Building of a geologic model of a field in the Slaughter area, West Texas

Detailed study of a field in the Slaughter area of Hockley County resulted in increased original-oil-in-place (OOIP) as compared to an earlier estimate from an internal company report (1975). An important aspect of the study was the inclusion of well logs drilled after the earlier estimate of OOIP. Log-core transforms for Compensated Neutron Logs (CNL) and Sidewall Neutron Logs (SNP) and Sonic logs were constructed. Three Old Neutron (ON) logs were normalized to improve the spatial control of the field. The normalization of the ON logs involved the correlating of the ON log data to a modern neutron log (CNL/SNP). Availability of more data made it feasible to obtain more accurate reservoir parameters for the field that was developed in 1930's. This paper describes the methodology involved in the construction of the geologic model to calculate the net pay, average reservoir porosity, permeability and water saturation. The OOIP was calculated using the isovolume and parametric averaging methods. The OOIP was increased by two folds from the earlier estimate but only 63% of the OOIP was movable.