Abstract
Sizing of hydraulic fracturing treatments in the Southeastern New Mexico (SENM) Morrow has historically relied on a trial-and error process whereby a three-dimensional fracturing model was built and run with simple gamma ray and compensated neutron density logs.Stress tables have been built utilizing over-simplified correlations involving conversions from gamma ray readings and effective porosity.The resulting simulated fracture-half lengths have been utilized in NPV (Net Present Value) optimizations to arrive at a final sizing decision.
Unfortunately, this process relies on the assumption that the initial modeling generates a propped fracture geometry simulation that is realistic.Past efforts to calibrate the 3-D models in the area focused on scattered attempts to gather sonic data that could be converted to stress differentials, and the use of conventional pressure buildups before and after the treatment.While the measurement of sonic properties during open-hole logging operations assisted somewhat in calculating relative stress differentials, its application was sporadic at best, and there was no way to check the results. Pre and post-stimulation pressure buildups required shutting the well in for a period of time and subsequently risking potential deceleration of reserve recovery.
A study of a variety of existing Morrow producers was undertaken to determine whether or not flowing pressure transient analysis of existing properties could be utilized to "calibrate" three-dimensional fracturing models, so that future projects would better reflect fracture geometries that were more realistic than current practice.
Results of the study are presented, and a practical, user-friendly model is demonstrated whereby flowing transient analysis may be utilized to adjust three-dimensional fracturing simulations as appropriate for optimizing stimulation NPV.
