Liquid Management System (LMS) Applications Relationships and Data Flow

Pipeline_Management_Solution.pdf

The above figure depicts the relationships among LMS applications. 

The heart of LMS is the Metering application where it gets meter data either from the flow computer or from a tank controlled by the tank management application.

Working together with Ticketing application, the Metering application defines the size of the batch in a ticket and the flow rate that will move this batch in the pipeline model of the batch tracking application. The batch tracking updates the position of the batch along the pipeline model and its linepack is calculated periodically.

As the batch tracking application reposition the batches in the pipeline model, the hydraulic profile is updated to reflect the effect of product in the batch on the pressure profile.

Finally, the metering data and linepack data along with the volume of product in the tanks are taken as input to do volume balancing in the PLM application.

 

Liquids Management Suite (LMS) will be deployed at the MCC SCADA as a centralized application.

LMS is a suite of applications that work together to provide the following liquid management functions :

·         Monitoring, correcting and recording of metering data.

·         Managing ticket operations.

·         Tracking of batches in the pipeline.

·         Tracking of anomalies (e.g., pig) in the pipeline.

·         Estimating the arrival (ETAs) of batches and anomalies at checkpoints/nodes of the pipeline.

·         Calculating and recording linepack information.

·         Detecting the potential leaks in the pipeline.

·         Monitoring pressures along the pipeline.

·         Monitoring tank information

The applications/modules of LMS to be used to provide the above functions are as follows :

·         Metering application will provide the monitoring and the correcting of metering data.

·         Ticketing application will provide the ticket operations management.

·         Batch tracking application will provide the tracking of batches and anomalies in the pipeline, and calculating the ETAs of the batches and anomalies at checkpoints.

·         Linepack application will calculate and record the linepack information of the pipeline.

·         Pipeline Leak Monitoring application (PLM) will provide the monitoring and detection of potential leaks in the pipeline.

·         Hydraulic Profile application will provide a visual representation of the pressure profile along the pipeline.

·         Tank Management application will provide tank monitoring and tank volume calculation.

Metering

Metering application allows LMS to read metering data directly from the Flow Computer and perform corrections if required (usually the Flow Computer has already done corrections on the raw meter data). The changes in meter data collected over time are used to calculate the flow rate of the meter. Several metering operating schemes can be accommodated, for example, metering can accommodate a rolling (meter count that never resets) or a batching (meter count that resets on a new ticket) metering count schemes.

Ticketing

Metering data collected and corrected by the metering application are stored in tickets. A ticket represents a batch of crude that passes through a meter. A ticket contains information about the batch such as its shipper and destination, the start and end times of the ticket, the projected and real sizes of the batch, and the product inside the batch. Moreover, tickets can be subjected to operations essential to ticket management such as ticket start, ticket stop and ticket cut. And most importantly, completed tickets will be stored in historical database for reporting purposes.

Batch Tracking

After a ticket defines a batch as the product passes through a meter, the location/position of the batch along the pipeline can be tracked using the batch tracking application. Using a model of the pipeline, a batch shall move along the pipeline proportional to the flow rate of the pipe segment it is in. This pipeline modeling provides an approximation of the batch position in the pipeline. To detect the actual batch position in the pipeline, interface detection instruments such as densitometers are needed to detect the actual start and end of a batch based on the density of the product in the batch. When there is a discrepancy between the modeling approximation and the interface detection data, an operator can do batch editing to fix the position and/or the size of the batch.

Other than approximating the position of the batch in the pipeline, the batch tracking application can also be used to approximate the position of anomalies such as a pig as it travels along the pipeline.

Using the position of the batch or anomaly in the pipeline, the batch tracking application can also calculate their estimated time of arrivals (ETAs) to checkpoints or nodes along the pipeline. Checkpoints are usually configured at the pig traps, the booster and delivery meter stations.

Linepack

Based on the pressure and temperature telemetry data and the product that is occupying the pipe segment, the linepack of the pipe segment can be calculated. And since the pipeline is just a concatenation of pipe segments, the linepack of the pipeline can also be calculated. The linepack of the pipeline represents the inventory of the pipeline which can be calculated and recorded periodically for reporting purposes.

Pipeline Leak Monitoring (PLM)

PLM attempts to monitor the pipeline for potential leaks. It uses a volume balancing methodology where it tries to monitor the line balance (meter in and meter out) and changes in linepack. PLM can be set to monitor this volume balancing over short and long term periods. Short period monitoring is usually used for detecting major leakages while the long period monitoring is better for detecting minor ones.

Hydraulic Profile

Other than PLM, pressure profile can also be used to detect potential leakage and sometimes its location. Using the telemetry pressure data from SCADA, a pressure profile of the pipeline can be monitored in real-time. An unusual drop of pressure can be visually reflected in the pressure profile which may indicate a potential leak. Moreover, the pressure profile can also be used to monitor for proper operating pressure of the pipeline. Along with the telemetry pressure data and pressure interpolation between the telemetry data, the maximum allowable operating pressure (MAOP) and elevation pressure are also represented in the profile.

Because the hydraulic profile depends on telemetry pressure data, the more transmitters installed along the pipeline, the better the resolution of the pressure profile. Telvent has recommended and made our assumption that there will be pressure and temperature transmitters installed at every station, pig trap and block valve locations.

Tank Management

Tank Management application allows monitoring of the level and product inventory inside a tank. Using data from tank level, pressure and temperature transmitters, the type of product inside the tank and the strap table of the tank, the volume of product inside the tank can be calculated and corrected.