Abstract: A New Method for Culling Pressure Data used in Hydrodynamic Studies

B. J. Rostron

Hydrodynamic and hydrogeologic studies of fluid migration rely on good-quality pressure data. It is important to include in these studies, only those pressures that are unaffected by hydrocarbon production. In the past, production influenced pressures have been culled using only qualitative methods: either by inspection of individual points or by arbitrary removal of anomalously low/high values. Neither of these culling techniques are considered optimal because they are time consuming for large datasets and they may remove anomalous, but completely valid, pressure points.

A computer-aided quantitative method of culling pressure data has been developed. Using a simplified production-history database, the program calculates the radial distance between the location of a pressure measurement and any previously producing wells. After determining the radial distances, pressure data are sorted and those within a minimum radial distance are culled. The minimum distance, commonly 2 to 20 km, depends on formation lithology.

This new algorithm has been tested in a recently completed petroleum hydrogeological study of west-central Alberta, Canada. Using this technique, more than 6000 pressures from 12 formations were culled quickly and easily. Results show that the simple algorithm is fast, easy to implement, and more than 80 percent effective for removing both low pressures caused by production and high pressures caused by water/gas injection.

The accuracy of future hydrodynamic and hydrogeologic studies could be improved using this technique.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994