Component Tracking in NextGen can track gas compositions, including energy content and specific gravity, throughout the pipeline system. Component Tracking includes a mixing algorithm on a molar weighted basis to calculate product mixing as gas is injected into the existing gas stream.
The gas composition of inlet gas can be measured by a chromatograph, and imported into the model using any of data integration modules, or can be entered manually using the built in component editors.
The following core gas components are supported and are also used in EOS calculations to calculate heating values, specific gravities, Z Factors, specific heats, Joules Thomson, and dew points:
C1, C2, C3, IC4, NC4, IC5, NC5, C6, C7, C8, C9, C10, H2, He, O2, N2, CO2, H2S
There is also a Remainder component that can be used to make up for missing components, and the user can add additional Custom Components.
Component Tracking provides the following enhanced features:
- Detailed Compositional Analysis, 18 Core components, Remainder, and Custom Components
- Calculation based on selected Equations of State (EOS) such as AGA-8, BWRS, PengRobinson,…
- Dew Point Pressure and Temperature Calculations
Source Tracking is similar to Component Tracking except that the percentages being tracked do not represent mole %. Instead the percentages are strictly for accounting purposes.
Any number of Sources can be defined, so the user might define 5 sources for one model, or 50 sources for another. The user can then provide the percent of each Source for each supply node or meter either manually or via an import, and the tracking algorithms will track the gas source percentages as they travel down the system and mix with other streams of gas.
This feature can be used to track individual sources of gas, for example supplier A could have 100% of Source#1, and 0% of Source#2, and supplier B could have 0% of Source#1, and 100% of Source#2. The Source Tracking calculations will then tell the user exactly how much gas from each supplier arrived at every delivery location.
It can also be used to track contracts or rate schedules. For example, Source#1 might be Firm, Source #2 might be Interruptible (and additional sources defined for as many rates as needed), and how much of each defined at every supply location, so that the user can then track how much Firm and how much Interruptible gas is actually traveling through various portions of the system and arriving at downstream locations.
The revenue tracking module in NextGen lets you track Construction Costs, Operating Costs, and even Revenues for a pipeline system. When combined with hydraulic modeling, this feature can be invaluable in estimating the cost and profitability of new pipelines, proposed pipeline expansions, and proposed contracts.
Construction Costs, Operating Costs, and Revenues are tracked separately and are supported in all simulation types: Steady State, Sequential, Transient Predictive, Transient Online, and Transient Look Ahead.
The easiest way to introduce Revenue Tracking into a model is to enter in revenue data in the Facility Library. For example, the construction cost for a 6” Globe Valve might be $1,800 (purchase cost and installation), and the maintenance cost $50 per year, construction cost for a particular class of 24” pipe might be $875,000 per mile, and so on.
Once all of this data is entered into a Facility Library, all users can make use of it to build new pipelines, or expand existing pipelines, or just run operating scenarios on the current pipeline, and all construction costs, operating costs, and optionally revenues, will be automatically calculated when Revenue Tracking is enabled.
For the time based simulations, cumulative costs and expenses are also kept track of so that overall construction costs, operating costs, and revenues over time can be estimated.
A Distribution company might use Revenue Tracking in Steady State to estimate construction costs for expanding their system.
A Midstream company might be modeling a gathering system in Sequential over a 10 year period, where new wells are being drilled, new pipe segments put into service, old wells being abandoned, and gas well production declining over time. The Revenue Tracking Module can be used to track constructions costs for each year, ongoing operating costs, and revenues from transportation or production.
A transmission company might track operating costs and revenues generated by different contracts and different capacities in a Transient Predictive simulation or even in real time with an Online system.
Questions that can be answered with Revenue Tracking:
- How much is this new pipeline or pipeline expansion going to cost?
- What are the estimated operating or maintenance expenses going to be?
- What is the projected revenue stream if the system operates at 100% capacity?
- What is the projected revenue stream if the system operates at 80% capacity?
- What is the projected revenue stream (perhaps revenue loss), if the system operates at 60% capacity?
- Given projected costs of gas, how much money can be made (or lost) over time by expanding the system next year instead of two years from now?
Construction and Operating Costs and Expenses can be viewed for individual locations, the entire system, or broken down by defined regions within the system, and the complete revenue and expense stream is modeled so you can even see revenue streams traveling down the pipeline, which is why hydraulic modeling combined with revenue tracking provides a unique way of analyzing the profitability of a pipeline.
Well Decline Analysis and Forecasting Module
NextGen’s Gas Well Decline Analysis application is a standalone NextGen application lets you import historical data for up to several tens of thousands of gas wells, and will use curve fitting routines to derive decline coefficients for each well, or groups of wells, that can then be used to forecast production rates for wells.
Given a future calendar date, the Gas Well application itself can perform a forecast of the projected production volume on that date, as well the total production since the startup of the well up to that date, for each well or group of wells.
Those forecasted volumes can then be exported out to NextGen models, Excel, or any other application or database.
This information can be used by Producers to estimate and forecast gas well production, and by Midstream pipeline companies to forecast flow rates coming from nodes and meters connected to one or more gas wells.
The decline coefficients that are derived can also be imported into the Facility Library of a NextGen model, so that the NextGen hydraulic model itself can perform the same forecasts based on the simulation time for all of the wells that are in the model.
In Steady State simulations, the well forecasts use the simulation datetime to calculate current production and cumulative production, and well decline can also be modeled in transient. However Sequential is the most useful simulation type to use for well analysis since the time frame is more in line with well decline time periods. For example, a user might use a 10 year simulation to model the decline of the wells in a field over time. Well Decline is also supported in the Transient Predictive section for shorter time periods.
By easily importing an Excel spreadsheet containing the historical values for each of the gas well flows, the application will plot the curves associated with each of the wells as they had performed over that time. You may be looking for a simple Exponential decline, or more likely the Harmonic, Hyperbolic for ARPS equations or the PLE equation.
The application will detect the most recent restart date of the well, or wells, based on the data, then fit the data using all three ARPS methods and the PLE method, suggesting which one is the best to use for each well or well group. The user can also auto generate all coefficients for all wells, as well as customize those wells that are hard to fit, by examining the data and manually adjusting the restart date, weight factors, and data filters.
NextGen’s Well Decline Analysis Application can:
- Produce ARPS and PLE regression curve fits.
- Advanced regression calculations.
- Automatic scanning for restart peaks.
- Gas Wells are grouped into individual projects for ease of management.
- The Weight scaling factor can control what parts of the data the regression will attempt to fit.
- Auto-Select will use the lowest MAD/Mean value of the ARPS or PLE equations.
- Number of Points per Average allows the program to use a rolling weighted average to smooth out the field data.
- Standard Deviation Limit controls the point envelope that the program will look for restart points.