A statistical study of "J" and Codell wells in the Denver-Julesburg (D-J) Basin was undertaken to determine which parameters influence well productivity. The parameters reviewed were open hole logging parameters and operational parameters. Parameters such as zone thickness, porosity, water saturation, shale indicators and the size of the hydraulic fracture treatment were reviewed. These parameters were chosen because they: 1) may be related to well productivity; 2) are easily obtainable from public sources; and 3) are related to theoretical hydraulic fracture models.
A non-linear multi-variate regression analysis was used in this study. The variables used in the regression analysis can be related to the variables in the "uniform flux fracture" model.
The results of the regression analysis can be used; 1) to determine which parameters are most correlative to well productivity, 2) to determine the relative magnitude of the parameters's influence and 3) the degree of certainty of the correlation.
The application of regression analysis determined which log characteristics are correlative with well productivity, quantified the influence of each parameter and quantify the degree of uncertainty. Regression analysis can be applied to reservoirs which are not amenable to conventional analysis.