Greeley, Colorado is situated right in the heart of the DJ Basin's Wattenberg Field, in what is referred to as the " Sweetest of the Sweet Spots" for hydrocarbon production from Niobrara chalks and the Codell sandstone. While horizontal drilling has been very active all around the city of Greeley in the past few years, very little activity has occurred within the city limits, due in part to a lack of subsurface control needed for effectively and safely drilling Niobrara and Codell horizontal targets. A privately held oil and natural gas producer based in Greeley put together a plan to acquire subsurface information in order to drill horizontal wells. In early 2013 they contracted to acquire one of the largest urban 3D seismic programs in the country. Accomplishing this 23 square mile survey was no small task and required many months of extensive pre-planning by both the operator and contractor in order to complete the 3D acquisition in an urban environment. Seismic data processing employed state-of-the-art static corrections and noise-reduction technologies so as not to smear any small faults and structures at the target level. Interpretation involved detailed structural analysis and framework modeling of the Niobrara and Codell formations as understanding of the structural dips and nature of the listric faulting at the target level is paramount in placing the laterals. Additionally, seismic reservoir analysis, using Neural Network inversion technologies, identified reservoir sweet spots within the Niobrara chalks & Codell sandstone for optimizing the frac staging and completion designs.
The operator is currently using the interpretation results from this 3D survey in their successful drilling program. To date, 10 extended reach horizontal wells have been drilled off this survey. The 3D survey has allowed for
correctly targeting Niobrara and Codell objectives, in terms of staying in the hydrocarbon layer while drilling the lateral,
avoid/navigate around geologic faults which could throw the well out-of-zone and impact ultimate production, and
reduce the number of drilling days and drilling costs.
