the stirrer.

[0013] Optionally: A cyclodextrin molecular cage is installed at the outlet of the modification tank.

[0014] Optionally: A heating component is integrated into the filter plate of the filter press for heating the filter plate during the unloading stage.

[0015] The present invention has the following technical effects: The device, constructed through a series of six units, ensures gradient separation and targeted conversion of the solid and liquid phases in drilling waste, ultimately recovering the filtrate for re-preparation of the gel solution. The gel breaker destabilizes the gel, creating optimal separation conditions for subsequent filtration. The filter press efficiently separates solids and liquids to produce a primary filtrate. The deionizer selectively adsorbs metal contaminants. The settling tank deeply clarifies the liquid phase and discharges a secondary filtrate. The modification tank restores key gel properties. The storage tank stores the restored filtrate, ultimately achieving the recycling and reuse of drilling waste.

[0016] The double-layer filter bed design improves ion removal. The upper coarse filter material effectively aggregates colloidal aggregates, reducing the load on the lower resin layer. The lower resin layer precisely captures metal ions, preventing residual ions from interfering with subsequent processes. The two layers of media are physically isolated yet functionally linked, balancing filtration efficiency with device compactness.

[0017] The anti-gradient assembly solves the problem of insufficient resin utilization at the bottom of the tank. The deflector forces the water flow to be evenly dispersed to the edge area, and the manifold simultaneously recovers liquids with different flow patterns. This structure ensures sufficient hydraulic contact at the bottom of the resin bed, eliminating the low-speed blind spot of traditional equipment.

[0018] The inclined vibrating plate improves sedimentation efficiency and enables self-cleaning of the tank wall. The inclined plate surface increases the sedimentation area and induces orderly particle deposition. Combined with micro-vibration, it continuously peels off attached dirt, eliminating downtime for descaling.

[0019] The buoyancy diffuser balances the energy distribution of the fluid entering the tank. The modular structure decomposes the impact potential energy of high-density fluids, preventing the density flow from rushing directly to the bottom of the tank and causing sedimentation and re-mixing, maintaining a stable flow pattern in the settling zone.

[0020] UV irradiation control systems inhibit microbial contamination. Specific wavelengths of light kill bacteria and eliminate biofilm growth, protecting subsequent unit activity without the risk of chemical residues.

[0021] The mixer achieves full-area modification of the colloid system, ensuring that the reaction proceeds fully at any point in the tank.

[0022] The anti-vortex cross baffle eliminates the safety hazard of liquid surface vortex. The baffle structure cuts off the vortex formation path, preventing the accumulation of combustible gas around the agitator shaft, ensuring the safety of high-speed mixing conditions.

[0023] Cyclodextrin molecular cages precisely intercept residual harmful components. The cyclodextrin molecular structure selectively captures contaminants of specific molecular weights, releasing beneficial components and ensuring chemical compatibility of reusable filtrates.

[0024] The filter plate heating mechanism eliminates filter cloth performance degradation. The released heat untangles polymer molecules, restoring the filter cloth's original pore structure and maintaining long-term stable processing capacity.

[0025] The technical effect of the entire device is reflected in: the treatment process is continuous and stable, the products meet the reuse standards, and the substantial transformation of waste into resources is truly realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A schematic structural diagram of a device for recycling and utilizing water-based drilling waste provided by an embodiment of the present invention; Figure 2 A schematic diagram of the structure of a deionization tank provided in an embodiment of the present invention; Figure 3 A schematic diagram of the structure of a sedimentation tank provided in an embodiment of the present invention; Figure 4 A schematic diagram of the structure of a modified tank provided in an embodiment of the present invention; Figure 5 The present invention provides a structural schematic diagram of a filter press.

[0028] Reference numerals

[0029] 0. Mud buffer tank; 1. Glue breaking tank; 2. Filter press; 3. Deionization tank; 4. Sedimentation tank; 5. Modification tank; 6. Storage tank; 31. Double-layer filter bed; 311. Upper coarse filtration layer; 312. Lower fine filtration layer; 313. Porous support plate; 331. Spiral guide plate; 332. Current collecting and stabilizing tube; 41. Inclined vibration plate; 42. Buoyancy diffuser; 43. UV lamp; 51. Mixer; 511. Anti-eddy current cross baffle; 512. Cyclodextrin molecular cage; 21. Filter plate; 211; Heating assembly. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0031] Figure 1A schematic diagram of the structure of a resource recycling device for water-based drilling waste provided in an embodiment of the present invention includes a mud buffer tank 0, a gel breaking tank 1, a filter press 2, a deionization tank 3, a sedimentation tank 4, a modification tank 5, and a storage tank 6. The drilling waste passes through the mud buffer tank 0, the gel breaking tank 1, the filter press 2, the deionization tank 3, the sedimentation tank 4, the modification tank 5, and the storage tank 6 in sequence; Among them, the mud buffer tank 0 is used to collect drilling waste, which is cached in the mud buffer tank 0 and then enters the gel breaking tank 1. The gel breaking tank 1 is used for gel breaking and destabilization. The filter press 2 is used to filter out the primary filtrate. Part of the primary filtrate is returned to the mud buffer tank 0, and the other part enters the deionization tank 3. The deionization tank 3 is used to remove at least part of the metal ions in the primary filtrate and form a precipitate. The sedimentation tank 4 is used to precipitate the precipitate and discharge the secondary filtrate. The modification tank 5 is used to restore the colloidal stability of the secondary filtrate to form a reused filtrate. The storage tank 6 is used to store the reused filtrate.

[0032] Specifically, the water-based drilling waste resource recycling and utilization device includes six core processing units, and each unit is connected in series to form a complete material flow path. The mud buffer tank 0 is at the starting position and is used to temporarily store drilling waste. The gel breaking tank 1 mainly implements colloidal structure destruction and stability elimination treatment for the viscous waste generated by drilling operations. The drilling waste completes molecular chain breakage and colloidal disintegration reactions in this unit to form a suspension system with fluidity. The fluid treated by the gel breaking tank 1 enters the filter press 2 to realize the key solid-liquid separation process. The filter press 2 adopts a high-pressure filtration mechanism, which uses a special filter cloth to intercept solid phase particles and produce a primary filtrate at the same time. After separation, the primary filtrate exhibits flowable characteristics.

[0033] The primary filtrate is divided into two parts, one part of which is first returned to the mud buffer tank 0 to mix with the existing drilling waste, dilute the drilling waste, and make the drilling waste present a liquid flow state to a greater extent, reducing the difficulty of transporting the drilling waste. The other part of the primary filtrate is transported to the deionization tank 3 for deep ion removal treatment. This unit promotes the directional adsorption and precipitation transformation of high-valent metal ions in the filtrate through a specific internal structure, and forms a flocculent precipitate with stable chemical properties during the treatment process. The mixed fluid that has completed the ion removal treatment enters the sedimentation tank 4 for precipitate enrichment and separation. The sedimentation tank 4 allows the precipitate to settle, and after sufficient static separation, the clarity of the liquid phase is significantly improved, and the secondary filtrate is discharged, and the secondary filtrate enters the next process.

[0034] The secondary filtrate is introduced into the modification tank 5 for colloid system repair. The unit has a built-in physicochemical reaction environment, which implements colloidal double layer reconstruction and molecular structure repair on the secondary filtrate after multi-stage treatment, effectively restoring the stability of the liquid phase colloid. The final output of the reused filtrate enters the storage tank 6 through a pipeline for temporary storage of the finished product. The storage tank 6 provides a constant temperature and pressure storage environment to ensure that the reused filtrate maintains stable physicochemical properties before reuse. The material flows through the gel breaking tank 1, filter press 2, deionization tank 3, sedimentation tank 4, modification tank 5, and storage tank 6 in sequence to form a continuous processing loop.

[0035] The units in this process chain have clear functional divisions and close integration, with preceding units creating the necessary conditions for subsequent processing. The colloid decomposition performed by the gel breaker 1 is a prerequisite for effective solid-liquid separation in the filter press 2. The quality of the primary filtrate produced by the filter press 2 directly impacts the processing efficiency of the deionization tank 3. The deep removal of specific metal ions by the deionization tank 3 provides sedimentation and separation targets for the sedimentation tank 4. The sedimentation efficiency of the sedimentation tank 4 determines the processing capacity of the modification tank 5. The colloid remediation completed by the modification tank 5 determines the reuse value of the product collected in the storage tank 6.

[0036] The key link in the operation of the device is to achieve the transformation of the fluid chemical properties in the modification tank 5, so that the unstable colloid in the secondary filtrate can recover its functional value. This process ultimately lays the foundation for resource utilization.

[0037] This combined structure achieves the dual benefits of environmental protection and resource recovery. Hazardous waste is converted into usable resources after treatment, and the reuse of treated products does not generate secondary pollution. This treatment model provides a new paradigm for waste disposal in the oil industry, and the technical approach has the potential for widespread application.

[0038] Figure 2 A schematic diagram of the structure of a deionization tank provided in an embodiment of the present invention. In some embodiments, a double-layer filter bed 31 is provided in the deionization tank 3. The double-layer filter bed 31 is composed of an upper coarse filter layer 311 composed of modified sponge iron and a lower fine filter layer 312 composed of a magnetically responsive chelating resin. The outlet end of the upper coarse filter layer 311 is connected to the inlet end of the lower fine filter layer 312. The primary filtrate passes through the upper coarse filter layer 311 and the lower fine filter layer 312 in sequence. A porous support plate 313 is provided at the bottom of the double-layer filter bed 31 .

[0039] Specifically, traditional single-layer filtration devices experience efficiency disparities when processing drilling waste containing complex components. Continuous exposure to high-concentration solutions causes the ion adsorption sites in the upper layer to rapidly saturate, leaving the lower layer largely unused. Furthermore, colloidal particles accumulate on the surface of the medium, forming a dense filter cake layer that dramatically increases flow resistance and imbalances the pressure differential in the device. This conflicting efficiency and frequent blockages severely limit the device's operational lifespan.

[0040] In this solution, the structural design of the double-layer filter bed 31 solves this problem from the perspective of functional zoning. The upper coarse filter layer 311 is filled with modified sponge iron spheres, which promote the aggregation reaction of colloidal particles to form large-sized flocs based on their microporous electrochemical action. The tortuous flow channels between the media significantly prolong the contact time of the colloid, achieving physical interception and chemical aggregation. The lower fine filter layer 312 is arranged with a magnetically responsive chelating resin, which reacts with metal ions such as calcium and magnesium in a directional manner through surface functional groups. The magnetic response characteristics of the medium reserve a technical interface for the regeneration stage, which can realize partitioned regeneration operation while the equipment is in continuous operation.

[0041] The bottom area of ​​the double-layer filter bed 31 is equipped with a porous support plate 313, which plays a key role in load-bearing. The pore structure is optimized through fluid simulation to maximize the flow area while ensuring sufficient support stiffness.

[0042] This structural innovation improves equipment operation. Deionization tank 3's continuous operating time is extended several times, and the system differential pressure remains consistently within safety thresholds. Residual metal ion concentrations after treatment are below safety limits, and the total amount of suspended colloids meets the requirements of subsequent treatment processes. This significantly extends the media replacement cycle while simultaneously reducing regeneration costs, resulting in greater overall operational stability.

[0043] Continue reading Figure 2 In some embodiments, an anti-gradient assembly is provided at the bottom of the deionization tank 3, and the anti-gradient assembly is located below the double-layer filter bed 31. The anti-gradient assembly includes: The spiral guide plate 331 has a through hole in its center, and the plate surface of the spiral guide plate 331 spirals and rises from the tank wall toward the center; The collecting and voltage-stabilizing tube 332 is vertically penetrated by the through hole. A water outlet hole group is arranged around the top of the collecting and voltage-stabilizing tube 332 . The bottom of the collecting and voltage-stabilizing tube 332 is externally connected to the inlet of the sedimentation tank 4 .

[0044] Specifically, the anti-gradient assembly installed at the bottom of deionization tank 3 is an improvement proposed to address the problem of uneven ion exchange efficiency. In traditional devices, gravity sedimentation forms a density gradient in the bottom area of ​​the resin bed, causing the fluid to preferentially flow through the central high-speed channel, leaving the resin at the edge immersed in a low flow rate for a long time. More seriously, the upper layer of resin intercepts the water flow, causing the kinetic energy of the bottom fluid to approach zero, and the ion exchange rate decays exponentially. This "bottom dormancy effect" caused by defects in the flow field distribution prevents a large amount of active medium from effectively participating in the reaction.

[0045] The spiral guide plate 331's coiled, inclined plate structure implements a kinetic energy conversion strategy. This component is fixed to the lower support structure of the tank wall. The surface of the spiral guide plate 331 rises in an involute trajectory from the circumference toward the central axis. When the fluid, having completed ion exchange, impacts the surface of the spiral guide plate 331 perpendicularly, some of the kinetic energy of the water flow is converted into vibrational energy of the plate and transmitted upward, while the remaining kinetic energy is decomposed tangentially into a rotational component. This conversion has a dual effect: the perturbation field transmitted by the plate's vibrations can disperse the adhesive flocs between the bottom resin, while the tangentially rotating water flow activates the pore exchange activity of the medium in the low-velocity zone at the bottom.

[0046] The layout of the water outlet group around the top of the collecting and stabilizing tube 332 is designed according to the flow state. The distribution density of the water outlet group is sparse in the center and dense at the edge, and it preferentially receives the high-energy fluid area diverted by the edge of the plate. A porous damping grid is set inside the tube cavity. When high-speed fluid is injected, the Venturi effect is triggered to form a local negative pressure. This negative pressure gradient acts in the reverse direction on the bottom area of ​​the resin bed through the flow channel. This design creates continuous micro-gravity suction, forcing the fluid in the low-speed area at the bottom to migrate directionally to the collecting area, effectively eliminating the fluid retention phenomenon in the dead corner area of ​​the medium.

[0047] The synergistic working mechanism of the structure manifests itself as the coupling of three physical fields. The mechanical vibration field loosens the resin surface binder, promoting renewal of the diffusion boundary layer; the fluid vortex field enhances material transfer at the solid-liquid interface; and the negative pressure gravitational field forces the migration of slow-moving fluids. This system significantly increases the proportion of working medium in the bottom area of ​​the resin bed, significantly reducing the concentration fluctuation range during the ion exchange process. This significantly improves the processing efficiency and stability of the device, enabling high-load continuous operation and alleviating the "gradient effect."

[0048] Figure 3 A schematic diagram of a settling tank structure provided by an embodiment of the present invention. In some embodiments, at least one set of oblique vibration plates 41 is obliquely arranged in the settling tank 4 .

[0049] The inclined vibrating plate 41 within the settling tank 4 primarily addresses the problem of scale deposits on the tank walls. During operation, solid particles continuously adhere to the tank walls, forming a hard scale layer. This buildup leads to three serious consequences: a reduction in the effective settling volume, a decrease in the tank's heat transfer efficiency, and the need for manual mechanical descaling operations to be stopped. Furthermore, conventional chemical cleaning can disrupt the microbial balance in subsequent modification processes.

[0050] The plate body of the oblique vibration plate 41 is installed at 55°-65° to the horizontal plane. This angle ensures two key effects: a wedge-shaped gap is formed between the plate surface and the tank wall, which promotes the acceleration effect of the water flow in this area; and at the same time, the projected area of ​​the plate body covers more than 80% of the tank wall area.

[0051] The core innovation lies in the integrated vibration generator on the back of the plate. Connected to the back of the plate via elastic supports, the vibration generator generates micro-oscillations at a specific frequency. When the device is operating, the vibration waves travel along the plate to the surrounding tank wall, forming an impact zone with a radius of 0.5 meters, shaking off newly deposited soft scale.

[0052] This structure transforms passive anti-scaling into active descaling, continuously maintaining the tank wall clean during operation.

[0053] Continue reading Figure 3 In some embodiments, a buoyancy diffuser 42 is provided at the inlet of the settling tank 4 .

[0054] Specifically, the buoyancy diffuser 42 installed at the inlet of settling tank 4 is designed to address the mixing challenge of density-stratified fluids. Useful components such as barite in shale gas drilling waste have a high density, while the density of the debonding fluid is relatively low. Traditional pipeline mixing results in a significant density gradient in the fluid entering the tank. When the density difference reaches a certain level, the high-density fluid entering settling tank 4 directly settles, creating a "mudfall" effect. This impacts the bottom sedimentation layer, causing a surge in the remixing rate of the settled solid phase. More seriously, the high-speed jet creates localized turbulence in the settling zone, causing fine particles to become resuspended and occupying the effective volume of settling tank 4.

[0055] To this end, the embodiment of the present invention additionally provides a buoyancy diffuser 42 to alleviate the "mudfall" effect. The working mechanism of the buoyancy diffuser 42 is based on the principle of fluid reconstruction. The internal flow channel of the device can adopt a multi-stage cross-sectional mutation design (not shown in the figure), forcing the high-velocity fluid to undergo an expansion-contraction cycle. When the density difference fluid passes through the variable diameter flow channel, the high-speed core area is forced to disperse into low-speed micro-turbulence, realizing micro-mixing of components with different densities. The built-in micro air cavity releases controllable airflow at a specific position, forming a micro-bubble curtain to block the density flow stratification trend. This micro-disturbance structure promotes pre-mixing of barite particles and light phase fluid, eliminating the impact inertia formed by the density difference.

[0056] This device can eliminate the "mudfall" phenomenon at the bottom of the tank. The back-mixing rate in the sedimentation zone is greatly reduced, the effective volume utilization rate of the sedimentation tank 4 is greatly increased, and the filtrate quality of the secondary filtrate discharged from the sedimentation tank 4 is improved.

[0057] Continue reading Figure 3 In some embodiments, an ultraviolet lamp 43 is installed in the sedimentation tank 4.

[0058] The core purpose of configuring the UV lamp 43 in the sedimentation tank 4 is to solve the sedimentation failure caused by biological contamination. Specifically, according to research, the saprophytic bacteria (TGB) contained in the drilling waste multiply exponentially during the sedimentation stage, with the number of colonies per milliliter reaching 10 6These microbial metabolic processes produce three destructive effects: extracellular polymers bind solid particles to form a scum layer; sulfiding bacteria produce acidic substances that corrode the tank walls; and, more critically, microbial metabolism alters the colloidal interfacial potential, increasing the hydrophobicity of the dense barite particles and significantly reducing their sedimentation rate. Traditional chemical biocide dosing methods are unable to inhibit the continued growth of biofilm on the tank walls.

[0059] The layout position and spectrum selection of the ultraviolet lamp 43 are optimized based on the depth of sterilization dynamics. The lamp tubes of the ultraviolet lamp 43 can be evenly distributed in three ring layers along the longitudinal axis of the sedimentation tank 4, covering more than 90% of the water volume. The wavelength is locked in the 265nm ultraviolet spectrum band, and the penetration ability of this band can reach a depth of 20cm in a suspension system, and the absorption efficiency of bacterial DNA reaches its peak. In addition, a pulse trigger mode is adopted: when the online bacterial community sensor detects a surge in TGB concentration, the system automatically switches to a high-intensity pulse mode, the instantaneous radiation intensity is increased, and the primary biofilm structure is effectively penetrated. This solution can effectively kill bacterial colony growth and improve corresponding problems.

[0060] Figure 4 A structural diagram of a modification tank provided in an embodiment of the present invention. In some embodiments, a stirrer 51 is installed in the modification tank 5.

[0061] The configuration of agitator 51 in modification tank 5 stems from the kinetic nature of the colloid activation reaction. Residual long-chain polymers such as hydrolyzed polyacrylamide in the secondary filtrate form a spatial network structure, resulting in non-Newtonian fluid properties. This rheological property presents two processing obstacles: at the macroscale, viscoelastic fluids exhibit a significant shear-thinning boundary layer, resulting in a gradient attenuation of the modifier distribution within the reaction system; at the microscale, the colloidal network hinders molecular diffusion, resulting in local reaction rate differences of orders of magnitude.

[0062] The architecture of the Mixer 51 is essentially about creating a dynamically balanced reaction field. The Mixer 51's drive unit utilizes a variable torque output mode. During startup, it applies instantaneous power that exceeds the colloid strength threshold, disrupting the polymer's three-dimensional network. During subsequent cycles, the system viscosity is maintained within the optimal range for the modification reaction by controlling the impeller speed. The three-bladed impeller's profile is optimized using non-Newtonian fluid dynamics, and the blade's leading edge, with its specific curvature, induces an extensional flow field, a flow regime advantageous for untangling polymer molecules.

[0063] The impeller structure creates two-stage flow control within the tank. A high-intensity shear layer forms in the near-field region, effectively tearing apart colloidal aggregates and releasing the internal reaction interface. In the far-field region, axial flow creates a circumferential circulation, ensuring continuous contact between the newly added reaction interface and the modifier. This flow pattern overcomes the "climbing pole effect" of viscoelastic fluids and eliminates the axial cyclonic phenomenon associated with traditional agitation, allowing for near-100% reaction volume utilization. This effectively mitigates the problem of the modifier's limited contact with the secondary filtrate, improving the reaction effect.

[0064] Continue reading Figure 4 In some embodiments, an anti-vortex cross baffle 511 is fixed on the top of the stirring shaft of the mixer 51.

[0065] Specifically, the anti-vortex cross baffle 511 equipped on the mixer 51 is used to eliminate the risk of gas phase enrichment during high-speed stirring. When the stirring shaft reaches the critical speed, the fluid in the tank forms a central low-pressure vortex, causing the liquid surface to appear funnel-shaped. This fluid dynamics phenomenon triggers a triple chain reaction: the liquid level drops sharply, causing the upper stirring shaft to be exposed, and metal dry friction sparks are generated at the shaft seal; the vortex center draws hydrogen sulfide gas deposited at the bottom of the tank to enrich it on the liquid surface; more importantly, the concentration of combustible gas at the gas-liquid interface can reach the explosion limit within a certain period of time.

[0066] To this end, an embodiment of the present invention provides an anti-eddy current cross baffle 511, and the design principle of this design is based on the eddy current field interference theory. Four groups of orthogonally distributed rigid plates are welded to the stirring shaft at a specific angle, and their radial positions are exactly in the key influence area of ​​vortex formation. When the rotating fluid hits the edge of the baffle, two essential changes occur: the moving fluid is forced to be diverted into multiple independent tributaries, breaking up the continuous boundary formed by the vortex; at the same time, the plate boundary layer induces high-frequency pulsation, destroying the pressure balance mechanism in the core area of ​​the vortex. This structural intervention compresses the amplitude of liquid level fluctuations to within the safety threshold.

[0067] The special configuration achieves the dual benefits of fluid control and safety protection. The baffle can be a curved surface, its profile optimized through computational fluid dynamics, to form a controllable secondary vortex system on the backflow side of the plate. These micro-scale vortex groups promote microscopic mixing of components of different densities, unexpectedly achieving the additional benefit of increasing the activation reaction rate.

[0068] Based on the above scheme, the embodiment of the present invention can eliminate the liquid funnel phenomenon, and the concentration of combustible gas is always controlled below the safety limit; the mixer 51 can achieve continuous operation at full power without affecting the rotation speed of the mixer 51, and the colloid activation efficiency is high.

[0069] Continue reading Figure 4 In some embodiments, a cyclodextrin molecular cage 512 is installed at the outlet of the modification tank 5 .

[0070] The core function of the cyclodextrin molecular cage 512 installed at the outlet of the modification tank 5 is to trap residual additive molecules. Field testing has revealed that after the organic components in the modifier complete their colloid repair process, some of the unconsumed substances enter the storage stage with the fluid. These residues pose two hazards during drilling fluid reuse: small molecule corrosion inhibitor fragments adsorb on the shale surface, forming a hydrophobic film that severely weakens the drill bit's cuttings-carrying capacity; and polymer fragments cross-link and agglomerate in high-temperature wellbore sections, frequently blocking the water channels of downhole tools.

[0071] The working principle of the cyclodextrin cage 512 is based on its molecular-level selectivity. Its main structure consists of immobilized β-cyclodextrin units on an alumina ceramic matrix. Its unique conical cavity forms a size-selective barrier. When the treatment fluid flows through the cage, a triple effect occurs: the 0.65-nanometer inner diameter cavity preferentially captures cyclic additive fragments with a molecular weight of 800-1500; the hydrophobic region of the cavity wall attracts hydrocarbon chains; and the hydrophilic groups on the cone edge anchor charged ionic groups. This selective mechanism ensures the smooth passage of beneficial additive molecules while retaining only specific harmful substances.

[0072] This device significantly reduces downhole tool blockage and drill bit balling. Crucially, the chemical stability of the filtrate is significantly improved, eliminating the need for additional conditioning agents under normal operating conditions. Maintenance is significantly simplified, requiring only a backflush to restore processing capacity, extending maintenance intervals.

[0073] Figure 5 A schematic diagram of the structure of a filter press provided by an embodiment of the present invention. In some embodiments, a heating assembly 211 is integrated into the filter plate 21 of the filter press 2 for heating the filter plate 21 during the unloading stage.

[0074] The purpose of integrating the heating assembly 211 within the filter plate 21 of the filter press 2 is to overcome the flux attenuation caused by the filter cloth's memory effect. Treatment practices have revealed that shale gas drilling waste contains large amounts of hydrolyzed polyacrylamide, and during the filter press process, this polymer forms a colloidal bridging network between the filter cloth fibers. Traditional shutdown chemical cleaning can only remove surface deposits, but the molecular-level polymer segments remaining in the fiber pores will irreversibly shrink and solidify. After five filter press cycles, the effective pore size of the filter cloth is reduced by 60%, ultimately leading to excessive pressure differential shutdowns as frequent as three times a day. More seriously, the mechanical stripping process damages the filter cloth coating, shortening its service life to only 30% of its original lifespan.

[0075] The heating assembly operates based on the principle of thermochemical depolymerization. When the unloading process begins, a heat source integrated into the filter plate flow channel is instantly activated, transmitting a controlled heat flux through the heat-conducting plate to the filter cloth interface. Once the heat penetrates the fiber surface, it has two core effects: polymer chains gain activation energy, disintegrating the cross-linked network into low-molecular-weight fragments; and colloid residues within the pores are carbonized and decomposed into gases that escape. This in-situ heat treatment achieves periodic regeneration of capillary pores.

[0076] This solution eliminates the filter cloth's memory effect, keeping flux decay within a stable threshold over multiple consecutive filter press cycles. Downtime due to excessive differential pressure is nearly eliminated, and the filter cloth's service life is restored to its original specifications. Furthermore, it reduces the use of chemical cleaning agents, resulting in significant annual savings in hazardous waste disposal costs.

[0077] In some embodiments, the gel breaker tank 1, as the head unit of the processing chain, undertakes the critical task of breaking down the colloidal structure of drilling waste. The tank is equipped with a stirring system to promote homogenization of the reaction, wherein the stirring shaft is mechanically sealed at the part where it passes through the tank to achieve dynamic and static isolation. This sealing structure has long been subject to the severe test of fluctuating operating temperatures. When low-temperature materials are added to the high-temperature tank, the temperature drops sharply, resulting in differential contraction of the sealing elements and the creation of leakage channels. Even more serious is the thermal stress fatigue effect, which causes the seals to prematurely become brittle and fail under alternating hot and cold conditions.

[0078] To address this bottleneck, a thermal compensation ring (not shown) can be added to the bottom of the sealed chamber of the debonding tank 1. This ring, formed from a spirally wound flexible graphite ribbon, fills the annular groove formed by the metal seal seat and the main fluororubber seal ring. As the temperature inside the tank drops, the fluororubber seal ring contracts, and the thermal compensation ring simultaneously contracts to free up space and eliminate the tensile stress on the fluororubber seal ring. When the temperature rises, the thermal compensation ring expands to fill the gap created by the softening of the fluororubber seal ring, maintaining a constant compression.

[0079] In some embodiments, to address the issue of dead-end retention in the dosing branch pipe of the modification tank 5, a spiral guide vane can be integrated into the inner wall of the elbow at the drug inlet of the modification tank 5. This spiral guide vane is a continuous spiral with a 28° rise angle. This creates a rotational flushing flow pattern when the fluid passes through it, eliminating the material accumulation area at traditional right-angle elbows. Field applications have shown that drug residue has been largely eliminated, and gel contamination incidents have ceased.

[0080] In some embodiments, to address the issue of residual liquid film on the walls of the modified tank 5, a composite coating treatment can be applied to the inner surface of the modified tank 5. The base layer is sandblasted to a roughened surface with a Ra of 3.5μm, and the surface layer is impregnated with a perfluorosilane monolayer. This structure increases the liquid contact angle to over 150°, achieving durable hydrophobicity. After treatment, adhesion to the tank wall is significantly reduced, and the total amount of polymer residue is reduced to a measurable level.

[0081] In some embodiments, micro-airbags may form at the end of the mixing blade of the mixer 51. After being wrapped by a polymer, the micro-airbags form a stable gas-liquid dispersion system, which suddenly ruptures during the high-pressure circulation of the drilling fluid, causing bottom hole pressure fluctuations. In order to eliminate the micro-airbags at the end of the mixing blade of the mixer 51, hemispherical bumps can be evenly distributed in the 1 / 3 area of ​​the outer edge of the blade. The bumps have a diameter of 3mm and a height of 0.8mm. This structure triggers the transformation of the turbulent boundary layer in advance, causing bubbles to coalesce and float up for release. After the transformation, the stability of the filtrate density parameters is significantly improved, the accuracy of downhole pressure control is significantly improved, and the safety risks of drilling operations are simultaneously reduced.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A resource recycling device for water-based drilling waste, characterized in that: It comprises a mud buffer tank (0), a gel breaking tank (1), a filter press (2), a deionization tank (3), a sedimentation tank (4), a modification tank (5) and a storage tank (6), wherein drilling waste passes through the mud buffer tank (0), the gel breaking tank (1), the filter press (2), the deionization tank (3), the sedimentation tank (4), the modification tank (5) and the storage tank (6) in sequence; The mud buffer tank (0) is used to buffer drilling waste, the gel breaking tank (1) is used to break the gel and destabilize, the filter press (2) is used to filter out the primary filtrate, a portion of the primary filtrate flows back to the mud buffer tank (0), and the other portion enters the deionization tank (3), the deionization tank (3) is used to remove at least part of the metal ions in the primary filtrate and form a precipitate, the sedimentation tank (4) is used to precipitate the precipitate and discharge the secondary filtrate, the modification tank (5) is used to restore the colloidal stability of the secondary filtrate to form a reused filtrate, and the storage tank (6) is used to store the reused filtrate.

2. The resource recycling device for water-based drilling waste according to claim 1, characterized in that: A double-layer filter bed (31) is provided in the deionization tank (3), and the double-layer filter bed (31) is composed of an upper coarse filter layer (311) composed of modified sponge iron and a lower fine filter layer (312) composed of a magnetic responsive chelating resin, the outlet end of the upper coarse filter layer (311) being connected to the inlet end of the lower fine filter layer (312), and the primary filtrate passes through the upper coarse filter layer (311) and the lower fine filter layer (312) in sequence; A porous support plate (313) is provided at the bottom of the double-layer filter bed (31).

3. The resource recycling device for water-based drilling waste according to claim 1, characterized in that: An anti-gradient assembly is provided at the bottom of the deionization tank (3), and the anti-gradient assembly is located below the double-layer filter bed (31). The anti-gradient assembly includes: A spiral guide plate (331) has a through hole at its center, and the plate surface of the spiral guide plate (331) spirals and rises from the tank wall toward the center; A current collecting and voltage-stabilizing tube (332) vertically penetrates the through hole, a water outlet hole group is provided around the top of the current collecting and voltage-stabilizing tube (332), and the bottom of the current collecting and voltage-stabilizing tube (332) is externally connected to the inlet of the sedimentation tank (4).

4. The resource recycling device for water-based drilling waste according to claim 1, characterized in that: At least one set of oblique vibration plates (41) is obliquely arranged in the sedimentation tank (4).

5. The resource recycling device for water-based drilling waste according to claim 1, characterized in that: A buoyancy diffuser (42) is provided at the inlet of the settling tank (4).

6. The resource recycling device for water-based drilling waste according to claim 1, characterized in that: An ultraviolet lamp (43) is installed in the sedimentation tank (4).

7. The resource recycling device for water-based drilling waste according to claim 1, characterized in that: A stirrer (51) is installed in the modification tank (5).

8. The resource recycling device for water-based drilling waste according to claim 7, characterized in that: An anti-vortex cross baffle (511) is fixed on the top of the stirring shaft of the stirrer (51).

9. The resource recycling device for water-based drilling waste according to claim 1, characterized in that: A cyclodextrin molecular cage (512) is installed at the outlet of the modification tank (5).

10. The resource recycling device for water-based drilling waste according to claim 1, characterized in that: A heating component (211) is integrated into the filter plate (21) of the filter press (2) for performing a heating treatment on the filter plate (21) during the unloading stage.

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