RU2459949C2 - Automated system for control of properties of drilling fluid prepared based on gaseous agents - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: automated system, which maintains preset density of drilling fluid prepared based on gaseous flushing agents and includes test equipment and remote monitors, contains also commutator, commutator of analogue-to-digital converter of computer interface card and variable speed drives for prompt control of flow of liquid or gas component of gaseous agents. Accuracy of control and responsiveness of the system is reached by use of digital form of transmission and processing of data with high accuracy of conversion. For this system density control is performed not by direct measurement but by calculation based on analytic dependences using data recorded by test equipment installed on transportation lines of foam preparation system. On-the-spot maintaining of required density of foam is performed using variable speed drives installed on compressor plant and pump for foam-forming fluid.

EFFECT: improving efficiency of control of properties of drilling fluid prepared based on gaseous flushing agents - foam solutions by means of accurate and prompt response of the system to its probable changes.

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Description

The invention relates to the drilling and overhaul of wells (KRS) of oil and gas wells with a reservoir pressure below hydrostatic.

A known system for regulating the properties of the drilling fluid, including mud parameters sensors, a regulator, a dosing unit connected to a pump, an adder and keys, an additional adder, an averaging unit, memory units, a key control unit, a time sensor, elements NOT, AND, OR, and comparators [A.S. USSR No. 1041677; publ. 09/15/83]. In this system, the regulation of the properties of drilling fluids is performed not only in the current cycle, but also in the previous one due to the introduction of binary logic elements NOT, AND, OR, which allows the system not to react to random fluctuations of the controlled parameter of the drilling fluid, thereby more accurately respond to possible changes.

Closest to the invention, the technical solution is an automated system for controlling the properties of the drilling fluid, comprising a ground circulation system consisting of a receiving tank for drilling fluid with a level gauge, connected by a transport line to the well through a cleaning unit, a hopper for bulk materials (with weighting agent), a dispenser, mixer, mixer pump, density sensors (densitometers) at the outlet and entrance to the well, respectively, control unit, adjustable gate valves and storage circuit [A.S. USSR No. 1423728; publ. 09/15/88]. In this system, the regulation of the properties of drilling fluids is carried out by maintaining their optimal density by means of a valve. The control unit is connected to the control inputs of the pump, the accumulating capacity for the pulp with a level gauge and a controlled gate, the pulp supply unit, and automatically maintains the density of the drilling fluid by the degree of opening of the adjustable valve in case of inconsistencies in the readings of the density meters installed at the input and output of the well.

After analyzing the above systems for controlling the properties of drilling fluids, we can conclude that the control system of the first system for automated monitoring of drilling fluid parameters lies on the logical elements that act as a switch. Information about the need to change the solution parameter is organized by comparing, using comparators, the signals recorded by the sensors with a certain averaged set constant, “wired” in the circuit board of the automation device. The control signal is generated after the third measurement cycle, and the control process ends when the deviation of the adjustable parameter falls into the tolerance zone [A.S. USSR, No. 1041677; publ. 09/15/83].

This system is characterized by a slow response to ongoing changes, i.e. the system’s responsiveness to rapidly changing conditions is excluded, which does not allow optimizing (setting optimal parameters) fast-changing processes, for example, operatively controlling the drilling fluid density in the case of using gaseous flushing agents.

The second system presented is designed to introduce corrections in the amount of direct measurement of the density of the drilling fluid - density meters. If a mismatch between the given density and the density measured by the densitometer located in the trench of the circulation system exists, then the position of the valve in the storage loop system remains unchanged. In the event of a mismatch in the readings between the density sensor and the set density value, the degree of opening of the control valve in the storage loop system changes by a proportional value [A.S. USSR No. 1423728; publ. 09/15/88].

In the presence of two or multiphase media, for example gaseous washing agents in the form of foam systems, direct measurement of the density of the medium by densitometers will not be accurate. Moreover, the regulation of the properties of the drilling fluid, which is performed by the degree of opening of the valve installed in the storage loop of the density control, is an inertial and low-current procedure.

The objective of the invention is to increase the accuracy and efficiency of regulating the properties of a drilling fluid prepared on the basis of gaseous flushing agents - foam solutions (foam), by accurately and quickly responding to possible changes in the system.

The technical result is an increase in the efficiency and accuracy of calculating the density of the foam, as well as, if necessary, adjust its density.

The technical result is achieved by the fact that an automated system for controlling the properties of a drilling fluid prepared on the basis of gaseous agents, containing remotely controlled transport lines: the first line, designed to measure the parameters of the gas component of the foam and regulate the gas supply and includes a compressor, commercially available frequency-controlled drives , two controlled valves, as well as a flow meter, thermometer and manometer, based on the readings of which with subsequent recounting by anal tactical dependencies in the value of the density of the foam formed the work of controlled devices - valves and compressor; the second line, which controls and regulates the fluid flow, located between the tank for the coolant and the ejector and includes two remotely controlled valves, a pump for supplying liquid, as well as a liquid flow meter, thermometer and manometer, based on the readings of which and conversion to the foam density value is formed operation of controlled devices - valves and controlled by a variable frequency drive of the pump; the third line, designed to control the dynamic properties of the foam and located immediately after the ejector in front of the wellhead, it includes a non-return valve, a manometer, a thermometer and a controlled valve, according to the invention is equipped with a switch, an ADC switch of a computer interface board and frequency-controlled drives connected with a compressor and a pump on the one hand and a computer on the other hand through the interface board switch, while remotely controlled via the commutator on all transport lines p gate valves.

Accuracy of control and quick response of the system is achieved using a digital form of transmission and processing of information with high conversion accuracy. For this system, density control is performed not by direct measurement, but by calculation using analytical dependencies, using data taken from instrumentation installed on transport lines of the foam preparation system. Operational maintenance of the required foam density is carried out using variable-frequency drives installed on the compressor unit and the pump for pumping liquid (RLF).

Through the ADC switch, with the necessary periodicity and high accuracy equal to the conversion accuracy, physical and dynamic parameters of the foaming agents are measured, based on which the foam density is calculated for its subsequent comparison with the set value. Based on the results of the calculated foam density, the foam density is adjusted using frequency-controlled drives connected to the compressor and the pump on the one hand and the computer on the other hand through the interface board switch; the adjustment is carried out quickly and accurately cyclically with a given step to the desired foam density, at if it is necessary to change the gas pressure, the compressor productivity will change, if necessary, change the pressure of the coolant, the productivity of the pump supplying coolant to the system will change mu. The system includes remotely controlled valves on all transport lines, remote devices are also controlled through the switch, all adjustable valves except the drain valve are open and participate in the system when there is a need to "purge" the ejector, the drain valve opens, while the rest of the valve closes, the drain valve the valve also opens when it becomes necessary to relieve pressure in the transport supply line of the coolant, for example, if the calculated value of the foam density exceeds required.

The invention is illustrated by drawings. The figure 1 presents a diagram of an automated system for regulating the properties of a drilling fluid prepared on the basis of gaseous agents. The system comprises a compressor 1, an ejector 2, a check valve 3, a flow meter 4, a controlled valve 5, a digital thermometer 6, a pressure gauge 7, a capacitor for life fluids 8, remotely controlled valves 9 and 10, a liquid flow meter with a remote controller 11, a liquid pump 12, controlled by an asynchronous motor with a frequency converter 13, a non-return valve 14, a thermometer 15, a pressure gauge 16, a wellhead 17, a non-return valve 18, a pressure gauge 19, a thermometer 20, a drain valve 21, remotely controlled valves 22 and 23, a pressure gauge 24 and a thermometer 25.

The figure 2 presents the algorithm of the automated system according to the invention.

The system described in this invention operates as follows.

The system includes three transport lines.

The first transport line controls and regulates the flow of air (gas) into the foam circulation system (Fig. 1). On the transport line in a horizontal position between the compressor 1 and the ejector 2 are the control and measuring and control lines for supplying air (gas). The air (gas) is supplied by the compressor 1 through the check valve 3, a flow meter 4, a controlled valve 5.

Instrumentation (Instrumentation) - a digital thermometer 6 and a manometer 7 comprise a control and measuring air supply line. Instrumentation is installed on the landing nodes of the control and measuring line.

The second transport line monitors and regulates the flow of fluid (LIV) in the foam circulation system. This line is located between the capacity for the RLP 8 and the ejector 2 and includes two remotely controlled valves 9 and 10, a liquid flow meter with a remote controller 11, a liquid pump 12 controlled by an asynchronous motor with a frequency converter 13, a check valve 14, a thermometer 15 and pressure gauge 16.

The supply of fluid to the system is carried out using a pump 12 from the tank 8 through a controlled valve 10 and a flow meter 11.

The third transport line is designed to control the dynamic properties of the foam solution. This line is located immediately after the ejector 2 in front of the wellhead 17. The third measuring section includes a check valve 18, a pressure gauge 19, a thermometer 20, as well as a drain valve 21.

To control the pressure drop in the wellbore, a pressure gauge 24 and a thermometer 25 are installed on the flow line of the well 17.

The foam is prepared using an ejector, the stable operation of which is maintained at the following values [3]:

where R _P is the pressure of the foam at the outlet of the ejector;

R _F - pressure foaming fluid (AL) at the inlet of the ejector.

For the air component, the stable operation of the ejector is determined from the conditions R _P > R _G , where R _G is the gas pressure at the inlet of the ejector.

Physico-dynamic parameters of the foam at the inlet of the well should have characteristics that are determined by the geological and technical conditions of drilling, i.e. well depth, ambient temperature, reservoir pressure, etc.

The density of the foam is the main parameter that is subject to automatic regulation using the proposed system. The density of the foam at the outlet of the ejector will be calculated by the formula, because A direct method for measuring density by densitometers is a low-efficient method due to the presence of two or more phases. For example, a high decrement of acoustic wave attenuation in the gas component of the foam is the reason for the low efficiency of acoustic (ultrasonic) densitometers. Gamma-gamma densitometers will have low efficiency due to the multiphase nature of the studied flow (foam).

Based on the foregoing, the algorithm of the automated system has the following structure (figure 2).

Input of the initial parameters and subsequent control of the physico-dynamic properties of the foam is carried out using the computer program interface.

Foam parameters are set - the pressure and density necessary for an optimal drilling process, taking into account possible changes in geological and technical conditions, as well as the pressure change step of the components that make up the foam, i.e. step change in pressure ROSH and step change in gas pressure.

Then, physical and dynamic parameters of the foam and the components involved in its preparation are measured, such as the pressure of the foam at the outlet of the ejector R, the pressure of the coolant at the inlet of the ejector P _, the gas pressure at the inlet of the ejector, the flow of the coolant Q, the _coolant , the gas flow Q _G and temperature of foam T.

The measured parameters are calculated the degree of aeration of the foam α _o, i.e. the ratio of gas flow Q _G in normal conditions, to the flow rate of the QoL _QoL [4]:

Further, by calculating the density of the foam ρ _PV is determined by the formula [4]:

where, ρ _W - the density of the life support, kg / m ³ ;

α _o is the degree of aeration;

ρ _g - the density of the gas used to prepare the foam, kg / m ³ ;

R _PI - foam pressure measured in the third transport line, MPa;

P _o - atmospheric pressure, MPa;

T _PI - the temperature of the foam, measured in the third transport line, ° K;

T _o - temperature at the wellhead, ° K;

Thus, the calculation of the foam density according to the instrumentation installed on the transport lines of the automated foam preparation system, with a given step, allows the system to respond to possible changes with similar discreteness.

The pressure control of the gas component of the foam will be carried out using a frequency converter - a frequency-controlled drive, which includes a frequency converter and an induction motor.

The pressure control of the dosing RLP pump will also be performed using a commercially available variable frequency drive.

Frequency converters are designed to convert a single or three-phase voltage with a constant frequency of 50 Hz to a three-phase voltage with a variable frequency in the range from 0.2 to 400 Hz. This property of frequency converters makes it possible to widely use them for stepless speed regulation of any asynchronous electric motors, including electric motors of compressors, pumps, hoists and other mechanisms.

Remote control of the performance of the compressor unit and pumps in accordance with the algorithm of the system will be performed automatically and cyclically to the level until the foam density reaches the required values, i.e. when the foam density deviation falls within the set tolerance zone, the density control process will be stopped.

The density control of the forming foam will be carried out analytically by the formula 3. For this purpose, the computer polls sensors that communicate with the computer through the ADC switch of the computer interface board. With a selectable polling step, the computer reads information about the temperature, pressure, flow rate of gaseous agents involved in the formation of foam. Information is read by means of instrumentation installed on the coolant supply line, such as a thermometer 15, pressure gauge 16, and flow meter 11. Then, information is read from a thermometer 6, pressure gauge 7, and flow meter 4 installed on the air (gas) transport line. Information from sensors installed on the third transport line from the thermometer 20 and the pressure gauge 19 — the foam supply line is removed by the computer through the same ADC switch of the computer interface board.

The ADC switch of the interface board is designed to determine the polling order of instrumentation installed on transport lines (see figure 1).

For automated control of the physico-dynamic properties of the foam using remotely controlled devices remote from the computer, it is preferable to use an interface with a current output.

The information necessary for calculating the density of the foam enters the computer. After performing the calculations, the computer compares the calculated density of the foam with the base density specified at the beginning of the polling cycle. In the case when the calculated value of the density of the foam does not coincide with the set value, the system, cycle by cycle, with a given step, changes the pressure of the coolant in the transport supply line of coolant. The pressure will be manipulated by a frequency-controlled drive 13 according to a predetermined algorithm, cycle by cycle, with the specified step, until the calculated density of the foam matches the specified value.

With a further change in the adjustable parameter and going beyond the set tolerance limit, the system operation is repeated. If the density of the foam calculated by formula (3) is less than the specified value, then with the help of a variable frequency drive, the pump capacity will increase. This will increase the pressure of the liquid component (AMPs) on the value of pitch δP _F. Similarly, the air pressure control system works through a controlled compressor unit. If the foam pressure measured in the third transport line (pressure gauge 19) is less than the set value P _P , then with the help of a frequency-controlled drive, the compressor capacity will be increased. In this case, the pressure of the gas component will be increased by the step size δP _G. Increasing the capacity of the pump or compressor to the required value is performed cyclically with the step set at the beginning of operation.

In both cases, the pump or compressor is controlled using commercially available variable frequency drives.

Remote devices, including valves 5, 9, 10, 21, 22, and 23, are controlled by a computer through an interface unit, consisting of: a communication switch of the interface board. For the presented system, it is enough to have two fixed positions of the controlled gate valves, open or closed. Gate valves of this design are commercially available. The opening of the valve 21 at the command of the computer is performed in the case when there is a need to "purge" the ejector, when the condition specified in formula (1) is not fulfilled, while the valves 22, 9 and 10 are closed. The opening of the valve 23, at the command of a computer, is also performed in the case when it becomes necessary to relieve pressure in the transport supply line of the coolant, for example, if the calculated value of the density of the foam exceeds a specified value by the operator. In this case, all remote valves except 5 are open and the system is in operation.

USED SOURCES

1. A.S. USSR 1423728, M.C. ⁷ ; E21B 44/00. Automatic system for regulating the properties of the drilling fluid / All-Union Research Institute for Well Attachment and Drilling Muds. Author: A.G. Avetisov, S.I. Mkhitarov, A.L. Ulyanov, Yu.M. Orlov, N.A. Kolesnikov (USSR). - No. 4140814 / 22-03; Declared July 25, 86. Publ. 09/15/88. - BI. - 1988. - No. 34.

2. A.S. USSR 1041677, M.C. ⁷ ; E21B 44/00. Automated system for controlling the properties of the drilling fluid / All-Union Research Institute for Well Attachment and Drilling Muds. Author: E.I. Tarabrin, A.L. Ulyanov (USSR). - No. 3439080 / 22-03; Declared 05/17/82. Publ. 09/15/83. - BI. - 1983 .-- No. 34.

3. Temporary instructions for killing wells using foam systems with filler in the conditions of the API. K.M. Tagirov, N.I. Kabanov, R. A. Gasumov and others - Stavropol, 1999.

4. Well development using foam systems. A.V. Amiyan. - Moscow, 1984.

Claims (1)

An automated system for controlling the properties of a drilling fluid prepared on the basis of gaseous agents, containing remotely controlled transport lines: the first line, designed to measure the parameters of the gas component of the foam and regulate the gas supply and includes a compressor, commercially available frequency-controlled actuators, two controlled valves, and also a flow meter, thermometer and manometer, based on the readings of which with subsequent conversion according to analytical dependencies in the density value and foam, the operation of controlled devices — valves and a compressor — is formed; the second line, which controls and regulates the fluid flow, located between the container for foaming liquid (POG) and the ejector and includes two remotely controlled valves, a pump for supplying liquid, as well as a liquid flow meter, thermometer and manometer, based on the readings of which the value of the density of the foam is formed by the operation of controlled devices - valves and controlled by a variable frequency drive of the pump; the third line, designed to control the dynamic properties of the foam and located immediately after the ejector in front of the wellhead, it includes a non-return valve, a manometer, a thermometer and a controlled valve, characterized in that a switch, an ADC switch of a computer interface board and a frequency adjustable drives connected to the compressor and pump on the one hand and computers on the other hand through the interface card switch, while remotely controlled via the commutator on all transport lines p gate valves.

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