Field-wide flow patterns for the 25-year waterflood production history of the medium-high permeability Gudong field, China have been carefully studied using a flow-based numerical simulation process. Through a history matching, field-wide streamline patterns and the cu1mulative flow between injector/producer well pairs can be displayed graphically and quantitatively via well allocation factors. By analyzing the flow pattern or streamline fields (field-wide and locally) for each time step through the reservoir production history, Predominant Streamline Fields (PSF) and Weak Streamline Fields (WSF) can be identified. The PSF can be classified into different levels based on statistically analyzing Strength Index of Streamline Field (SISF), which is a function of both allocation factor and the swept volume of the specific well pair at a given time step. Generally speaking, areas with strong PSF most likely indicate where reservoir channeling occurred at this specific time period, and this channeling is likely to persist until enough change is done. The relative stable WSF zones, with reasonable formation thickness have good potential to be bypassed pay.

To verify the findings above, a dozen conceptual models have been built and tested, and consistent results were found. This dynamic reservoir study processes provided an extra tool for reservoir scale waterflood optimization, well selection for profile modification/water shutoff, and infill drilling.

The Gudong case study indicated that PSF behavior began about 4~ 6 years from the start of water injection. That time period was consistent with a lot of other history data. The findings helped EOR and infill drilling in Gudong field.

Conclusions from this study have led to a better understanding of the displacement mechanisms and the nature-and-man-made dynamic-heterogeneity in the field, which may not be able to obtain otherwise.

You can access this article if you purchase or spend a download.