RU2802646C2 - Method for increasing oil recovery and device for its implementation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: in particular, a method is proposed for enhancing oil recovery using equipment that has modules for storing, preparing and supplying technical water, bulk and liquid chemicals to the well. An installation consisting of separate units is placed in a van of an all-wheel drive vehicle and the injectivity of the well and its operating conditions are determined, the installation is switched to the reagents injection mode. Service water is supplied from the water conduit of the pipeline for maintaining reservoir pressure and forcing high pressure into the well with its entry into an adjustable jet apparatus, which is connected to a preparation tank with a mechanical agitator of the preparation and mixing unit, from which a solution of chemical reagents is fed into the high-pressure pump through the pipeline through the densitometer and gate valves. Loose chemical reagents of low concentration are fed from two hoppers through spring screw feeders of low productivity and a pipeline into an adjustable jet apparatus, which is connected to the preparation tank. Bulk chemical reagents of high concentration are fed from the hopper along a high-capacity vertical auger into the preparation tank. The density of a solution of chemical reagents is determined. Next, liquid chemicals are fed from the loading pump into two tanks, filters for cleaning from mechanical impurities, dosing pumps of low and high pressures. Moreover, the low-pressure dosing pump is connected to the pipeline near the preparation tank. The high-pressure dosing pump is connected to the high-pressure pipeline. Using a high-pressure pump, chemical reagents are simultaneously pumped into the well through a high-pressure injection pipeline with a check valve, a vibration-resistant and electric contact pressure gauge, and an automatic safety valve. Then, a solution of chemical reagents is forced through with technical water using the energy of the water pipeline to maintain formation pressure, and the injectivity of the well is determined.

EFFECT: increased efficiency of formation stimulation with reagent solutions using a universal manoeuvrable unit, which is easier to set up for complex technological operations, having an increased resource of power units.

3 cl, 2 dwg

Description

The invention relates to the oil and gas industry, namely to a new method of increasing oil recovery from a productive formation, including carrying out repair and isolation work in a well, using more advanced equipment, which is tied only to this method.

As analogues of the proposed invention, RF patents for utility models No. 9887, 60610, 74162 with expired validity are known.

The installation for preparing and pumping polymer compositions into a well (patent No. 9887) is one continuous production line.

The installation for the preparation and injection of sediment-forming systems in the form of gels (RF patent No. 60610) additionally has an electrically driven mixer in the mixing tank and a frequency converter in the injection pump system to change the productivity.

The installation (patent No. 74162) made it possible to prepare and inject combined sediment-forming polymers into the formation, also in the form of gels. It made it possible to supply and filter process water, load and dose dry polymer and liquid cross-linking solution, and also prepare a polymer solution.

Common disadvantages of technical models were the limited use of devices designed only for supplying certain components into the well, the lack of reliable equipment, including without sensors to determine their characteristics and reservoir injectivity.

There is a RF patent for utility model No. 129550, class. E21B 41/00, 2013. An installation for preparing and pumping solutions of bulk and liquid chemical reagents into a well with two bunkers and other equipment is located in modules on one or more vehicle chassis.

The installation uses imperfect equipment that does not allow mixing components to be supplied to the well in the required concentrations; there are no sensors for measuring the characteristics of mixtures; the injectivity of the formation is not determined, which does not allow finding the optimal mode of its operation.

There is a RF patent for the invention No. 2205946 C1, E21B 43/22, published 03/10/2003, bulletin. No. 16). This is a method of developing an oil deposit by injecting into the reservoir an aqueous suspension based on polyacrylamide, bentonite clay and a chromium compound and an aqueous suspension based on wood flour, condensed sulfite-alcohol stillage and potassium bichromate. With its help, the injectivity profile is leveled and the reservoir coverage is increased by waterflooding by clogging highly permeable water-flooded zones.

The disadvantages of the method are low efficiency for oil fields with zonal heterogeneity due to the shallow depth - filtration of dispersed particles in the reservoir volume and the limited duration of its use. Disadvantages include clogging of individual reservoir intervals when wood flour is injected and blocking of oil reserves in low-permeability intervals.

The invention “Method of preparing and pumping multicomponent technological systems into a well” is known (RF patent for invention No. 2250368 C2, class E21B 43/32, published 04/20/2005, bulletin No. 27). The claimed method ensures dosed injection of working agents into the well - suspensions of wood flour, clay powder, polyacrylamide, crosslinker (chromium acetate), pushing them into the formation with water. But without the chemical activity of the reagents in relation to each other, there will only be waterproofing of the productive formation without increasing oil recovery.

The output of the first dispenser of the installation is connected to the input of the ejector mixer. The second input of the mixer is connected to the water supply pipeline, and the output is connected to the mixing tank connected to the first input of the injection pump.

The pump outlet is connected to the well.

The output of the second dispenser is connected to the second ejector mixer, the output of which is connected to the mixing tank connected to the second input of the injection pump. Ejector mixers have replaceable nozzles for the required mode of pumping components into the well.

To start the electric motor of the injection pump under the required injection mode, it is necessary to calculate a certain frequency range of equipment operation, which is determined using the mathematical formulas given in the claims.

The need to stop the equipment, carry out calculations with many parameters and then replace the mixer nozzles for installation with complex equipment that depends on these modes are the disadvantages of the proposed technology.

The prototype for the claimed invention is the RF patent for the invention of the Russian Federation No. 2704402 “Installation for storage and dosed supply of working agents into the productive formation” (C1, IPC 21B 43/22, publ. 10/28/2019, Bulletin No. 31).

The description says that it is necessary to develop the installation to ensure its safety in the case of using chemically active working agents. The proposed installation consists of 32 separate blocks, units, pumps, pipelines, etc. An example is given for two modules for storing and supplying chemical reagents (hydrogen peroxide and methanol), and a module for supplying water from a container. Controlled check valves are located in the pipelines of each of them (outlet and discharge).

Separate supply of components ensures safe operation of the installation, because Contact of hydrogen peroxide and methanol under certain conditions forms an explosive mixture. In the supply pipeline, when water is pumped through it, the appearance of stagnant zones with the accumulation of a chemical reagent is completely eliminated.

First, hydrogen peroxide, methanol and water are pumped in. Then the operation of the installation is interrupted, followed by repeating the specified supply of working reagents into the productive formation until they are delivered in the required volume.

The disadvantages of the installation include the cyclic separate supply of the chemical reagents specified in the description into the formation in order to prevent the possibility of explosions when they are mixed. It is clear that the continuous supply of already mixed selected reagents increases the efficiency of the technology, because in rocky and viscous environments it is more difficult to connect them to each other, especially in fields with highly viscous oil.

The installation does not allow the use of more promising reagents, for example, cross-linked polymer and polymer-dispersed systems, bentonite clay powder, surfactants and others. It cannot be used for repair and insulation work.

As with other analogues, the proposed technology does not allow determining the injectivity of the formation, which can be used to adjust the operating mode of the installation, at which there will be a maximum increase in oil recovery from the formation. Installation options and related technology are limited. They are suitable only for certain geological and technical conditions of wells.

To eliminate these shortcomings, a new device is needed with the arrangement of equipment in it in the form of separate units, blocks, instruments, etc., with appropriate design and functional connections, including means for monitoring, regulating and measuring the characteristics of reagents before they are supplied to the reservoir after preliminary determination of its acceptability.

The purpose of the claimed invention is based on these requirements. We need a more efficient and safe technology for selecting, mixing chemical reagents and feeding them into the formation to increase its oil recovery using a compact mobile unit specially designed for this.

The essence of the claimed invention is illustrated by graphic material (Fig. 1). A general view of the mobile installation is shown in Fig. 2.

The goal is achieved by the fact that in the known method of increasing oil recovery using equipment that has units for storing, preparing and supplying process water, bulk and liquid chemical reagents into the well, what is new is that to enhance the oil recovery effect, an installation of of individual units, determine the injectivity of the well and its operating mode, bring the installation to the reagent injection mode, for which process water is supplied from the reservoir pressure maintenance system through the process water pipeline with its flow into an adjustable jet apparatus, which is connected to the preparation tank with a mechanical stirrer of the unit preparation and mixing, from which a solution of chemical reagents is supplied to the liquid injection pump through a pipeline through a density meter and gate valves, while bulk chemical reagents are supplied from two hoppers through spring screw dispensers and a pipeline into an adjustable jet apparatus, and additionally a bulk chemical reagent is supplied from the third bunker via a vertical auger directly into the preparation container, at the output of which the density of the solution of chemical reagents is determined; liquid chemical reagents are also additionally supplied through a loading pump into two containers, from which, through filters for removing mechanical impurities by dosing pumps, the reagents are supplied to the inlet of the liquid injection pump and into a discharge pipeline containing a check valve, vibration-proof and electrical contact pressure gauges and an automatic safety valve, wherein the first dosing pump is connected to a pipeline located at the outlet of the preparation vessel, and the second dosage pump is connected to the discharge pipeline, with the help of a liquid injection pump , the specified chemical reagents are pumped into the well through an injection pipeline, after which the solution of chemical reagents is pressed with industrial water using the energy of the formation pressure maintenance system and the injectivity of the well is determined.

In the known installation for enhancing oil recovery using equipment, including units for storing, preparing and supplying process water, bulk and liquid chemicals into the well, what is new is that, to enhance the effect of oil recovery, the installation consists of separate units mounted in a van of an all-wheel drive vehicle, and has a pipeline for supplying process water from the system for maintaining reservoir pressure into the well, a pressure gauge and a flow meter installed in series, configured to determine the injectivity of the well and its operating mode and to enable the installation to enter the reagent injection mode, and connected to an adjustable jet apparatus and an injection pipeline through a pipeline for pushing a solution of chemical reagents with industrial water, a preparation and mixing unit containing a preparation tank with a mechanical stirrer, a liquid injection pump connected by its inlet to the specified tank for preparing the chemical reagent and the outlet to a discharge pipeline, including a sequentially installed automatic safety valve, vibration-resistant and electric contact pressure gauges, a faucet and a check valve, the first unit for dosing and supplying bulk chemical reagents into an adjustable jet apparatus, which is connected to the container of the preparation unit, and the first unit for dosing and supplying bulk chemical reagents consists of two hoppers with spring screw dispensers connected by a pipeline to capacity of the preparation unit through an adjustable jet apparatus, a second unit for dosing and supplying bulk chemical reagents to the preparation container, consisting of a hopper and a vertical screw, a unit for dosing and supplying liquid chemical reagents, including a loading pump connected to two containers through taps, mechanical cleaning filters impurities connected by inputs to the indicated containers and outputs to dosing pumps, with the first dosing pump connected to the output pipeline of the chemical reagent preparation tank, and the second dosing pump connected by a pipeline with a tap and check valve installed in series with the discharge pipeline.

If the installation is located in a car van, then the fluid injection pump is driven by a power take-off from the chassis engine with a rigid connection by cardan shafts. It is possible to use a hydraulic drive. The installation can be located in a trailer van. In this case, the drive of the liquid injection pump is an electric drive, a hydraulic drive or an internal combustion engine.

A detailed description of the operation of the installation with references to Fig. 1.

Designations for Fig. 1:

1 - preparation tank, 2 - mechanical stirrer, 3 - process water pipeline, 4 - flow meter, 5, 28, 31, 35, 36, 37, 39, 44 - taps, 6 - pressure gauge, 7 - adjustable jet device, 8, 23, 33 - pipelines, 9, 10 - spring screw dispensers, 11, 12, 13 - hoppers, 14 - vertical auger, 15 - first dosing pump, 16 - second dosing pump, 17, 18 - filters, 19 - loading pump, 20, 21 - containers for liquid chemicals, 22 - liquid injection pump, 24 - discharge pipeline, 25 - automatic safety valve, 26 - vibration-resistant pressure gauge, 27 - electric contact pressure gauge, 29, 32 - check valves, 30, 34 pipelines, 38 - density meter, 40, 41, 42 - gate valves, 43 - circulation pipeline.

The order of work is as follows.

The injectivity and operating mode of the well are determined by passing process water from the formation pressure maintenance system through the process water pipeline 3 through the flow meter 4, valve 35 and pipeline 34 into the injection pipeline 24 and further into the well.

The installation is brought to the operating injection mode by entering process water from the system for maintaining reservoir pressure into the installation through a process water pipeline 3 with an installed pressure gauge 6 through a flow meter 4 indicating the instantaneous fluid flow to regulate the precise supply of bulk and liquid reagents. Next, through tap 5, process water is supplied to an adjustable jet device 7, which allows you to regulate the flow of liquid and the suction power of bulk chemicals without stopping, after which the dosing equipment is fine-tuned.

Bulk reagents are supplied simultaneously to the receiving jet apparatus 7 from the first dosing unit through two hoppers 11 and 12 by spring screw dispensers 9 and 10 through pipeline 8, the mixture is fed into the preparation tank 1 with a mechanical stirrer 2.

The dosage and supply of the bulk reagent from the second dosing unit is carried out from the hopper 13 along a vertical screw 14 into container 1 with a mechanical stirrer 2. Next, the multicomponent solution is fed into the liquid injection pump 22 through pipeline 23 through gate valves 40 and 41 and a density meter 38, which allows determining the density reagent solution.

Using a loading pump, liquid reagents are supplied through taps 36 and 37 into containers for liquid reagents 20 and 21. Then from container 20 through filter 17 by the first dosing pump 15 into pipeline 33, connected through tap 39 to pipeline 23. From the second container 21 through filter 18 The second dosing pump 16 supplies liquid reagents through pipeline 30 through tap 31 and check valve 32 directly into the discharge pipeline 24.

The second dosing pump 16 also makes it possible to supply liquid reagents directly into the well without operating the liquid injection pump 22.

Using a liquid injection pump 22, a multicomponent solution is pumped into the well through an injection pipeline 24 equipped with an automatic safety valve 25, which is activated at the maximum permissible injection pressure and automatically returns to its operating position, a tap 28, a check valve 29, a vibration-resistant pressure gauge 26 and an electric contact pressure gauge 27 , which allows you to turn off the installation when the pressure is exceeded.

After pumping the multicomponent solution, it is forced with technical water from the formation pressure maintenance system through the technical water pipeline 3 through the flow meter 4, valve 35 and pipeline 34 into the injection pipeline 24 and further into the well. The final injectivity of the well is determined.

Provision is made for the selection of a multicomponent solution from the preparation tank 1 into an external mobile pumping unit and the intake of liquid through a gate valve 42 from the external tank, followed by pumping it into the well by a liquid injection pump 22.

Increasing the efficiency of oil recovery using the proposed reliable and safe technology and new equipment is achieved:

- due to its use in a continuous rather than cyclic mode;

- the use of non-explosive chemical reagents, for example, water-soluble, water-swellable polyacrylamides, polyoxyl chlorides, wood flour, calcium chloride and others;

- expansion of the design capabilities of the installation to establish certain installation modes with control of its operation (11 additional units were used compared to the prototype);

- creation of functional interactions of individual units of existing equipment, allowing the successful use of the method, i.e. correctly select the concentrations of the selected reagents during their preparation, further mixing and feeding into the reservoir with process water;

- the ability to determine the injectivity of the formation, which determines the operating modes of the installation.

Example of implementation of the invention

Using the method and the corresponding equipment (mobile unit), the injectivity of the well and its operating mode are determined, stored, mixed, and then simultaneously supplied dry mixtures and liquid reagents to the selected well in the required concentrations. Polyacrylamides, chromium acetate, clay powder and a surfactant are used as reagents. Ultimately, the reagents are injected into the well with technical water using a system for maintaining formation pressure and re-determining the injectivity of the formation.

As a result of using the method and installation, oil recovery from the injection well reservoir is increased.

The proposed technology and installation are recommended for any oil-producing regions.

Claims (2)

1. A method for increasing oil recovery using equipment that has units for storing, preparing and supplying process water, bulk and liquid chemicals into a well, characterized in that to enhance the oil recovery effect, an installation of separate units is placed in the van of an all-wheel drive vehicle, the injectivity of the well is determined and its operating mode, the installation enters the reagent injection mode, for which process water is supplied from the formation pressure maintenance system through a process water pipeline with its flow into an adjustable jet apparatus, which is connected to the preparation tank with a mechanical stirrer of the preparation and mixing unit, from which the solution chemical reagents are supplied to the liquid injection pump through a pipeline through a density meter and gate valves, while bulk chemical reagents are supplied from two hoppers through spring screw dispensers and a pipeline into an adjustable jet apparatus, and additionally, bulk chemical reagents are supplied from the third hopper via a vertical screw directly to the preparation container, at the output of which the density of the solution of chemical reagents is determined; also, through a loading pump, liquid chemical reagents are supplied into two containers, from which, through filters for removing mechanical impurities by dosing pumps, the reagents are supplied to the inlet of the liquid injection pump and into the discharge pipeline containing a check valve , vibration-resistant and electric contact pressure gauges and an automatic safety valve, wherein the first dosing pump is connected to a pipeline located at the outlet of the preparation tank, and the second dosing pump is connected to the injection pipeline, while using the liquid injection pump, the specified chemical reagents are pumped into the well along the injection pipeline, after which the solution of chemical reagents is pressed with industrial water using the energy of the reservoir pressure maintenance system and the well's injectivity is determined. 2. An installation for enhancing oil recovery, including units for storing, preparing and supplying process water, bulk and liquid chemicals into a well, characterized in that, to enhance the effect of oil recovery, the unit consists of separate units mounted in a four-wheel drive van, and has a pipeline for supplying technical water from the system for maintaining reservoir pressure into the well, a pressure gauge and a flow meter installed in series, configured to determine the injectivity of the well and its operating mode and to enable the installation to enter the reagent injection mode, and connected to an adjustable jet apparatus and an injection pipeline through a pipeline for pushing the solution chemical reagents with industrial water, a preparation and mixing unit containing a preparation tank with a mechanical stirrer, a liquid injection pump connected by its inlet to the specified tank for preparing the chemical reagent and the outlet to a discharge pipeline, including a sequentially installed automatic safety valve, vibration-resistant and electric contact pressure gauges, a tap and a check valve, the first unit for dosing and supplying bulk chemical reagents into an adjustable jet apparatus, which is connected to the container of the preparation unit, and the first unit for dosing and supplying bulk chemical reagents consists of two hoppers with spring screw dispensers connected by a pipeline to the capacity of the preparation unit through an adjustable jet apparatus, a second unit for dosing and supplying bulk chemical reagents to the preparation tank, consisting of a hopper and a vertical screw, a unit for dosing and supplying liquid chemical reagents, including a loading pump connected to two containers through taps, filters for removing mechanical impurities, connected by inputs to the indicated containers and outlets with dosing pumps, while the first dosing pump is connected to the output pipeline of the chemical reagent preparation tank, and the second dosing pump is connected by a pipeline with a tap and check valve installed in series with the discharge pipeline.