Method for detecting and controlling the presence of sand in a hyrdocarbon production well equipped with a gas lift

Abstract

It is provided a computer-implemented method for detecting and controlling the presence of sand in a hydrocarbon production well (250a) equipped with a gas lift system (244). The method comprises automatically detecting the presence of sand in the well. The method comprises controlling a choke valve (221) and / or a wing valve (220) of the well depending on the detection of the presence of sand, including partially closing the choke valve so as to reduce a well production rate, or fully closing the choke valve and then the wing valve so as to stop well production. The method forms an improved solution for detecting and controlling the presence of sand in a hydrocarbon production well equipped with a gas lift.

Description

[0001] METHOD FOR DETECTING AND CONTROLLING THE PRESENCE OF SAND IN A HYRDOCARBON PRODUCTION WELL EQUIPPED WITH A GAS LIFT

[0002] Technical field

[0003] The present disclosure relates to the field of sand detection in hydrocarbon production wells, and more specifically to a method for detecting and controlling the presence of sand in a hydrocarbon production well equipped with a gas lift system. The disclosure also relates to a system for automatically detecting and controlling the presence of sand in a hydrocarbon production well equipped with a gas lift system. It is also provided a computer program, a data storage medium, and equipment, for performing the method.

[0004] Technical background

[0005] The presence of sand in a hydrocarbon production wells (and therefore, in the produced hydrocarbons) is a known phenomenon occurring in the field of oil and gas, which can cause significant issues relating to well productivity. The presence of sand can cause particular problems for production wells equipped with an artificial gas lift activation system. In fact, if there is a known risk of having sand in the well, the implementation of an artificial activation system in the form of a electrical submersible pump (ESP) is generally avoided altogether. For wells for which there is a known risk of a sand presence, gas lift systems are often used. However, despite being preferable to an ESP, the sand still has an adverse effect on the gas lift system and can damage the system. This can consequently slow down, disrupt or hinder well production altogether (i.e. it can cause a loss in production until the sand has been cleared and / or gas lift system equipment has been replaced or repaired). The well is generally protected by filters placed on the interface between the well and the hydrocarbon reservoir. Some solutions exist to detect the presence of sand in a production well, for example by monitoring normal and abnormal behavior of the well and by identifying the behavior.

[0006] Within this context, there is a need for an improved method for detecting and controlling the presence of sand in a hydrocarbon production well equipped with a gas lift.

[0007] Summary It is therefore an object of this disclosure to provide a computer- implemented method for detecting and controlling the presence of sand in a hydrocarbon production well equipped with a gas lift system, the method comprising automatically: detecting the presence of sand in the well; controlling a choke valve and / or a wing valve of the well depending on the detection of the presence of sand, including: o partially closing the choke valve so as to reduce a well production rate; or o fully closing the choke valve and then the wing valve so as to stop well production.

[0008] The method may comprise one or more of the following features:

[0009] - detecting the presence of sand in the well comprises taking at least one measurement;

[0010] - the measurement is an acoustic measurement for the detecting of the presence of sand being successful when the measurement exhibits an instantaneous signal spike or a continuous signal spike;

[0011] - the acoustic measurement is expressed as a percentage of a baseline noise;

[0012] - the method comprises assessing a set of one or more first conditions respective to the fully closing and a set of one or more second conditions respective to the partially closing, the method performing the fully closing if either first condition is met, the method else performing the partially closing if either second condition is met;

[0013] - the partially closing takes place upon identification of either one of a respective set of one or more situations, the set of one or more situations respective to the partially closing including: o the detecting occurring more than a predetermined number of times over a first predetermined period of time and exceeds a first threshold; and / or o the detecting occurring continuously over a second predetermined period of time and exceeds the first threshold;

[0014] - the first threshold lies between 0.1 and 10%, for example between 0.5 and 5%, for example between 1 and 5%, for example 2% of the baseline noise; - the first predetermined period of time is a number of hours, for example, 24 hours;

[0015] - the second predetermined period of time is a number of minutes, for example, 15 minutes;

[0016] - the method further comprises automatically configuring the first threshold;

[0017] - the fully closing takes place upon identification of either one of a respective set of one or more situations, the set of one or more situations respective to the fully closing including: o the detecting occurring more than another predetermined number of times over a third predetermined period of time and exceeds a second threshold; and / or o the detecting occurring continuously over a fourth predetermined period of time and exceeds the second threshold;

[0018] - the third predetermined period of time is a number of hours, for example, 24 hours;

[0019] - the fourth predetermined period of time is a number of minutes, for example, 1 hour;

[0020] - the second threshold lies at least 0.5% above the first threshold, for example at least 1 % above the first threshold, for example at least 2% above the first threshold;

[0021] - the method further comprises automatically configuring the second threshold;

[0022] - the method further comprises implementing a sand detection counter, the counter counting the or a number of sand signal spikes over a period of time; and / or

[0023] - the counter starts upon a first detection of sand, the counter being stopped and reset to zero upon full closing of the choke and / or wing valves.

[0024] It is also provided a computer program comprising instructions which, when executed by a processor, cause the processor to perform the method.

[0025] It is also provided a data storage medium having recorded thereon the computer program.

[0026] It is also provided a system for automatically detecting and controlling the presence of sand in a hydrocarbon production well equipped with a gas lift system, the system comprising:

[0027] - a memory having recorded thereon the computer program; and - a processor for executing the program;

[0028] The system may further comprise one or more of the following features:

[0029] - the system further comprises a choke valve and / or a wing valve of the well;

[0030] - the system further comprises at least one sensor for the detecting of the presence of sand in the well; and / or

[0031] - the sensor is an acoustic sensor.

[0032] It is also provided equipment for a hydrocarbon production well, the equipment including a gas lift system, the equipment further including the system.

[0033] Brief description of the drawings

[0034] Non-limiting examples will now be described in reference to the accompanying drawings, where:

[0035] FIG. 1 shows an example of a production well equipped with a gas lift system;

[0036] FIG. 2 shows an example of the detecting according to a graph displaying ASD (Acoustic Sand Detector) signal (expressed as a percentage) as a function of time;

[0037] FIG. 3 shows an example of the detecting according to a graph displaying ASD signal (expressed as a percentage) as a function of time;

[0038] FIG. 4 shows an example of the detecting according to a graph displaying ASD signal (expressed as a percentage) as a function of time;

[0039] FIG. 5 shows an example of the detecting according to a graph displaying ASD signal (expressed as a percentage) as a function of time; and

[0040] FIG. 6 shows an example of an acoustic sand detector positioned along a liquid hydrocarbon flowline.

[0041] Detailed description

[0042] It is proposed a computer-implemented method for detecting and controlling the presence of sand in a hydrocarbon production well equipped with a gas lift, wherein the method comprises automatically detecting the presence of sand in the well and automatically controlling a choke valve and / or a wing valve of the well depending on the detection of the presence of sand. It is further provided a system for automatically detecting and controlling the presence of sand in a hydrocarbon production well equipped with a gas lift, according to the method. The method comprises detecting the presence of sand in the well. In other words, the method monitors the well and identifies that sand is present and / or a quantity of sand present and / or a frequency of presence of sand at one or more times or period of times. The method further comprises controlling a choke valve and / or a wing valve of the well depending on the detection of the presence of sand. In other words, depending on the result of the detection, the method may or may not act on the choke valve and / or a wing valve. At times, the method comprises effectively acting on the choke valve and / or the wing valve. The controlling includes partially closing the choke valve so as to reduce a well production rate, or fully closing the choke valve and then the wing valve so as to stop well production. In other words, the method may at times partially close the choke valve, and additionally or alternatively, the method may at (other) times fully close the choke valve and then fully close the wing valve.

[0043] Such a method and system form an improved solution for detecting and controlling the presence of sand in a hydrocarbon production well equipped with a gas lift.

[0044] Detecting the presence of sand in the well allows for an overview of the “sand status” or quantity (if any) of sand in the well at any given time. Further, the detecting allows for appropriate actions to be taken to overcome any damage that the sand can cause to the well and to production.

[0045] Controlling a choke valve and / or a wing valve of the well enables effectively managing production as a function of the quantity or frequency of sand detected. Controlling a choke valve and / or a wing valve specifically enables directly adjusting production by adjusting the rate at which the hydrocarbons are gas-lifted to the surface.

[0046] Partially closing the choke valve, depending on the presence of sand detected, so as to reduce a well production rate allows for responding to the presence of sand in a manner that still allows for production to continue. In other words, the method may in such a case permit avoiding a systematic stopping of production for each detection of sand in the well. By reducing production, for example due to a detection of sand that is non-critical, not only can production continue, but the rate at which sand accumulates within the gas lift system can also reduce, which in turn protects the well and production system. “Non-critical” may relate to a quantity of sand at a particular point in time, or a quantity of sand over a certain period of time, i.e. over a certain duration. “Non-critical” may take the current or actual condition of the gas lift system (for example, lifecycle), or indeed of another production well component or equipment into account. A non-critical detection may be a detection that meets a value below a certain threshold.

[0047] Fully closing the choke valve and then the wing valve, depending on the presence of sand detected, so as to stop well production, allows for a higher protection level of the gas lift system when sand is detected. This may occur, for example, for a detection of sand that is critical. “Critical” may relate to a quantity of sand at a particular point in time, or a quantity of sand over a certain period of time, i.e. over a certain duration. A critical detection may be a detection that meets a value above a certain threshold. “Critical” may take the current or actual condition of the gas lift system (for example, lifecycle), or indeed of another production well component or equipment into account.

[0048] The system may be configured for performing both types of controlling, thus both partially closing the choke valve so as to reduce a well production rate and fully closing the choke valve and then the wing valve so as to stop well production, depending on the situation, in particular depending on the output of the sand detection process. For example, the method may comprise assessing a set of one or more first conditions respective to the fully closing and a set of one or more second conditions respective to the partially closing. The method may then performing the fully closing if either first condition is met, the method else performing the partially closing if either second condition is met. If none of the first and second conditions are met, the method may leave the choke valve and the wing valve fully open. The first conditions thus allow to identify situations respective to the fully closing (situations where the fully closing is appropriate), while the second conditions allow to identify situations, when none of the first conditions are met, respective to the partial closing (where the partial closing is appropriate). The first conditions may run in parallel with the second conditions. In other words, the system may simultaneously check to see if the partially closing is to take place while checking to see if the fully closing may take place. According to some examples, the method may decide which controlling option to execute first. The first conditions may be primary conditions and the second conditions may be secondary conditions. If both the first conditions and the second conditions are met at the same time, the method may perform the fully closing. If the first conditions are met, and subsequently the second conditions are met but the first conditions are still being met, the system may maintain the fully closing. In other words, the method may prevent a partial opening of the choke (i.e. a partial close) while the first conditions are still being met. However, if the method performs a fully closing, and during the fully closing, the first conditions are no longer met and the second conditions are met, the method may partially open (i.e. partially close) the choke.

[0049] By controlling the choke valve in such a case by either partially closing the choke valve or fully closing the choke valve and then the wing valve, the method facilitates not only protecting the well and production system, but allows for an adaptable or flexible protection method that can still allow production to continue despite the presence of sand having been detected. The choke valve may be located on the production line of the well. The production line may be a liquid line. The wing valve may also be located on the production line of the well. The choke may be downstream of the wing valve. The choke valve may be a remote control valve (RCV). The RCV may be along the liquid flow line of the hydrocarbon production system. The RCV may be remote-controlled.

[0050] Further, by automatically detecting and automatically controlling, there is no need for an operator action between the two phases of detecting and controlling. In other words, after launching, the method runs as a fully automatic process, which may fully automatically reduce or stop production depending on the result of a fully automated sand detection. This in turn both simplifies work for the operator and also allows for a faster action to control the well upon detecting the presence of sand, which consequently optimizes the production of hydrocarbons from the well.

[0051] The presence of sand may refer to a quantity of sand that is above a minimal quantity of sand, for example above a certain baseline (for example, trace quantities of sand may not qualify as a presence of sand). The detecting may comprise not only determining if sand is present, but also how much sand (i.e. what quantity of sand, perhaps as a percentage of the baseline) is present. The detecting may comprise detecting the presence of sand at a given point in time, for example instantaneously, or over a certain duration or period of time.

[0052] Detecting the presence of sand in the well may comprise taking at least one measurement. This at least one measurement may enable determining the type of controlling which should follow; the partially closing or the fully closing. The detecting may comprise taking several measurements. The detecting may comprise taking several measurements over a certain period of time or according to a sampling rate. The detecting may comprise taking measurements every 10 milliseconds, every 100 milliseconds, 1 second, 10 seconds or 30 seconds. The sampling rate may lie in a range from 1 sampling per second to 1 sampling per minute. The sampling rate may comprise 1 measurement per millisecond, or 2 measurements per millisecond, or up to 10 measurements per millisecond, or 1 sample per second, or up to 100 samples per second. The detecting may run continuously over a predetermined run period.

[0053] The at least one measurement may be an acoustic measurement for the detecting of the presence of sand being successful when the measurement exhibits an instantaneous signal spike or the measurement exhibits a continuous signal spike. A device such as, for example, an acoustic sand detector (ASD), may take the at least one measurement. The system may comprise at least one sensor for the detecting the presence of sand in the well. The sensor may be an acoustic sensor. The sensor may be a microphone that may take the at least one (in this case, acoustic) measurement. In addition to the artificial gas lift system, the at least one sensor may be part of the equipment for the hydrocarbon production well. The acoustic measurements may be in the form of the noise of grains of sand moving against the wall of the pipes comprising the well. The method may comprise quantifying the detected noise so as to determine the quantity of sand in the well. The acoustic measurement may be expressed as a percentage of a baseline noise. The device taking the at least one measurement, or another device in connection with the device taking the at least one measurement at least one measurement may provide the at least one measurement at an acoustic signal, or an ASD (Acoustic sand Detector) signal. The method may comprise expressing the signal as a percentage of a baseline signal (for example, a noise signal indicating a presence of sand in the well).

[0054] It is also provided a computer program comprising instructions which, when executed by a processor, causes the processor to perform the method. The program may comprise instructions for executing the detecting and the controlling. The program may comprise at least one if statement. The program may comprise at least two if statements. For example, the program may first run an if statement wherein the “if’ condition may be the first conditions respective to the fully closing criteria being met. If the condition is met, the program instructions may execute the fully closing. The program may comprise a second if statement. In the second if statement, the “if’ condition may be the second conditions respective to the partially closing criteria being met. If the condition is met, the program instructions may execute the partial closing. If the condition is not met, the program may comprise instructions to run the check again. The program may run an the respective if statement for each set of conditions in parallel. In other words, the system may simultaneously check, such as via respective if statements, for a presence of sand for a partial closing and for a presence of sand for a full closing. The program may implement the statements in a loop so as to check for either set of conditions on a continuous basis.

[0055] It is also provided a data storage medium having recorded thereon the computer program. The system comprises a memory having recorded thereon a computer program according to the method, and a processor for executing the program. The memory may also store a database. The memory may be any hardware adapted for such storage, possibly comprising several physical distinct parts (e.g. one for the program, and possibly one for the database). The computer program may comprise instructions executable by a computer, the instructions comprising means for causing the above system to perform the method. The program may be recordable on any data storage medium, including the memory of the system. The program may for example be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. The program may be implemented as an apparatus, for example a product tangibly embodied in a machine-readable storage device for execution by a programmable processor. The processor may be a programmable processor executing a program of instructions to perform the method steps or the functions of the method by operating on input data and generating output. The processor may thus be programmable and coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system, at least one input device, and at least one output device. The program may comprise at least one instruction to control the choke valve and / or wing valve remotely so as to execute the partial or fully closing. Depending on the detection of sand, the processor may execute the program instruction to either partially or fully close the choke and / or wing valve. The executing of the instructions may comprise wirelessly communicating the instructions. Alternatively executing of the instructions may comprise communicating the instructions via a wired network. The method may for example comprise sending the instructions wirelessly or via a wired connection to an actuator on the choke valve and / or wing valve respectively so as to adjust the opening of the valve to the desired position.

[0056] The method may comprise producing hydrocarbons from the production well, taking at least one sample of the hydrocarbons, and determining the sand content in the sample. The method may comprise taking the at least one measurement (for example, a sound measurement), and making a comparison between the at least one measurement and the quantity of sand in the at least one sample. This may be a pre-analysis, i.e. an analysis implemented before the detecting and the controlling. The pre-analysis may determine the baseline noise, for example in the form of a baseline signal. This can allow for determining which measurement value can be considered equivalent to a detection of sand in the well. Additionally, this may allow for the determining of thresholds (e.g. threshold, second threshold) for the partial closing of the choke valve and wing valve and / or fully closing of the choke valve. Additionally or alternatively, this may allow for the determining of the duration (e.g. first predetermined period of time, second predetermined period of time, third predetermined period of time, fourth predetermined period of time) for triggering the partial closing of the choke valve and wing valve and / or fully closing of the choke valve. Additionally or alternatively, this may allow for the determining of the number of times (e.g. predetermined number of times, other predetermined number of times) for triggering the partial closing of the choke valve and wing valve and / or fully closing of the choke valve. Consequently, the method can enable configuring the system so as to cater to the detected quantity of sand in question, as such thresholds, durations and number of times can depend on the nature of the sand in the well, the type of well completion, cycle life to the well, restart period, well start-up or stabilized conditions, and / or well equipment conditions.

[0057] The program may comprise instructions for executing the detecting and the controlling.

[0058] The partially closing may take place upon identification of either one of a respective set of one or more situations. In other words, the partially closing may take place after identification of either one of a respective set of one or more situations, such as immediately after or once the identification has been made, or such as within a predetermined period of time after which the identification has been made. The set of one or more situations respective to the partially closing may include if the detecting occurs more than a predetermined number of times over a first predetermined period of time and exceeds a first threshold. In other words, the partial closing may take place upon detection of a number of fluctuations around a first threshold over a certain duration. For example, the partially closing may take place if the at least one measurement may be higher than the first threshold (ASD_H1 ) more than a predetermined number of times (ASD_Multi1 ) during a day sampling period signal spike’s detection. The first period of time may be a number of hours, for example, 24 hours, or more than 24 hours, for example, 36 hours, or 72 hours. Alternatively, the first period of time may be a number of days, for example greater than 3 days or less than 3 days. The third period of time may be greater than or equal to 24 hours. Alternatively, the first period of time may be a number of hours less than 24 hours, for example, less than or equal to 12 hours, or greater than or equal to 12 hours. The number of times may also be referred to as the number of detections. The predetermined number of times (i.e. detections) may be a number of times greater than or equal to 10 times. Alternatively, the predetermined number of times may be a number of times less than or equal to 10 times. The predetermined number of times may for example be 2 times over 2 hours. One number of time, or one detection, can be equal to a single detection. For example, the detection may be one single instantaneous signal spike. Alternatively, one number of time, or one detection, can be an accumulation of individual detections. For example, the detection may be a non-instantaneous signal spike. The non-instantaneous signal spike may last a number of seconds, or a number of minutes, for example less than or equal to 5 minutes, or greater than or equal to 5 minutes, or less than or equal to 10 minutes, or greater than or equal to 10 minutes, or less than or equal to 15 minutes, or greater than or equal to 15 minutes, or less than or equal to 20 minutes, or greater than or equal to 20 minutes, or less than or equal to 25 minutes, or greater than or equal to 25 minutes. The non- instantaneous signal spike may for example last up until 1 hour. The non- instantaneous signal spike may comprise a number of small signal spikes, the average of the total number of small signal spikes being above the first threshold.

[0059] Additionally or alternatively, the set of one or more situations respective to the partially closing may include the partially closing taking place if the detecting occurs continuously over a second predetermined period of time and exceeds the first threshold. In other words, the partially closing may take place if the detecting occurs consistently above the first threshold over a certain duration. The detecting occurring continuously may be equivalent to a non- instantaneous signal spike, which may comprise any of the features of the above described non-instantaneous signal spike. The second period of time may be a number of minutes, for example, 15 minutes, or for example less than or equal to 5 minutes, or greater than or equal to 5 minutes, or less than or equal to 10 minutes, or greater than or equal to 10 minutes, or less than 15 minutes, or greater than 15 minutes, or less than or equal to 20 minutes, or greater than or equal to 20 minutes, or less than or equal to 25 minutes, or greater than or equal to 25 minutes. The second period of time may for example last up until 1 hour. The first threshold may be based on an evaluation of a percentage of the noise base line that represents sand production. This evaluation may depend a lot on how the noise baseline can be impacted by external noise that is not representative of sand. The first threshold may lie between 0.1 and 10%, for example between 0.5 and 5%, for example between 1 and 5%, for example 2% of the baseline noise.

[0060] The fully closing may take place upon identification of either one of a respective set of one or more situations. The set of one or more situations respective to the fully closing may include if the detecting occurs more than another predetermined number of times (i.e. a predetermined number of times not necessarily the same as the predetermined number of times of the partially closing) over a third predetermined period of time and exceeds a second threshold. For example, the at least one measurement may be higher than the second threshold (ASD_H2) more than a predetermined number of times (ASD_Multi2) during a day sampling period pike’s detection. The third predetermined period of time may be a number of hours, for example, 24 hours, or more than 24 hours, for example, 36 hours, or 72 hours. Alternatively, the third period of time may be a number of days, for example greater than 3 days or less than 3 days. The third period of time may be greater than or equal to 24 hours. Alternatively, the third period of time may be a number of hours less than 24 hours, for example, less than or equal to 12 hours, or greater than or equal to 12 hours.

[0061] The other number of times (i.e. detections) may be greater than or equal to 5 times. Alternatively, the predetermined number of times may be a number of times less than or equal to 5 times, for example, 3 times. The other number of times may for example be 2 times over a period of 2 hours.

[0062] One number of times, or one detection, can be equal to a single detection. For example, the detection may be one single instantaneous signal spike. Alternatively, one number of time, or one detection, can be an accumulation of individual detections. For example, the detection may be a non-instantaneous signal spike, as previously described in the method.

[0063] Alternatively, the fully closing may take place if the detecting occurs continuously over a fourth predetermined period of time and exceeds the second threshold. The detecting occurring continuously may be equivalent to a non-instantaneous signal spike, which may comprise any of the features of the above described non-instantaneous signal spike. The fourth predetermined period of time may be a number of minutes, for example, 1 hour. The second threshold may lie at least 0.5% above the first threshold, for example at least 1 % above the first threshold, for example at least 2% above the first threshold. The first threshold may be less than the second threshold.

[0064] By providing a method that controls a choke valve and / or a wing valve of the well depending on the detection of the presence of sand, the method may allow for selection of the most appropriate action for the given sand circumstance. Therefore, a finer control of the system can be obtained.

[0065] The method may comprise automatically configuring the first threshold. Additionally or alternatively, the method may comprise automatically configuring the second threshold. The configuring may take the baseline noise into account. The configuring may take different parameters of the hydrocarbon production well into account, such parameters possibly including parameters relating to the equipment of the well (for example, the gas lift system). The parameters may comprise user-supplied information or values measured by sensors of the production well, for example flow sensors, pressure sensors and / or temperature sensors. Alternatively, the method may comprise manually configuring the first threshold. Additionally or alternatively, the method may comprise manually configuring the second threshold. The method may comprise automatically configuring any of the first predetermined period of time, second predetermined period of time, third predetermined period of time and / or fourth predetermined period of time. Additionally or alternatively, the method may comprise manually configuring any of the first predetermined period of time, second predetermined period of time, third predetermined period of time and / or fourth predetermined period of time. The method may comprise automatically configuring the predetermined number of times and / or the other predetermined number of times. Additionally or alternatively, the method may comprise manually configuring the predetermined number of times and / or the other predetermined number of times.

[0066] For the controlling, the method may comprise executing the partially closing in a first step, carrying out the detecting once more, and then executing the fully closing in a second step. Alternatively, for the controlling, the method may comprise executing the fully closing in a first step, carrying out the detecting once more, and then executing the partial closing in a second step, i.e. the system executes a partial opening. This may be for the case where there is a decrease in presence of sand. This may be a precautionary step before detecting once more, and then fully opening the control valve. Alternatively, the system may execute a full opening directly upon the decrease in the presence of sand, i.e. without the precautionary step. The method may comprise implementing a sand detection counter. The counter may count the or a number of sand signal spikes over a period of time (e.g. a predetermined period of time). The counter may start upon a first detection of sand, the counter being stopped and reset to zero upon the full closing of the choke and / or wing valves.

[0067] FIG. 1 shows an example of a production well equipped with a gas lift system. FIG. 1 displays a well 250a and wellhead 250b equipped with a gas lift system 244 beneath a production packer 242. The gas lift system is shown to comprise a gauge 201 and downhole safety valve (DHSV) 204 along liquid production line 246 for oil and water. The line 246 also comprises valves such as a production master valve (PMV) 214, annulus master valve (AMV) 212, production wing valve (PWV) 220, and RCV 221 (also referred to as the choke valve). Sensors are also located along the line 246, such as wellhead temperature (WHT) sensor 218, wellhead pressure (WHP) sensor 216, flow line pressure (FLP) sensor 224, liquid flow rate (QTH) sensor 226, acoustic sand detector (ASD) 228, and a differential pressure sensor dP 222 through RCV 221. Likewise, there is a gas line 248 connected to the well 250a, along which valves such as annulus safety valve (ASV) 202, pressure valve control (FCV) 234, and annulus wing valve (AWV) 236 are located. The W 236 is located upstream of the RCV 221 . Sensors are also located along the line 248, such as casing head pressure (CHP) 230, injection gas-lift rate (IGR) 232 and gas-lift pressure (GLP) 238. A data acquisition line 206 is also depicted to connect gauge 201 to an acquisition unit 208 and bottom hole pressure (BHP) sensor 210.

[0068] The computer program of the system may instruct the acoustic sand detector (ASD) 228 to start the detecting of the presence of sand in the well. The detector may take at least one measurement, for example at least one acoustic measurement. At least one of the measurements may correspond to a baseline noise. The detector may detect at least one or more signal spikes, i.e. the detector may take at least one measurement corresponding to a signal spike value. The signal spikes may be instantaneous or non-instantaneous signal spikes. At least one of the detected signal spikes may be greater than or equal to the first threshold, and / or greater than or equal to the second threshold. The detector may communicate the detected signal spikes in the form of a signal to a data acquisition line similar to the data acquisition line 206. The acquisition line may provide the signal to an acquisition unit similar to the acquisition unit 208 (or indeed, to the same acquisition unit 208). The acquisition unit may be connected to the processor of the system. The processor may for example execute post-processing on the detected signals, for example to quantify the detected noise signals as quantities of sand in the well. The system may provide the at least one measurement in real-time. The processor may communicate the signal to an operator. The system may comprise a graphical user interface (GUI). The processor may send the signal to a GUI, which may present the detected sand in the form of a graph (for example, presence of sand as a function of time). The operator may receive the data (such as, for example, the graph of the at least one measurement or signal) on the GUI in real-time. Depending on the measurements, the processor may execute program instructions to perform either a partial closing or a fully closing of the choke valve (i.e. a full closing that stops production). In other words, the system may automatically execute the controlling after the detection of a presence of sand sufficiently high that a protection of the gas lift system is preferable. If the detected signal spikes occurs more than a predetermined number of times over a first predetermined period of time and exceeds a first threshold, or continuously over a second predetermined period of time and exceeds the first threshold, the processor may send instructions to the RCV 221 to partially close. The partial closing instruction (also referred to as a reduction rate) may be a degree of closing. The closing may be expressed a percentage of the opening. Fully closed may be equal to 0% of the opening. For example between 1 % and 10% closed (i.e. between 99% and 90% open), or for example between 10% and 50% closed (i.e. between 90% and 50% open), such as 33% closed (i.e. such as 67% open), or for example between 50% and 80% closed (i.e. between 50% and 20% open). This partial closing allows for a reduced rate of production, thereby reducing the quantity of sand through the gas lifted well or flow line, while at the same time avoiding a complete production stop of the well.

[0069] The partial closing may be user-configured, i.e. the operator may configure the system so that, depending on the quantity of sand detected (fir example, instantaneously or over a given duration), the system applies a reduction rate (partial closing) of a suitable value that can effectively manage the detected sand. For example, the choke valve may take on a fixed fall-back position, at for example 25% of the opening.

[0070] If the detecting occurs more than another predetermined number of times over a third predetermined period of time and exceeds a second threshold, or continuously over a fourth predetermined period of time and exceeds the second threshold, the processor may send instructions to the RCV 221 to fully close (i.e. closing is 100%). Production can therefore be safely stopped, reducing risk of potential damage to the gas lift.

[0071] Whether the RCV is partially closed or fully closed (i.e. completely closed), the acoustic sand detector (ASD) 228 may meanwhile continue taking measurements. If the presence of sand decreases, the processor may execute program instructions to fully open the RCV (i.e. degree of closing or reduction rate is from 100% to 0%). Alternatively, if the presence of sand decreases, the processor may execute program instructions to reduce the degree to which the RCV is partially closed, that is to say, to partially open the RCV (for example, the degree of closing may pass from 10% to 5%). Alternatively, in the case where the RCV is fully closed, the processor may execute program instructions to partially open the (for example, the degree of closing may pass from 100% to 95%). If the measurements of the acoustic sand detector (ASD) 228 continue to show a decrease in the presence of sand, the program may send instructions to open the RCV (i.e. degree of closing is 0%).

[0072] The acoustic sand detector (ASD) 228 can be seen to be positioned at a bend in the line 246. Such a configuration can be examined in more detail in the example of FIG. 6. FIG 6 displays an acoustic sound detector 228 positioned downstream of a 90° bend 504 of a liquid line 246. The sand detector 228 comprises clamps 510, 512 which as an external connection for fixing the ASD 228 to the line 246. Grains of sand 502 can be seen to be moving in the direction of arrows 506, 508. As the grains 502 move up the vertical segment of the line 246 along the direction indicated by arrow 506, the grains 502 are spread mostly uniformly across the line 246 diameter. However, as they approach the bend 504, the grains 502 gather towards the top of the bend and hence the top section 514 of the line 246, flowing in the direction of arrow 508. The positioning of the ASD 228 at this top section 514 of line 246, opposite to the bottom section 516 of line 246, can therefore allow for effective detecting of the sand, as this is the portion at which the sand is most likely to accumulate. The ASD 228 can detect the sound of the grains 502 as they come into contact with the walls of the line 246.

[0073] FIG. 2 shows an example of the detecting according to a graph displaying ASD Signal (expressed as a percentage) as a function of time. The line 118 (Threshold-ASD_H1 ) defines a first threshold. The line 116 (Threshold-ASD_H2) defines a second threshold. The graph displays a baseline noise in the form of a baseline signal (expressed as an ASD%) 100; This signal may result from the detecting, indicating the presence of sand in the well. The graph also displays 10 signal spikes 102 (expressed as an ASD%). Signal spikes 1 , 2, and 4 to 10 represent instantaneous signal spikes. Signal spike 3 represents a non-instantaneous signal spike. The signal spike 3 comprises 4 small signal spikes 108, 110, 112, 114, all of which are above the first threshold 118. The signal spike 3 has a duration 106 of 15 minutes (ASD_D1 ), triggering, as can be seen from reduced rate star 120, a reduced rate (partial closing), as the signal spike 3 is both continuously above the first threshold 118, and for a duration (15 minutes) being equal to or exceeding a predetermined period of time (also referred to as the “second predetermined period of time”), for example, 15 minutes. All signal spikes 1 to 10 are above the first threshold 118. This also constitutes a partial closing, as the detecting occurs more than a predetermined number of times (10 times) over a predetermined period of time 104 (also referred to as the first predetermined period of time), which in this case is 24 hours, and also exceeds the first threshold 118. The signal spikes 1 , 4, 7 and 8 also exceed the second threshold 116 (Threshold-ASD_H2). In this case, this is not considered sufficient to execute a full closing of the well (for example, not enough signal spikes over a predetermined period of time), the partial closing is considered more appropriate.

[0074] FIG. 3 shows an example of the detecting according to a graph displaying ASD Signal (expressed as a percentage) as a function of time. In this case, unlike in FIG. 2, signal spike 3 does not result in a reduced rate, as the signal spike 3 lasts a duration less than the predetermined period of time of 15 minutes. Instead, there are 10 signal spikes 1 to 10 (the detecting occurs more than a predetermined number of times) over a predetermined period of time (also referred to as a first predetermined period of time) being equal to 24 hours in this case, while also exceeding the first threshold 118. The signal spike 10, in this case an instantaneous signal spike, triggers, as can be seen from reduced rate star 120, a reduced rate (partial closing), as the signal spike 10 is the 10thsignal spike above the first threshold 118 within the 24 hour duration.

[0075] FIG. 4 shows an example of the detecting according to a graph displaying ASD Signal (expressed as a percentage) as a function of time. In this case, before the requirements of partial closing are met, as described in FIG. 2 and FIG. 3, signal spikes 1 , 4, 7, 8 and 9 (equating to signal spikes (1 ), (2), (3), (4), (5)) all exceed the second threshold 116, resulting in requirements for fully closing being met first. Unlike in FIG. 2 signal spike 3 does not result in a reduced rate, as the signal spike 3 lasts a duration less than the predetermined period of time of 15 minutes. In addition, unlike in FIG. 3, although all signal spikes 1 to 10 (and 11 ) are above the first threshold 118, the requirements for fully closing are met before the occurrence of the signal spikes 10 and 11. The detecting in fact occurs more than another predetermined number of times (i.e. not necessarily the same number of times as the number of times relating to the first threshold) over a predetermined period of time (also referred to as the third period of time), in this case 24 hours, that also exceeds the second threshold 116. The signal spike (5), an instantaneous signal spike in this case being the 5thsignal spike, triggers, as can be seen from Full Control Well (FCW) 2.0 Stop star 320, a full closing of the choke valve. FIG. 4 also provides an example of a signal spike 302, which, although a signal spike is not of a value large enough to meet the first threshold 118 and so cannot be considered to contribute to criteria for executing a partial closing of the choke valve.

[0076] FIG. 5 shows an example of the detecting according to a graph displaying ASD Signal (expressed as a percentage) as a function of time. FIG. 5 also provides an example for which full closing of the choke valve takes place. Like in FIG. 4, the reduced rate is not triggered as signal spike 3 does not last the predetermined period of time of 15 minutes. Also, although there are only 9 signal spikes, 3 of which are over the second threshold 116, fully closing still takes place as signal spike 7, or signal spike (3), and as indicated by stop star 320. The full closing occurs as the signal spike 7 / (3) takes place continuously over a predetermined period of time (ASD_D2) (also referred to as the fourth predetermined period of time). In this case the predetermined period of time is equal to 10 minutes (as indicated by the line 400), and exceeds the second threshold. The predetermined period of time triggering the stopping of production in this case lapses before even the end of signal spike 7 / (3) itself. The signal spike 7 is an example of a non-instantaneous signal spike, comprising 4 smaller signal spikes 402, 404, 406, 408. Each of the smaller signal spikes remains above the second threshold.

Claims

CLAIMS1. A computer-implemented method for detecting and controlling the presence of sand in a hydrocarbon production well equipped with a gas lift system, the method comprising automatically:- detecting the presence of sand in the well;- controlling a choke valve and / or a wing valve of the well depending on the detection of the presence of sand, including: o partially closing the choke valve so as to reduce a well production rate; or o fully closing the choke valve and then the wing valve so as to stop well production.

2. The method according to claim 1 , wherein detecting the presence of sand in the well comprises taking at least one measurement.

3. The method according to claim 2, wherein the measurement is an acoustic measurement for the detecting of the presence of sand being successful when the measurement exhibits an instantaneous signal spike or a continuous signal spike.

4. The method according to claim 3, wherein the acoustic measurement is expressed as a percentage of a baseline noise.

5. The method according to any one of claims 1 to 4, wherein the method comprises assessing a set of one or more first conditions respective to the fully closing and a set of one or more second conditions respective to the partially closing, the method performing the fully closing if either first condition is met, the method else performing the partially closing if either second condition is met.

6. The method according to any one of claims 1 to 5, wherein the partially closing takes place upon identification of either one of a respective set of one or more situations, the set of one or more situations respective to the partially closing including:- the detecting occurring more than a predetermined number of times over a first predetermined period of time and exceeds a first threshold; and / or- the detecting occurring continuously over a second predetermined period of time and exceeds the first threshold.

7. The method according to claim 6, wherein the first threshold lies between 0.1 and 10%, for example between 0.5 and 5%, for example between 1 and 5%, for example 2% of the baseline noise.

8. The method according to claim 6 or 7, wherein the first predetermined period of time is a number of hours, for example, 24 hours.

9. The method according to any one of claims 6 to 8, wherein the second predetermined period of time is a number of minutes, for example, 15 minutes.

10. The method according to any one of claims 6 to 9 wherein the method further comprises automatically configuring the first threshold.

11. The method according to any one of claims 1 to 10, wherein the fully closing takes place upon identification of either one of a respective set of one or more situations, the set of one or more situations respective to the fully closing including:- the detecting occurring more than another predetermined number of times over a third predetermined period of time and exceeds a second threshold; and / or- the detecting occurring continuously over a fourth predetermined period of time and exceeds the second threshold.

12. The method according to claim 11 , wherein the third predetermined period of time is a number of hours, for example, 24 hours.

13. The method according to claim 11 or 12, wherein the fourth predetermined period of time is a number of minutes, for example, 1 hour.

14. The method according to any one of claims 11 to 13 wherein the second threshold lies at least 0.5% above the first threshold, for example at least 1 % above the first threshold, for example at least 2% above the first threshold.

15. The method according to any one of claims 11 to 14 wherein the method further comprises automatically configuring the second threshold.

16. The method according to any one of claims 1 to 15, wherein the method further comprises implementing a sand detection counter, the counter counting the or a number of sand signal spikes over a period of time .

17. The method according to claim 16, wherein the counter starts upon a first detection of sand, the counter being stopped and reset to zero upon full closing of the choke and / or wing valves.

18. A computer program comprising instructions which, when executed by a processor, cause the processor to perform the method of any one of claims 1 to 17.

19. A data storage medium having recorded thereon a computer program according to claim 18.

20. A system for automatically detecting and controlling the presence of sand in a hydrocarbon production well equipped with a gas lift system, the system comprising:- a memory having recorded thereon a computer program according to claim 18; and- a processor for executing the program.21 . The system according to claim 20, wherein the system further comprises a choke valve and / or a wing valve of the well.

22. The system according to claim 20 or 21 , wherein the system further comprises at least one sensor for the detecting of the presence of sand in the well.

23. The system according to claim 22, wherein the sensor is an acoustic sensor.

24. Equipment for a hydrocarbon production well, the equipment including a gas lift system, the equipment further including a system according to any one of claims 20 to 23.

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