Real Time Target Optimization and Geosteering multi-well case study utilizing onsite while-drilling XRD, XRF, and Mass Spectrometry, Niobrara and Codell Formations, DJ Basin
Eleven wells in the DJ Basin were drilled utilizing acquired-whiledrilling (AWD) Geochemistry in an effort to aid real-time geosteering in optimum rock quality, to provide petrophysical characterization useful to completion design, and to identify geohazards and compartmentalization. The data collected from this effort profoundly improved the ability to geosteer in the best target consistently, and was immediately relevant and incorporated into completion design. Geochemical signatures for subseismic faults and fractures were also detected, along with clear identification of stratigraphic location of the borehole. Mass spectrometry (MS), combined with collected thermal maturity data helped advance petroleum system mapping and understand well performance. These methods were found to be safer to run than horizontal wireline logs, while providing detailed petrophysical characterization. In a pilot study, two extended reach laterals, one Niobrara C well and one Codell well, were drilled in 2017, with samples collected every 100 feet and tested for Energy-dispersive X-ray Fluorescence (ED_XRF), Bulk X-ray Diffraction (XRD), and HAWK Pyrolysis to compliment MS analyzing the full hydrocarbon spectrum of C1-C12 and inorganic gasses collected while drilling. The data was synthesized after completion and four main observations were made: 1.) Mineralogical characterization using XRD along the borehole could immediately and precisely identify rock type and stratigraphic zone of drilling (In-zone/Out of zone). 2.) Mineralogical 57 Wyoming Geological Association – September 15-18, 2019 Brittleness obtained from XRD was immediately correlated to completion issues and incorporated into completion design 3.) XRF trace yielded a surprising fault and fracture indicator that also became useful to completion design 4.) MS also yielded interesting qualitative comparisons of hydrocarbon fluids and gases, and provided further compartmentalization characterization for each well. Together, these collected components led to a significant greater understanding of the borehole than gamma ray, cuttings, mudlogs, and horizontal logs combined. These findings were immediately incorporated into a real-time drilling protocol for the 2018 program consisting of total of nine wells: a mix of short and extended reach laterals in the Niobrara A, Niobrara B, Niobrara C and Codell. A mobile lab was set up for the program and XRF, XRD, and MS were collected real-time. XRF proxies were created for the key mineralogical and brittleness criteria associated with the optimum reservoir target for each zone. All nine wells were drilled with this protocol, improving our in-zone statistics across the program within optimal zone, as well as providing key information (mineralogical brittleness and subseismic faulted zones) utilized directly in completion design. Utilization of this data on a real time basis represents a step change in geosteering to better place lateral in the optimum intervals in each zone drilled.
AAPG Datapages/Search and Discovery Article #90357 ©2019 AAPG Rocky Mountain Section Meeting, Cheyenne, Wyoming, September 15-18, 2019