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PVT simulation: an essential tool for protecting revenue value

Shared production system challenges
In the oil and gas industry, it is common to have a wide variety of hydrocarbon simultaneously in the production and processing streams. In many situations, gas and liquids (gas, oil and water) are present and in thermodynamic equilibrium. But due to changes in pressures and temperatures, the equilibrium shifts, which has consequences for the flow rates, the average molecular weight of the different streams, the physical properties of the phases and the flow rates. This is of prime importance when flows of different sources (reservoirs) and different owners are commingled in shared production systems, as typically happens in off-shore production. If this is not taken into account, severe errors in the allocated streams and the related monetary value can be introduced.

The importance of accurate physical properties
In many of these shared production systems, multi-phase and wet-gas meters are employed, as they are the only cost-effective options for flow rate measurement under such difficult conditions. However, the meters require accurate physical properties, like densities, of the different fluids to give sufficiently accurate figures for the flow rates. If incorrect values are used, systematic errors occur, which account for under- or over-estimation of the monetary value of the well flows. This is undesirable for the producers and the buyers, as it is in conflict with “Good Business Principles” of the parties involved and interferes with common work practices, such as Reconciliation. Furthermore, large sums of money are at stake if there is no way to mitigate property errors, as the following example illustrates:

Assume a well producing 1,000 bbls/d. Multi-phase flow meters can achieve an uncertainty of 5%; but when the physical properties are incorrect, an additional systematic error of 5% is potentially introduced, resulting in a loss of over US$ 900,000/yr at an oil price of US$ 50/bbl.

PVT simulator software adds certainty
We recognize that incorrect data pertaining to physical properties are “a must to avoid,” and we now have the technology solution making it feasible to do so. Hint’s AML- PVT (Pressure, Volume, Temperature) simulator allows you to calculate the distribution of components over different phases and their physical properties “on the fly.” These PVT values can be incorporated into the data-acquisition software, so the most accurate information is available at any given point in time. The ability to perform continuous calculations of such properties—even when pressure and temperature at the meter change due to operational constraints—significantly decreases the uncertainty of past measurement methods. More complex allocations can also benefit greatly by using PVT simulation during critical processing steps, like HP separation.

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Contact our expert consultants to obtain more information about PVT simulation for your specific case.

Hans van Maanen (Hint Global, B.V.)