Compaction within the South Belridge diatomite

Compaction is incorporated into a field-scale finite-difference thermal simulator to allow practical engineering analysis of reservoir compaction caused by fluid withdrawal. Capabilities new to petroleum applications include hysteresis in the form of limited rebound during fluid injection and the concept of relaxation time (i.e., creep). Experimental data indicate that (1) Compaction energy accelerates production during pressure depletion of a reservoir. (2) The presence of rebound during waterdrive is detrimental to production because injection energy is spent expanding the compacted reservoir. (3) The use of strain functions incorporating relaxation times can introduce time delays into the onset of compaction. (4) The use of compaction coefficients that are functions of effective stress permits modeling of the effects of position-dependent overburden stress, as in dipping reservoirs.