High-gas-liquid-ratio lifting method and device

Abstract

The invention discloses a high-gas-liquid-ratio lifting method and device. The lifting method comprises the steps that a production well is selected, and a gas anchor is installed; a remote control one-way valve is mounted on the wall of the oil pipe; a bottom gas flowmeter and a bottom pressure gauge are mounted at the bottom of the production well; a remote control one-way valve on the wall of the oil pipe is closed, and well bottom gas flow, well bottom pressure and oil production data are monitored; when the gas-liquid ratio of the production well exceeds a first set threshold value or the bottom hole pressure is lower than a second set threshold value of saturation pressure, the remote control one-way valve on the oil pipe wall is opened, and annular gas enters the oil pipe; when the bottom hole pressure rises to a third set threshold value of the original formation pressure or the gas-liquid ratio decreases and is lower than a fourth set threshold value, the remote control one-way valve on the oil pipe wall is closed; and monitoring production parameters, and repeatedly executing the steps of starting the separated gas auxiliary lifting and closing the separated gas auxiliary lifting. And lifting is assisted through separated gas, the annulus pressure of an oil pipe and an oil sleeve is balanced, and safe lifting of a high-gas-liquid-ratio well is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield exploitation, and in particular relates to a high gas-liquid ratio lifting method and device. Background Art

[0002] During oil production, production wells often experience high gas-liquid ratios (GLRs). There are two main reasons for this high GLR. First, as volatile oil reservoirs deplete, the formation's supply capacity gradually decreases. As formation pressure gradually falls below saturation pressure, crude oil in the near-wellbore region and the wellbore begins to degas, leading to an increase in the GLR. Second, with the increasing application of new gas injection flooding technologies such as CO2 flooding, oxygen-reduced air flooding, and air-thermal miscible flooding, formation heterogeneity can lead to localized gas breakthroughs during the gas injection flooding process, similarly increasing the GLR in the wellbore. For high-GLR production wells, both gas and liquid phases are always pumped simultaneously during the pumping process. This gas inflow inevitably reduces the amount of liquid entering the pump, thereby reducing the pump's fill factor and efficiency. Severe gas effects can even lead to "gas lock," whereby the compression and expansion of gas within the pump during pumping prevents the pump's intake and discharge valves from opening properly, resulting in a loss of oil.

[0003] Based on this background, the lifting process problems caused by the high gas-liquid ratio have gradually become a technical difficulty that needs to be overcome urgently on site. In response to the high gas content in oil wells, the main solution at present is the use of anti-air pumps and gas-liquid separators (air anchors). During the application process, the anti-air pump has problems such as low volumetric efficiency, easy damage to the plunger part, complex structure, high production costs, and short service life. According to the statistics of the field application effect, gravity-type air anchors are only suitable for oil production in production wells with low production, while spiral air anchors are not suitable for production conditions with high wax deposition and sand production. The oil wells on site have complex production conditions and high lifting costs, and it is necessary to study and optimize the lifting methods to address this problem. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of low pump efficiency and high lifting cost in the lifting process of existing oil production technology, and at the same time reduce the difficulty of processing the gas produced by high gas-liquid ratio production wells.

[0005] In view of the above problems, the present invention discloses a high gas-liquid ratio lifting method, comprising the following steps:

[0006] Select production wells and install gas anchors;

[0007] A remote-controlled one-way valve is installed on the oil pipe wall, and a bottom-hole gas flow meter and a bottom-hole pressure gauge are installed at the bottom of the production well;

[0008] At the beginning of production, the remote-controlled one-way valve on the tubing wall is closed, and the bottomhole gas flow, bottomhole pressure, and oil production data are monitored;

[0009] Start separation gas assisted lifting: When the gas-liquid ratio of the production well exceeds the first set threshold, or the bottom hole pressure is lower than the second set threshold of the saturation pressure, the remote-controlled one-way valve on the tubing wall is opened to allow the annular gas to enter the tubing;

[0010] Close separation gas-assisted lift: When the bottomhole pressure rises to the third set threshold of the original formation pressure or the gas-liquid ratio decreases to below the fourth set threshold, the remote-controlled one-way valve on the tubing wall is closed, and production is carried out by relying on the gas anchor and rod pump;

[0011] Monitor production parameters and repeat the steps of starting the separation gas assisted lift and shutting down the separation gas assisted lift.

[0012] Furthermore, the specific steps of selecting a production well are as follows:

[0013] Select a gas-liquid ratio greater than 100m 3 / m 3 production wells.

[0014] Furthermore, the remote-controlled one-way valve is 100 to 500 meters away from the wellhead.

[0015] Furthermore, the first set threshold value ranges from 500 to 1000m 3 / m 3 .

[0016] Furthermore, the second set threshold value ranges from 80% to 100%.

[0017] Furthermore, the third set threshold value ranges from 100% to 120%.

[0018] Furthermore, the fourth threshold value is in the range of 200 to 500 m. 3 / m 3 .

[0019] The present invention also discloses a high gas-liquid ratio lifting device based on the above-mentioned high gas-liquid ratio lifting method, comprising: casing, oil pipe, remote-controlled one-way valve, rod pump, bottom hole gas flow meter, gas anchor, bottom hole pressure gauge, one-way valve, drillable bridge plug and oil layer;

[0020] The oil pipe is arranged in the casing;

[0021] The remote control one-way valve is arranged on the wall of the oil pipe;

[0022] The rod pump is arranged in the oil pipe;

[0023] The air anchor is installed on the oil pipe and is located at the bottom of the well;

[0024] The bottom hole gas flow meter is arranged at the bottom of the well and is located above the gas anchor;

[0025] The bottom hole pressure gauge is arranged at the bottom of the well and below the air anchor;

[0026] The one-way valve is arranged at the bottom end of the oil pipe;

[0027] The drillable bridge plug is arranged between the oil pipe and the casing and below the air anchor;

[0028] The casing extends into the oil layer.

[0029] Furthermore, it also includes: remote control host;

[0030] The remote control host is electrically connected to the remote control unidirectional valve.

[0031] Furthermore, it also includes: a data acquisition system;

[0032] The data acquisition system is connected to a bottom hole gas flow meter and a bottom hole pressure gauge respectively.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] 1. It can be applied to various types of high gas-liquid ratio production wells with different development methods and reservoir types to achieve efficient production of high gas-liquid ratio oil wells, effectively alleviate the difficulty of tail gas treatment in oilfield production, reduce costs, significantly increase single well production, and achieve cost reduction and efficiency improvement in oilfield production;

[0035] 2. The combined monitoring method of bottom hole and surface metering is used to accurately measure production parameters, solving the problem of gas production in production wells that cannot be measured, and providing a reliable basis for the next step of production control measures;

[0036] 3. Use remote control devices to control the connection between the tubing and the casing annulus, rationally utilize the gas energy produced by high gas-liquid ratio production wells, form gas-assisted lifting in the well, and achieve low-cost high gas-liquid ratio lifting;

[0037] 4. Through the separation gas assisted lifting circulation measures, the annular pressure of the tubing and casing is balanced, and the production wells with high gas-liquid ratio and high liquid production can be lifted safely and efficiently, which greatly improves the oil production capacity and no longer limits the liquid production of the production wells.

[0038] Other features and advantages of the present invention will be described in detail in the following description. The objectives and other advantages of the present invention can be realized and obtained through the structures indicated in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some application examples of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 Schematic diagram of a high gas-liquid ratio lifting device.

[0041] Figure numerals: 1. Remote control host; 2. Data acquisition system; 3. Remote control one-way valve; 4. Rod pump; 5. Bottom hole gas flow meter; 6. Gas anchor; 7. Bottom hole pressure gauge; 8. One-way valve; 9. Drillable bridge plug; 10. Oil layer. DETAILED DESCRIPTION

[0042] To make the implementation objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the application examples of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the application example solutions of the present invention, all other implementation solutions obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] High gas-liquid ratio: During the oil well production process, the associated gas produced by crude oil degassing and the gas medium injected into the formation by the oil reservoir recovery enhancement measures are produced from the oil well, resulting in a decrease in the oil well fluid volume, an increase in the gas-liquid ratio, and a poor production effect. 3 / m 3 All wells can be considered as high gas-liquid ratio wells.

[0044] Lifting: When the formation's natural energy is insufficient to sustain spontaneous flow, or when spontaneous flow is possible but the production rate falls short of expectations, mechanical equipment is lowered into the wellbore to work on the fluid, allowing it to flow to the surface. The preferred oil recovery method is often the choice of artificial lift.

[0045] In response to the high gas content in oil wells, the main solution at present is the design and application of anti-gas pumps and air anchors 6. The anti-gas pump processes mainly include the anti-gas rod pump process and the anti-gas electric submersible pump process. Both processes are locally optimized based on the original pump structure. At this stage, the more commonly used is the rod pump. On the one hand, the anti-gas pump can prevent the occurrence of gas locks when the gas content is very high, and on the other hand, it can improve the working efficiency of the pump when the gas content is not large. The basic gas separation principle of the air anchor (gas-liquid separator) 6 is based on the difference in oil and gas density. By designing different structures and using gravity or centrifugal force to separate oil and gas, the device can prevent free gas from reaching the pump inlet, thereby reducing gas interference and the occurrence of gas locks, and improving the working efficiency of the oil pump.

[0046] When the gas-liquid ratio is less than 1000m 3 / m 3 At present, only the anti-air pump is needed to meet the needs of on-site production. The strong opening and closing anti-air pump, the ring valve anti-air pump and the middle exhaust anti-air pump are the mainstream anti-air oil pumps. Under the condition of setting the economic pump efficiency of 45%, the gas-liquid ratio limits are 300, 190 and 230m3 respectively. 3 / m 3 , the middle annular space and variable diameter anti-air pump are suitable for 500m 3 / m 3 Among them, the ring valve anti-air pump can effectively alleviate the gas lock degree of the oil well and is applicable to a wide range of liquid volumes. The medium exhaust anti-air pump is limited by the length of the pump plunger and is suitable for production below 10m 3 / d oil well.

[0047] Gravity-type air anchors, which rely on the gravity slippage effect, are significantly affected by fluid velocity. The longer the separation process, the better the separation effect. Therefore, gravity air anchors are significantly affected by fluid velocity and separation chamber length. The longer the separation chamber, the slower the flow rate, and the better the separation effect. They are suitable for oil wells with low production capacity, low gas-liquid ratios, slow flow rates, and low crude oil viscosity. Spiral air anchors, which rely on centrifugal force for separation, are more adaptable than gravity air anchors and can accommodate a variety of displacements by changing the impeller.

[0048] When the gas-liquid ratio is greater than 1000m 3 / m 3 When using air-proof pumps alone, they cannot meet the production requirements of the oil field. For production wells with self-flowing ability, the self-flowing production method should be adopted as much as possible. For wells without self-flowing ability, it is generally necessary to use air anchors 6, air-proof pumps, and other flow-aiding lifting technologies in combination with production.

[0049] The present invention proposes a high gas-liquid ratio lifting method, comprising the following steps:

[0050] Step (1), selecting a production well, selecting a suitable air anchor 6 according to the production dynamics of the selected production well, and installing and testing the air anchor 6;

[0051] Step (2): Install a remote-controlled one-way valve 3 on the oil pipe wall, and install a bottom-hole gas flowmeter 5 and a bottom-hole pressure gauge 7 at the bottom of the production well;

[0052] Step (3), at the initial stage of production, the remote-controlled one-way valve 3 on the oil pipe wall is closed, and the gas anchor 6 is used to meet production needs; gas is produced from the annulus of the oil casing, and liquid is produced from the oil pipe. During the production process, the bottom hole gas flow, bottom hole pressure and oil production data are monitored in real time;

[0053] Step (4), starting the separation gas assisted lift: as production continues, when the gas-liquid ratio of the production well exceeds a first set threshold, or the bottom hole pressure is lower than a second set threshold of the saturation pressure, the remote-controlled one-way valve 3 on the oil pipe wall is opened by remote control, and the annular gas enters the oil pipe;

[0054] Based on the formation pressure and dissolved gas-oil ratio curve, the amount of crude oil degassing in the near-wellbore area at the current formation pressure is estimated. The amount of annular gas entering the tubing is approximately 0.9 to 1.2 times this value. This increases the pressure in the tubing, causing the lifting fluid to mix with the produced gas again, reducing the fluid density, thereby reducing stroke loss, reducing the elastic expansion and contraction of the sucker rod and tubing strings, and increasing the piston's free volume, thereby improving pump efficiency.

[0055] Step (5) closing the separation gas assisted lift: when the bottom hole pressure rises to the third set threshold value of the original formation pressure or the gas-liquid ratio decreases to below the fourth set threshold value, the remote controlled one-way valve 3 on the oil pipe wall is remotely closed, and production is carried out by relying on the gas anchor 6 and the rod pump 4;

[0056] Step (6): closely monitor the production parameters. When the gas-liquid ratio and the bottom hole pressure reach the corresponding standards in step (4), remotely control the opening of the remote-controlled one-way valve 3 on the oil pipe wall, and repeat steps (4) and (5) (i.e., repeatedly execute the steps of starting the separation gas assisted lifting and closing the separation gas assisted lifting).

[0057] The present invention proposes a high gas-liquid ratio lifting method, which is more comprehensive and practical. It uses bottom hole and ground metering and monitoring means to improve the production data collection of high gas-liquid ratio oil wells, uses separation gas to assist in lifting, optimizes the development process of high gas-liquid ratio oil wells, rationally utilizes the energy in the oil wells, alleviates the difficulty of tail gas treatment in oil field production, reduces costs, and further reduces the difficulty of exploiting high gas-liquid ratio oil wells, thereby achieving cost reduction and efficiency improvement.

[0058] When parameters such as pressure and gas volume reach certain values, the remote-controlled one-way valve 3 on the oil pipe wall is opened, and the gas separated in the oil casing annulus enters the oil pipe, providing a scientific and reliable basis for the reasonable design of the lifting process under high gas-liquid ratio conditions, while alleviating the problem of tail gas treatment in high gas-liquid ratio oil wells, and ultimately achieving safe, stable and efficient development of high gas-liquid ratio oil wells.

[0059] In some embodiments, the specific steps of selecting a production well are as follows:

[0060] Select a gas-liquid ratio greater than 100m 3 / m 3 production wells.

[0061] In some embodiments, the remote-controlled one-way valve 3 is located 100 to 500 meters from the wellhead. By setting the remote-controlled one-way valve 3 according to the above conditions, sufficient gas-liquid separation space and wellhead mixing space can be reserved.

[0062] In some embodiments, the first set threshold value ranges from 500 to 1000 m 3 / m 3 .

[0063] In some embodiments, the second set threshold value ranges from 80% to 100%.

[0064] In some embodiments, the third set threshold value ranges from 100% to 120%.

[0065] In some embodiments, the fourth set threshold value ranges from 200 to 500 m 3 / m 3 .

[0066] like Figure 1 As shown, based on the above-mentioned high gas-liquid ratio lifting method, the present invention also proposes a high gas-liquid ratio lifting device, comprising: casing, oil pipe, remote-controlled one-way valve 3, rod pump 4, bottom hole gas flow meter 5, gas anchor 6, bottom hole pressure gauge 7, one-way valve 8, drillable bridge plug 9 and oil layer 10;

[0067] The oil pipe is arranged in the casing;

[0068] The remote control one-way valve 3 is arranged on the wall of the oil pipe;

[0069] The rod pump 4 is arranged in the oil pipe;

[0070] The air anchor 6 is installed on the oil pipe and is located at the bottom of the well;

[0071] The bottom hole gas flow meter 5 is arranged at the bottom of the well and is located above the gas anchor 6;

[0072] The bottom hole pressure gauge 7 is arranged at the bottom of the well and is located below the air anchor 6;

[0073] The one-way valve 8 is arranged at the bottom end of the oil pipe;

[0074] The drillable bridge plug 9 is arranged between the oil pipe and the casing and is located below the air anchor 6;

[0075] The casing extends into the oil layer 10 .

[0076] Remote control one-way valve 3, used to control the connection between the oil pipe and the casing annulus;

[0077] Rod pump 4, used for production well lifting;

[0078] Bottom-hole gas flowmeter 5, used to monitor the gas production of the production well;

[0079] Air anchor 6, for 200-500m 3 / m 3 Gas-liquid ratio and bottom-hole gas-liquid separation;

[0080] A bottom hole pressure gauge 7, used to monitor the bottom hole pressure;

[0081] One-way valve 8, a safety gas injection device, is used to inject gas into the predetermined layer;

[0082] Drillable bridge plug 9, safety gas injection device.

[0083] Monitoring the increase in gas production as early as possible is the key to dealing with high gas-liquid ratio production wells. Therefore, the present invention utilizes a combination of bottom hole and ground metering and monitoring devices to achieve accurate measurement of production parameters such as gas production, oil production and bottom hole pressure, while the dynamic parameters obtained by measurement provide a reliable basis for control measures. Gas-liquid separation devices such as gas anchors 6 are installed at the bottom of the well to perform gas-liquid separation. This method utilizes a combination of small holes on the oil pipe wall and a remote-controlled one-way valve 3 to re-inject an appropriate amount of gas in the casing annulus into the oil pipe, further optimize the lift, rationally utilize the gas energy in the oil well, and improve the oil well recovery rate. At the same time, it reduces the difficulty of tail gas treatment in oil wells with high gas-liquid ratios and reduces costs.

[0084] In some embodiments, the high gas-liquid ratio lifting device further includes: a remote control host 1;

[0085] The remote control host 1 is electrically connected to the remote control one-way valve 3.

[0086] The remote control host 1 can accurately control the opening or closing of the remote control one-way valve 3 according to the gas flow detected by the bottom hole gas flow meter 5 and the bottom hole pressure detected by the bottom hole pressure gauge 7, as well as the surface oil production, and make the best lifting method selection more quickly according to the actual production conditions of the production well.

[0087] In some embodiments, the high gas-liquid ratio lifting device further includes: a data acquisition system 2;

[0088] The data acquisition system 2 is connected to the bottom hole gas flow meter 5 and the bottom hole pressure gauge 7 respectively.

[0089] The data acquisition system 2 is used to collect bottom hole gas flow and bottom hole pressure.

[0090] Application Examples

[0091] In an air injection test area in Jilin, the target layer is buried at a depth of 2850m, with an effective thickness of 15m, a permeability of 1-5mD, a porosity of 13.2%, a formation temperature of 85-105℃, and an underground crude oil viscosity of 2mPa.s. One gas injection well and five first-line production wells are deployed, with a spacing of 120-180m between the injection and production wells. The production wells are fracturing and put into production, and the early stage of depletion is converted to development. The current test formation pressure is 17MPa. The ventilation and sealing string is converted to air injection development. A remote-controlled one-way valve 3 is installed on the oil pipe wall 500m below the wellhead. An underground gas injection production anti-air pump is equipped. The maximum stable production gas-liquid ratio is tested at 500-800m. 3 / m 3 .

[0092] (1) In the initial stage of production, the gas injection volume of the gas injection well is 15000m 3 / d, single well liquid production 3~5m 3 / d, gas production 200~500m 3 / d, at this time, the remote controlled one-way valve 3 on the oil pipe wall is closed for production; (2) As the thermal oxidation front advances steadily, the injection-production displacement relationship is established, and the liquid production rate increases by 5-8m 3 / d, at this time the production well with the largest gas production is 3500m 3 / d or more, gas-liquid ratio 600~750m 3 / m 3 (The first threshold is set to 500m 3 / m 3 ), approaching the rated stable production index of gas anchor 6, serious leakage occurred in the production well, the pump efficiency decreased, and the development effect was affected; (3) According to the downhole monitoring data, the separation gas assisted lifting was started, and the remote control one-way valve 3 on the oil pipe wall was opened. The annular separation gas entered the oil pipe to assist in stable production. After the implementation of the measures, the highest single well liquid production in the main sand body direction reached 15.6m 3 / d, gas production is stable at 2500~4500m 3 / d, greatly improving pump efficiency and significantly increasing production; (4) Wait for the gas-liquid ratio to stabilize at 500m 3 / m 3 Next, close the remote control one-way valve 3 and collect downhole data for adjustment in the next stage.

[0093] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the exemplary technical solutions of the present invention.

Claims

1. A high gas-liquid ratio lifting method, characterized in that: The following steps are involved: Select a production well and install an air anchor (6); A remote-controlled one-way valve (3) is installed on the wall of the oil pipe, and a bottom-hole gas flow meter (5) and a bottom-hole pressure gauge (7) are installed at the bottom of the production well; At the beginning of production, the remote controlled one-way valve (3) on the oil pipe wall is closed, and the bottom hole gas flow, bottom hole pressure and oil production data are monitored; Start separation gas assisted lifting: when the gas-liquid ratio of the production well exceeds a first set threshold, or the bottom hole pressure is lower than a second set threshold of the saturation pressure, open the remote controlled one-way valve (3) on the oil pipe wall to allow the annular gas to enter the oil pipe; Close separation gas assisted lifting: when the bottom hole pressure rises to the third set threshold of the original formation pressure or the gas-liquid ratio decreases to below the fourth set threshold, close the remote controlled one-way valve (3) on the oil pipe wall and rely on the gas anchor (6) and the rod pump (4) for production; Monitor production parameters and repeat the steps of starting the separation gas assisted lift and shutting down the separation gas assisted lift.

2. The high gas-liquid ratio lifting method according to claim 1, characterized in that: The specific steps of selecting a production well are as follows: Select a gas-liquid ratio greater than 100m 3 / m 3 production wells.

3. The high gas-liquid ratio lifting method according to claim 1, characterized in that: The remote controlled one-way valve (3) is 100 to 500 meters away from the wellhead.

4. The high gas-liquid ratio lifting method according to claim 1, characterized in that: The value range of the first set threshold is 500~1000m 3 / m 3 .

5. The high gas-liquid ratio lifting method according to claim 1, characterized in that: The second set threshold value ranges from 80% to 100%.

6. The high gas-liquid ratio lifting method according to claim 1, characterized in that: The third set threshold value ranges from 100% to 120%.

7. The high gas-liquid ratio lifting method according to claim 1, characterized in that: The fourth threshold value range is 200-500m 3 / m 3 .

8. A high gas-liquid ratio lifting device based on the high gas-liquid ratio lifting method according to any one of claims 1 to 7, characterized in that: include: Casing, oil pipe, remote control one-way valve (3), rod pump (4), bottom hole gas flow meter (5), gas anchor (6), bottom hole pressure gauge (7), one-way valve (8), drillable bridge plug (9) and oil layer (10); The oil pipe is arranged in the casing; The remote control one-way valve (3) is arranged on the wall of the oil pipe; The rod pump (4) is arranged in the oil pipe; The air anchor (6) is installed on the oil pipe and is located at the bottom of the well; The bottom hole gas flow meter (5) is arranged at the bottom of the well and is located above the gas anchor (6); The bottom hole pressure gauge (7) is arranged at the bottom of the well and is located below the air anchor (6); The one-way valve (8) is arranged at the bottom end of the oil pipe; The drillable bridge plug (9) is arranged between the oil pipe and the casing and is located below the air anchor (6); The casing extends into the oil layer (10).

9. The high gas-liquid ratio lifting device according to claim 8, characterized in that: Also includes: Remote control host (1); The remote control host (1) is electrically connected to the remote control one-way valve (3).

10. The high gas-liquid ratio lifting device according to claim 8, characterized in that: Also includes: Data acquisition system (2); The data acquisition system (2) is connected to a bottom hole gas flow meter (5) and a bottom hole pressure meter (7) respectively.

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