SU1698429A1 - Pressure gauge for measurements in the annulus - Google Patents

Abstract

The invention relates to well logging and is intended to study the physical processes in the annulus of the well. The goal is to improve measurement accuracy. For this, case 3 is made with two opposite cavities 10 and 11 connected by channel 9. The device has a mechanism for converting the pressure of medium 6 made in the form of an elastic chamber 8 connected to channel 9 bounded from the opposite end. The chamber 8 is installed in the cavity of the housing from the side of the window 12, in the opposite cavity of the housing the source 4 of gamma radiation is fixed. The gamma-ray source 5 is placed in the channel 9 with a possibility of movement. Chamber 8 and channel 9 are filled with fluid. The device also has an additional elastic chamber filled with liquid and bounding the channel from the opposite end. By registering with high accuracy the distance between sources 4 and 5, the pressure in the annular space of the well is determined from the calibration characteristic. The invention allows to ensure the independence of the recorded information from the position of the recording unit inside the column of the composition and density of the liquid filling the column, the identity of the sources used to study the type of radiation converter of the recording device. 1 hp f-ly, 3 ill.

Description

The invention relates to well logging, in particular, devices for studying physical processes in the annulus of the well.

The purpose of the invention is to improve the accuracy of measuring the pressure of the medium in the annulus of the well.

FIG. 1 shows the proposed device, a general view; in fig. 2 is a graphical example of a registered chart; in fig. 3 is a graphical example of the calibration characteristic of a measuring sensor.

The device contains a column of tubes 1 lowered into the well, on the outside of which measuring sensors 2 are installed. Each measuring sensor 2 has a housing 3 in which gamma-radiation sources 4 and 5 are installed and the pressure conversion mechanism of medium 6 in the annulus

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filled with liquid 7 of an elastic chamber 8 connected to channel 9; Case 3 is made WITH 10/1 ANTI-POSITIVE CAVITIES

11 connected by a channel 9. A gamma-ray source 4 is fixed in the cavity 11 of the housing 3, and a source 5 is movably installed in the channel 9, which is bounded on the side of the cavity 10 of the housing 3. Elastic chamber 8 is installed in the cavity 11 of the housing. In case 3, a window 12 is formed on the side of the elastic chamber 8, which through it is hydraulically connected with medium b in the annulus of the well,

In order to expand the pressure measurement range and provide temperature compensation, an additional identical elastic chamber 13 can be introduced, limiting channel 9 from the opposite end. The chamber 13 is installed in the cavity 10 of the housing, i.e., without the possibility of interaction with the medium. Elastic chambers 8 and 13 can be performed, for example, in the form of metal bellows.

Channel 9 of the measuring sensor accommodates a movable source 5 and any change in the volume of chambers 8 and 13 when the pressure of medium 6 changes causes proportional movement of source 5, the amount of source movement is determined using registering unit 14. The latter is lowered into the pipe string 1 on the logging cable 15 and mounted against the measuring sensor 2. The recording unit 14 includes a housing 16 within which a narrowly collimated detector 17 is installed with the possibility of longitudinal reciprocating movement a conductive lead of the screen 18 with a circular slit-like window and a receiving transducer 19, is performed for the registration of gamma radiation sources 4 and 5 of the measuring probe 2 and transmitting the received information to the surface,

The recording unit 14 is provided with a drive consisting, for example, of a reversing electric motor 20, a gearbox 21, a drum 22 with a cable 23, the free end of which is mechanically attached to the detector 17, and electrically connected with the receiving converter 19 and the limit switches 24 providing the change the direction of rotation of the drive motor 20, and the signal contacts 25, mounted along the motion of the detector 17, at a known distance from each other and marking along the length of the recorded diagram by signaling ala with the sequential closure of the contacts 25 by a moving detector 17.

The device works as follows

During the descent into the well of the column of pipe 1 on its outer surface at pre-calculated points install the measuring sensor 2, which converts the pressure of the liquid phase of the medium 6 in the annulus of the well into the movement of moving sources 5 of the measuring sensor 2.

The pipe string 1 is lowered into the well, and the measurement sensors 2 are installed at predetermined intervals in the annulus. The fluid in the annular space of the well exerts on

the elastic chambers 8 of each sensor 2 have a certain pressure depending on the state

environment in the enclosed space, causes

deformation of elastic chambers and movement of working fluid 7 in the channel connecting them

9. Fluid 7 moves the moving source 5 installed in the channel, the amount of movement of which is proportional to the pressure of the fluid in the annulus. The amount of movement of the mobile source is determined using the registering unit 14, the distances between the mobile 5 and the fixed 4 sources of gamma radiation of the measuring sensor 2 are determined. The registering unit 14 is

part of the device for measuring the pressure of the medium in the annulus of the well. It is lowered into the string of pipes 1 on the geophysical cable 15 and installed sequentially against each measuring sensor. In the initial position, the movable detector 17 of the recording unit 14 is in the extreme position (near the cable head of the recording unit), at which the recording unit 14 is descended until registration gamma radiation from a fixed source 4 of the measuring sensor 2. According to the maximum of the recording radiation, the block 14 is set against

the source 4 of the measuring sensor 2, then raise it a few centimeters higher and turn on the drive of the recording unit 14, which leads to a longitudinal translation

narrowly collimated detector. 17

When moving past the stationary 4 and mobile 5 gamma-radiation sources of the measuring sensor 2, the detector 17 of block 14 fixes their position on the diagram (see Fig. 2, positions 24 and 25, respectively) as a function of time. At the same time, the same diagram is laid out along the length due to the sequential closure of the contacts 25 by a moving detector (positions 26-31).

The diagram also shows the operation of limit switches 24 (Fig. 2; positions 32 and 33), the intervals between positions 32-26 and 31-33 correspond to the section for acceleration and deceleration of the detector 17, while in the remaining intervals the detector moves uniformly. Measuring in the diagram the distances between positions 24 and 25 (the position of the sources 4 and 5 of the measuring sensor 2) and the distance in the recording unit between the contacts 25, giving positions 26 and 29 on the diagram, are determined with high accuracy (error no more than ± 2 mm) distance between fixed 4 and mobile 5 sources. Each measuring sensor 2 has its own calibration characteristic, determined by the design parameters of the sensor (stiffness of elastic chambers, diameter of the longitudinal channel, etc.), which establishes the functional dependence of the distance between the stationary and moving gamma radiation source from the pressure acting on the measuring sensor. An example of a calibration characteristic is shown in FIG. 3. By registering with high accuracy the distance between the radiation sources of the measuring sensor, the pressure of the medium in the annulus of the well is determined from the calibration characteristic.

With the full movement of the mobile source equal to 50 cm, in the range of pressure variation of the medium 0-22 MPa using the proposed device, the error of pressure measurement does not exceed 0.09 MPa.

The invention makes it possible to increase the accuracy of measurements by ensuring the independence of the recorded information from the position of the recording unit of devices inside the column, our pipes, composition and dense C (and the liquid filling the column, the identity of the applied radiation sources used in the measuring sensors, type of radiation converter recorder.

Claims (1)

Claim 1. Device for measuring the pressure of the medium in the annular space of the well, comprising a housing with a window for communicating with the medium, two sources of gamma radiation installed in the housing and a medium pressure transducer mechanism, on the side of which the window is made, distinguishes it with that, in order to improve the measurement accuracy, the casing is made with two opposite cavities connected by a channel, the medium pressure conversion mechanism is made in the form of an elastic chamber connected to a channel bounded with olozhnogo end and mounted in the cavity of the housing from the side window in the housing cavity opposite fixedly mounted one of the sources of gamma radiation, the second of which is situated in the duct for movement, wherein the resilient chamber and a channel filled with liquid. "2 Device pop, 1, characterized in that it is equipped with an extra. liquid-filled elastic chamber that bounds the channel from the opposite end 1