We introduce a no-compromise advanced workflow for imaging and prestack inversion of 3D seismic data for unconventional resource plays. The imaging portion of the workflow includes a calibrated tomography that simultaneously solves for vertical velocity and TI anisotropy, ensuring accurate well ties during prestack depth migration. The prestack inversion portion of the workflow includes both azimuthal traveltime and amplitude inversion schemes. The derived seismic attributes are then well-suited to help predict future well performance in field-development planning.
Unconventional tight shale oil and gas plays have recently become major targets for exploration companies. What started in the United States as a new way to exploit these plays using extended horizontal drilling and hydraulic fracturing technologies has now expanded worldwide. Current development of these plays is a statistical process where evenly laid out drilling locations allow a company to hold land leases and ensure a projected ROI based on early initial and cumulative production numbers from neighboring wells. The challenge then becomes the design of the infill drilling program and how best to maximize the ultimate recovery of resource from each field in a timely fashion.
With a typical 10500ft lateral well with more than 30 completion stages costing USD 8 million and upwards (upstreamonline.com 2011), the infill plan dramatically impacts long-term economics of the program. For very little relative additional cost, 3D seismic technology can be effectively utilized to reduce the risk of drilling cost overruns and maximize ultimate recovery from the field. The key is processing the seismic data specifically for these types of plays without taking shortcuts due to perceived time and cost constraints. We present a case study from the Bakken shale play in North Dakota, U.S.A., where advanced imaging and inversion techniques unlock the true predictive power of 3D seismic methodology for optimal development of unconventional resource plays.