An Efficient Approach to History Matching a Large Oilfield, a Successful Case Study

Field A is a large oilfield located in West Siberia, Russia. To date some 600 wells have been drilled into the structure. The field is managed using a large scale waterflooding strategy. Wells are drilled in an inverted 5- and 9 spot pattern. History matching such a large field on a well basis can be quite involved and time consuming. For field A, a “fit-for-purpose,” approach was adopted.

The selected approach can be used to assess large scale re-development options. It cannot be used to assess small scale production optimisation activities eg. water shut offs or identify whether a single infill well targets a flushed zone or not. It was decided to history match the field by defining several reservoir areas, so called well- groups. Production data were combined of wells in each of these individual areas, which enabled matching on a “group” basis. The bottom hole pressures were matched on a group level using a simple but effective cross-plotting technique.

A satisfactory history match was achieved within the timeframe set. Furthermore a novel approach was adopted and applied successfully to ensure a smooth transition between history match and forecast.