SU883375A1 - Device for measuring flowrate of heat carrier in injection wells - Google Patents

Description

I

The invention relates to the oil and gas industry and can be used to measure the flow rate of wet steam into productive formations of injection wells during thermal treatment.

A downhole flowmeter for hot water is known, equipped with a non-power automatically opening packer, an unbraked measuring turbine, a reed switch for rotational speeds into an output pulse signal and a single-core cable as a remote communication channel. I

Also known is a downhole flow meter, comprising a housing, a turbine, a tachometer transducer, including a permanent magnet fixed to the shaft of the turbine and a core with a winding placed in the housing. which, and the secondary converter 2.

The drawbacks of the devices are the impossibility of their use for measuring the flow of wet steam. This is due to the fact that hitting wet steam significantly depends on the degree of dryness of the steam, which, in its

 turn, depends on the downhole conditions for temperature and pressure.

Therefore, the volume of steam obtained from the same amount of liquid (water) can change its value significantly (hundreds of times) in the process of passing through different parts of the wellbore, and these changes much overlap the capabilities of the high-speed tachometric flow converter across the width (overlap ) range.

 Based on the data obtained on the surface about the wellhead steam flow when it is pumped into the well, it is impossible to predict with a sufficient degree of accuracy the boundaries of the measuring range required at the scheduled well point and select their optimum values Even with a random coincidence of the selected boundaries with the flow rate in the planned 1 {o the point of the measured parameter due to the narrowness of the range can easily go beyond the selected limits. This will result in overloading of the turbine and the possibility of device failure. In addition, borehole overload protection is a fundamental requirement for downhole flow unit designed to operate in a wet steam environment.

Uejib invention - increasing the reliability of the device.

The end goal is achieved by introducing a cut-off frequency generator, a comparison circuit, a control unit and a DC source, with the ends of the tachometer converter winding being connected to a secondary converter and a control unit connected to the DC source and the output of the comparison circuit, the inputs which is connected to the secondary transducer and the edge frequency generator.

FIG. 1 shows a general view of the flow meter, a section; in fig. 2 is an electrical diagram of a flow meter; in fig. 3 and 4 - knot induction, the converter in various operating modes.

The flow meter consists (Fig. 1) of the housing I, in which the turbines 3 are rotated on the supports 2 under the action of a stream passing through the inlet 4 and outlet 5 of the housing window. A packer 6 is provided to form the flow and direct it to the measurement channel.

On the shaft of the turbine 3, a permanent magnet 7 is radially fixed, which interacts with the transducer coil located in. a sealed compartment of the housing 1, comprising a toroidal core 8 and a winding 9 connected by a remote communication channel - cable 10 to the equipment located on the surface (the equipment is not shown). Winding 9 consists (Fig. 2) of two sections P and 12 which are the same for the number of turns, dividing the coil into two equal parts, the direction of winding the opposite sections (if both sections are viewed either along or counterclockwise), and the windings are turned on consistently. With such an execution of the coil in the process of simultaneous intersection of the turns of its sections by magnetic field lines of opposite polarity (Fig. 2 and 3), in both sections an emf of the same sign is induced, summing up at the output of the coil. After the magnet 7 has completed half a revolution (after changing the polarity of the magnet relative to the sections), the sign of the total emf in the winding is reversed.

The output ends of the coil are connected via a remote communication channel 10 to the secondary equipment, including an electronic converter 13, a limit frequency generator 14, a comparison circuit 15, a control unit 16, and a direct current source 17, through a separation capacitor with the device works as follows.

When a controlled flow enters the measuring channel, the turbine 3 begins to rotate at a rate proportional to the volumetric flow rate. The magnet 7, which is located on the same shaft as the turbine, rotates similarly. When the coils are crossed by the magnetic power lines, the total emf is induced. When the poles change during the rotation of the magnet (Fig. 2 and 3)

total emf reverses the sign.

Consequently, during half the turnover, the total emf has one sign, for the other - the opposite. The alternating voltage thus obtained, whose frequency is proportional to the flow rate, flows through channel 10 to electronic converter 13, where it is recorded. In addition, the same signal arrives simultaneously with the boundary frequency produced by the generator 14 to the comparison circuit 15. With the limiting increase in the turbine speed, the frequencies entering the circuit approach each other and after they coincide, the circuit produces a pulse, at the command of which the control unit 16 connects the constant voltage source 17 to the coil 9. The inverter coil acquires well-pronounced voltage under constant voltage the properties of an electromagnet, the poles of which (Fig. 4) are located at the junction points of the sections. In the embodiment shown in FIG. At the 4 position, the magnetic field of the coil begins to prevent further rotation of the magnet. When the charging voltage reaches a certain value, the magnet 7 completely loses mobility (for any possible

5 media expenses).

The effect of the implementation of the proposed technical solution lies in expanding the field of application of a high-speed tachometric flow converter.

The availability of information on the flow rate of wet steam into productive formations of injection wells during thermal exposure allows optimizing the mode of exposure 5 in order to enhance oil recovery.

Claims (2)

Invention Formula A device for measuring the flow rate of coolant in injection wells, comprising a housing, a turbine, a tachometer converter, including a permanent magnet fixed to the turbine shaft and a core with a winding placed in the housing, and a secondary converter, are distinguished by the fact that will introduce it. He, cut-off frequency cutter, srnneni scheme. , a control unit and a dc source, the tachometer converter winding ends being connected to a secondary converter and a control unit connected to the dc source and the output of the comparison circuit, the inputs of which are connected to the secondary converter and the edge frequency generator. 5 Sources of information taken into account in the examination 1. Petrov A.I., Bar-Sliva V.I. Terek-3-borehole flow meter for hot water. Neft nick, 1979, p. I & II. 2. USSR author's certificate No. 514947, cl. E 21 B 47/10, 1974 (prototype). FIG.