3D hydraulic fracture simulation modeling integrated with 4D time-lapse seismic and microseismic data were used to evaluate the efficiency of hydraulic fracture treatments in a one square mile spacing test within Wattenberg Field, Colorado. The study was conducted over a section within Wattenberg Field containing eleven horizontal wells that were hydraulically fracture stimulated and produced. The 4D time- lapse multicomponent seismic data were acquired pre-hydraulic fracturing, post-hydraulic fracturing, and after two years of production. The 3D simulation results integrated with and dynamic seismic observations are used to analyze the effect of geological heterogeneity on hydraulic fracturing efficiency and hydrocarbon production.

A 3D geomechanical model was generated using geostatistical methods as an input to hydraulic fracture simulation and incorporated the faults and the lithological changes in the study area. The 3D geomechanical model was calibrated through the use of DFIT data from offset wells. A hydraulic fracture simulation model using a 3D numerical simulator was generated and analyzed for hydraulic fracturing efficiency and interwell fracture interference between the eleven wells. The 3D hydraulic fracture simulation is validated using observations from microseismic and 4D multicomponent (P-wave and S- wave) seismic interpretations. The validated 3D simulation results provide insight into the effect of geological heterogeneity on the hydraulic fracturing efficiency by providing information relative to the induced fracture lengths, resultant effective fracture lengths and established fracture conductivity.

The 3D simulation result and dynamic seismic interpretations both reveal that variations in reservoir properties (faults, rock strength parameters, and in-situ stress conditions) influence and control hydraulic fracturing geometry and stimulation efficiency. Microseismic data is observed to capture hydraulic fracture lengths over 1000 ft. This was also confirmed using tracer analysis. The P-wave time-lapse seismic response from hydraulic fracturing is shown to be affected by pressure pulses created from stimulating the reservoir. The 4D P-wave response is indicative of the presence of pressure compartmentalization caused by fault barriers within the reservoir. The P-wave response also confirms the results from the 3D hydraulic fracture simulation demonstrating an effective stress barrier above the Niobrara formation which allows hydraulic fracture containment to occur. Shear wave (S-wave) time- lapse seismic data are shown to provide a close estimate for effective fracture lengths that result from hydraulic fracturing based on a successful match to the simulation results. The effective fracture length is defined as the propped fracture length that provides communication with the wellbore during the production cycle.

Through this integrated 3D hydraulic fracture simulation modeling more confidence is placed on results from the simulation as a guide for further optimizing the development of the Niobrara Formation within the Wattenberg Field. The integrated analysis provides valuable insight into optimizing well spacing, increasing recovery and improving production performance in the Niobrara, as well as highlighting intervals with bypassed potential within the reservoir.

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