Pipeline Management

Print


Pipeline Management Functions include Batch Management for Liquids Pipelines and Capacity Management for Gas Pipelines.

BATCH MANAGEMENT

Batch Management can comrpise of up to three functions - Batch Tracking to track the products as they traverse the pipeline length, Batch scheduling toschedule and optimise the batch delivery process and Batch Predictive to predict the detailed movement of scheduled batches considering the complete hydraulic setup of the system.

Batch Scheduling

The scheduling process is undertaken by the operator or the planner before transfer of batches occurs. VariSim Batch scheduling allows the user to specify a batch schedule (a list of pumpable products) at a supply location and the demand requirements at each of the terminal locations. If the user wishes to consider tank volumes that change during the simulation, the user can specify the tank maximum and current volumes at each of the terminals. This includes the supply tanks and the product type that the tanks retain. Included in the tank specification are the ‘dead’ volumes that can not be pumped. Initial line fill can be defined by the user or it can be taken from a calculated state (a previous simulation or from a real time simulator).Batch Scheduling

The scheduler then performs a high speed simulation and can perform two tasks. It has the ability to simply calculate the batch movement based on the specified flows or it can optimise the batch schedule based on the users defined batch schedule and the time-based demand requirements of the tanks at the terminals.

 Within the scheduling process, the mixed interface volumes are calculated and can be set to only deliver contamination to a particular terminal if required. The scheduler also ensures that the supply tanks do not run empty and that the demand tanks do not overflow. Output includes the graphical display of the movement of product using colour coded batches, rail road diagrams and a series of reports including verification of the ability to transfer the batches to the required destinations.



At the end of the batch schedule simulation, a report is generated which includes:-

  •  A schedule report that describes all the activities at the supply location.
  •  A delivery report that describes all batches delivered to each terminal.
  •  A pump schedule report that tabulates the batches, their volumes and the estimated supply times.
  • A batch report listing the product names, volumes destinations and their ‘slug’ name.
  • An inlet flowrate report listing the flows to be achieved at the required times.
  • An interface volume report related to slugs.
  • A railroad diagram


The batch schedule can be made available to the predictive batch tracking process.


Batch Tracking

Once the schedule is defined and submitted, the volumes of product entering the pipe can be monitored in accordance with the schedule with over-delivered and under-delivered volumes clearly identified to the operator. The batches are tracked in the physical sense by the online VariSim simulator, and the progress of each batch can be accurately monitored as it progresses through the pipeline or network. Estimated times of arrival are continually provided for any defined locations on the pipeline or network. Virtual batch volumes and stripped batch volume can be monitored for efficient transfer of batches to the pipeline customers.

Batch Predictive

Batch predictive functions take the schedule and predict the future movements of the schedule of batches throughout the pipeline using an offline VariSim simulator. The operator is able to specify pump statuses and tank starting conditions that will continue to exist over the duration of the batching process. It is also possible to define the set-points of any flow and pressure control valves. Predictive simulations are able to use the batch schedule as an input and determine the movement of the batches over the batching timeframe.

CAPACITY AND STORAGE MANAGEMENT

There are three levels to the standard Capacity / Storage Management process which can be easily expanded to include more complex management functions.

Current inventory distribution is available directly from the VariSim simulator which can be made available to an offline simulator. At each supply or customer demand, pre-defined future flow or pressure variations can be used to drive the simulator model. These variations may be nominations, they may be fixed values, they may be user input or they may be taken automatically from historical input or load forecasting tools.

Gas InventoryRapid simulations are then conducted to establish the future inventory distribution, future flow, pressure and temperature profiles and variation in the available capacity / storage levels. Alarms will be raised for the user if zone inventories exceed or fall below allowable limits or if maximum / minimum allowable operating pressures are exceeded.

The actual storage variation can be monitored against the predicted storage variation. At any stage the user can change the future flow variations to predict the future actual and available capacity / storage variance.