Micropaleontology and paleoecology of the Tununk member of the Mancos shale

1973 ◽  
Keyword(s):  
Mancos Shale

Insights into productivity drivers for the Niobrara-equivalent horizontal play in the Piceance Basin, Colorado

2020 ◽  
Vol 57 (4) ◽  
pp. 309-354
Author(s):  
Jason Eleson ◽  
Chip Oakes ◽  
Graham McClave
Keyword(s):  
Powder River Basin ◽  
Fault System ◽  
Piceance Basin ◽  
Thermal Maturity ◽  
Data Set ◽  
Horizontal Drilling ◽  
Child Effects ◽  
Mancos Shale ◽  
Low Degree ◽  
Future Potential

Limited horizontal drilling has occurred within the Niobrara-equivalent section of the Mancos Shale in the Piceance Basin, and the results from individual wells are highly variable. Prior studies have suggested that thermal maturity and completion techniques were the primary drivers for the observed production trends, but further analysis of well results indicates there are more variables at play. This study leveraged a comprehensive data set from the Piceance Basin, including core analyses, pressure data, and drilling and completion methods to provide additional context for the production results. From this analysis, several key trends were identified. North/south variations in thermal maturity were confirmed, as well as additional trends were identified revealing later exhumation south of the Rangely fault system resulted in significant depressurization, particularly in the western Piceance Basin. The semi-regional depressurization was the result of decrease in overburden pressures that allowed vertical migration of hydrocarbons out of the Mancos Shale. In addition to the semi-regional depressurization, there were more local depressurization events that resulted from faulting in areas such as the Orchard Unit in the southern Piceance Basin where thrust faults allowed hydrocarbons to migrate vertically into overlying formations. Northwest to southeast production trends are present in the southern Piceance Basin and are interpreted to reflect structurally undeformed areas based on high formation pressures and better producing horizontal wells. Parent-child effects have been observed locally and are linked to lower initial production rates and faster decline rates. The northern Piceance Basin exhibits higher reservoir pressure in the liquids window than was observed to the south due to the relatively low degree of exhumation and/or faulting in areas where horizontal Niobrara wells were drilled. Horizontal well results in the northern Piceance Basin have been mixed, largely due to inefficient completion strategies. By comparing the northern Piceance Basin wells with similar horizontal Niobrara wells in the Powder River Basin of northeastern Wyoming, it is concluded that drilling into the over-pressured liquids rim and utilizing slickwater frac fluid with friction reducer and 100 mesh sand will yield improved economic results over those obtained so far in the Piceance Basin. Though relatively few laterals have been drilled in the Piceance Basin Niobrara play, the basin has great future potential.

Microseismic Feedback Enhanced Real-Time Diversion Evaluation in Mancos Shale, Piceance Basin Completions

2016 ◽  
Author(s):  
E. L. Scott ◽  
J. H. Cape ◽  
K. D. Mahrer ◽  
N. Li ◽  
A. R. Childers
Keyword(s):  
Real Time ◽  
Piceance Basin ◽  
Mancos Shale

Mineralogical, chemical, organic and microbial properties of subsurface soil cores from Mars Desert Research Station (Utah, USA): Phyllosilicate and sulfate analogues to Mars mission landing sites

2011 ◽  
Vol 10 (3) ◽  
pp. 269-289 ◽  
Author(s):  
Carol R. Stoker ◽  
Jonathan Clarke ◽  
Susana O.L. Direito ◽  
David Blake ◽  
Kevin R. Martin ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Organic Content ◽  
Research Station ◽  
Morrison Formation ◽  
Soil Cores ◽  
Ion Chemistry ◽  
Geologic History ◽  
Mancos Shale ◽  
Dakota Sandstone ◽  
Desert Research

AbstractWe collected and analysed soil cores from four geologic units surrounding Mars Desert Research Station (MDRS) Utah, USA, including Mancos Shale, Dakota Sandstone, Morrison formation (Brushy Basin member) and Summerville formation. The area is an important geochemical and morphological analogue to terrains on Mars. Soils were analysed for mineralogy by a Terra X-ray diffractometer (XRD), a field version of the CheMin instrument on the Mars Science Laboratory (MSL) mission (2012 landing). Soluble ion chemistry, total organic content and identity and distribution of microbial populations were also determined. The Terra data reveal that Mancos and Morrison soils are rich in phyllosilicates similar to those observed on Mars from orbital measurements (montmorillonite, nontronite and illite). Evaporite minerals observed include gypsum, thenardite, polyhalite and calcite. Soil chemical analysis shows sulfate the dominant anion in all soils and SO4>>CO3, as on Mars. The cation pattern Na>Ca>Mg is seen in all soils except for the Summerville where Ca>Na. In all soils, SO4correlates with Na, suggesting sodium sulfates are the dominant phase. Oxidizable organics are low in all soils and range from a high of 0.7% in the Mancos samples to undetectable at a detection limit of 0.1% in the Morrison soils. Minerals rich in chromium and vanadium were identified in Morrison soils that result from diagenetic replacement of organic compounds. Depositional environment, geologic history and mineralogy all affect the ability to preserve and detect organic compounds. Subsurface biosphere populations were revealed to contain organisms from all three domains (Archaea, Bacteria and Eukarya) with cell density between 3.0×106and 1.8×107cells ml−1at the deepest depth. These measurements are analogous to data that could be obtained on future robotic or human Mars missions and results are relevant to the MSL mission that will investigate phyllosilicates on Mars.

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