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Old Rocks, New Ways: The Precambrian through Devonian of far west Texas and New Mexico
Field Trip Leader:
Chevron North America E & P
Suttles Logging, Inc.
Additional sponsors are welcome!
Thursday, May 6 – Sunday, May 9
$750 Member / $800 Non-member
TRIP ABSTRACT & ITINERARY:
Precambrian through Devonian strata exposed in the Franklin, Organ, and Sacramento Mountains are nearly identical in thickness and lithology to the equivalent subsurface interval in the Permian Basin. WTGS’s off-cycle field trip for Spring 2021 will visit these areas, each of which provides unique insights to deep saltwater disposal zones, conventional reservoirs, and unconventional target zones. Over three days we will investigate this section, which covers over 100 million years of time, and the major bounding unconformities, several of which represent a more than 10-million-year time gap each.
This field trip is limited to 15 participants so sign up soon! Please call the office 432.683.1573 or email to reserve your spot.
This meeting will be held at the Bush Convention Center. Please register by 3pm Friday, May 7th. Luncheon charge is $25 for pre registration and $35 for onsite. Please note that there will be limited seating and food for those not pre-registered. Please register on the website, by email email@example.com by by phone 432.683.1573.
Robert F. Lindsay
Lindsay Consulting & Brigham Young University
Midland, Texas and Provo, Utah
Cores of Barnett and Wolfcamp unconventional source rock were found to contain calcite beef that emplaced into horizontally-oriented (dominate) and vertically-oriented (subordinate) fractures. Calcite beef emplacement was by a minimum of two phases of horizontal-oriented hydraulic fracturing, followed by an additional vertically-oriented phase of emplacement.
Classic calcite beef refers to fibrous minerals in bedding-parallel veins, where fibers are perpendicular to margins. In this case, beef has been found to be white fibrous to equant calcite cement, all part of the same emplacement process.
Petrography of horizontal-oriented fractures containing calcite beef suggest forceful compressional injection into weak, ductile, mud-rich, source rock laminae. Calcite beef filled fractures are horizontal to slightly inclined and subtly crosscut source rock laminae. Breccia fragments of source rock float between fibrous calcite beef that grew vertically up and down, perpendicular to fractures. Calcite beef is interpreted to have precipitated so quick that breccia fragments did not have an opportunity to settle to the floor of the fracture.
Petrography of vertical-oriented fractures containing calcite beef suggest emplacement via transtension. Vertical-oriented fractures at first glance appear linear, but upon closer examination contain sinuous vertical-oriented micro-stylolites. Micro-stylolites are indicative of compression and/or transtension.
Preliminary data suggest that horizontal and vertical fractures, containing calcite beef, were emplaced by compressional re-activation of pre-existing faults/fractures during latest phases of Laramide orogeny (horizontal fractures) and during transtension associated with Rio Grande rifting (vertical fractures). In either case fault/fracture movement created forceful injection of fluids into source rock laminae. This injection process is referred to as seismic pumping.
Fluid inclusions from calcite beef in Wolfcamp shale contained only hydrocarbon inclusions. However, fluid inclusions from calcite beef in Barnett shale contain both hydrocarbon and aqueous inclusions. Aqueous inclusions are composed of fresh water (<10,000 ppm), with homogenization temperatures of 148° C. Surprisingly, these salinities and homogenization temperatures are similar to fluid inclusions associated with residual oil zone (ROZ) ramp/shelf margin plays throughout the Permian Basin.
This data suggests that during development of the Southern Rocky Mountain Epeirogen, during Late Eocene-Early Miocene, hot, high pressure, high volume meteoric recharge not only swept Permian Basin ramp/shelf porosity fairways, to form ROZ’s, but also swept down-dip through debris flows connected to ramp/shelf margins and charged open fault/fracture systems. This process connected: 1) ramp/shelf porosity fairways; 2) basin debris flows; and 3) faults/fractures as an open system.
Source rock strata where calcite beef was emplaced behaved as weak strata, which preferentially hydraulically fractured horizontally and vertically in mud-rich lithofacies. Surprisingly, no calcite beef emplaced into brittle debris flows, grain flows, or silt flows.
Born and raised in Utah (United States)
University of Aberdeen 2014 – Ph.D. in Geology
Bob has worked for:
Bob has served as:
He has published 104 abstracts and papers
Bob spends his retirement time giving back to academia and industry by:
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