CN108386173B - Underground dosing device and method for foam drainage gas production process - Google Patents

Abstract

The invention discloses a downhole drug dosing device and method for foam drainage and gas recovery technology. The device mainly consists of a drug storage tank, a liquid phase capillary, an injection pump, a liquid phase flow control valve, a liquid flow meter, a liquid phase Check valve, nitrogen gas source, compressor, gas storage tank, gas phase capillary, gas flow meter, gas phase flow control valve, gas phase check valve, tubing, casing and downhole agitator, the downhole agitator is mainly composed of bearings , outer rotating blade, power hole, mixing chamber, inner rotating blade and agitator cylinder. The method includes: determining the filling flow rate of the foaming agent and nitrogen; opening the nitrogen supply system; opening the foaming agent supply system; and dynamically adjusting the filling flow rate of the foaming agent and nitrogen. The invention can control the agitation strength of the downhole agitator by adjusting the nitrogen injection rate, and can effectively enhance the foaming effect especially for gas wells with too low gas production, thereby improving the foam drainage efficiency and application range.

Description

A downhole dosing device and method for foam drainage and gas recovery technology

technical field

The invention relates to a foam drainage gas recovery technology in the field of natural gas exploitation, in particular to an downhole dosing device and method for foam drainage gas recovery.

Background technique

During the development of gas reservoirs, as the gas is produced, the formation pressure continues to drop, and the gas production rate will also gradually decrease, eventually causing the gas to be unable to bring the liquid out of the wellbore, resulting in bottomhole fluid accumulation. Injecting foaming agent into the wellbore is an economical and effective drainage and gas recovery process, which is called foam drainage. In this process, the liquid accumulated in the wellbore forms a foam under the agitation of the produced gas by injecting a foaming agent, thereby reducing the density of the mixture and discharging the bottom-hole fluid.

The effective generation of a large amount of foam is the decisive factor in determining the effect of the foam drainage gas recovery process, and the generation of a large amount of foam requires mixing the foam discharge agent with the bottom hole fluid and fully stirring with the natural gas produced from the formation. There are currently several approaches to increasing the efficiency of foam generation. The capillary injection method used in the patent application with application number 201210215258.4 "A Liquid Foaming Agent Injection Method" and the patent application with application number 201310199496.5 "A device and method for automatic dosing under foam drainage and gas recovery wells" can directly inject foam The drainage agent is injected below the liquid level of the effusion to make it more fully contact with the bottom hole effusion. The agitator used in the patent application "A Cohesive Foam Drainage Agitator" with application number 201510295693.6 relies on the output gas to drive the blades to rotate to increase gas-liquid agitation. These methods can improve the foaming effect to a certain extent, but the mixing degree of the foaming agent and the bottomhole fluid and the gas-liquid stirring intensity are completely determined by the gas production rate, and ground operators cannot control it. For gas wells with too low gas production, bubble flow occurs below the liquid accumulation surface, and the produced gas is not sufficiently stirred to form a large number of bubbles.

The purpose of the patent of this invention is to overcome the deficiencies of the existing foam drainage and gas recovery technology, and provide an downhole dosing device which can fully mix the foam drainage agent and the bottom well liquid and improve the gas-liquid stirring intensity in gas wells with too low gas production. method.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies existing in the existing foam drainage gas recovery technology, and provide a downhole dosing device for the foam drainage gas recovery process, aiming at simultaneously solving the problem of uneven mixing of injection foam drainage agent and bottom fluid accumulation and gas Insufficient agitation of the solution. In order to achieve the above technical objectives, the present invention provides the following technical solutions.

The present invention is an underground dosing device for foam drainage and gas recovery process, which mainly consists of a medicine storage tank, a liquid phase capillary, an injection pump, a liquid phase flow control valve, a liquid flow meter, a liquid phase check valve, a nitrogen gas source, Composed of compressor, gas storage tank, gas phase capillary, gas flow meter, gas phase flow control valve, gas phase check valve, tubing, casing and downhole agitator.

The drug storage tank is sequentially connected in series with the injection pump, the liquid flow meter, the liquid flow control valve and the liquid check valve by means of the liquid phase capillary to form a foam discharge agent supply system; the nitrogen gas source is sequentially connected with the compressor, A gas storage tank, a gas flow meter, a gas phase flow control valve and a gas check valve are connected in series to form a nitrogen gas supply system; the liquid phase capillary is bundled with the gas phase capillary and is lowered from the wellhead to the bottom of the well through the tubing, upstream of the bottom well agitator The liquid-phase capillary is connected to the gas-phase capillary; the downhole agitator is mainly composed of a bearing, an outer rotating blade, a power hole, a mixing chamber, an inner rotating blade and an agitator cylinder; the gas-phase capillary is connected to the bearing by spot welding Sealed connection.

The mixing chamber provides a space for the gas-phase capillary to fully mix the foaming agent and nitrogen to improve the mixing degree of the gas-liquid two-phase; there are 6 external rotating blades, which are evenly connected to the gas-phase capillary by spot welding. The outer side of the agitator cylinder; there are 4 inner rotating blades in total, which are evenly connected to the inner side of the agitator cylinder by spot welding. The position corresponds to the adaptation of the inner rotating blade.

A downhole dosing method of the foam drainage gas recovery process of the present invention comprises the following steps: 1. Determine the injection flow rates of the foam drainage agent and nitrogen according to the production conditions such as the oil casing pressure difference and the gas production rate of the gas well; 2. Turn on the compressor , adjust the gas phase flow control valve to adjust the nitrogen flow to the required filling flow of the gas well; 3. Turn on the injection pump, adjust the liquid phase flow control valve to adjust the foam discharge agent flow to the required filling flow of the gas well; 4. According to the production situation of the gas well Dynamically adjust the injection flow rate of the foaming agent and nitrogen until the liquid in the gas well is completely discharged.

The invention overcomes the deficiencies of the prior art and provides an downhole drug dosing device used in the foam drainage and gas recovery process, which can fully mix the foam drainage agent and bottom well fluid, and increase the liquid discharge per unit volume of the foam drainage agent. At the same time, according to the degree of liquid accumulation in the gas well, the stirring intensity can be artificially controlled by injecting nitrogen on the ground to improve the injection effect of the foaming agent. Especially for gas wells with low gas production, it can effectively improve the production efficiency and application of the foam drainage gas recovery process. scope.

Description of drawings

Fig. 1 is a kind of structural representation of the downhole dosing device and method for foam drainage and gas recovery technology in the present invention;

Fig. 2 is a schematic structural diagram of the downhole mixer of the present invention.

In the figure: 1. Storage tank, 2. Injection pump, 3. Liquid flow meter, 4. Liquid phase flow control valve, 5. Liquid phase check valve, 6. Nitrogen gas source, 7. Compressor, 8. Storage Gas tank, 9. Gas flow meter, 10. Gas phase flow control valve, 11. Gas phase check valve, 12. Liquid phase capillary tube, 13. Gas phase capillary tube, 14. Casing tube, 15. Oil pipe, 16. Fluid level, 17. Downhole agitator, 17-1. Bearing, 17-2. Outer rotating blade, 17-3. Power hole, 17-4. Mixing chamber, 17-5. Inner rotating blade, 17-6. Agitator barrel body.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

As shown in Figure 1 and Figure 2, wherein, Figure 1 is a structural schematic diagram of the downhole dosing device and method used in the foam drainage gas recovery process of the present invention; Figure 2 is a structural schematic diagram of the downhole agitator of the present invention.

The invention provides an downhole dosing device for foam drainage and gas recovery process, which mainly consists of a medicine storage tank 1, a liquid phase capillary 12, an injection pump 2, a liquid flow meter 3, a liquid phase flow control valve 4, a liquid phase single flow Valve 5, nitrogen gas source 6, compressor 7, gas storage tank 8, gas phase capillary tube 13, gas flow meter 9, gas phase flow control valve 10, gas phase check valve 11, casing 14, tubing 15 and downhole agitator 17 .

The drug storage tank 1 is connected in series with the injection pump 2, the liquid flow control valve 3, the liquid flow meter 4 and the liquid check valve 5 in sequence by means of the liquid phase capillary 12 to form a foam discharge agent supply system; the nitrogen gas source 6 relies on The gas phase capillary 13 is connected in series with the compressor 7, the gas storage tank 8, the gas flowmeter 9, the gas phase flow control valve 10 and the gas check valve 11 in sequence to form a nitrogen gas supply system; the liquid phase capillary 12 and the gas phase capillary 13 are bundled and pass through The tubing 12 is lowered from the wellhead to the bottom of the well; the liquid-phase capillary 12 communicates with the gas-phase capillary 13 and communicates with the bottom-hole agitator upstream, so that the foaming agent and nitrogen form a common channel and are injected into the downhole agitator 17 together; the downhole The agitator 17 is mainly composed of a bearing 17-1, an outer rotating blade 17-2, a power hole 17-3, a mixing chamber 17-4, an inner rotating blade 17-5 and an agitator cylinder 17-6; the gas phase capillary 13 and the bearing 17-1 are sealed and connected by spot welding.

The mixing chamber 17-4 provides a space for the gas-phase capillary 13 to fully mix the foaming agent and nitrogen to improve the mixing degree of the gas-liquid two-phase; the outer rotating blades 17-2 are 6 in total, passing through The welding method is evenly connected to the outside of the agitator cylinder; the inner rotating blades 17-5 are 4 in total, which are evenly connected to the inside of the agitator cylinder by spot welding, and the rotation direction of the blades is the same as that of the outer rotation blades. On the contrary; there are four power holes 17-3 in total, and their positions are adapted and corresponding to the inner rotating blades 17-5. The downhole dosing method of a kind of foam drainage gas recovery process of the present invention comprises the following steps: 1. respectively determine the filling flow rate of foam discharge agent and nitrogen according to production conditions such as gas well oil casing pressure difference and gas production; 2. Open compressor 6, Adjust the gas phase flow control valve 10 to adjust the nitrogen flow to the injection flow required by the gas well; ③ turn on the injection pump 2, adjust the liquid phase flow control valve 4 to adjust the flow of the foaming agent to the injection flow required by the gas well; ④ change according to the production of the gas well If the situation is different, dynamically adjust the injection flow rate of the foaming agent and nitrogen until all the liquid in the gas well is discharged.

Compared with the shortcoming and deficiency of prior art, the beneficial effect of the present invention is:

1) Nitrogen injection can increase the downhole gas flow rate of gas wells with low gas production, thereby increasing the degree of gas-liquid agitation and improving the foaming effect; 2) The mixing chamber can use nitrogen injection to disperse the foaming agent, and inject nitrogen and gas under the action of injection pressure The mixed fluid of the foaming agent can pass through the power hole at high speed and hit the inner rotating blade, and then the foaming agent is more dispersed and evenly mixed with the bottom hole fluid.

3) The inner rotating blade drives the downhole agitator to rotate under the impact of the injected mixed fluid, and the outer rotating blade can fully agitate the bottomhole fluid, produced gas, injected foaming agent and nitrogen, so as to achieve the best foaming effect.

Claims (1)

1. A downhole dosing device for foam drainage and gas recovery technology, characterized in that it mainly consists of a medicine storage tank, a liquid phase capillary, an injection pump, a liquid phase flow control valve, a liquid flow meter, a liquid phase check valve, Nitrogen gas source, compressor, gas storage tank, gas phase capillary, gas flow meter, gas phase flow control valve, gas phase check valve, tubing, casing and downhole mixer, of which: The drug storage tank is sequentially connected in series with the injection pump, the liquid flow meter, the liquid flow control valve and the liquid check valve by means of the liquid phase capillary to form a foam discharge agent supply system; The nitrogen gas source is connected in series with the compressor, the gas storage tank, the gas flow meter, the gas phase flow control valve and the gas check valve sequentially by means of the gas phase capillary to form a nitrogen supply system; The downhole agitator is mainly composed of a bearing, an outer rotating blade, a power hole, a mixing chamber, an inner rotating blade and an agitator cylinder; The liquid-phase capillary is bundled with the gas-phase capillary and lowered from the wellhead to the bottom of the well through the tubing, and the liquid-phase capillary is connected to the gas-phase capillary upstream of the downhole agitator; There are 6 outer rotating blades in total, which are evenly connected to the outside of the downhole mixer cylinder by spot welding; There are 4 power holes in total, and their positions correspond to those of the inner rotating blades; There are 4 inner rotating blades in total, which are evenly connected to the inner side of the agitator cylinder by spot welding, and the direction of rotation of the blades is opposite to that of the outer rotating blades; The mixing chamber provides a space for the gas-phase capillary to fully mix the foaming agent and nitrogen, so as to improve the mixing degree of the gas-liquid two-phase.

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