RU2758931C1 - Method for increasing the inclinometry accuracy in process of drilling oil-and-gas wells and device for its implementation - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention relates to the associated geophysical research and work in wells for oil and gas production. To implement a method for increasing compensation level of distortion created by ferromagnetic drill pipes during drilling of oil-and-gas wells, inclinometric measurements of the well bottom location are initially carried out by a sensor system. The time interval for measuring inclinometric sensors is divided into two sub-intervals. During the first sub-interval, inclinometric sensors measure preliminary values of the inclination angle of borehole axis against the Earth's magnetic field vector and azimuth of the borehole axis against horizontal component of the Earth's magnetic field vector. The measured values are sent to microprocessor, then microprocessor sends control commands to the digital potentiometers. Digital potentiometers form control packages including direction of currents and amperage and supply them to working compensation solenoids installed anywhere on ferromagnetic drill pipes of the bottom-hole above and below the packaging arrangement axis. Compensating solenoids create a compensating magnetic field, then during the second sub-interval inclinometric sensors carry out repeated measurements of the inclination angle of borehole axis against the Earth's magnetic field vector and azimuth of the borehole axis against horizontal component of the Earth's magnetic field vector, which determine the updated values of the bottom-hole point inclinometry.

EFFECT: increase in compensation level of distortion created by large ferromagnetic drill pipes.

2 cl, 4 dwg

Description

The invention relates to related geophysical research and work in wells for oil and gas production [E21B 47/022, G01V1 / 44].

Inclinometry process - determination of the spatial exact position of the borehole being drilled by continuous measurement of deviations of the direction of the borehole from magnetic north (azimuth) and its angle of inclination using inclinometers.

The work of the main group of borehole inclinometers used in the process of drilling directional wells is based on the principle of measuring the parameters of the magnetic induction of the measuring solenoids under the influence of the Earth's magnetic field vector.

The measurement quality is influenced by the presence of massive magnetic complexes with high values of magnetic permeability near the measuring sensor, vibration of the drilling tool and other reasons.

From the prior art, there is a METHOD FOR INCLINOMETRY INCLINATION ACCURACY IN THE PROCESS OF DRILLING INCLINED-DIRECTED WELLS FOR OIL AND GAS [2005121778/28, publ. July 11, 2005], which consists in carrying out a system of sequential operations of converting the components of the Earth's gravitational and magnetic field into proportional electrical signals using gravitational sensors - signals using triaxial accelerometers and magnetometers, amplifying and scaling sensor signals, integrating analog-to-digital conversion of electrical signals , determination of the three components of the gravitational and magnetic fields by the measured output signals of geosteering sensors, determination of the inclinometric parameters of the well bottom by the measured components of the geophysical fields, characterized in that, in order to increase the accuracy of inclimation measurements during the drilling of wells, under the influence of vibrations from the operation of rock cutting tools , measuring the parameters of vibration noise, determining the required volume of the initial sample of the output signals of accelerometers, limiting the initial sample using the correlation on the analysis and determination of the true values of the output signals of the accelerometers as a result of the iterative procedure for processing the generated sample of the specified output signals.

Also known from the prior art is the "SHORT DRILL - HEAVY DRILL PIPE" METHOD - a mathematical method for reducing azimuthal errors caused by the magnetic effect of the components of the bottom hole assembly of the bottom hole (BHA), in which during the removal of the inclinometric measurement
the absolute azimuth is taken into account, which is the calculated one.

The technology is based on “the impossibility of using a sufficient number of NCCTs (non-magnetic drill collars), in the presence of which there is interference along the Bz axis located along the tool axis. To solve this problem, Dip (the angle at which the arrow deviates under the action of the Earth's magnetic field in the vertical plane) and Be (the value of the Earth's magnetic field strength at the wellhead) are introduced into the azimuth calculation formula and exclude the Bz component ”.

The use of this method, in physical essence, is a semi-automatic introduction into the measured component Bz of a correction calculated depending on the geometric parameters of the BHA and, in particular, on the location of the ferromagnetic components in the BHA.

The disadvantage of analogs is that they take into account and eliminate only one type of interference, namely, interference created by self-induction in a complex of directional sensors during vibration during drilling.

Also, the disadvantage of the second analogue is that the method takes into account only one orthogonal component Bz, which means that it allows a priori, practically unaccounted for error in other components measured by directional survey.

The closest in technical essence is the METHOD BASED ON COMPENSATION OF THE MAGNETIC FIELD OF THE SHIP [http://www.radioland.mrezha.ru/statia/mor_electr_01/mor_electr_01.htm, publ. 09/17/2019], characterized by the fact that due to a system of solenoids distributed over the deck of the ship or a special cable, which is placed on the deck or suspended from the outside of the sides, passing an electric current through it, an artificial magnetic field is created opposite to the field of the ship.

Distinguish between winding and non-winding demagnetization of the ship. In the first case, several cable windings are permanently installed on the ship and create
they contain a magnetic field that compensates for the ship's magnetic field. In the case of winding-free demagnetization, the ship is exposed to an external magnetic field at stationary or mobile demagnetization stations.

The main technical problem of the prototype is the low level of compensation for interference created by large ferromagnetic masses due to the fact that
The prototype uses a complex and not amenable to regular accounting dependence of the external induced magnetic field of the ship on the ratio of the axis of the ship and the total vector of the Earth's magnetic field, which makes it impossible to fully compensate for the magnetic fields.

The objective of the invention is to eliminate the disadvantages of the prototype.

The technical result of the invention is to increase the level of compensation for interference caused by large ferromagnetic masses.

The specified technical result is achieved due to the fact that the method for increasing the level of compensation of interference created by large ferromagnetic masses in the process of drilling oil and gas wells is characterized by the fact that the inclinometric measurements of the location of the borehole bottom are initially carried out by a system of sensors, while the time interval for measuring the inclinometric sensors is divided into two subinterval, during the first subinterval the directional sensors measure the preliminary values of the borehole axis inclination in relation to the vector of the Earth's magnetic field and the azimuth of the borehole axis relative to the horizontal component of the Earth's magnetic field vector, then the measured values are fed to the microprocessor, then the microprocessor sends control commands to the digital potentiometers, then digital potentiometers generate control signals and supply them to the working compensation solenoids, in accordance with the control signals, the compensation solenoids create compensation Then, during the second subinterval, the directional sensors perform repeated measurements of the borehole axis inclination angle with respect to the Earth's magnetic field vector and the borehole axis azimuth relative to the horizontal component of the Earth's magnetic field vector, which determine the updated values of the bottomhole inclinometry.

The specified technical result is achieved due to the fact that the device for increasing the level of compensation of interference created by large ferromagnetic masses in the process of drilling oil and gas wells, consists of inclinometric sensors placed on non-magnetic blocks connected to a microprocessor, which is connected to digital potentiometers, which are connected to workers compensation solenoids, while digital potentiometers and working compensation solenoids are placed on the ferromagnetic blocks of the bottom of the drill string.

Brief Description of Drawings

FIG. 1 shows the device for increasing the level of compensation for interference created by large ferromagnetic masses in the process of drilling oil and gas wells.

FIG. 2 shows an illustration of the process of measuring the angle of inclination of the axis of the borehole in relation to the vector of the earth's magnetic field.

FIG. 3 shows an example of the implementation of the control device for working compensation solenoids.

FIG. 4 is a plot of the induced magnetic field versus the angle between the borehole axis and the direction of the earth's magnetic field.

The figures indicate: 1 - ferromagnetic blocks; 2 - non-magnetic blocks; 3 - inclinometric sensors; 4 - microprocessor; 5 - digital potentiometer; 6 - working compensation solenoid.

Implementation of the invention

Device for increasing the level of compensation for interference created by large ferromagnetic masses in the process of drilling oil and gas wells, consists of elements of the bottom hole assembly, which may include ferromagnetic blocks 1 and non-magnetic blocks 2. At the same time, at a distance from the ferromagnetic blocks 1 located in the lower part of the drill strings, inclinometric sensors 3 are located on non-magnetic blocks 2. In one embodiment, inclinometric sensors 3 can be placed on non-magnetic drill pipe weights. As part of one device to increase the level of compensation of interference created by large ferromagnetic masses in the process of drilling oil and gas wells, several inclinometric sensors 3 can be used. In this inclinometric sensors 3 are made with the ability to measure the angle of inclination of the borehole axis with respect to the vector of the Earth's magnetic field and the azimuth of the axis wells with respect to the horizontal component of the Earth's magnetic field vector. The inclinometric sensors 3 are connected to the microprocessor 4. In one embodiment, the inclinometric sensors 3 are connected to the microprocessor 4 by means of a cable. Microprocessor 4, in turn, is connected to digital potentiometers 5, which are connected to working compensation solenoids 6. In this case, digital potentiometers 5 and working compensation solenoids 6 are placed on ferromagnetic blocks 1 of the bottom of the drill string.

Also an optional device for increasing the level of compensation for interference created by large ferromagnetic masses in the process of drilling oil and gas wells can be equipped with a battery to power the microprocessor 4, digital potentiometers 5 and compensation solenoids 6, which can be a special downhole battery (not shown in the figure).

The method for increasing the level of compensation for interference created by large ferromagnetic masses during the drilling of oil and gas wells is characterized by the fact that initially inclinometric sensors 3 measure the angle of inclination of the borehole axis with respect to the vector of the Earth's magnetic field and the azimuth of the borehole axis relative to the horizontal component of the Earth's magnetic field vector.

The time interval of measurements of the inclinometric sensors 3 is divided into two main sub-intervals, while the duration of the main time interval of measurements is constant and does not change.

During the first time subinterval, directional sensors 3 perform preliminary measurements of the borehole axis inclination angle with respect to the Earth's magnetic field vector and the borehole axis azimuth relative to the horizontal component of the Earth's magnetic field vector. In this case, preliminary measurements are understood as measurements that include interference caused by the presence of a magnetic field from ferromagnetic blocks 1. Further, preliminary measurements are sent for processing to the microprocessor 4. After that, the microprocessor 4, having received preliminary data from the inclinometric sensors 3, generates a command to control the voltage supplied to a digital potentiometer 5, which generates a signal to the working compensation solenoid 6, located on each ferromagnetic block 1 to create a magnetic field in order to constantly compensate for interference.

During the second time subinterval, the directional sensors 3 perform repeated measurements of the borehole axis inclination angle with respect to the Earth's magnetic field vector and the borehole axis azimuth relative to the horizontal component of the Earth's magnetic field vector. In this case, repeated measurements are characterized by the fact that they take into account the corrections for the influence of large ferromagnetic masses of ferromagnetic blocks 1, calculated during the first subinterval. Thus, the data obtained from the directional sensors 3 during the second sub-interval determine the real values of the downhole directional survey.

The implementation of measurements during the second subinterval allows a priori to reduce the number of additional mathematical operations for the introduction of various kinds of corrections for measuring directional data while drilling oil and gas wells.

Separately, it should be noted that for the implementation of the claimed method, a microprocessor 4 with sufficient computing power is used to carry out the required number of computational operations during the measurement interval without a time delay in the arrival of data.

Consider the option of achieving a technical result.

Initially, inclinometric sensors 3 are placed on non-magnetic blocks 2 of the bottom of the drill string. In this case, for clarity of the example, we will assume that the magnetic azimuth of the borehole axis β is equal to zero. In this case, the position of the ferromagnetic blocks 1 (borehole axis) and the vector of the Earth's magnetic field are illustrated in FIG. 2. In this case, α is the angle between the borehole axis and the vector of the Earth's magnetic field. Let us introduce one more approximation: let the internal magnetization of ferromagnetic blocks 1 be a constant value (H = const) and equal to the earth's magnetic field H ⁰ (without taking into account the inhomogeneous magnetization of the body). For an approximate assessment, we take typical parameters L = 10.6 m (length of ferromagnetic blocks 1), h = 8.5 m (distance between ferromagnetic blocks 1 and the measurement point (directional sensors 3)), angle α from 0 to 90 °;

;

;

modulus Н ⁰ = 40 A / m, S = πD / 4, where D is the diameter of the rod = 0.17 m, В ⁰ _х = 50 nT (where В ⁰ _х is the orthogonal component of magnetic induction acting on ferromagnetic blocks 1).

In practice, more accurate calculations of the resulting field are often used, for example, numerical methods for solving a system of integral equations using the 3D-MAGNIT software. The calculation results for similar initial data: L = 10 m, h = 10 m, S = 0.01 m ² , H ⁰ = 40 A / m are shown in Fig. 4.

Analysis of FIG. 4 allows us to conclude that at any angle between the axis of the rod (ferromagnetic blocks 1 of the bottom hole assembly (BHA)) located on the axis of the well and the magnetic field lines of the Earth, an obstacle appears, which needs to be taken into account when fixing the inclinometry parameters of the position of the bottom hole wells.

The actual distance between the ferromagnetic blocks 1 of the BHA and the measurement point of the inclinometry data (the location of the inclinometric sensors 3), as well as the actual length of each ferromagnetic block 1, is important. For example, moving such a block from a distance of 10.6 meters to 3.7 meters (three times) will to a sharp increase in the interfering magnetic field created by the magnetic block by a factor of five. The issue of determining the distance between ferromagnetic blocks 1 of the BHA and the point of measurement of the directional survey data is not related to the essence of the considered technical solution, this issue is solved depending on the dimensions of the functional elements of the BHA at the design stage.

After placing the inclinometric sensors 3 on the non-magnetic blocks 2 of the bottom of the drill string, measurements are taken on the first time interval. Microprocessor 4 receives data on the angle of inclination of the borehole axis in relation to the vector of the Earth's magnetic field (α) and the azimuth of the borehole axis relative to the horizontal component of the Earth's magnetic field vector (β). Further, the microprocessor 4 implements the following operations: calculates the orthogonal components of the magnetic induction acting on the ferromagnetic blocks 1, according to the following relations:

В ⁰ _х = В ₀ cos β cos α;

В ⁰ _y = В ₀ cos β sin α,

where α and β are the values coming from the inclinometric sensors 3,

В ₀ - induction of the Earth's magnetic field (is a constant value).

The following relation is known for the induced magnetic field of the ferromagnetic block 1:

В = µ µ ₀ N (I / L),

where μ is the relative magnetic permeability of the medium of the working compensation solenoid 6 (depends on the type of working compensation solenoid 6, for example 50),

µ ₀ - magnetic constant - is a constant value 4 π 10 ^-7 (H / m),

L is the length of the working compensation solenoid 6, m,

N is the number of turns of the working compensation solenoid 6.

Using the given ratio, microprocessor 4 calculates the value of the operating current:

I = B / µ µ ₀ n,

where n is the number of turns per unit length of the working compensation solenoid 6.

By calculating the direction and amplitude of the operating current I (for example, "+" or "-"), form the direction and amplitude of the induced magnetic field equal to the generated component of the induced magnetic field of the ferromagnetic block 1 under the influence of the effective component of the Earth's magnetic field, thereby practically compensating it ...

Further, measurements are carried out on the second time sub-interval: the inclinometric sensors 3 carry out repeated measurements of the parameters α and β, which determine the real values of the inclinometry of the bottomhole point.

An example of the implementation of the control of the working compensation solenoids 6 is shown in FIG. 3. According to this scheme, the microprocessor 4 calculates the voltage that must be applied between points W and C to create conditions for the flow of compensation current through the resistance R _{1 of the} working compensation solenoid of length L. To set the digital potentiometer to the desired position to create a given voltage, it is necessary from the microprocessor 4 send a sequence of pulses over a digital interface (SPI or I2C). In the absence of such a sequence, the potentiometer is set to the middle position (sleep mode). During the creation of an operating voltage of 5 V, it is necessary to send a sequence of pulses to set the potentiometer to the uppermost position (Fig. 4): for example, to set the potentiometer with 256 steps to the upper position, it is necessary to send the value 255.

The technical result of the invention is achieved due to the fact that inclinometric sensors 3 are located on the non-magnetic blocks 2, made with the ability to measure the angle of inclination of the borehole axis with respect to the vector of the Earth's magnetic field and the azimuth of the borehole axis relative to the horizontal component of the Earth's magnetic field vector. Inclinometric sensors 3 are connected to microprocessor 4. Microprocessor 4, in turn, is connected to digital potentiometers 5, which are connected to working compensation solenoids 6. In this case, digital potentiometers 5 and working compensation solenoids 6 are placed on the lower ferromagnetic blocks 1 of the bottom of the drill string. Due to the presence of the microprocessor 4, it is possible to control the compensation solenoids 6, which create a magnetic field in order to constantly compensate for the interference. In this case, constant compensation of interference is realized due to the fact that the time interval for making measurements of the inclinometric sensors 3 is divided into two subintervals. During the first subinterval, preliminary measurements of the borehole axis tilt angle with respect to the Earth's magnetic field vector and the borehole axis azimuth relative to the horizontal component of the Earth's magnetic field vector are carried out, after which the working compensation solenoids 6 create a magnetic field in order to permanently compensate for the interference. During the second subinterval after the interference compensation, the updated values of the bottom hole inclinometry are determined. At the same time, due to the fact that during the second subinterval, corrections for the influence of large ferromagnetic masses of ferromagnetic blocks 1 are taken into account, the level of compensation for interference caused by these masses is significantly increased.

The applicant has developed a device and implemented the claimed method, the approbation and testing of which confirmed the achievement of the claimed technical result. The increase in the level of compensation for interference caused by large ferromagnetic masses was about 30%.

Claims (2)

1. A method of increasing the level of compensation of interference created by ferromagnetic drill pipes during drilling of oil and gas wells, characterized in that the inclinometric measurements of the location of the borehole are initially carried out by a system of sensors, while the time interval for making measurements of the inclinometric sensors is divided into two sub-intervals, during the first sub-interval directional sensors measure preliminary values of the borehole axis inclination in relation to the Earth's magnetic field vector and the borehole axis azimuth relative to the horizontal component of the Earth's magnetic field vector, then the measured values are fed to the microprocessor, then the microprocessor sends control commands to digital potentiometers, then digital potentiometers form control packages, including the direction of currents and amperages, and feed them to the working compensation solenoids installed anywhere on the ferromagnetic drill pipes of the BHA above and below along the axis of the assembly, in accordance with which the compensation solenoids create a compensation magnetic field, then, during the second time sub-interval, the directional sensors perform repeated measurements of the borehole axis inclination angle with respect to the Earth's magnetic field vector and the azimuth of the borehole axis relative to the horizontal component of the vector of the Earth's magnetic field, which determine the updated values of the bottomhole inclinometry. 2. A device for increasing the level of compensation of interference created by ferromagnetic drill pipes during well drilling, consisting of inclinometric sensors located on non-magnetic blocks of the bottom drill string assembly and connected to a microprocessor that generates a package of control commands for digital potentiometers, which is connected to digital potentiometers generating data for the working compensation solenoids, while the working compensation solenoids are installed in an arbitrary place on the ferromagnetic drill pipes of the BHA.

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