Multi-type tertiary oil recovery chemical flooding agent continuous skid-mounted injection device and method

Abstract

The invention discloses a multi-type tertiary oil recovery chemical flooding agent continuous skid-mounted injection device which comprises a water treatment unit, a material storage unit, a material preparation unit and a wellhead injection unit, the water treatment unit comprises an oil removal tank and an ultrafiltration membrane filter, and the oil removal tank 111 is connected with a walnut shell filter through a pipeline; the walnut shell filter is connected with the fiber ball filter through a pipeline, and the ultrafiltration membrane filter is connected with the degassing membrane filter through a pipeline. The device is suitable for being used in various environments such as land and offshore platforms, on one hand, the problem of high cost of establishing an injection allocation station on the land is solved, and on the other hand, the problems that the space of the offshore platform is limited, a large injection allocation station cannot be established, and rapid injection is required are solved. And thirdly, the problems that various types of medicaments such as different solids and liquids need to be injected by adopting different processes and devices, the flow is complicated, and continuous injection cannot be realized by using one set of device are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield chemistry, and specifically relates to a continuous skid-mounted injection device and method for chemical flooding agents of multiple types in tertiary oil recovery. Background Art

[0002] After more than 30 years of development of onshore polymer flooding, a perfect polymer flooding theory system and rich practical experience have been formed. However, due to the different viscosities, dissolution times and dissolution conditions of different types of polymers, there are still problems that the on-site injection process cannot be unified, and the purpose of continuous injection of different flooding systems cannot be achieved by switching with one process at any time. At the same time, when viscosity stabilizers, bactericides and other auxiliary agents need to be used in combination at the polymer injection site, problems such as reasonable setting of injection process, injection sequence, injection position, and reasonable consideration of floor area will occur.

[0003] Polymer flooding on offshore platforms is even more special. First of all, due to the narrow space of offshore oilfields, the huge onshore polymer injection equipment cannot be installed on offshore platforms. Secondly, due to the complex reservoir conditions and large reservoir changes in offshore oilfields, multiple types of polymers need to be used to meet the reservoir requirements. However, the single-form polymer flooding injection process is difficult to adapt to the complex well conditions of offshore oilfields. Therefore, considering the problems existing in onshore and offshore polymer flooding processes, it is of great significance to use a set of injection process to achieve efficient injection of multi-type flooding agents on land and at sea, which has broad application prospects, optimizes the on-site injection process, improves injection efficiency, and saves floor space.

[0004] Domestic scholars have achieved certain results in the research on skid-mounted injection equipment for chemical flooding agents. The invention patent CN110094190B proposes a skid-mounted gel dispersion soft heterogeneous composite flooding system wellhead injection device, injection method and application, which realizes the multi-component continuous injection of displacement control agents such as gel dispersion soft bodies and microspheres through a pump suction system, a stirring and mixing system and a wellhead injection system. However, this method is only applicable to the mixing and injection of displacement control agents with certain fluidity or liquid types, and is not applicable to the injection of dry powder displacement control agents;

[0005] The invention patent CN117189055B proposes a skid-mounted particle injection device and method with scalable classification and multi-medium transportation, which adds a particle screening module, can recycle solid particles in industrial waste flue gas, and prepares a variety of composite displacement media through classification screening to enrich the displacement system. However, this method is still only applicable to the preparation and injection of multiphase fracturing fluids and high-temperature fluids, and is not applicable to the injection of dry powder displacement control agents;

[0006] The invention patent CN117846555B proposes a polymer injection skid-mounted integrated device and method. It adopts detachable connections. Starting from the treatment of oilfield produced water, it uses the treated and qualified water quality to prepare different types of polymers, and finally injects them into the wellhead to achieve fully automated polymer injection throughout the process. However, this method is only applicable to conventional polymer injection and is not applicable to the injection of functional polymers, liquid flooding agents or other gel-like products that require an increased dissolution rate.

[0007] Therefore, in view of the above problems, a continuous skid-mounted injection device and method for multi-type chemical flooding agents in tertiary oil recovery are proposed. Summary of the Invention

[0008] The object of the present invention is to provide a continuous skid-mounted injection device for multi-type chemical flooding agents in tertiary oil recovery, which includes a water treatment unit, a material storage unit, a material preparation unit, and a wellhead injection unit. The water treatment unit includes an oil removal tank and an ultrafiltration membrane filter. The oil removal tank 111 is connected to a walnut shell filter through a pipeline, the walnut shell filter is connected to a fiber ball filter through a pipeline, and the ultrafiltration membrane filter is connected to a degassing membrane filter through a pipeline;

[0009] The material storage unit includes four power pumps and a polymer feeding hopper. The four power pumps are respectively connected to a water treatment chemical storage tank, a solid material storage tank, a crosslinking agent storage tank, and a liquid material storage tank. The four power pumps are also respectively connected to a vacuum self-priming pump. The polymer feeding hopper is connected to a screw feeder through a pipeline, the screw feeder is connected to a Venturi powder-sucking demulsification pump through a pipeline, and the Venturi powder-sucking demulsification pump is connected to a ripening tank through a pipeline;

[0010] The material preparation unit includes a primary filter, a secondary filter, and a tertiary filter. The primary filter, secondary filter, and tertiary filter are connected to a static mixer through a pipeline, and the static mixer is connected to a stirring kettle through a pipeline;

[0011] The wellhead injection unit includes two high-pressure piston pumps. Flow controllers are respectively arranged on the two high-pressure piston pumps, and check valves are respectively arranged on the outlet pipelines of the two high-pressure piston pumps;

[0012] The total intelligent control system respectively includes a water treatment unit control system, a material storage unit control system, a material preparation unit control system, a wellhead injection unit control system, and a injection allocation process control system. The water treatment unit control system is connected to the water treatment unit 1 through a line. The material storage unit control system is connected to the material storage unit through a line. The material preparation unit control system is connected to the material preparation unit through a line. The wellhead injection unit control system 54 is connected to the wellhead injection unit through a line. The water treatment unit control system, the material storage unit control system, the material preparation unit control system, and the wellhead injection unit control system are respectively connected to the injection allocation process control system through lines.

[0013] Preferably, the water treatment chemical storage tanks are respectively connected to the oil removal tank, the walnut shell filter, and the fiber ball filter through pipelines. The solid material storage tank is respectively connected to the oil removal tank, the polymer feeding hopper, the screw feeder, and the ripening tank through pipelines under the control of an electric control valve.

[0014] Preferably, the fiber ball filter and the degassing membrane filter are respectively connected to the Venturi powder-sucking demulsification pump through a power pump, and an electric control valve for controlling the inflow of water is provided on the pipeline.

[0015] Preferably, the vacuum self-priming pump is respectively connected to the Venturi powder-sucking demulsification pump, the stirring kettle, and the ripening tank through pipelines. The ripening tank is connected to the first-stage filter and the stirring kettle through pipelines.

[0016] Preferably, the first-stage filter, the second-stage filter, and the third-stage filter have the same structure, only the internal filter holes are different. Filter flanges are respectively provided at the upper and lower ends of the first-stage filter. Filter holes are provided inside the first-stage filter, and a solution drainage device is provided below the filter holes.

[0017] Preferably, the filter holes of the first-stage filter are 10 meshes, the filter holes of the second-stage filter are 20 meshes, and the filter holes of the third-stage filter are 40 meshes.

[0018] Preferably, a liquid level control component is provided on one side of the stirring kettle, and a stirring device is provided inside the stirring kettle.

[0019] Preferably, the ripening tank and the static mixer are respectively connected to one of the high-pressure piston pumps through pipelines, and the stirring kettle is connected to the other high-pressure piston pump through a pipeline.

[0020] Preferably, the stirring blades of the stirring devices in the ripening tank 214 and the stirring kettle 32 are set as oval smooth blades with a certain thickness, distributed on both sides of the stirring shaft. The length of a single blade is 1 / 2 of the radius of the stirring kettle 32, which can ensure that a 3-4 cm high vortex is formed on the liquid surface during stirring, facilitating the rapid dispersion and dissolution of the polymer.

[0021] Preferably, the steps of the injection method are as follows:

[0022] Step 1: Water quality treatment:

[0023] Step 11: For the produced water from onshore oilfields, oil removal, suspended solid removal, ferrous ion removal, and sterilization treatment are required. The produced water from onshore oilfields is transported through pipelines to the oil removal tank. At the same time, the demulsifier in the water treatment chemical storage tank is pumped into the oil removal tank by a power pump. The double-blade stirring device installed in the oil removal tank is used for stirring. After stirring for a certain period of time, the flocculant in the solid material storage tank is pumped into the oil removal tank by a vacuum self-priming pump for flocculation sedimentation. After sedimentation for a certain period of time, the upper clear water after oil removal is transported through pipelines to the walnut shell filter for further oil and suspended solid removal;

[0024] Step 12: If sterilization treatment is required, the bactericide in the water treatment chemical tank is pumped into the inlet pipeline of the walnut shell filter by a power pump, and converges with the produced water in the pipeline and then enters the walnut shell filter for filtration and sterilization;

[0025] Step 13: If the bacterial content in the produced water is not high, sterilization treatment is not required. Just close the electric control valve of the inlet pipeline. The treated water flows into the fiber ball filter through pipelines for further oil and suspended solid removal. The water quality indicators after treatment basically meet the injection requirements;

[0026] Step 14: For seawater used on offshore platforms, the key is to remove suspended solids and dissolved oxygen. The water is transported through pipelines to the ultrafiltration membrane filter to remove suspended solids. The treated water flows into the degassing membrane filter to remove dissolved oxygen. The suspended solids and dissolved oxygen in the water quality after treatment basically meet the injection requirements;

[0027] Step 2: Material storage:

[0028] Step 21: For powder products, including but not limited to polymers, flocculants, and volume expansion particles, they are stored in the solid material storage tank for standby. If the on-site space is limited, no storage tank is equipped, and they are transported to the site by vehicle in ton barrels. Since different products have different injection methods, for example: polymers need to be dissolved in water to form polymer solutions for injection, and volume expansion particles are directly injected. Therefore, two sets of material storage and transportation processes are set up;

[0029] Step 22: First, for polymers, they are pumped from the solid material storage tank or the ton barrel by a vehicle-mounted vacuum self-priming pump into the polymer feeding hopper, and evenly enter the screw feeder through the feeding port. The water after being processed in Step 1 is transported by a power pump to the pipeline at the outlet of the screw feeder. The polymer contacts the water in the pipeline and then enters the Venturi powder-sucking demulsifier. The water is sprayed under high pressure to form a vortex. The polymer is evenly dispersed in the vortex water flow and flows into the ripening tank for ripening. For instant polymers that do not require ripening, they do not enter the ripening tank and directly enter the next unit;

[0030] Step 23: Second, for granular products, granular products need to be injected into the well with the polymer solution carried. Therefore, they are pumped from the solid material storage tank or the ton barrel by a vehicle-mounted vacuum self-priming pump into the ripening tank. The stirring device is turned on, and after being stirred and mixed evenly with the already ripened polymer solution, they can be directly transported to the high-pressure plunger pump for injection into the well;

[0031] Step 24: For liquid products, liquid products include but are not limited to emulsion polymers, microspheres, nano oil displacement agents, gel dispersions, and surfactants. They are stored in the liquid material storage tank for standby. If the on-site space is limited, the storage tank is not equipped, and they are transported to the site by vehicle in ton barrels for use. The crosslinking agent storage tank is used to store the delayed crosslinking agent. For the gels used in profile control and flooding, the ripened polymer solution in the ripening tank and the crosslinking agent in the crosslinking agent storage tank are pumped into the material preparation unit for crosslinking reaction together. Since the emulsion polymer has a low viscosity itself, it also needs to react with the crosslinking agent. The emulsion polymer is directly transported from the liquid material storage tank to the material preparation unit by a power pump for crosslinking reaction;

[0032] The crosslinking agent storage tank and the liquid material storage tank are temporary devices, which are temporarily equipped according to the on-site needs. If not needed, they are transported to the site in ton barrels by vehicle. After adding the materials, the vehicle leaves the site in time to save the occupied space;

[0033] Step 3: Material preparation:

[0034] Considering that different types of polymers have different dissolution rates, for polymers with slow dissolution, the functional polymer solution ripened in the ripening tank in Step 2 is pumped into the first-stage filter by a power pump. The swelling clusters are preliminarily sheared by a 10-mesh sieve. The sheared solution then enters the static mixer for re-mixing and then enters the second-stage filter. The swelling clusters are secondarily sheared by a 20-mesh sieve. The sheared solution enters the static mixer for secondary mixing again. Finally, it enters the third-stage filter. The swelling clusters are tertiarily sheared by a 40-mesh sieve. After being sheared, it returns to the static mixer for uniform mixing again. After being sheared by the third-stage filter, the insoluble polymer swelling clusters are basically completely dissolved;

[0035] Step 32: For liquid products, some need to undergo multi-component mixing reactions. For example, a gel dispersion needs to be mixed with a surfactant to form a gel soft body, and a polymer solution needs to react with a crosslinking agent to generate a delayed crosslinked gel. For such products, the polymer solution prepared in Step 31 and various liquid materials stored in the storage tank are respectively pumped into the stirring tank by a power pump according to the usage requirements, and are fully stirred evenly by a stirring device under heating conditions. For liquid products that do not require mixing and stirring, they are directly transported to a high-pressure plunger pump by a power pump and injected into the well.

[0036] Step 4: Wellhead injection:

[0037] Inject various chemical agents prepared in Steps 2 and 3 into the well through a high-pressure plunger pump, and install a check valve to prevent liquid backflow;

[0038] Step 5: Automatic control system:

[0039] The total intelligent control system is connected to the above four units through circuits, and is used to control the automated operations of each unit. The water treatment unit control system is used for the automated feeding, discharging, and flow control of the water treatment unit; the material storage unit control system is used for the automated feeding, discharging, and flow control of the material storage unit; the material preparation unit control system is used for the automated feeding, discharging, flow, stirring speed, and temperature control during the preparation process of the material preparation unit; the wellhead injection unit control system is used for the automated control of the high-pressure plunger pump and the check valve; the injection allocation process control system is used for the automatic control of the polymer injection volume, powder feeding volume, and viscosity parameters.

[0040] Preferably, the polymer includes: anionic polyacrylamide, poly surfactant, associative polymer, polymer microspheres, nano oil displacement agent, instant soluble temperature and salt resistant polymer;

[0041] The crosslinking agent is a low molecular weight polyphenol crosslinking agent or an aluminum citrate crosslinking agent;

[0042] The gel dispersion soft body is a gel dispersion formed by the polymerization of polyacrylamide and N, N-methylenebisacrylamide, and is obtained by reacting the gel dispersion with a surfactant such as sodium dodecyl sulfate or alkylphenol polyoxyethylene ether carboxylate or alkylbenzene sulfonate;

[0043] The water treatment chemicals include: bactericide, demulsifier, ferrous ion treatment agent, flocculant;

[0044] The demulsifier is a polyoxyethylene, polyoxypropylene copolymer or propylene glycol block polyether.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] 1. The device and method of the present invention achieve the online continuous injection of various types of chemical flooding agents for tertiary oil recovery, such as solids and liquids, and can realize the online mixing and injection of agents such as polymers, volume-expandable particles, polymer gel systems, gel dispersion soft bodies, and polymer microspheres, meeting the operation requirements of large-scale profile control and flooding, oil displacement, etc.

[0047] 2. The present invention is applicable to various environments such as onshore and offshore platforms. On the one hand, it solves the problem of high cost in establishing a blending and injection station on land, and on the other hand, it solves the problems of limited space on offshore platforms, inability to establish a large-scale blending and injection station, and the requirement for rapid injection.

[0048] 3. The present invention is detachable, and each unit can be used independently. Each unit is arranged on a skid and can be freely moved. Each device is connected through pipelines and circuits to realize the automatic control of online mixing and injection.

[0049] 4. The present invention has the advantage of reducing viscosity loss. A new water treatment unit can treat produced water and seawater through equipment and agents to meet the blending and injection requirements, ensure the viscosity of the polymer, and at the same time, each unit adopts a reasonable layout to minimize the pipeline length and further reduce the loss of polymer viscosity during long pipeline transportation.

[0050] 5. The present invention has the advantage of improving the dissolution rate. A new three-stage filter is added, which uses sieves with three different pore sizes of 10 mesh, 20 mesh, and 40 mesh respectively. The swollen micelles of products with slow dissolution such as associative polymers can be filtered through the sieve to shear the micelles and reduce the micelle size, thereby achieving the purpose of accelerating dissolution, reducing the ripening time. At the same time, the stirring blades of the stirring device in the ripening tank and the stirring kettle are set as oval smooth blades with a certain thickness, distributed on both sides of the stirring shaft, and the single blade length is 1 / 2 of the radius of the stirring kettle, which can ensure that a 3 - 4 cm high vortex is formed on the liquid surface during stirring, facilitating the rapid dispersion and dissolution of the polymer.

[0051] 6. The present invention has the advantages of flexible and efficient operation and saving floor space. The ripening tank can be used not only as a device for ripening and dissolving polymer solutions but also as a device for mixing polymer solutions and volume-expandable particles. The dual use of one tank saves floor space, and the effective utilization of the ripening tank can realize the simultaneous preparation of solid-liquid mixtures and all-liquid mixtures, improving efficiency; the storage tank is a temporary device, which can be flexibly set according to the on-site floor area and the needs of the Party A. When not needed, it can be replaced by a ton barrel or a tanker truck to be transported to the site for direct addition, with flexible operation.

[0052] 7. The present invention innovatively uses a Venturi powder-sucking demulsifier, which can form a high-pressure environment to achieve the dual functions of uniform powder feeding of polymer dry powder and demulsification of water-in-oil emulsion polymers, greatly improving the on-site blending and injection viscosity and ensuring the maximum exertion of product performance. Description of the Drawings

[0053] Figure 1 It is a schematic structural diagram of the device of the present invention; Figure 2 It is a schematic diagram of the material configuration unit of the present invention.

[0054] The reference numerals and names in the figure are as follows:

[0055] 1. Water treatment unit; 111. Oil removal tank; 112. Walnut shell filter; 113. Fiber ball filter; 121. Ultrafiltration membrane filter; 122. Degassing membrane filter;

[0056] 2. Material storage unit; 211. Polymer hopper; 212. Screw feeder; 213. Venturi powder suction demulsification pump; 214. Aging tank; 22. Power pump; 221. Vacuum self-priming pump;

[0057] 3. Material preparation unit; 311. Primary filter; 3111. Filter flange; 3112. Filter holes; 3113. Solution drainage device; 312. Secondary filter; 313. Tertiary filter; 314. Static mixer; 32. Stirring kettle; 321. Liquid level control component; 322. Stirring device;

[0058] 4. Wellhead injection unit; 41. High-pressure piston pump; 42. Flow controller; 43. Check valve;

[0059] 5. Total intelligent control system; 51. Water treatment unit control system; 52. Material storage unit control system; 53. Material preparation unit control system; 54. Wellhead injection unit control system; 55. Injection allocation process control system;

[0060] A. Water treatment chemical storage tank; B. Solid material storage tank; C. Crosslinking agent storage tank; D. Liquid material storage tank. Specific implementation mode

[0061] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0062] Example 1:

[0063] For a medium-temperature well in an onshore oilfield, pre-crosslinked swellable particles are used for profile control. The designed profile control fluid volume of this well is 1000 cubic meters. The swellable particles mainly play the role of adjusting the water absorption profile and have no strict requirements for water quality. There is no need to treat the produced water, so the water treatment unit can be omitted and start from the material storage unit. Since the profile control particles need to be carried into the formation by the polymer solution, the polymer solution needs to be prepared first.

[0064] The on-site space of this well is relatively large, and storage tanks can be placed. The volume-expandable particulate matter is stored in the solid material storage tank B and pulled into the site. The polymer is placed in a ton barrel and pulled into the site by a vehicle. The polymer is pumped into the polymer feeding hopper 211 by a vacuum self-priming pump 221 in the ton barrel, and evenly enters the screw feeder 212 from the feeding port. Then, the incoming water is transported by the power pump 22 to the pipeline at the outlet of the screw feeder 212. After the polymer contacts the water in this pipeline, it enters the Venturi powder-sucking demulsifier 213. Among them, the powder feeding amount of the polymer is controlled by the total intelligent control system 55, maintained at 5 - 10 cubic meters per hour, ensuring a polymer concentration of 0.2%. The water is ejected under high pressure to form a vortex. The polymer is evenly dispersed in the vortex water flow and enters the ripening tank 214 for ripening. The stirring device is turned on to stir and ripen for 30 - 40 minutes, and then the stirring is stopped. The volume-expandable particles are pumped into the ripening tank 214 from the solid material storage tank B by the vacuum self-priming pump 221. The stirring device is turned on, and the well-ripened polymer solution and the volume-expandable particles are fully stirred for 5 - 10 minutes until evenly mixed. Then, the electric control valve on the pipeline connecting the outlet of the ripening tank 214 and the high-pressure plunger pump 41 is opened, and it is injected into the well by the high-pressure plunger pump.

[0065] Example 2:

[0066] For a high-temperature and high-salt well in an onshore oilfield, polymer gel profile control is adopted. The designed profile control fluid volume of this well is 3000 cubic meters. The ferrous iron content in the produced water is 15 ppm, and the SRB bacteria content reaches 14,000 cells / mL. Ferrous iron treatment agents and bactericides are required to treat the water quality. The temperature and salinity of this well are relatively high, and associative polymers are required to ensure the viscosity of the gel system and cooperate with the crosslinking system to form a high-strength gel to achieve the purpose of efficient profile control. To ensure the polymer viscosity, the produced water needs to be treated, and the associative polymer needs to adopt a device to improve the dissolution rate. A total of 4 unit processes are completed.

[0067] Step 1: The on-site space of this well is relatively large, and storage tanks can be placed. A water treatment chemical storage tank A, a solid material storage tank B, and a crosslinking agent storage tank C are set up on-site, storing demulsifiers and flocculants respectively. First, the produced water is transported by the power pump 22 through the pipeline to the oil removal tank 311. Then, the demulsifier in the water treatment chemical storage tank A is pumped into the oil removal tank 311 by the power pump 22. The stirring device is turned on. After stirring for 10 - 15 minutes, the flocculant in the solid material storage tank B is pumped into the oil removal tank 311 by the vacuum self-priming pump 221. After flocculating and settling for 5 - 10 minutes under stirring, the upper clear water after oil removal is transported through the pipeline to the walnut shell filter 112 for further oil removal and suspension removal. After the addition of the demulsifier is completed, bactericides are pumped into the water treatment chemical storage tank A, and then the bactericides are pumped into the inlet pipeline of the walnut shell filter 112 by the power pump 22. After converging with the produced water in the pipeline, they enter the walnut shell filter 112 and flow through the walnut shell filter 112 from top to bottom for filtration and sterilization;

[0068] The treated water flows into the fiber ball filter 113 through a pipeline for further oil and suspended solid removal. After the bactericide dosing is completed, a ferrous ion stabilizer is pumped into the water treatment chemical storage tank A, and then pumped into the inlet pipeline of the fiber ball filter 113 by the power pump 22. It converges with the produced water in the pipeline and then enters the fiber ball filter 113. After flowing through the fiber ball filter 113 from top to bottom, the water quality indicators at the outlet basically meet the injection requirements.

[0069] Step 2: After adding the flocculant, an associative polymer is pumped into the solid material storage tank B, and then pumped into the polymer feeding hopper 211 by the vacuum self-priming pump 221, and evenly enters the screw feeder 212 from the feeding port; the water treated in the above Step 1 is transported to the pipeline at the outlet of the screw feeder 212 by the power pump 22. The polymer contacts the water in the pipeline and then enters the Venturi powder-sucking demulsifier 213. The polymer powder feeding amount is controlled by the total intelligent control system 55, maintained at 5 - 10 cubic meters per hour, the liquid volume is 3000 cubic meters, the concentration is 0.3%, the water is sprayed under high pressure to form a vortex, and the polymer is evenly dispersed in the vortex water flow and flows into the ripening tank 214 for ripening. The stirring device is turned on and ripened for 20 - 30 minutes;

[0070] Step 3: The preliminarily ripened polymer solution in Step 2 is pumped into the first-stage filter 311 by the power pump 22, and the swelling mass is preliminarily sheared through a 10-mesh sieve. The sheared solution then enters the static mixer 314 for re-mixing, and then enters the second-stage filter 312, where the swelling mass is sheared again through a 20-mesh sieve. The sheared solution enters the static mixer 314 for secondary mixing; finally, it enters the third-stage filter 313, where the swelling mass is sheared three times through a 40-mesh sieve. After shearing, it returns to the static mixer 314 for uniform mixing again. At this time, the polymer solution is basically completely dissolved. Finally, the completely dissolved polymer solution is pumped into the stirring kettle 32 by the power pump 22. At the same time, the crosslinking agent in the crosslinking agent storage tank C is pumped into the stirring kettle 32 by the power pump. The addition amounts of the polymer solution and the crosslinking agent are respectively controlled by the liquid level control component 321 in the kettle to ensure that the crosslinking agent concentration is 0.3%. The stirring device 322 is turned on and fully stirred for 10 - 15 minutes for sufficient reaction.

[0071] Step 4: Inject the solution prepared in Step 3 into the well through the high-pressure piston pump 41.

[0072] Example 3:

[0073] In a certain onshore oilfield, a polymer-surfactant combination flooding experiment was carried out on a well after polymer flooding. The designed injection volume of the polymer-surfactant combination in this well is 2,000 cubic meters. The ferrous iron content in the produced water is 10 ppm, and the content of SRB bacteria reaches 45,000 cells / mL. Ferrous iron treatment agents and bactericides are required to treat the water quality. The polymer-surfactant combination belongs to a functional polymer, with the dual oil displacement effects of both polymer and surfactant, and is a new type of high-efficiency oil displacement agent with "multiple functions in one agent". Conducting experiments on this product aims to open up a new technical path for improving oil recovery after polymer flooding in the future. To ensure viscosity, it is necessary to treat the produced water and perform three-stage filtration to increase the dissolution rate.

[0074] Step 1: The on-site space of this well is small, and no material storage tanks are set up. Solid materials are contained in ton barrels, and liquid materials are contained in horizontal tanks, which are transported to the site by vehicles. First, the produced water is transported through a pipeline by a power pump 22 to an oil removal tank 311. Then, the demulsifier in the tanker is pumped into the oil removal tank 311 by the power pump 22. The stirring device is started. After stirring for 10 - 15 minutes, the flocculant in the ton barrel of the transport vehicle is pumped into the oil removal tank 311 by a vacuum self-priming pump 221. After flocculating and settling for 5 - 10 minutes under stirring, the upper clear water after oil removal is transported through a pipeline to a walnut shell filter 112 for further oil removal and removal of suspended solids;

[0075] Then, the bactericide in the tanker is pumped into the inlet pipeline of the walnut shell filter 112 by the power pump 22. After converging with the produced water in the pipeline, it enters the walnut shell filter 112 and flows through the walnut shell filter 112 from top to bottom for filtration and sterilization. The treated water flows into a fiber ball filter 113 through a pipeline for further oil removal and removal of suspended solids. Then, the ferrous ion stabilizer in the tanker is pumped into the inlet pipeline of the fiber ball filter by the power pump 22. After converging with the produced water in the pipeline, it enters the fiber ball filter 113 and flows through the fiber ball filter 113 from top to bottom. The water quality indicators at the outlet basically meet the injection requirements;

[0076] Step 2: The polymer-surfactant combination in the ton barrel of the transport vehicle is pumped into a polymer feeding hopper 211 by a vacuum self-priming pump 221 and evenly enters a screw feeder 212 through the feeding port. The water treated in the above Step 1 is transported to the pipeline at the outlet of the screw feeder 212 by the power pump 22. The polymer-surfactant combination contacts the water in the pipeline and then enters a Venturi powder-sucking demulsifier 213. The polymer powder feeding volume is controlled by a total intelligent control system 55 and maintained at 5 - 10 cubic meters per hour, with a liquid volume of 2,000 cubic meters and a concentration of 0.15%. The water is sprayed under high pressure to form a vortex. The polymer is evenly dispersed in the vortex water flow and flows into a ripening tank 214 for ripening. The stirring device is started and ripened for 20 - 30 minutes;

[0077] Step 3: Pump the preliminarily matured polymer surfactant solution in Step 2 into the first-stage filter 311 with a power pump 22, and conduct preliminary shearing of the swelling mass through filtration by a 10-mesh sieve; after the sheared solution enters the static mixer 314 for remixing, it enters the second-stage filter 312, and the swelling mass is sheared again through a 20-mesh sieve. After being sheared, the solution enters the static mixer 314 for secondary mixing; finally, it enters the third-stage filter 313, and the swelling mass is sheared three times through a 40-mesh sieve. After shearing, it returns to the static mixer 314 for uniform mixing again. At this time, the polymer surfactant solution is basically completely dissolved.

[0078] Step 4: Inject the solution prepared in Step 3 into the wellbore through a high-pressure piston pump 41.

[0079] Example 4:

[0080] A certain platform in an offshore oilfield adopts a fast-dissolving temperature- and salt-resistant polymer for enhanced oil recovery. The seawater salinity is 21,000 mg / L, and the reservoir temperature is 110 °C. The designed polymer injection volume for this well is 2,500 cubic meters. It is necessary to filter the seawater before preparing the polymer solution. This fast-dissolving temperature- and salt-resistant polymer is an independently developed product of Binhai Company, with a relatively fast dissolution rate. It can be completely dissolved in 10 - 15 minutes under high salinity conditions and does not require three-stage filtration.

[0081] Step 1: The space on the offshore platform is small, and no material storage tank is set up. Solid materials are packed in ton barrels and transported to the site by vehicles. First, the seawater is transported through a pipeline to the ultrafiltration membrane filter 121 and flows through the ultrafiltration membrane filter 121 from top to bottom to remove suspended solids. The treated water flows into the degassing membrane filter 122 and flows through the degassing membrane filter from top to bottom to remove dissolved oxygen. The suspended solids and dissolved oxygen in the treated water basically meet the injection requirements.

[0082] Step 2: Pump the fast-dissolving temperature- and salt-resistant polymer in the ton barrel of the transport vehicle into the polymer feeding hopper 211 with a vacuum self-priming pump 221, and evenly enter the screw feeder 212 from the feeding port; transport the seawater treated in the above Step 1 to the pipeline at the outlet of the screw feeder 212 with a power pump 22. The fast-dissolving temperature- and salt-resistant polymer contacts the water in the pipeline and then enters the Venturi powder-sucking demulsifier 213. The polymer powder feeding amount is controlled by the total intelligent control system 55 and maintained at 10 - 15 cubic meters per hour, with a liquid volume of 2,500 cubic meters and a concentration of 0.2%. The water is ejected under high pressure to form a vortex. The polymer is evenly dispersed in the vortex water flow and flows into the ripening tank 214 for ripening. Turn on the stirring device, and it can be completely dissolved after ripening for 10 - 15 minutes;

[0083] Step 3: Inject the solution prepared in Step 2 into the wellbore through a high-pressure piston pump 41.

[0084] Example 5:

[0085] A platform in an offshore oil field uses an emulsion polymer plus a cross-linking agent system to flood oil. The seawater mineralization is 16500 mg / L, the reservoir temperature is 90°C, the platform is designed to inject 2000 cubic meters of polymer, and the polymer concentration is 0.5%. The seawater needs to be filtered before preparing the polymer solution. The oil-in-water emulsion polymer has a low viscosity and is very easy to inject. In order to ensure the displacement viscosity, a cross-linking agent needs to be used to form a gel system to increase the system viscosity.

[0086] Step 1: The space on the offshore platform is small, and no material storage tanks are set up. Liquid materials are pulled into the site by tank trucks. First, the seawater is transported to the ultrafiltration membrane filter 121 through a pipeline, and the suspended matter is removed after flowing through the ultrafiltration membrane filter 121 from top to bottom. The treated water flows into the degassing membrane filter 122, and the dissolved oxygen is removed after flowing through the degassing membrane filter 122 from top to bottom. After treatment, the suspended matter and dissolved oxygen in the water quality basically meet the injection requirements.

[0087] Step 2: The emulsion polymer in the tank truck is pumped into the Venturi powder demulsifier 213 through the power pump 22, wherein the emulsion polymer displacement is controlled by the general intelligent control system 55 and maintained at 15-20 cubic meters / hour, the liquid volume is 2000 cubic meters, and the concentration is 0.5%. The emulsion polymer is demulsified under the action of high-speed shear, and then the seawater treated in step 1 is pumped into the Venturi powder demulsifier 213 through the power pump 22, the demulsified polymer is mixed with the high-pressure seawater, and flows into the maturation tank 214 for maturation, and the stirring device is turned on. After maturation for 5-10 minutes, the polymer is completely dissolved.

[0088] Step 3: The fully matured emulsion polymer solution in step 2 is pumped into the stirring kettle 32 by the power pump 22, and the crosslinking agent in the tank truck is pumped into the stirring kettle 32 by the power pump. The amount of polymer solution and crosslinking agent added is controlled by the liquid level control device 321 in the kettle to ensure that the concentration of the crosslinking agent is 0.5%. The stirring device 32 is turned on to stir for 10-15 minutes to fully react.

[0089] Step 4: Inject the cross-linking system prepared in step 3 into the well via a high-pressure plunger pump 41.

[0090] Utilizing the technical solution described in the present invention, or those skilled in the art designing a similar technical solution inspired by the technical solution of the present invention to achieve the above-mentioned technical effects, all fall within the protection scope of the present invention.

Claims

1. A multi-type tertiary oil recovery chemical flooding agent continuous skid-mounted injection device, comprising a water treatment unit (1), a material storage unit (2), a material preparation unit (3), and a wellhead injection unit (4), characterized in that: The water treatment unit (1) comprises an oil removal tank (111) and an ultrafiltration membrane filter (121), the oil removal tank (111) is connected to a walnut shell filter (112) via a pipeline, the walnut shell filter (112) is connected to a fiber ball filter (113) via a pipeline, and the ultrafiltration membrane filter is connected to a degassing membrane filter (122) via a pipeline; The material storage unit (2) comprises four power pumps (22) and a polymer feeding hopper (211). The four power pumps (22) are respectively connected to a water treatment agent storage tank (A), a solid material storage tank (B), a cross-linking agent storage tank (C), and a liquid material storage tank (D). The four power pumps (22) are also respectively connected to a vacuum self-priming pump (221). The polymer feeding hopper (211) is connected to a screw feeder (212) via a pipeline. The screw feeder (212) is connected to a Venturi powder suction and demulsification pump (213) via a pipeline. The Venturi powder suction and demulsification pump (213) is connected to a maturation tank (214) via a pipeline. The material preparation unit (3) comprises a primary filter (311), a secondary filter (312), and a tertiary filter (313); the primary filter (311), the secondary filter (312), and the tertiary filter (313) are connected to a static mixer (314) via a pipeline; and the static mixer (314) is connected to a stirring tank (32) via a pipeline; The wellhead injection unit (4) comprises two high-pressure plunger pumps (41), each of which is provided with a flow controller (42), and each of which is provided with a check valve (43) on its outlet pipe. The overall intelligent control system (5) comprises a water treatment unit control system (51), a material reserve unit control system (52), a material preparation unit control system (53), a wellhead injection unit control system (54), and an injection process control system (55). The water treatment unit control system (51) is connected to the water treatment unit (1) via a line, the material reserve unit control system (52) is connected to the material reserve unit (2) via a line, the material preparation unit control system (53) is connected to the material preparation unit (3) via a line, the wellhead injection unit control system (54) is connected to the wellhead injection unit (4) via a line, and the water treatment unit control system (51), the material reserve unit control system (52), the material preparation unit control system (53), and the wellhead injection unit control system (54) are respectively connected to the injection process control system (55) via lines.

2. A multi-type tertiary oil recovery chemical flooding agent continuous skid-mounted injection device according to claim 1, characterized in that: The water treatment agent storage tank (A) is connected to the oil removal tank (111), the walnut shell filter (112), and the fiber ball filter (113) through pipelines, and the solid material storage tank (B) is connected to the oil removal tank (111), the polymer feeding hopper (211), the screw feeder (212), and the maturation tank (214) through pipelines and under the control of a point control valve.

3. The multi-type tertiary oil recovery chemical flooding agent continuous skid-mounted injection device according to claim 1 is characterized in that: The fiber ball filter (113) and the degassing membrane filter (122) are respectively connected to the Venturi powder suction and demulsification pump (213) via a power pump (22).

4. The multi-type tertiary oil recovery chemical flooding agent continuous skid-mounted injection device according to claim 1 is characterized in that: The vacuum self-priming pump (221) is connected to the Venturi powder suction and demulsification pump (213), the maturation tank (214) and the stirring tank (32) through pipelines, respectively; the maturation tank (214) is connected to the primary filter (311) and the stirring tank (32) through pipelines.

5. The multi-type tertiary oil recovery chemical flooding agent continuous skid-mounted injection device according to claim 1 is characterized in that: The structures of the primary filter (311), the secondary filter (312), and the tertiary filter (313) are the same, and only the internal filtering holes are different. The upper and lower ends of the primary filter (311) are respectively provided with filter flanges (3111), the first filter (311) is provided with filter filtering holes (3112) inside, and a solution drainage device (3113) is provided below the filter filtering holes (3112).

6. The multi-type tertiary oil recovery chemical flooding agent continuous skid-mounted injection device according to claim 1 is characterized in that: The filter pores of the primary filter (311) are 10 meshes, the filter pores of the secondary filter (312) are 20 meshes, and the filter pores of the tertiary filter (313) are 40 meshes.

7. The multi-type tertiary oil recovery chemical flooding agent continuous skid-mounted injection device according to claim 1 is characterized by: A liquid level control component (321) is provided on one side of the stirring tank (32), and a stirring device (322) is provided inside the stirring tank (32).

8. The multi-type tertiary oil recovery chemical flooding agent continuous skid-mounted injection device according to claim 1 is characterized by: The maturation tank (214) and the static mixer (314) are respectively connected to one of the high-pressure plunger pumps (41) through pipelines, and the stirring tank (32) is connected to the other high-pressure plunger pump (41) through a pipeline.

9. The method for injecting a multi-type tertiary oil recovery chemical flooding agent continuous skid-mounted injection device according to claim 1, characterized in that: The steps of the injection method are: Step 1: Water treatment: Step 11: The produced water from the onshore oil field is transported to the deoiling tank (111) via a pipeline, and at the same time, the demulsifier in the water treatment agent storage tank (A) is pumped into the deoiling tank (111) by a power pump (22), and stirred by a double-blade stirring device provided in the deoiling tank (111). After stirring for a certain period of time, the flocculant in the solid material storage tank (B) is pumped into the deoiling tank (111) by a vacuum self-priming pump (221) for flocculation and sedimentation. After sedimentation for a certain period of time, the upper layer of clear water after deoiling is transported to the walnut shell filter (112) via a pipeline to continue to remove oil and suspended matter; Step 12: If sterilization is required, the sterilizer in the water treatment agent tank (A) is pumped into the inlet pipeline of the walnut shell filter (112) by the power pump (22), and then merged with the produced water in the pipeline and enters the walnut shell filter (112), where it is filtered and sterilized; Step 13: If the bacterial content in the produced water is not high, sterilization treatment is not required. The electric control valve of the inlet pipeline can be closed. The treated water flows into the fiber ball filter (113) through the pipeline to further remove oil and suspended matter. After treatment, various water quality indicators basically meet the injection requirements; Step 14: For seawater used in offshore platforms, the focus is on removing suspended solids and dissolved oxygen. The water is transported to an ultrafiltration membrane filter (121) through a pipeline to remove suspended solids. The treated water flows into a degassing membrane filter (122) to remove dissolved oxygen. After treatment, the suspended solids and dissolved oxygen in the water quality basically meet the injection requirements. Step 2: Material storage: Step 21: For powder products, including but not limited to polymers, flocculants, and bulking particles, they are stored in solid material storage tanks (B) for standby use. If the space on site is limited, no storage tank is provided and the powder products are packed in ton barrels and transported to the site by vehicles. Due to different injection methods for different products, polymers need to be dissolved in water to prepare polymer solutions for injection, while bulking particles are directly injected. Therefore, two sets of material storage and transportation processes are set up; Step 22: First, polymers are pumped into the polymer feeding hopper (211) by a solid material storage tank (B) or a ton barrel truck vacuum self-priming pump (221), and uniformly enter the screw feeder (212) from the feeding port. The water treated in step 1 is transported to the pipeline at the outlet of the screw feeder (212) by the power pump (22). The polymer contacts the water in the pipeline and then enters the Venturi powder suction demulsifier (213). The water is sprayed at high pressure to form a vortex. The polymer is uniformly dispersed in the vortex water flow and flows into the maturation tank (214) for maturation. For instant polymers that do not need to be matured, they do not enter the maturation tank and directly enter the next unit; Step 23: The second is granular products. Granular products need to be carried by polymer solution and injected into the well. Therefore, the solid material storage tank (B) or the ton barrel truck uses a vacuum self-priming pump (221) to pump into the maturation tank (214), turn on the stirring device, stir and mix with the already matured polymer solution, and then directly transport to the high-pressure plunger pump (41) to be injected into the well; Step 24: For liquid products, including but not limited to emulsion polymers, microspheres, nano oil displacement agents, gel dispersions, and surfactants, they are stored in liquid material storage tanks (D) for standby use. If the on-site space is limited, no storage tank is provided and the products are packed in ton barrels and transported to the site by vehicles. The crosslinker storage tank (C) is used to store delayed crosslinking agents. For gels used for profile adjustment and flooding, the polymer solution matured in the maturation tank (214) and the crosslinker in the crosslinker storage tank (C) are pumped into the material preparation unit (3) for crosslinking reaction. Since the emulsion polymer has a low viscosity, it also needs to react with the crosslinker. The emulsion polymer is directly transported from the liquid material storage tank (D) to the material preparation unit (3) by a power pump (22) for crosslinking reaction; Step 3: Material preparation: Step 31: Considering that different types of polymers dissolve at different speeds, for polymers that dissolve more slowly, the functional polymer solution that has been matured in the maturation tank in step 2 is pumped into a primary filter (311) by a power pump (22), and the swollen mass is preliminarily sheared through a 10-mesh sieve. The sheared solution enters a static mixer (314) for mixing again, and then enters a secondary filter (312). The swollen mass is sheared for a second time through a 20-mesh sieve. The sheared solution enters a static mixer (314) for mixing again, and finally enters a tertiary filter (313). The swollen mass is sheared for a third time through a 40-mesh sieve. After shearing, the solution returns to the static mixer (314) for mixing evenly. After shearing through the tertiary filter, the insoluble polymer swollen mass is basically completely dissolved; Step 32: For liquid products, some of which require a multi-component mixing reaction, the polymer solution prepared in step 31 and various liquid materials stored in the storage tank are pumped into the stirring tank (32) through the power pump (22) according to the use requirements, and are fully stirred and uniformly stirred through the stirring device (322) under heating conditions. If the liquid product does not require mixing and stirring, it is directly transported from the power pump (22) to the high-pressure plunger pump (41) and injected into the well. Step 4: Wellhead injection: The various chemical agents prepared in step 2 and step 3 are injected into the well through a high-pressure plunger pump (41), and a check valve (43) is installed to prevent the liquid from flowing back; Step 5: Automatic Control System: The overall intelligent control system is connected to the above four units through circuits and is used to control the automatic operation of each unit. The water treatment unit control system (51) is used for the automatic inlet and outlet and flow control of the water treatment unit (1); the material storage unit control system (52) is used for the automatic inlet and outlet and flow control of the material storage unit (2); the material preparation unit control system (53) is used for the automatic inlet and outlet, flow, stirring speed and temperature control of the material preparation unit (3) during the preparation process; the wellhead injection unit control system (54) is used for the automatic control of the high-pressure plunger pump 41 and the check valve 43; the injection process control system (55) is used for automatically controlling the polymer injection amount, powder amount and viscosity parameters.

10. The injection method of a continuous skid-mounted injection device for multi-type tertiary oil recovery chemical flooding agents according to claim 9, characterized in that: The polymers include: anionic polyacrylamide, polymer surface agent, associative polymer, polymer microsphere, nano oil displacement agent, fast-dissolving temperature-resistant and salt-resistant polymer; The cross-linking agent is an oligomeric polyphenol cross-linking agent or an aluminum citrate cross-linking agent; The jelly dispersion soft body is a jelly dispersion polymerized from polyacrylamide and N,N-methylenebisacrylamide, and is obtained by reacting the jelly dispersion with sodium dodecyl sulfate or alkylphenol polyoxyethylene ether carboxylate or alkylbenzene sulfonate surfactant; The water treatment agents include: bactericide, demulsifier, ferrous ion treatment agent, flocculant; The demulsifier is polyoxyethylene, polyoxypropylene copolymer or propylene glycol block polyether.

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