Proposal
development
of pipeline leak detection software
Prepared for Royal Fannavaran Nikan Company
by Sergey Gumerov
CEO of Digital Twin LLC
Table of content
- About company
- Methodology
2.1. Initial problem setup
2.2. Approach introduction
2.3. Solution
2.4. Method of calculations
2.5. Infrasound device
- Digital twin preconcept
3.1. Initial problem setup
3.2. Initial technological design
3.3. Log of elements
3.4. Leak vibration result
3.5. Possible visualisation
- Software design
- Timeline & cost
1. About company
Digital Twin LLC (DT) was founded in 2019 to develop and promote the Digital Twin methodology and software, which should have a significant impact on increasing the efficiency, reliability and security of the company.
The company’s specialists are engineers, mathematicians and physicists, former leading experts of IBM, Transneft and Sberbank.
The portfolio of products includes software and hardware for digital twin development. The references list include major petroleum, utilities & financial corporations
2. Methodology
2.1. Initial problem setup
Petroleum Engineering & Development Company (PEDEC) has intended to transfer Light Crude Oil and Heavy Crude Oil from Gurreh facilities in Bushehr Province to Jask Port in Hormozgan Province with the capacity of 1,000,000 bbl/day via approximately 994 km pipeline with 5 pump stations 1
The objective of request for proposal is “Development of software for pipeline leak detection” by hybrid Mass balance method & Negative Wave Pressure Method or Real Time Transient Model (RTTM/Extended RTTM) depending on our decision.
Major concern is Real Time Monitoring 1000 km Pipeline with large diameter (42”) and establishing Virtual Pipeline2 to calculate how the flow in the pipeline should be if there is no leak.
To answer on that objectives & concerns Digital Twin made the proposal for software development with replenishment of measuring devices based on some assumtions :
- the technological design of the pipeline that is the basis for the digital twin
- pipeline element log for each 1166 meters, where should be installed 1 ultrasonic device
- calculation of the probable vibration, that can be recorded by infrasound devices
2.2. Approach introduction
The achievements in the field of rapid detection and localization of leaks in oil pipelines (leak detection systems - LDS) today look something like this:
The minimum detectable leak is 1.8% of the pipeline flow rate for stationary pumping mode and 6% for non-stationary mode. For the oil pipeline in question (see Initial data ) losses are equal to 750 barrels per hour (~$45,000 / hour) and 2,500 barrels per hour (~$150,000 / hour).
The minimum leak detection time is 30 minutes.
The number of false positives leading to the pipeline shutdown and the corresponding losses is limited (in the some technical requirements for oil transportation) to 5 cases per year
In general, the results achieved by common technologies to be quite modest. In our opinion, this is due to the fact that in most LDS measures and analyzes the parameters of the flow of the pumped product. This approache creates the following difficulties:
Measurements of the flow characteristics can significantly depend on the properties of the pumped product, which have a significant natural dispersion.
- The reference “calculated” hydraulic solution may have two types of errors:
- model errors,
- incomplete accounting of the actual parameters of oil and pipes.
In general, a hydraulic calculation that takes into account transients, and provides the required accuracy between minimizing leakage and eliminating false triggering, is too complex.
Many technological processes (starting / stopping of main / back-up pumping units, triggering of pressure limiting systems - PLS, beginning / ending / changing of pumping capacity by oil companies, changing of pump unit rotation speed, etc.) can lead to false alarms.
Summarizing .2, we can say that attempts to directly identify the anomalous “behavior” of the flow corresponding to leaks will always have limited accuracy due to the natural irregularity of the flow itself. Methods (for example, Negative Wave Pressure) that analyze the dynamic phenomena in the flow of the transported product, which are characteristic of leaks, looks for us more promising.
We propose to go even further: to analyze not the flow dynamics, but the dynamic behavior of the pipe in the event of leaks. The fact is that when a leak occurs, there are dynamic transverse loads on the pipeline, which can not be confused with anything (except that with the arrival of a bulldozer). These loads should lead to vibrations that can be fixed. Below we give an example of wave propagation at leakage.
- Based on the initial data provided, we carried out preliminary technological design of the pipeline - the digital twin basis, determined the pressure at the inlet and outlet of the pumping stations, calculated the wall thickness, and selected pipes for high and low pressure sections.
The next step was to simulate the behavior of the pipeline in the event of a leak of 0.1 % of the nominal flow rate. Modeling includes:
building a 7D geotechnical model see inlet from the NPS and Entrance to the NPS.
the solving of the mechanical dynamic problem, which takes into account the joint operation of the pipeline and the base with boundary conditions in the form of displacements or forces (in our case, the forces arising from the formation of a leak). As a result of solving dynamic problems (for high-loaded and low-loaded pipeline sections), the distributions of displacements, rotation angles, siols, and moments in each element and any section of the pipeline are obtained.
The distributions of movements at different frequencies (in the range from 40 to 10,000 Hz) show (see the outlet from the oil pump station and the inlet to ) that for the pipeline under consideration, a leak of 0.1 % leads to noticeable movements in the zone of ± 1 km (up to 140 mm at the NPS outlet, up to 40 mm at the inlet), which can be registered by the ultrasonic device.
Digital Twin proposed the integrated technology for calculating the dynamics loads on pipelines and ultrasonic devices for full-scale measurement of associated with loads vibrations, which can be implemented (after adaptation and calibration) as a leak detection system.
We find it very interesting to jointly solve connected thermohydraulic and mechanical dynamic problems for pipeline systems.
2.3. Solution scope
The technical solution based on 3 technologies developed by Digital Twin LLC:
- Integrated method of losing strength and durability (see)
- Infrasound device for pipe dynamic characteristics monitoring (see )
- Pipeline geotechnical Digital Twin (see preconcept)
2.4. Method of calculations
The software supposes 3 modes of calculations.
- Development of a geotechnical 7D model (Digital twin) of the geotechnical system of the pipeline, taking into account:
- its own characteristics of the structure,
- technological modes,
- anchorages,
- environmental characteristics (geological, atmospheric).
- Batch, high-load calculations, including {#anchor_2_3_2}
- determination and updating the criteria for the occurrence of leakage and an unacceptable combination of vibration level and internal pipe pressure,
- determination of the actual and predicted technical condition of pipelines, based on ,
- search and identification of vulnerable places of pipelines, based on the properties of the structure, metal, dynamic and static loads,
- development of recommendations to ensure the safe operation of pipelines under actual conditions.
- Real-time processing of unplanned events (the system is waiting for signals about a significant change in vibration characteristics) coming from the pipeline infrasound control devices and flowmeters, including:
- signals filtration not confirmed by the technical condition of the pipeline,
- signals filtration out from threshhold calculates during batch calculation,
- assessment of the location and intensity of the leak.
2.5. Infrasound device
Due to pipeline structure is continuously subjected to a complex of dynamic loads from: + environment (temperature, pressure, movement of soil and foundations), + working loads (pumping oil), + own weight and geometry, + leaks due to natural and unauthorized damage to the structure,
Digital Twin LLC offer to equip the pipeline additional ultraasonic measurement devices as shown on Diagram 1, which allow the collection of data on the dynamic loads tested by the pipeline structure.
Diagram 1. Schematic diagram of the placement of infrasound monitoring devices
The photo of ultrasonic measurement device presented on Figure 1 and let the leakege system enrich data flow by mechanical dynamic characteristics and parameters of the pipeline.
{#figure2} Figure 1. Device photo
With the help of accelerometers and gyroscopes built into the ultrasonic device, linear accelerations along 3 orthogonal axes and angular velocities along 3 orthogonal axes are measured. The measured values are recorded 400 times per second.
The operating time of the device is:
- >1 hour for one-time initial and periodic (not often than 2 time per year) assessments of technical condition, what generated about 300Mb package from each device - <24 hours during the leakage event, what generated till 7200Mb package from only 3 devices near leakage.
The measurement results are processed by digital filters of low and high frequency. Using numerical integration, linear displacements are determined by accelerations, and rotation angles are determined by angular velocities. Then, using the Laplace transform, the amplitude-frequency characteristics of the movements and the angles of rotation of the controlled pipeline points (where device installed).
Table 1. Technical parameters and characteristics of the ultrasonic test device
| № | Parameter name | Value |
|---|---|---|
| 1 | Overall dimensions, mm | 112 х 48 х 27 |
| 2 | Mass, kg | 0.25 |
| 3 | Operating temperature, °C | from -20 till 500 °C |
| 4 | Acceleration sensor (3 axes) | MEMS accelerometer LSM303C@ST |
| 5 | Limits of linear acceleration measurement, m / s2 | from -20 to 20 |
| 6 | Angular velocity sensor (3 axes) | MEMS gyroscope |
| L3GD20H@ST | ||
| 7 | Limits of measurement of angular velocity rad/s | from -250 to 250 |
| 8 | Sensor readings recording frequency, Hz | 400 |
| 9 | Memory capacity, Gbit | 2500 |
| 10 | Maximum battery life, h | 30 |
Interpretation of the data from the device allows you to calculate the actual loads acting on the pipeline, determine the deadlines and conditions for the safe operation of the pipeline and its individual elements.
The onboard hardware and software complex of the portable device for measuring the dynamic characteristics and parameters of the pipeline provides the following operating modes:
- Mode 1, designed for testing, calibration, programming, and reading data. The device switches to Operation Mode 1 automatically after the on-board electronics of the device are supplied with power from batteries or an external source, at the user’s commands from an external control terminal (laptop computer) connected via the interface device via the miniUSB interface.
- Mode 2 is designed for autonomous operation to collect diagnostic and service information and record it in the on-board data carrier
- Mode 3 is a “sleep” mode (standby state) designed to charge the battery of a portable infrasonic device, as well as to perform data transmission to an external terminal.
On-board electronics provide registration and storage of the following information:
a) linear acceleration data from the accelerometer
b) spatial displacement data from the gyroscope
c) spatial orientation data from the magnetometer
d) temperature data from the temperature sensor
e) service information data
As a storage medium, non-volatile “Flash-memory” type drives with a total capacity of at least 32 Gbit are used. The on-board software provides:
- Operation of the on-board electronics in Mode 1 and Mode 3 under the control of an external terminal and in Mode 2 according to the settings
- Recording of all data in the memory with reference to the time
- Output of data from the memory to an external terminal at the user’s commands
The embedded software can be installed cross-platform on Windows XP operating systems./7/8/8.1/10 and Windows Server (2003/2008/2012/2016), having a configuration not already as follows: Minimum server system requirements:
- Processor-INTEL Xeon E5-2XXX v3/V4, 8 cores, 3.3 GHz - RAM – 16GB - DBMS - MS SQL Server 2008 R2/PostgreSQL 9.5 - Minimum system requirements for workstations: - Processor - Pentium 4 2.5 GHz Intel Core 2 Duo/AMD Athlon 64 X2 - RAM – 1GB - Hard drive – 8GB - Availability of the installed software package Microsoft Office 2013 and higher
The standard service life is 6 years from the date of commissioning of the device for measuring the dynamic characteristics and parameters of the pipeline in operation or the operating time of 1200 charge-discharge cycles.
The product is made of aluminum carbide materials and is equipped with a thermal protection platform and a magnet for attachment to metal surfaces.
Packaging
The product is transported from the supplier to the consumer and stored in the manufacturer’s packaging, subject to the conditions provided for electronic products.
Before storage, the portable infrasonic device must be preserved together with a set of auxiliary equipment for the product, a set of spare parts, a set of tools and accessories in accordance with the Operating Instructions. Products of these components that do not have standard packaging must be packed in packaging containers that protect the components from damage during transportation and protect them from external influences.
3. Digital twin preconcept
3.1. Definition
In the proposal we use Gatrner’s Digital Twin definition.
A digital twin is a digital representation of specific pipeline from Gurreh facilities in Bushehr Province to Jask Port in Hormozgan Province. The implementation of the pipeline digital twin is an encapsulated software object or model that mirrors pipeline processes, pipeline construction & natural environment of pipeline.
The delivery of pipeline digital twin includes:
- datasets (comma separated format),
- complex of program modules (on R & Java language),
- documentation (in html) for users and administrators. Datasets package includes but not limited to the next deliveries:
a. log of all pipeline elements and their initial & calculated, actual & predicted technical & enviromental parameters sufficient to detect and prevent oil leaks,
b. input and output message templates intended for exchange with measuring instruments,
c. input and output message templates intended for the exchange of customer information systems that register an event related to a leak,
d. masterdata and metadata information,
e. information processing and settlement procedures. Complex of program modules package includes but not limited to the next modules:
a. Frequency response processor
b. Pipeline mechanical dynamic solver
c. Preventive maintanance planner
d. Leakage detection clarification
e. Orchestrator for "on_demand" operation
f. Digital Twin 7D visualisation & alarm system Documentation package includes but not limited to the next documents:
a. Digital twin architecture
b. Data structure
c. Data procedures
d. Calculation procedures 3.2. Initial technological design
The basic master data data set for Digital Twin is set of initial technological parameters. Their initial estimation looks like below.
Table 2. Technological design of the pipeline
| № | Parameter (indicator) | unit | value |
|---|---|---|---|
| 1 | 2 | 3 | 4 |
| 1 | Acceleration, g | m / s2 | 9,81 |
| 2 | Pipeline | ||
| 3 | Transported product-oil | ||
| 4 | Product Density | kg / m3 | 810 |
| 5 | Padding | ||
| 6 | Performance, Q | bbl / day | 1000000 |
| 7 | l / day | 158988000 | |
| 8 | m3 / day | 158988 | |
| 9 | t / day | 128780 | |
| 10 | mln t / year | 45,07 | |
| 11 | m3 / s | 1,84 | |
| 12 | m3 / hour | 6625 | |
| 13 | Flow rate (flow rate) | m / s | 2,14 |
| 14 | pressure | MPa | |
| 15 | inlet (pmax) | MPa | 6,3 |
| 16 | outlet (pmin) | MPa | 0,4 |
| 17 | Pressure (oil column height) | m | |
| 18 | inlet (hmax) | m | 793 |
| 19 | outlet (hmin) | m | 50 |
| 20 | Pipe | ||
| 21 | Diameter | inch | 42 |
| 22 | mm | 1067 | |
| 23 | Wall thickness | mm | |
| 24 | min | mm | 10,3 |
| 25 | max | mm | 15,9 |
| 26 | calculated (highest) | mm | 14,72 |
| 27 | by API 5L | inch | 0,625 |
| 28 | calculated (lowest) | mm | 9,91 |
| 29 | by API 5L | inch | 0,406 |
| 30 | Passage area | mm2 | 859605 |
| 31 | m2 | 0,8596 | |
| 32 | Steel grade | X70 | |
| 33 | Modulus of elasticity | MPa | 203000 |
| 34 | Ultimate strength | MPa | 570 |
| 35 | Yield | MPa | 485 |
| 36 | Strength Design resistance | MPa | 255 |
| 37 | Leak | ||
| 38 | Leak rate | ||
| 39 | highest | m / s | 125 |
| 40 | lowest | m / s | 31 |
| 41 | Hole | ||
| 42 | diameter | mm | 10 |
| 43 | area | mm2 | 78,5 |
| 44 | m2 | 0,0000785 | |
| 45 | Leak loss | ||
| 46 | largest | m3 / s | 0,009796 |
| 47 | smallest | m3 / s | 0,002468 |
| 48 | largest | m3 / h | 35,3 |
| 49 | smallest | m3 / h | 8,9 |
| 50 | largest (as a % of performance) | % | 0,532331 |
| 51 | smallest (as a % of performance) | % | 0,134135 |
| 52 | The force acting on the pipe | ||
| 53 | from the pressure (highest) | N | 494,8 |
| 54 | from the pressure (lowest) | N | 31,4 |
| 55 | reactive (highest) | N | 989,6 |
| 56 | reactive (lowest) | N | 62,8 |
| 57 | Detection | ||
| 58 | Losses due to recorded leakage | m3 / h | 6,62 |
| 59 | m3 / s | 0,00184 | |
| 60 | as a % of productivity | % | 0,1 |
| 61 | Hole area (at pmax) | mm2 | 14,8 |
| 62 | Hole diameter (at pmax) | mm | 4,3 |
| 63 | Hole area (at pmin) | mm2 | 58,6 |
| 64 | Hole diameter (at pmax) | mm | 8,6 |
| 65 | Force acting on the pipe | ||
| 66 | from pressure (largest) | N | 92,9 |
| 67 | from pressure (smallest) | N | 23,4 |
| 68 | reactive (largest) | N | 185,9 |
| 69 | reactive (smallest) | N | 46,8 |
| 70 | total (largest) | N | 278,8 |
| 71 | total (smallest) | N | 70,3 |
| 72 | The amplitude of ultrasonic vibrations (in the zone of ± 1 km) | ||
| 73 | Pressure-6.3 MPa, pipe-42" x 0.625" (outlet with NPS) | mm | <140 |
| 74 | Pressure-0.4 MPa, pipe-42" x 0.406" (PS inlet) | mm | <40 |
3.3. Log of elements
The log of all pipeline’s elements will be inludes in package of Data Twin delivery.
Here are examples of 2 logs of pipeline elements at the outlet and inlet to the oil pumping station, indicating:
- standarts & types of materials, - diameters & wall thickness, - coordinates and distances between individual pipe sections, - place for ultrasonic device installation.
To monitor vibrations at each section of the pipeline presented in the log, 1 ultrasonic device is required.
Log of pipeline elements are the basis for creating the spatial pipeline design - the foundation of the pipeline digital twin.
- Log of 1,17 km of pipeline at the outlet of the oil pumping station. Outlet pressure - 6.3 MPa, leakage-6.62 m3 / h, hole diameter-4.3 mm
- log of 1,17 km of pipeline at the outlet of the oil pumping station. Outlet pressure - 0.4 MPa, leakage-6.62 m3 / h, hole diameter - 8.6 mm
3.4. Leak vibration result
Leak detection functionality Digital Twin based on precalculated patterns calculated in “Frequency response processor” module and have to be updated (calibrated) during experimental stage of operation
A preliminary calculation (on the theoretical design of the pipeline) shows that to ensure high accuracy and speed of leak detection, it is necessary to additionally equip the pipeline with ultrasonic control devices at a distance of 1.3 km (before entering the oil pumping station) - 1.8 km (after the station).
Thus, for the entire pipeline with a length of 1000 meters, it is advisable to install about 625 devices, and in total, taking into account the stock - 700 pieces.
3.5. Possible visualisation
Digital Twin technology included in the proposal allows use pipeline digital twin as for actual place & volume of leak detection, as well as for early prediction the place & time for possible failuries and leakages.
The most vulnerable points, stress concentrations and residual technical resource for an example of a separate pipeline is presented below
back to 2.1.Methodology description
5. Timeline & cost
5.1. Work order
5.2. Time line
5.3. Cost of work & materials
5.4. Terms and conditions
Current proposal prepared at 06.05.2021 and valid till 06.06.2021