For mature fields, significant optimization potential exists simply by updating well rates that promote sweep vs. fluid cycling to realign patterns. Unfortunately, engineers typically only know which producers are high watercut or high water rate wells, but not which injectors are responsible for these effects making realignment difficult. Using Streamsim's streamline-based analysis, injector-producer pairs are easily computed to quantify all well-pair connections at any given time. Next, floodOPT takes this well-pair information, along with current watercuts to identify fluid cycling vs efficient sweep. The goal of floodOPT is to provide new well rate targets for both injectors and producers that prompt the effcient connections and demote the inefficient connections. In this manner, floodOPT provides a systematic reservoir engineering approach, based on historical injection/production data, dynamic patterns and allocation factors, to give next month's well rate targets.
The floodOPT Workflow
One powerful aspect of streamline simulation is the ability to create a snapshot of which injectors support which producers, and how much fluid is allocated between injector/producer pairs. Thus it is possible to related injected water volumes to off-set oil production down to a well-pair level and be displayed using Streamsim's patented Flux Pattern map (FPmap).
Since offset oil production is related to water injection this information can also be displayed in a cross-plot for every injector in the field at any given point in time. This novel information leads to the idea of injection efficiencies--a ratio of off-set oil production to water injected--which in turn can be used to manage the flood. The injection efficiency is defined as the ratio of off-set oil production to water injected. Note the following about the injection efficiency:
Once the injection efficiency is known for each well-pair, efficient producers and efficient injectors are known, as well as inefficient producers and inefficient injectors. Next, new rates which promote good connections vs. poor connections can be computed, and a plot or listing of suggested well rate changes is given (as in the figure at right). Because the definition of good vs. poor is arbitray, the user can set this based on economic watercut, field water cut, or a specific value. This definiton, along with min and max allowable rate changes, defined a weighting function that gives the updated well rates for each defintion scenaro.
For details see on floodOPT, the weight funciton, and workflow see Thiele, M.R. and Batycky, R.P.; "Using Streamline-Derived Injection Efficiencies for Improved Waterflood Management," SPEREE April 2006, Vol 9, No 2, pp187-196.
floodOPT is based on either a surveillance or simulation model and allows to:
|floodOPT Example Workflow within studioSL|
studioSL offers a convenient way to apply floodOPT to a 3DSL run for flood management purposes and forecasting. The starting point is a 3DSL simulation with an acceptable well-level history match (see more about history matching here). The well-level history match is an important component of any reliable forecast. Since floodOPT uses well-pair injection/production information, an acceptable well-level history matching is an important pre-requisite for applying the workflow. The basic steps in a floodOPT workflow are:
Download our surveillance dataset here.
Follow our surveillance tutorial here, to create the FPmap from the production data.
Follow our floodopt tutorial here, to create a floodOPT project.