Three-phase metering method based on direct measurement of non-eccentric oil wells

Abstract

The present invention provides a three-phase metering method based on direct measurement of non-eccentric oil wells. The specific steps are as follows: Place the serpentine fully flexible logging instrument inside the annular space, pass the cable through the bidirectional gooseneck guide and connect it to the ground acquisition remote control measuring instrument. Lower the serpentine fully flexible logging instrument to the target depth, and combine the measured pressure data to calculate the liquid level height under the oil well in real time. Lower the liquid level in the well below the target depth by accelerating the movement speed of the sucker rod. Stop the action of the sucker rod, and an oil-water interface is formed under the action of gravity differentiation. Record the time, pressure, and temperature when the oil-water interface passes through each oil-water interface sensor, and calculate the production of the oil, gas, and water phases respectively. The present invention directly measures the oil-water interface, pressure, and temperature of the oil well through the serpentine fully flexible logging instrument, meets the measurement requirements of oil wells with non-eccentric wellhead configurations, has a wide range of applications, and can provide technical support for increasing the efficiency of oil fields.

Description

Technical Field

[0001] The present invention relates to the technical field of oil extraction, and relates to an oil well test metering technology, and particularly relates to a three-phase metering method based on direct measurement of an eccentric-free oil well. Background Art

[0002] The monitoring of the pressure and temperature of an oil well is an important task in the production management of an oil field. By measuring the pressure and temperature with high precision, parameters such as the liquid level depth and formation pressure of the oil well are determined. These parameters are of great significance for increasing the production capacity of the oil well and reducing the electric energy consumption of the oil well pumping unit. In addition, the metering of the oil well output, especially the separate-phase metering of oil, gas and water, is also a task in the production management of an oil field. Accurately and timely metering the output of the oil well is of great significance for the evaluation of the production status of the oil field and the formulation of the production plan.

[0003] Currently, the domestic oil fields mainly use the eccentric static pressure measurement method for oil well pressure measurement. If the oil well to be measured is not equipped with an eccentric wellhead, a liquid level automatic monitor is used. For the eccentric static pressure measurement method, the existing eccentric wellheads in the oil fields are equipped less and less, and there are few eccentric wellhead configurations in the external oil fields, resulting in a smaller and smaller actual applicable range. Coupled with well conditions such as wax deposition and blockage, and foreign objects at the wellhead, the scenarios that meet the construction conditions will be further reduced; when using a liquid level automatic monitor for pressure testing, due to the complex distribution of the fluid in the wellbore during the entire testing process, errors in pressure conversion under single-sonic excitation will occur, and there is a certain gap in the testing accuracy compared with direct actual measurement.

[0004] Currently, the oil well output metering methods used in domestic oil fields mainly include glass tube oil measurement, tipping bucket oil measurement, software oil measurement, two-phase separation density method, three-phase separation metering method, etc. Most of these methods require the cooperation of ground equipment, some need to build facilities such as metering rooms, and generally have problems of low measurement accuracy. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a three-phase metering method based on direct measurement of non-eccentric oil wells. Specifically, a serpentine fully flexible logging instrument is sent into the inner part of the annular space composed of a sucker rod and a casing, and the second end of the cable connected to the serpentine fully flexible logging instrument passes through a two-way gooseneck guide and is connected to a ground acquisition remote control measuring instrument. The parameters such as the oil-water interface, pressure and temperature measured by the serpentine fully flexible logging instrument meet the direct measurement requirements of the oil well pressure with a non-eccentric wellhead configuration, and have the dual advantages of wide application range and high measurement accuracy. By changing the movement speed of the sucker rod, the liquid in the oil well is pumped out, so that the liquid slowly moves towards the wellhead. Under the action of gravity differentiation, an oil-water interface is formed, and the time, pressure value and temperature value when the oil-water interface reaches each oil-water interface sensor are measured by sensors to calculate the production of oil, gas and water phases, so as to accurately calculate the daily production of oil, gas and water phases, which is convenient for timely adjustment of the production plan.

[0006] The present invention provides a three-phase metering method based on direct measurement of non-eccentric oil wells. The specific implementation steps are as follows:

[0007] S1. Shut down the motor connected to the sucker rod to stop the movement of the sucker rod, and open the vent valve. Use the casing pressure-temperature combined sensor to monitor the pressure of the casing at the oil wellhead in real time until the pressure of the casing at the oil wellhead drops to atmospheric pressure, and then remove the vent valve.

[0008] S2. Connect the installation end of the serpentine fully flexible logging instrument and the first end of the cable. Then, pass the serpentine fully flexible logging instrument through the first side outlet of the three-way joint and the gas vent of the four-way flange in sequence and enter the inside of the four-way flange, and rotate to make the serpentine fully flexible logging instrument enter the inside of the annular space.

[0009] S3. Pass the second end of the cable through the two-way gooseneck guide, and push the two-way gooseneck guide into the inside of the four-way flange. Then, connect the first symmetric outlet of the three-way joint to the gas vent of the four-way flange through a universal clamp, and install a sealed blowout preventer and a vent valve at the second side outlet and the third side outlet of the three-way joint respectively. Connect the second end of the cable to the ground acquisition remote control measuring instrument and close the vent valve.

[0010] S4. Start the serpentine fully flexible logging instrument, lower the serpentine fully flexible logging instrument to the target depth, and lock the second end of the cable extending out of the first side outlet of the three-way joint through the sealed blowout preventer.

[0011] S5. Transmit the oil well temperature and pressure collected by the instrument temperature sensor and the instrument pressure sensor respectively to the ground acquisition remote control measuring instrument to calculate the formation pressure of the oil well, and control the motor connected to the sucker rod to make the oil well submergence reach the design requirements.

[0012] S6. Calculate the liquid level height in the oil well in real time by combining the downhole pressure data measured by the instrument pressure sensor with the pressure data measured by the casing pressure-temperature combined sensor for measuring the casing, and pump out the liquid in the oil well by changing the movement speed of the sucker rod. When the liquid level height reaches the target depth, pump out the liquid in the oil well at a certain time;

[0013] S7. Close the motor, production valve, and casing valve connected to the sucker rod in sequence, so that the liquid slowly moves towards the wellhead, forming an oil-water interface, and measure the pressure value and temperature value of the oil-water interface reaching each oil-water interface sensor through the sensor;

[0014] S8. Calculate the oil, gas, and water three-phase production respectively based on the above data:

[0015] S81. Calculate the average mass flow rate Q of the water phase per day between any two adjacent oil-water interface sensors wn-1 , and the specific expression is:

[0016] Q wn-1 = 3600×24×K×h a ×S×ρ 水 / (t n - t n-1 )

[0017] where h a is the distance between two adjacent oil-water interface sensors, S is the cross-sectional area of the casing space, K is the area influence factor, ρ 水 is the average density of the water phase, t n is the time when the oil-water interface reaches the nth oil-water interface sensor, and t n-1 is the time when the oil-water interface reaches the n - 1th oil-water interface sensor;

[0018] S82. Calculate the average mass flow rate Q of the oil and water two-phase per day between any two oil-water interface sensors own-1 , and the specific expression is:

[0019] Q own-1 = 3600×24×((P n - P 0n ) - (P n-1 - P 0n-1 ))×K×S / (g×(t n - t n-1 ))

[0020] where P n is the pressure measured by the snake-shaped fully flexible logging instrument at time t n , P n-1 is the pressure measured by the snake-shaped fully flexible logging instrument at time t n-1 , and P 0n is at time tn The casing pressure measured by the casing pressure-temperature combined sensor at the wellhead at a certain moment, P 0n-1 is t n-1 The casing pressure measured by the casing pressure-temperature combined sensor at a certain moment, S is the cross-sectional area of the casing space, K is the area influence factor, g is the acceleration due to gravity, t n is the time when the oil-water interface reaches the nth oil-water interface sensor, t n-1 is the time when the oil-water interface reaches the (n - 1)th oil-water interface sensor;

[0021] S83. Calculate the average mass flow rate of the oil phase per day between any two adjacent oil-water interface sensors. The specific expression is: Q on-1 = Q own-1 - Q wn-1 ;

[0022] S84. Calculate the volume V of the gas in the casing after being converted to normal temperature and pressure at the moment of t n , and the specific expression is: 0n

[0023] V 0n = K × S × ((h1 - (n - 1) × h a ) - (P n - P 0n - ρ 水 × g × (n - 1) × h a ) / (ρ 油 × g)) × P 0n × T0 / (P0 × (T0 + W 0n ))

[0024] where S is the cross-sectional area of the casing space, K is the area influence factor, P0 is the air pressure under standard conditions, T0 is the Kelvin temperature under standard conditions, h1 is the distance from the first oil-water interface sensor to the wellhead, h a is the distance between two adjacent oil-water interface sensors, P n is the pressure measured by the serpentine fully flexible logging instrument at the moment of t n , P 0n is the casing pressure measured by the casing pressure-temperature combined sensor at the wellhead at the moment of t n , ρ 水 is the average density of the water phase, ρ 油 is the average density of the oil phase, g is the acceleration due to gravity, W 0n is the temperature of the gas in the casing at the moment of t n , and n is the number of oil-water interface sensors passed by the oil-water interface;

[0025] S85. Calculate the average volume flow rate Q of the gas phase per day between any two adjacent oil-water interface sensors gn-1 , and the specific expression is:​

[0026] Q gn-1 = 3600×24×(V 0n - V 0n-1 ) / (t n - t n-1 )

[0027] Wherein, V 0n is the volume of the gas in the casing at time t under normal temperature and pressure, and V n is the volume of the gas in the casing at time t under normal temperature and pressure. t 0n-1 is the time when the oil-water interface reaches the nth oil-water interface sensor, and t n-1 is the time when the oil-water interface reaches the (n - 1)th oil-water interface sensor. n n-1

[0028] Preferably, the shape of the serpentine fully flexible logging tool is a long strip tube, the outer diameter of the serpentine fully flexible logging tool is less than 18 mm, and the end of the serpentine fully flexible logging tool is a conical structure.

[0029]

[0030] Preferably, the annular space is the gap between the tubing string and the casing, and the interval of the gap is 18 mm.

[0031] Preferably, the depth of the serpentine fully flexible logging tool entering the oil well is 3 - 5 m.

[0032] Preferably, the cable is kept at a 90° angle with the gas vent of the four-way flange under the positioning action of the sealed blowout preventer box.

[0033] Preferably, the ground acquisition remote control measuring instrument includes a power supply module, a wireless transmission module, an on-well information acquisition module, a down-well information acquisition and decoding module, an oil well operation control module, a monitoring and anti-theft module, and a central control unit.

[0034] Compared with the prior art, the present invention has the following advantages:

[0034] (1) The present invention directly measures parameters such as the oil-water interface, pressure, and temperature by lowering the serpentine fully flexible logging tool through the vent valve, meeting the direct measurement requirements of the oil well pressure with an eccentric-free wellhead configuration, and having the dual advantages of a wide application range and high measurement accuracy.

[0035] (2) The present invention realizes the remote two-way communication of oil well data and control signals through the ground acquisition remote control measuring instrument. Among them, the control part can automatically control the submergence degree of the oil well to the optimal value through pressure conversion, realizing oil production increase and power saving in the oil production industry, without the need for workers to be on duty, and is an important technical guarantee for reducing staff and increasing efficiency.

[0036] (3) By using the oil-water interface, pressure, and temperature data measured in real time and combining with the proposed calculation method, the daily oil, gas, and water production can be accurately calculated. By remotely controlling the measuring instrument through ground collection, the working conditions of the oilfield can be understood, which is convenient for timely adjustment of the production plan.

[0037] (4) As a conventional oil well production and monitoring method, the present invention can be widely used in oilfields. It can obtain accurate and reliable oil well operation data in a timely manner, and the overall operation is convenient and simple. It plays an important supporting role in the dynamic analysis of oilfield production, the adjustment of working systems, and the formulation of various measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is the construction drawing of the downhole without eccentricity in the three-phase metering method based on direct measurement of non-eccentric oil wells of the present invention;

[0039] Figure 2 It is the schematic diagram of the acquisition of downhole metering parameters of the three-phase flow in oil wells in the three-phase metering method based on direct measurement of non-eccentric oil wells of the present invention;

[0040] Figure 3 It is the structural diagram of the serpentine fully flexible logging instrument in the three-phase metering method based on direct measurement of non-eccentric oil wells of the present invention;

[0041] Figure 4 It is the working diagram of the ground acquisition remote control measuring instrument in the three-phase metering method based on direct measurement of non-eccentric oil wells of the present invention;

[0042] Figure 5 It is the flow chart of the three-phase metering method based on direct measurement of non-eccentric oil wells of the present invention.

[0043] MAIN REFERENCE MARKS:

[0044] Sucker rod 1, production tubing 2, four-way flange 3, two-way gooseneck guide 4, guide pulley 5, four-way flange gas vent 6, positioning support unit 7, casing 8, serpentine fully flexible logging instrument 9, cable 10, sealed blowout preventer box 11, side outlet of three-way joint 12, vent valve 13, three-way joint 14, casing pressure and temperature combined sensor 15, universal clamp 16, gas phase 17, oil phase 18, oil-water interface 19, water phase 20, instrument temperature sensor 21, instrument pressure sensor 22, first oil-water interface sensor 23, second oil-water interface sensor 24, third oil-water interface sensor 25, nth oil-water interface sensor 26. DETAILED DESCRIPTION OF THE INVENTION

[0045] To elaborate on the technical content, structural features, achieved objectives, and effects of the present invention in detail, the following will be described in detail with reference to the accompanying drawings of the specification.

[0046] The three-phase metering method based on direct measurement of non-eccentric oil wells is as Figure 5As shown below, the specific implementation steps are as follows:

[0047] S1. Shut down the motor connected to the sucker rod 1 to stop the movement of the sucker rod 1, and open the vent valve 13. Use the casing pressure and temperature combined sensor 15 to monitor the pressure of the casing 8 at the wellhead in real time until the pressure of the casing 8 at the wellhead drops to atmospheric pressure, then remove the vent valve 13.

[0048] S2. As Figure 1 shown, connect the installation end of the serpentine fully flexible logging tool 9 and the first end of the cable 10. Then, pass the serpentine fully flexible logging tool 9 through the first side outlet of the three-way joint 14 (a joint with three communication directions, and the whole structure is T-shaped) and the vent port 6 of the four-way flange into the interior of the four-way flange 3, and rotate to make the serpentine fully flexible logging tool 9 enter the interior of the annular space.

[0049] Specifically, the serpentine fully flexible logging tool 9 uses a flexible tube as the only instrument housing. The serpentine fully flexible logging tool 9 is in the shape of a long strip tube. The outer diameter of the serpentine fully flexible logging tool 9 is less than 18 mm, and the end of the serpentine fully flexible logging tool 9 is a conical structure. The housing of the serpentine fully flexible logging tool 9 is made of a low-friction flexible material. Small-diameter sensors required for logging such as pressure, temperature, and several oil-water interface sensors are integrally installed inside the tube of the serpentine fully flexible logging tool 9. The tube is filled with tungsten powder as a weight to ensure a certain stiffness while maintaining its own flexible characteristics, facilitating passing through the right-angle turning point at the vent port 19 of the four-way flange during the manual introduction stage, and can automatically fall into the well under the action of gravity. The annular space is the gap between the production tubing 2 and the casing 8, and the interval of the gap is 18 mm.

[0050] S3. Pass the second end of the cable 10 through the two-way gooseneck guide 4, and push the two-way gooseneck guide 4 into the interior of the four-way flange 3. Then, connect the first symmetric outlet of the three-way joint 14 to the vent port 6 of the four-way flange through the universal clamp 16, and install a sealed blowout preventer 11 and a vent valve 13 at the second side outlet and the third side outlet of the three-way joint respectively. Connect the second end of the cable 10 to the ground acquisition remote control measuring instrument, and close the vent valve 13.

[0051] Furthermore, connect a cable tensioner (to control the downhole depth of the cable), a motor drive power cord (to control the start and stop of the motor connected to the sucker rod), a motor frequency converter (to change the speed of the motor connected to the sucker rod), a signal line of a revolution detection sensor (to detect the speed of the motor connected to the sucker rod), a casing pressure and temperature combined sensor, a sucker rod tension sensor (to detect the tension of the sucker rod 1 for calculating the pump efficiency, and a reasonable pump efficiency can improve the oil production efficiency), a belt speed detector (to detect whether the drive belt between the motor and the sucker rod slips), an electric belt tensioner (to tighten the belt when it slips), an external antenna (to receive and transmit signals, receive external operation instructions, and send real-time operation status information of the oil well), and a monitoring device (to ensure equipment safety and prevent theft) to a ground acquisition remote control and measuring instrument (mainly responsible for decoding the signals collected by the sensors and performing corresponding calculations).

[0052] S4. Start the serpentine fully flexible logging instrument 9, lower the serpentine fully flexible logging instrument 9 to the target depth, and lock the second end of the cable 10 extending from the first side outlet of the three-way joint 14 through a sealed blowout preventer box 11 with a locking function.

[0053] Specifically, the sealed blowout preventer box 11 has an anti-theft function to protect the property safety of the oil well-related equipment in the case of unmanned operation in the wild; the cable 10 is positioned by the sealed blowout preventer box 11 to keep the cable 10 at the side outlet 12 of the three-way joint at a 90° angle with the straight pipe at the gas vent 19 of the four-way flange, realizing further pressing on the two-way gooseneck guide 4. The target depth is at any position of the customer-designed depth (usually 500 - 3500 m). Before starting the well testing winch, the current depth needs to be calibrated. The depth at which the serpentine fully flexible logging instrument 9 enters the oil well should be 3 - 5 m, and the depth that still needs to be lowered by the winch is calculated according to this depth.

[0054] S5. Transmit the oil well temperature and pressure collected by the instrument temperature sensor 21 and the instrument pressure sensor 22 to the ground acquisition remote control and measuring instrument to calculate the formation pressure of the oil well, and control the motor connected to the sucker rod 1 to make the submergence degree of the oil well meet the design requirements. The specific process is as follows:

[0055] The pressure of the casing 8 at the oil wellhead is collected by the combined casing pressure and temperature sensor 15, and the submergence of the oil well is calculated by combining with the formation pressure of the oil well. The difference between the calculated submergence of the oil well and the designed submergence is compared, and a signal is sent to the motor frequency converter connected to the sucker rod 1 through the ground acquisition remote control measuring instrument to adjust the stroke frequency of the sucker rod 1 in the tubing string 2. Through the feedback principle, the submergence of the oil well meets the design requirements (a reasonable submergence can improve efficiency). The force on the sucker rod 1 is monitored in real time by the sucker rod tension sensor, and then the pump efficiency is calculated (the pump efficiency is an important index reflecting the overall system operation efficiency of the oil well); whether the belt slips is detected by the belt speed detector, and if it slips, it can be tensioned by the electric belt tensioner (belt slipping will affect efficiency).

[0056] S6. Combine the downhole pressure data measured by the instrument pressure sensor 22 with the pressure data measured by the combined casing pressure and temperature sensor 15 for measuring the casing 8 to calculate the liquid level height in the oil well in real time. The movement speed of the motor connected to the sucker rod 1 is increased to accelerate the movement speed of the sucker rod 1 in the tubing string 2, so as to pump out the liquid in the oil well. When the liquid level height reaches the target depth, continue pumping for 10 minutes.

[0057] S7. Close the motor, production valve and casing valve connected to the sucker rod 1 in sequence, so that the liquid slowly runs towards the wellhead direction to form an oil-water interface 19, and the pressure value and temperature value when the oil-water interface reaches each oil-water interface sensor are measured by the sensor.

[0058] Specifically, when the oil-water interface 19 reaches the first oil-water interface sensor 23, the timer of the ground acquisition remote control measuring instrument is recorded as t1. At this time, the pressure measured by the serpentine fully flexible logging instrument 9 is P1, and the casing pressure measured by the combined casing pressure and temperature sensor 15 is P 01 , and the temperature is W 01 ; as the oil-water interface 19 continues to rise and reaches the second oil-water interface sensor 24, the timer of the ground acquisition remote control measuring instrument is recorded as t2. At this time, the pressure measured by the serpentine fully flexible logging instrument 9 is P2, and the casing pressure measured by the combined casing pressure and temperature sensor 15 is P 02 , and the temperature is W 02 ; the oil-water interface 19 will pass through the third oil-water interface sensor 25 and the nth oil-water interface sensor 26 in sequence. The timer of the ground acquisition remote control measuring instrument is recorded as t n , and the pressure measured by the serpentine fully flexible logging instrument 9 at this time is P n , and the casing pressure measured by the combined casing pressure and temperature sensor 15 is P 0n , and the temperature is W 0n .

[0059] S8. Calculate the oil, gas and water three-phase production respectively according to the above data:

[0060] S81. Calculate the average mass flow rate Q of the aqueous phase 20 per day between any two adjacent oil-water interface sensors wn-1 , and the specific expression is as follows:

[0061] Q wn-1 = 3600×24×K×h a ×S×ρ 水 / (t n -t n-1 )

[0062] Where h a is the distance between two adjacent oil-water interface sensors, S is the cross-sectional area of the casing space, K is the area influence factor (S decreases due to wax deposition on the inner wall of the casing and the outer wall of the tubing, between 0.9 - 1.0, and hot washing of the well is required when it is lower than 0.9), ρ 水 is the average density of the aqueous phase 20, which is usually a constant for each well and can be taken as 1 kg / m 3 , t n is the time when the oil-water interface 19 reaches the nth oil-water interface sensor 26, and t n-1 is the time when the oil-water interface 19 reaches the (n - 1)th oil-water interface sensor.

[0063] S82. Calculate the average mass flow rate Q of the oil and water phases per day between any two oil-water interface sensors own-1 , and the specific expression is as follows:

[0064] Q own-1 = 3600×24×((P n -P 0n )-(P n-1 -P 0n-1 ))×K×S / (g×(t n -t n-1 ))

[0065] Where P n is the pressure measured by the snake-shaped fully flexible logging instrument 9 at time t n , P n-1 is the pressure measured by the snake-shaped fully flexible logging instrument 9 at time t n-1 , P 0n is the casing pressure measured by the casing pressure and temperature combination sensor 15 when the liquid in the oil well is pumped out at a certain time at time t n , P 0n-1 is the casing pressure measured by the casing pressure and temperature combination sensor 15 at time t n-1 , S is the cross-sectional area of the casing space, K is the area influence factor, g is the acceleration due to gravity and can be taken as 9.8 N / kg, and t n is the time when the oil-water interface 19 reaches the nth oil-water interface sensor 26, and tn-1 is the time when the oil-water interface 19 reaches the (n - 1)-th oil-water interface sensor.

[0066] S83. Calculate the average mass flow rate of the oil phase 18 per day between any two adjacent oil-water interface sensors. The specific expression is: Q on-1 = Q own-1 - Q wn-1 .

[0067] S84. Calculate the volume V n of the gas in the casing 8 at time t 0n after being converted to normal temperature and pressure. The specific expression is:

[0068] V 0n = K × S × ((h1 - (n - 1) × h a ) - (P n - P 0n - ρ 水 × g × (n - 1) × h a ) / (ρ 油 × g)) × P 0n × T0 / (P0 × (T0 + W 0n ))

[0069] where S is the cross-sectional area of the casing space, K is the area influence factor, P0 is the atmospheric pressure at standard conditions, 101.325 Kpa, T0 is the Kelvin temperature at standard conditions, 273.15 K, h1 is the distance from the first oil-water interface sensor 23 to the wellhead, h a is the distance between two adjacent oil-water interface sensors, P n is the pressure measured by the snake-shaped fully flexible logging instrument 9 at time t n , P 0n is the casing pressure measured by the casing pressure-temperature combination sensor 15 at the wellhead at time t n , ρ 水 is the average density of the water phase 20, ρ 油 is the average density of the oil phase 18, g is the acceleration due to gravity, W 0n is the gas temperature in the casing 8 at time t n , and n is the number of oil-water interface sensors passed by the oil-water interface 19.

[0070] S85. Calculate the average volume flow rate Q gn-1 of the gas phase 17 per day between any two adjacent oil-water interface sensors. The specific expression is:

[0071] Q gn-1 = 3600 × 24 × (V 0n - V 0n-1 ) / (t n - t n-1)

[0072] Among them, V 0n is the volume of the gas in the casing 8 at time t under normal temperature and pressure, V n is the volume of the gas in the casing 8 at time t under normal temperature and pressure, t 0n-1 is the volume of the gas in the casing 8 at time t under normal temperature and pressure, t n-1 is the volume of the gas in the casing 8 at time t under normal temperature and pressure, t n is the time when the oil-water interface 19 reaches the nth oil-water interface sensor 26, t n-1 is the time when the oil-water interface 19 reaches the (n - 1)th oil-water interface sensor.

[0073] In a preferred embodiment of the present invention, as Figure 4 shown, the ground acquisition remote control measuring instrument includes a power supply module, a wireless transmission module, an on-well information acquisition module, a downhole information acquisition and decoding module, an oil well operation control module, a monitoring and anti-theft module, and a central control unit. After the wireless transmission module of the ground acquisition remote control measuring instrument receives a remote instruction, the acquisition unit of the downhole information acquisition and decoding module supplies power to the snake-shaped fully flexible logging instrument 9 downhole through a cable, and at the same time acquires data of sensors such as temperature and force therein, and uploads it to the central control unit. The central control unit calculates the formation pressure of the oil well in real time, and then calculates the submergence depth of the oil well according to the casing pressure and temperature combined sensor 15. By comparing the difference between the designed submergence depth and the measured value, a signal is sent to the frequency converter connected to the motor of the sucker rod 1 to adjust the stroke frequency of the sucker rod 1. Through the feedback principle, finally the submergence depth of the oil well reaches the design requirements. At the same time, the central control unit also receives the force parameters of the sucker rod, and calculates the pump efficiency according to the force condition of the sucker rod. In addition, the on-well information acquisition module detects whether the belt slips in real time through a belt speed sensor, and cooperates with the electric belt tensioner of the oil well operation control module to adjust the tightness of the belt to reach the best requirements, increase the production capacity of the oil well, and reduce the power consumption. Finally, parameters such as formation pressure recovery, submergence depth, real-time power of the pumping unit, pump efficiency, belt operation condition, wellhead casing pressure, oil pressure, oil temperature, well site video, fault alarm, anti-theft photo, etc. are uploaded to the customer control terminal through the wireless transmission module.

[0074] As Figure 4 shown, the installation process of the ground acquisition remote control measuring instrument is as follows: Connect two live wires (connecting live wires is because the ground wire of some pumping units is in poor contact, which may affect measurement or even burn out the equipment). The instrument internally uses a 380V power conversion module, and then sequentially connect to the analog (0 - 10)V signal input terminal of the pumping unit motor frequency converter (this port is a standard speed control port); the power supply wire for the cable tensioner motor and the signal wire for the rotation speed detection sensor; the electric belt tensioner and the belt speed sensor; the wellhead casing pressure and temperature combined sensor and the sucker rod tension sensor; the external wireless transmission antenna; the well site monitoring equipment.

[0075] The following further describes a three-phase metering method based on direct measurement of non-eccentric oil wells of the present invention in conjunction with embodiments:

[0076] S1. Determine whether to perform hot washing of the well. If construction is carried out after hot washing of the well, there is basically no casing gas at this time, which is environmentally friendly and safe. If hot washing of the well is not performed, then turn off the motor connected to the sucker rod 1 to stop the movement of the sucker rod 1, and open the vent valve 13. Use the casing pressure and temperature combined sensor 15 to continuously monitor the pressure of the casing 8 at the oil wellhead, and release the casing pressure until the pressure of the casing 8 at the oil wellhead drops to atmospheric pressure. Then remove the vent valve 13 and install a tee joint 14. The purpose of installing the tee joint 14 is to leave an installation opening for the subsequent installation of the original vent valve 13, without affecting the subsequent vent operation.

[0077] S2. Connect the installation end of the serpentine fully flexible logging instrument 9 and the first end of the cable 10. Manually pass the serpentine fully flexible logging instrument 9 through the first side outlet of the tee joint 14 and the vent port 6 of the four-way flange into the interior of the four-way flange 3, and rotate to make the serpentine fully flexible logging instrument 9 descend 5 m into the oil well along the gap between the production tubing 2 and the casing 8 under the action of gravity. Stop releasing the cable 10. In this embodiment, the gap between the production tubing 2 and the casing 8 is 18 mm.

[0078] S3. Pass the second end of the single-core cable 10 with a diameter of 3.5 mm through the top notch of the double swan-neck guide 4 and press it against the inner guide pulley 5, and push the double swan-neck guide 4 into the interior of the four-way flange 3. Then connect the first symmetric outlet of the tee joint 14 to the vent port 6 of the four-way flange through the universal clamp 16, and use the positioning support unit 7 to achieve the positioning of the guiding position. The universal clamp 16 locks the tee joint 14 and the four-way flange 3. At this time, the double swan-neck guide 4 is in an arched shape as a whole, and a sealed blowout preventer 11 and a vent valve 13 are respectively installed at the second side outlet and the third side outlet of the tee joint. Connect the second end of the cable 10 to the ground acquisition remote control measuring instrument, and close the vent valve 13.

[0079] S4. Power the serpentine fully flexible logging tool 9 and conduct preliminary tests. After testing that the pressure and temperature signal composite requirements are met, start the well testing winch. Calculate the required depth of the well based on the target depth. In this embodiment, lower the serpentine fully flexible logging tool 9 to a depth of 3500 m in the oil well. Since it was manually lowered 5 m in the second step, there is still a need to lower it 3495 m. Lower it to the target depth according to the operating procedures of the well testing winch. The target depth ensures on the one hand that the serpentine fully flexible logging tool 9 has entered the oil well, and on the other hand, it prevents problems such as cable 10 wear and manpower consumption caused by excessive depth of the oil well. Lock the second end of the cable 10 extending from the first side outlet of the three-way joint 14 through the airtight blowout preventer box 11 with a locking function. Remove the remaining cable 10 from the winch, put on a protective steel sleeve. The steel sleeve is flexible and can be bent. Then connect the cable 10 to the signal input end of the ground acquisition remote control measuring instrument and complete the ground acquisition remote control measuring instrument. Straighten out the small amount of excess cable 10 and place it in a pre-prepared cable sorting box and lock it.

[0080] In this specific embodiment, the overall structure of the two-way gooseneck guide 4 is in an arched shape. A number of guide pulleys 5 are installed inside it, which can provide guiding, supporting and resistance reducing functions for the cable 10, enabling the smooth passage of the two right-angle bends at the side outlet 12 of the three-way joint and the gas vent 6 of the four-way flange, avoiding direct friction with the two right-angle bends, and preventing the cable 10 from wearing out and even breaking due to excessive lowering depth. The positioning and supporting unit 7 realizes the positioning of the two-way gooseneck guide 4 to the predetermined guiding position through the convex platform at the left end. The predetermined guiding position enables the curved sections at both ends of the two-way gooseneck guide 4 to be exactly located at the two right-angle bends at the side outlet 12 of the three-way joint and the gas vent 6 of the four-way flange, and realizes the pressing and fixing of this position under the action of the universal clamp 16.

[0081] S5. Transmit the oil well temperature and pressure collected by the instrument temperature sensor 21 and the instrument pressure sensor 22 to the ground acquisition remote control measuring instrument to calculate the formation pressure of the oil well, and control the motor connected to the sucker rod 1 to change the stroke frequency of the sucker rod 1 to make the fluid level in the oil well reach the design requirements.

[0082] Turn on the power supply of the power distribution cabinet. After testing that the equipment is normal, start the pumping unit and observe for 15 minutes without abnormalities. The installation process is completed. The customer can monitor the operation status of the oil well through the real-time parameters of the oil well received on the control terminal, and can send new instructions at any time to manually intervene in the operation of the oil well, such as tightening the belt, setting the fluid level in the oil well in real time, opening and closing the well, etc., to achieve staff reduction and efficiency increase, and intelligent oil production.

[0083] S6. Combine the downhole pressure data measured by the instrument pressure sensor 22 with the pressure data measured by the casing pressure and temperature combined sensor 15 of the measuring casing 8 to calculate the liquid level height in the oil well in real time. Increase the movement speed of the motor connected to the sucker rod 1 to accelerate the movement speed of the sucker rod 1 in the sucker rod barrel 2, so as to pump out the liquid in the oil well. When the liquid level height reaches the target depth, continue pumping for 10 minutes.

[0084] S7. Close the motor, production valve, and casing valve connected to the sucker rod 1 in sequence to make the liquid slowly move towards the wellhead. Due to the lack of disturbance from the sucker rod 1, an oil-water interface 19 is formed, as Figure 2 shown, and the pressure value and temperature value of the oil-water interface reaching each oil-water interface sensor are measured by the sensor.

[0085] As Figure 3 shown, when the oil-water interface 19 reaches the first oil-water interface sensor 23, the timer of the ground acquisition remote control measuring instrument is recorded as t1. At this time, the pressure measured by the snake-shaped fully flexible logging instrument 9 is P1, and the casing pressure measured by the casing pressure and temperature combined sensor 15 is P 01 , and the temperature is W 01 ; Subsequently, as the oil-water interface 24 continues to rise, it will successively pass through the second oil-water interface sensor 24, the third oil-water interface sensor 25, and the nth oil-water interface sensor 26. The time is respectively recorded as t2, t3....t n , and the downhole pressure at each moment is respectively recorded as P2, P3....P n through the instrument pressure sensor 22, and the wellhead pressure at each moment is recorded as P 02 , P 03 ....P 0n by the casing pressure and temperature combined sensor 21, and the temperature at each moment is W 02 , W 03 ...W 0n .

[0086] S8. Calculate the oil, gas, and water three-phase production according to the above data respectively:

[0087] S81. The measurement of the water phase 20 flow rate can be represented by calculating the volume increment of the water phase within a certain time. The certain time is the time interval t n - t n-1 between reaching two adjacent oil-water interface sensors. The volume increment of the water phase is h a × S × K, where h ais the distance between two adjacent oil-water interface sensors, S is the cross-sectional area of the casing space, and K is the area influence factor (the cross-sectional area S of the casing space will decrease due to wax deposition on the inner wall of the casing and the outer wall of the tubing, etc. The value of K is usually between 0.9 and 1.0. Hot washing of the well is required when it is lower than 0.9). Therefore, calculate the average mass flow rate Q of the water phase 20 between any two adjacent oil-water interface sensors per day wn-1 , and the specific expression is:

[0088] Q wn-1 = 3600×24×K×h a ×S×ρ 水 / (t n -t n-1 )

[0089] where h a is the distance between two adjacent oil-water interface sensors, S is the cross-sectional area of the casing space, K is the area influence factor (S decreases due to wax deposition on the inner wall of the casing and the outer wall of the tubing, etc., between 0.9 and 1.0. Hot washing of the well is required when it is lower than 0.9), ρ 水 is the average density of the water phase 20, which is usually a constant for each well and can be taken as 1 kg / m 3 , t n is the time when the oil-water interface 19 reaches the nth oil-water interface sensor 26, and t n-1 is the time when the oil-water interface 19 reaches the (n - 1)th oil-water interface sensor.

[0090] S82. The oil phase flow rate can be obtained by subtracting the water phase 20 flow rate from the liquid phase flow rate within a certain period of time. Calculate the average mass flow rate Q of the oil and water phases between any two adjacent oil-water interface sensors per day own-1 , and the specific expression is:

[0091] Q own-1 = 3600×24×((P n -P 0n )-(P n-1 -P 0n-1 ))×K×S / (g×(t n -t n-1 ))

[0092] Preferably, the derivation process of the above formula is as follows:

[0093] ΔP n =(P n -P 0n )-(P n-1 -P 0n-1 ) = ρ 均 ×g×Δh n

[0094] ΔPn ×K×S=ρ 均 ×g×Δh n ×K×S=Δm n ×g

[0095] Q own-1 =3600×24×Δm n / Δt n =3600×24×ΔP n ×K×S / (g×(t n -t n-1 ))

[0096] Among them, P n t n The pressure measured by the serpentine fully flexible logging tool 9 at the moment, P n-1 t n-1 The pressure measured by the serpentine fully flexible logging tool 9 at the moment, P 0n t n The casing pressure measured by the casing pressure and temperature combination sensor 15 at the wellhead at the moment, P 0n-1 t n-1 The casing pressure measured by the casing pressure and temperature combination sensor 15 at the moment, S is the casing space cross-sectional area, K is the area influence factor, g is the gravity acceleration, which can be taken as 9.8N / kg, t n is the time when the oil-water interface 19 reaches the nth oil-water interface sensor 26, t n-1 is the time when the oil-water interface 19 reaches the n-1th oil-water interface sensor, △P n t n-1 to n The increase in liquid phase pressure during time, ρ 均 is the average density of the liquid phase, △h n is the liquid phase height increase, △m n is the mass increase of the liquid phase.

[0097] S83, calculate the average mass flow rate of the oil item 18 per day between any two adjacent oil-water interface sensors, the specific expression is: Q on-1 =Q own-1 -Q wn-1 .

[0098] S84, gas phase 17 flow rate can be converted into gas volume at normal temperature and pressure through the ideal gas state equation, and obtained by subtracting the volume at adjacent moments to calculate t n The volume V of the gas in the casing 8 at the moment converted to normal temperature and pressure is 0n , the specific expression is:

[0099] V 0n =K×S×((h1-(n-1)×ha )-(P n -P 0n -ρ 水 ×g×(n - 1)×h a ) / (ρ 油 ×g))×P 0n ×T0 / (P0×(T0 + W 0n ))

[0100] Preferably, the above formula derivation process is as follows:

[0101] P0×V 0n / T0 = P 0n ×V n / T n

[0102] V 0n = P n ×V n ×T0 / (T n ×P0)

[0103] T n = T0 + W 0n

[0104] V n = K×S×(h n - h on )

[0105] h n = h1 - (n - 1)×h a

[0106] h on = (P n - P 0n - ρ 水 ×g×(n - 1)×h a ) / (ρ 油 ×g)

[0107] Wherein, S is the cross-sectional area of the casing space, K is the area influence factor, P0 is the atmospheric pressure at standard conditions 101.325 Kpa, T0 is the Kelvin temperature at standard conditions 273.15 K, h1 is the distance from the first oil-water interface sensor 23 to the wellhead, h a is the distance between two adjacent oil-water interface sensors, P n is the pressure measured by the serpentine fully flexible logging instrument 9 at time t n , P 0n is the casing pressure measured by the casing head pressure-temperature combined sensor 15 at time t n , ρ 水 is the average density of the water phase 20, ρ 油 is the average density of the oil phase 18, g is the acceleration due to gravity, W0n is the gas temperature in the casing 8 at time t, n is the number of oil-water interface sensors passed by the oil-water interface 19, and V n is the gas temperature in the casing 8 at time t, n is the number of oil-water interface sensors passed by the oil-water interface 19, and V 0n is the gas temperature in the casing 8 at time t, n is the number of oil-water interface sensors passed by the oil-water interface 19, and V n is the volume of the gas in the casing at time t converted to the volume at normal temperature and pressure through the ideal gas equation, and T n is the gas temperature in the casing 8 at time t, n is the number of oil-water interface sensors passed by the oil-water interface 19, and V n is the actual Kelvin temperature of the gas in the casing at time t, and V n is the gas temperature in the casing 8 at time t, n is the number of oil-water interface sensors passed by the oil-water interface 19, and V n is the actual volume of the gas in the casing at time t, and h n is the distance from the nth oil-water interface sensor to the wellhead, and h on is the gas temperature in the casing 8 at time t, n is the number of oil-water interface sensors passed by the oil-water interface 19, and V n is the height of the oil phase liquid column in the casing at time t.

[0108] S85. Calculate the average volume flow rate Q of the daily gas phase 17 between any two adjacent oil-water interface sensors gn-1 , and the specific expression is:

[0109] Q gn-1 = 3600×24×(V 0n - V 0n-1 ) / (t n - t n-1 )

[0110] wherein, V 0n is the volume of the gas in the casing 8 at time t under normal temperature and pressure, and V n is the volume of the gas in the casing 8 at time t under normal temperature and pressure, and t 0n-1 is the time when the oil-water interface 19 reaches the nth oil-water interface sensor 26, and t n-1 is the time when the oil-water interface 19 reaches the (n - 1)th oil-water interface sensor. n is the time when the oil-water interface 19 reaches the nth oil-water interface sensor 26, and t n-1 is the time when the oil-water interface 19 reaches the (n - 1)th oil-water interface sensor.

[0111] In summary, by calculating the values of Q gn-1 , Q on-1 and Q wn-1 , the daily average three-phase flow rate can be obtained, and the data can be sent to the oil well management personnel in real time through the ground acquisition remote control measuring instrument, so as to understand the working condition of the oil well in real time, formulate relevant production plans, and further improve the effect of reducing staff and increasing efficiency.

[0112] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A three-phase metering method based on direct measurement of non-eccentric oil wells, characterized in that, The specific implementation steps are as follows: S1. Shut down the motor connected to the sucker rod to stop the movement of the sucker rod, open the vent valve, and use the casing pressure-temperature combined sensor to continuously monitor the pressure of the casing at the wellhead until the pressure of the casing at the wellhead drops to atmospheric pressure, then remove the vent valve; S2. Connect the installation end of the snake-shaped fully flexible logging instrument to the first end of the cable. Then, pass the snake-shaped fully flexible logging instrument through the first side outlet of the three-way joint and the gas vent of the four-way flange in sequence to enter the interior of the four-way flange, and rotate to make the snake-shaped fully flexible logging instrument enter the interior of the annulus; S3. Pass the second end of the cable through the guide and push the guide into the interior of the four-way flange. Then, connect the first symmetric outlet of the three-way joint to the gas vent of the four-way flange, install a sealed blowout preventer and a vent valve at the second side outlet and the third side outlet of the three-way joint respectively, connect the second end of the cable to the ground acquisition remote control measuring instrument, and close the vent valve; S4. Start the snake-shaped fully flexible logging instrument, lower the snake-shaped fully flexible logging instrument to the target depth, and lock the second end of the cable extending out of the first side outlet of the three-way joint through the sealed blowout preventer; S5. Transmit the well temperature and pressure collected by the instrument temperature sensor and the instrument pressure sensor respectively to the ground acquisition remote control measuring instrument to calculate the formation pressure of the oil well, and control the motor connected to the sucker rod to make the submergence degree of the oil well meet the requirements; S6. Combine the downhole pressure data measured by the instrument pressure sensor with the pressure data measured by the casing pressure-temperature combined sensor for measuring the casing to calculate the liquid level height in the oil well in real time. Pump out the liquid in the oil well by increasing the movement speed of the sucker rod. When the liquid level height reaches the target depth, continue to pump out the liquid in the oil well for 10 minutes; S7. Shut down the motor, production valve, and casing valve connected to the sucker rod in sequence to make the liquid slowly move towards the wellhead. Under the action of gravity differentiation, an oil-water interface is formed, and the time, pressure value, and temperature value when the oil-water interface reaches each oil-water interface sensor are measured by the sensor; S8. Calculate the oil, gas, and water three-phase production respectively based on the above data: S81. Calculate the average mass flow rate Q of the aqueous phase per day between any two adjacent oil-water interface sensors wn-1 , and the specific expression is as follows: Q wn-1 = 3600 × 24 × K × h a × S × ρ 水 / (t n - t n-1 ) where h a is the distance between two adjacent oil-water interface sensors, S is the cross-sectional area of the casing space, K is the area influence factor, ρ 水 is the average density of the aqueous phase, t n is the time when the oil-water interface reaches the nth oil-water interface sensor, and t n-1 is the time when the oil-water interface reaches the (n - 1)th oil-water interface sensor; S82. Calculate the average mass flow rate Q of the oil and water phases per day between any two oil-water interface sensors own-1 , and the specific expression is as follows: Q own-1 = 3600×24×((P n - P 0n ) - (P n-1 - P 0n-1 )) × K × S / (g × (t n - t n-1 )) Among them, P n is the pressure measured by the serpentine fully flexible logging instrument at time t n , P n-1 is the pressure measured by the serpentine fully flexible logging instrument at time t n-1 , P 0n is the casing pressure measured by the casing pressure and temperature combined sensor at the wellhead at time t n , P 0n-1 is the casing pressure measured by the casing pressure and temperature combined sensor at time t n-1 , S is the cross-sectional area of the casing space, K is the area influence factor, g is the acceleration due to gravity, t n is the time when the oil-water interface reaches the nth oil-water interface sensor, t n-1 is the time when the oil-water interface reaches the (n - 1)th oil-water interface sensor; S83. Calculate the average mass flow rate of the oil phase per day between any two adjacent oil-water interface sensors. The specific expression is: Q on-1 = Q own-1 - Q wn-1 ; S84. Calculate t n The volume V of the gas in the casing at the moment after being converted to normal temperature and pressure 0n , and the specific expression is as follows: V 0n = K × S × ((h1 - (n - 1) × h a ) - (P n - P 0n - ρ 水 × g × (n - 1) × h a ) / (ρ 油 × g)) × P 0n × T0 / (P0 × (T0 + W 0n )) Wherein, S is the cross-sectional area of the casing space, K is the area influence factor, P0 is the air pressure under standard conditions, T0 is the Kelvin temperature under standard conditions, h1 is the distance from the first oil-water interface sensor to the wellhead, h a is the distance between two adjacent oil-water interface sensors, P n is the pressure measured by the serpentine fully flexible logging instrument at time t n , P 0n is the casing pressure measured by the combined casing pressure and temperature sensor at the wellhead at time t n , ρ 水 is the average density of the aqueous phase, ρ 油 is the average density of the oil phase, g is the acceleration due to gravity, W 0n is the temperature of the gas in the casing at time t n , and n is the number of oil-water interface sensors passed by the oil-water interface; S85. Calculate the average volume flow rate Q of the gas phase per day between any two adjacent oil-water interface sensors gn-1 , and the specific expression is as follows: Q gn-1 = 3600×24×(V 0n - V 0n-1 ) / (t n - t n-1 ) Among them, V 0n is the volume of the gas in the casing at time t n under normal temperature and pressure, and V 0n-1 is the volume of the gas in the casing at time t n-1 under normal temperature and pressure. t n is the time when the oil-water interface reaches the nth oil-water interface sensor, and t n-1 is the time when the oil-water interface reaches the (n - 1)th oil-water interface sensor.

2. The three-phase metering method based on direct measurement of non-eccentric oil wells according to claim 1, characterized in that, The snake-shaped fully flexible logging instrument has a long strip tubular shape, the outer diameter of the snake-shaped fully flexible logging instrument is less than 18 mm, and the end of the snake-shaped fully flexible logging instrument is a conical structure.

3. The three-phase metering method based on direct measurement of non-eccentric oil wells according to claim 1, wherein The annulus is the gap between the production tubing and the casing, and the width of the gap is 18 mm.

4. The three-phase metering method based on direct measurement of an eccentric-free oil well according to claim 1, characterized in that The depth at which the snake-shaped fully flexible logging instrument enters the oil well is 3 - 5 m.

5. The method for directly measuring the oil-water interface, pressure and temperature and three-phase metering of an oil well without eccentricity according to claim 1, characterized in that, The cable is kept at a 90° angle with the gas vent of the four-way flange under the positioning action of the sealed blowout preventer.

6. The three-phase metering method based on direct measurement of an eccentric-free oil well according to claim 1, wherein The ground acquisition remote control measuring instrument includes a power supply module, a wireless transmission module, an on-well information acquisition module, a downhole information acquisition and decoding module, an oil well operation control module, a monitoring and anti-theft module, and a central control unit.

7. The three-phase metering method based on direct measurement of non-eccentric oil wells according to claim 1, characterized in that The guide is a two-way gooseneck guide.

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