EA032018B1 - Method for determining parameters of a multi-component downhole flow - Google Patents

Abstract

The invention relates to a measuring technique and can be used in the oil and gas industry to measure in real time the phase composition of a multicomponent three-phase flow medium. EFFECT: reduction of measurement time due to reduction of signal processing time while maintaining the specified accuracy. In the method, groups of gamma-quanta beams crossing the flow section are formed by passing a primary fan-shaped beam diverging from the center of the radiation source through the collimator, signals are detected after passing the controlled medium by the beams, and after processing the signals, the group of beams is re-formed, eliminating those beams necessary for further control of the environment by blocking part of the holes of the collimator.

Description

The invention relates to measuring equipment and can be used in the oil and gas industry, for example, to measure in real time the phase composition (percentage of phases) of a stream of a multicomponent three-phase medium, including gas condensate, gas and water, namely, the flow of well fluid, and also to determine the mass and volumetric flow rate of liquid and gaseous hydrocarbons as part of other measuring systems at oil and gas production and oil and gas treatment facilities.

To ensure effective control and regulation of the oil production process, it is necessary to measure as accurately as possible the amount of hydrocarbons extracted from the reservoir, thereby ensuring the optimal operating mode and the highest total production over the life of the field. It is necessary to measure the production of individual wells individually, since, for example, a sharp increase in water cut in a single well is difficult to detect when measuring the total production from several wells, and even more so from group measurements it is impossible to accurately determine in which particular well the water cut increased carry out procedural work or work on it to reduce production costs.

Therefore, there is a great need for a device that meets the following set of requirements: the device must provide continuous determination of the volume concentrations of the components in a linear fluid (water, liquid hydrocarbons and gas);

the device should provide control over the accuracy of measurements of the phase composition of the linear fluid with changes in flow conditions and the shape of the distribution of phases in the cross section of the pipe;

the device must provide the calculation of the volume concentration of the components in the linear fluid during emergency and other situations in the field (aquifer breakthrough, casing flows, sand removal, etc.) in the shortest possible time.

The methods for determining the parameters of a borehole multicomponent flow, implemented using such devices, with their general similarity also differ in their duration and quality of the results.

A known method for measuring the percentage of liquid and gas phases in a multiphase fluid flowing through a flow meter (see patent RU 2533318, IPC G01F1 / 36, published November 20, 2014), which consists in the formation of a narrow beam of gamma rays crossing the studied stream strictly in diameter, which are formed by passing through the collimator of the primary beam from the source of gamma rays installed outside the stream, detecting the beam of the formed group of gamma rays after they pass through the analyzed medium by the detector, e is established stream and subsequent processing of the detected signal.

A significant disadvantage of this method is that in the analysis of multiphase flow only one narrowly focused beam of photons is used. For different types of flow and different Reynolds numbers of the linear fluid, the distribution function of the condensate-gas factor (GHF) over the radius will be unstable, that is, the shape of the flow may be different depending on the radial coordinate. The use of one beam of a gamma densitometer when restoring the radial dependence of the GHF at different flow diagrams can introduce significant errors in the measurements.

Closest to the claimed method in technical essence is a method for determining the parameters of a borehole multicomponent flow (see the description of patent RU 2399879, IPC G01F1 / 00, published September 20, 2010), adopted as a prototype, which consists in the formation of a group of gamma-ray beams, intersecting the studied stream, which are formed by passing through the collimator of the primary beam from the source of gamma rays installed outside the stream, detecting each of the beams of the formed group of gamma rays after passing and medium and analyzed detectors also mounted outside the stream, and the subsequent processing of the detected signals.

The measurement geometry in the known method is multi-beam: five fan beams in the pipeline, one of which is directed strictly along the diameter of the pipeline, and the four remaining - in pairs, symmetrically relative to the first. Two more rays (sixth and seventh) are directed by the same fan behind the pipeline symmetrically with respect to the first diametrical one. The detector unit consists of nine detectors: the first five measure the number of photons from the first five rays on different chords of the pipeline, two more (sixth and seventh) measure undetected radiation along the sixth and seventh rays for calibration.

This measurement geometry takes into account the radial inhomogeneity of the flow. However, the known method has several disadvantages, such as the lack of control over the accuracy of measurements of the phase composition of the linear fluid with changes in flow patterns and the shape of the phase distribution in the pipe cross section, due to the invariance of the measurement geometry and the number of analyzed gamma-ray beams, and not the shortest possible time for measuring the flow rate with due accuracy , also due to the inability to change the number of gamma-ray beams.

The objective of the present invention is to remedy these disadvantages, namely the development of a method that allows with high accuracy to determine the real shape of the stream and to control its further state.

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The technical results of the proposed method is to reduce the measurement time at a given accuracy, as well as the possibility of constant monitoring of the real shape of the stream over time.

Technical results are achieved by the fact that in the method for determining the parameters of a borehole multicomponent stream, which consists in forming a group of gamma-ray beams crossing the cross-section of the studied stream, formed by passing through the collimator a primary gamma-ray beam, fan-shaped diverging from the center of the radiation source installed outside the flow section, detecting the formed group of beams after they pass the controlled medium by detectors installed outside the flow section, and process and detected signals, according to the results of processing the detected signals, a group of gamma-ray beams is formed again by passing through the collimator a primary gamma-ray beam diverging fan-shaped from the center of the radiation source installed outside the flow cross section, minimizing the number of beams in accordance with the results of the primary exposure by overlapping part of the holes of the collimator, which, in accordance with the results of the analysis of the primary exposure, are not necessary for further control of the flow shape, the detection of the formed group of beams after they pass the controlled medium by detectors installed outside the flow section, and the final processing of the detected signals.

The invention is illustrated in the drawing, which shows a diagram of the implementation of the proposed method.

The diagram shows a radiation source 1, which emits a primary beam of 2 gamma rays passing through a collimator 3, containing holes 4 with diaphragms 5, beams 6 of gamma rays crossing the cross section of the flow 7 of the controlled medium in the pipeline 8, detectors 9 and analysis device 10 and installation management.

The implementation of the proposed method is as follows.

From a source 1 of ionizing radiation (for example, an x-ray tube), which is located outside the cross section of the pipe 8, produce a fan-shaped diverging beam of 2 gamma quanta.

The beam 2, passing through the holes 4 of the collimator 3, is divided into identical beams 6, passing further through the pipeline 8 with a flow of a controlled medium 7 moving through it. Beams 6 that passed through the pipeline 8 and interacted with the flow of the controlled medium 7 enter the detectors 9, the signals from which enter the device 10, in which they are processed and further analyzed.

As a result of the analysis, a real picture of the distribution in stream 7 is obtained and, in accordance with it, the beams 6 are re-formed, leaving those openings 4 of the collimator 3 that are necessary open and blocking those which are not with the help of dampers 5, thus minimizing the number of beams 6. This minimization allows reducing the processing and analysis of signals received from the detectors 8 (without reducing the quality of the control of the shape of the stream 7) (since the number of these signals is reduced to the required minimum).

This invention can be implemented, for example, as part of a multiphase flow meter to determine the phase composition of a linear mixture. With a decrease in the number of scanning beams, for example, from 10 to 2, the signal processing time with a sufficient level of measurement error decreases by 5 times, which is important for decision-making in emergency and other situations at the field (aquifer breakthrough, headwaters, sand removal, etc. d.). According to the calculations, even with exotic flow diagrams, measurements on 2 optimal rays can give up to 1% of the relative error in the determination of CGF, which is more than sufficient for the interests of the oil and gas industry. If you need extremely accurate measurements of the phase composition without time limits, it is possible to use all the holes of the collimator for flow analysis.

The inventive method for determining the parameters of a borehole multicomponent stream allows a high degree of accuracy to control the state of the medium in the stream at any time, reducing the discreteness of such control.

Claims (1)

CLAIM A method for determining the parameters of a borehole multicomponent stream, which consists in forming a group of gamma-ray beams crossing the cross-section of the studied stream, formed by passing through the collimator a primary gamma-ray beam diverging fan-shaped from the center of the radiation installed outside the flow section, detecting the formed group of beams after they pass controlled environment by detectors installed outside the flow section, and processing the detected signals, characterized in that according to the results of processing the detected signals, a group of gamma-ray beams is re-formed by passing through the collimator a primary gamma-ray beam diverging fan-shaped from the center of the radiation source installed outside the flow section, minimizing the number of beams in accordance with the results of the primary exposure by blocking part of the holes of the collimator, which, in accordance with the results of the analysis of the primary exposure, are not necessary for further control of the flow shape, detecting the formed group of beams after they pass the controlled medium by detectors installed outside the flow section, and the final processing of the detected signals.