Study confirms normalizing cluster count, injection rates keys to enhancing production
Eagle Ford, South Texas
The operator completed its early wells with 17-stage sliding sleeve/frac valve systems with 5 1/2-in. cemented casing, using 20/40-mesh premium white sand proppant. Although the targets, as well as the completion and stimulation designs, were identical, production from the first four wells varied as much as 135%. The transition to various iterations of plug and perf completions resulted in equally mixed results, further reinforcing that factors other than completion types obviously influenced maximum reservoir drainage.
At the operator’s request, STRATAGEN evaluated drilling, completion, and production data, employing, among other methods, bivariate and multivariate statistical analysis and neural network modeling, to determine the parameters that had the most influence over well productivity and net present value (NPV). Through data visualization analysis and predictive modeling, the multi-faceted evaluation revealed that contrary to historical stimulation experiences, higher proppant concentration per effective cluster strongly affected production rates. Furthermore, the study showed that normalizing production data to account for different completion designs was critical for evaluating the performance of individual fractures.
On the basis of the analysis, the operator altered its completion and stimulation design, resulting in improved production rates. Specifically, within the operator’s asset, the highest production to date was realized with a completion/stimulation design incorporating more than 100 perforation clusters at 30 to 50-ft spacing with 80,000 lbm proppant/cluster. Moreover, injection rate per cluster was found to strongly influence fracture performance with best results seen thus far with a percluster injection rate of 20 bbl/min. The evaluation also yielded new insights on the completion-production relationship that will provide opportunities to further optimize recoveries.