Black-Oil to Compositional Delumper (BOz)
This is a bread-and-butter application, providing accurate delumping of black-oil gas and oil rates into detailed compositional streams. Our BOz method is accurate because we make the conversion at each simulator well grid connection at every time step. The BOz tables needed for our black-oil delumping are created when black-oil tables are generated, using the same EOS or compositional PVT description used to generate the black-oil tables.
Once delumped into compositional streams, further conversion can be made with Streamz to the compositional description used in Process engineering applications. Streamz Process can make the detailed process calculations directly, providing accurate rates of multiple products such as crude, condensate, napha, NGL, sales gas, fuel gas, and CO2. Else you can use the Process simulator of your choice to generate products.
Another application of the BOz delumping method is to generate black-oil gas and oil rates, but with a different set of separator conditions than used to generate the original set of black-oil tables. This is particularly important for gas condensates where separator conditions have a significant impact on condensate rates (CGRs).
Streamz Process – Complex Surface Processing
Allows complex surface processing similar to Hysys, but without heat and energy balance calculations. Each processing unit has specified pressure and temperature, though these may vary for each stream being processed. Each process unit can use different flash methods (EOS, K-values, split factors), and conversions of incoming stream component slates are automatically handled.
The Streamz Process module allows multiple products to be generated, as would a simulator like Hysys. Our experience on a number of industrial projects is that we can model complex surface processes with product amounts almost exactly as predicted with more sophisticated models like Hysys.
Compositional to Black-Oil Conversion
This is a special application of Streamz Process whereby the EOS used in reservoir simulation generates well stream compositions that need to be converted to traditional "black-oil" gas and oil rates.
One application of this method was the conversion of a compositional simulation model for the Oseberg field where oil wells were starting to cone significant amounts of gas-cap and injected gas. The operator wanted to know the percentage of total surface oil rate that came from the coning reservoir gas; this information was not available from the compositional EOS-based simulator.
Streamz was used to process compositional streams from each well-grid connection into reservoir gas and reservoir oil compositional streams. Each reservoir stream was then sent through the surface process separately, yielding the required split of total surface oil from reservoir oil and reservoir gas.
Similar requirements may be found in fields where ownership is different in the reservoir gas and reservoir oil zones. Wells producing from both reservoir zones (e.g. by coning) require separation of produced surface crude into “condensate” and “oil”.
Meter-Rate Converter
Converts volumetric rate data metered at varying pressure-temperature conditions into compositional well streams. The compositional well streams are then processed into gas and oil rates for a specified (fixed-condition) surface process.
Typical metered rates include:
(a) Short-term well tests associated with sampling and pressure transient analysis.
(b) Continuous rates from online meters.
(c) Periodic (e.g. monthly) well tests used for production allocation.
One important application of the Meter-Rate Converter is ensuring rate consistency used in history matching reservoir models. Measured test rates should be quantified with the same surface process used to generate rates in the reservoir simulator. For gas condensates and high-GOR oils wells, comparing consistent rates (apples vs apples) can be critical.
The Meter-Rate Converter can be designed to automatically convert measured rates (with varying meter or separator conditions) into gas and oil rates consistent with reservoir model rates, including automatic generation of rate control input read by the reservoir simulator.
Another application of the Meter-Rate Converter is delumping black-oil rates into compositional streams when black-oil PVT properties were not created with a specific EOS model and feed composition (as required by our standard BOz method for black-oil delumping). Many "old" black-oil PVT tables were generated with empirical correlations, or taken directly from black-oil PVT reports.
Molecular Tracking
Petrostreamz Pipe-It allows the tracking of individual molecular species, like CO2, throughout the entire upstream-to-downstream flow path in a project. Similar tracking capability is integral to other features like Composite Crude Assay module, Custody Allocation and Custody Transfer.
ExxonMobil recently introduced the concept of Molecular Management in downstream applications. Petrostreamz Molecular Tracking technology extends this capability from reservoir to refining, and at all points in between, providing the quantitative information to manage molecules with sophisticated production processing and refining.
Allocation & Custody Transfer
Petrostreamz Pipe-It™ allows a detailed accounting and tracking of components and resource ownership from initial production in the reservoir (e.g. gas cap condensate vs. oil zone crude) to individual geological zones, individual wells, connection/mixing points in the production system, throughout pipeline networks, in storage facilities, and in crude transportation.
Composite Crude Assay
Multiple oil sources, each with different crude assays, may result in an export crude with changing composite assay. This is a result of time variations in the contribution of originating sources, and changes in the crude makeup of each source.
The Petrostreamz Composite Crude Assay module generates a composite crude assay for a multi-source crude oil mix. The time variation in contributions from each crude oil source is accounted for with the Petrostreamz Pipe-It, as well as the change in assay cut distributions for each crude source – due to reservoir recovery mechanisms (depletion, gas injection, etc.).
Crude oil properties, as quantified by assay measurements, have a direct impact on project revenues, decisions about refinery selection and optimal field in-phasing.
Layer Allocataion
History matching reservoirs producing from commingled wells is difficult, and particularly when each separate layer produces fluids with different composition (gas-oil ratio, GOR). Consider, for example, a well perforated in three separate zones. The producing GOR is 1000. The first zone has a producing GOR of 400, the second zone 1000, and the third zone 1500. How much production comes from each zone? Using only GOR data, an infinite number of layer contributions gives the same producing GOR of 1000!
The Petrostreamz Layer Allocation module allows produced compositions (instead of simply GOR) to be used for estimating how much production comes from each layer. Differences in CO2, H2S, methane, ethane, …, C7+ from each layer makes the task feasible. The use of isomers and geochemical information can also be used, if such data are available. PLT data can also be used to “force” a specific contribution, or range of contribution, from individual layers.