Controls on deposition, lithologic variability, and reservoir heterogeneity of prolific western interior shelf sandstone reservoirs: Tocito and El Vado sandstones, San Juan Basin, NM

The Tocito and El Vado Sandstones have proven to be highly prolific hydrocarbon reservoirs in the largest domestic onshore conventional gas basin in the U.S., the San Juan Basin (SJB). Application of modern drilling technology and favorable petroleum commodity prices have resulted in increased exploration interest in the SJB. Despite 50 years of development and extensive research, our understanding of the distribution and variability of productive reservoir facies and the factors influencing reservoir heterogeneity is unclear. The Tocito Sandstone is a locally deposited, coarse-grained, glauconite rich sandstone with a unique depositional style involving multiple depositional sequences and complex erosional contacts due to focused tidal influence in local paleogeographic lows. The El Vado Sandstone is a low porosity, low permeability regressive-transgressive, storm wave-influenced shelf sand that produces in vertical wells from natural fractures and extends deep into the SJB. Despite being commonly encountered in wells as stacked reservoir intervals, the Tocito Sandstone and El Vado Sandstone are lithologically unique, stratigraphically separate and require different technologies to exploit. Ample opportunity exists for new exploration in both, especially in areas previously un-explored using unconventional techniques. Through extensive regional well log correlations, core analysis and thin section petrography, this study characterizes the controls on deposition of the Tocito and El Vado Sandstones, the regional variability of the nature of these sandstones, the vertical relationships of the Tocito and El Vado Sandstones and underlying units and the influencing factors on reservoir properties and exploration success.

Name thesis:degree_name

Master of Science (M.S.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Geology and Geological Engineering

Grantor dc:publisher

Colorado School of Mines. Arthur Lakes Library

Year dc:date.issued

2018

Author dc:creator

• Cheney, Alexander King

Advisor dc:contributor.advisor

• Wood, Lesli J.

Committee members dc:contributor.committeemember

• Jobe, Zane R.
• Anderson, Donna S.

• Late Cretaceous
• San Juan Basin
• Western Interior Seaway
• Mancos
• El Vado
• Tocito

Statement dc:rights

• Copyright of the original work is retained by the author.

Language dc:language.iso

eng, English

Identifier

T 8451

OAI identifier oai:identifier

oai:repository.mines.edu:11124/172162