scholarly journals Petrophysical properties of bypassed Cenozoic clastic reservoirs in the Cesar sub-basin, Colombia

2021 ◽  
Vol 25 (3) ◽  
pp. 275-284
Author(s):  
Helmer Fernando Alarcón Olave ◽  
Edwar Hernando Herrera Otero
Keyword(s):  
Effective Porosity ◽  
Coal Bed ◽  
Hydrocarbon Generation ◽  
Oil Saturation ◽  
Reservoir Rocks ◽  
Volume Porosity ◽  
And Migration ◽  
Oil Expulsion ◽  
Clastic Reservoirs ◽  
Reservoir Potential

The Cesar-Ranchería basin has all the necessary elements for the generation, expulsion, and migration of hydrocarbons and considerable potential for coal bed methane (CBM) in Colombia. Previous studies in the Cesar basin focused on understanding the tectonic evolution, stratigraphy, hydrocarbon generation potential, and evaluation of reservoir potential in Cretaceous calcareous units and quartzose sandstones from the Paleocene Barco Formation. These studies had confirmed the existence of an effective petroleum system, with several episodes of oil expulsion and re-emigration in the Miocene period, turning the Cenozoic clastic succession (Barco, Los Cuervos, La Loma, and Cuesta formations) into an element of significant exploratory interest to clarify the potentiality of the basin in terms of hydrocarbon accumulation. The petrophysical parameters of Cenozoic units (shale volume, porosity, water, and oil saturation) were determined by integrating wells log and core samples analyses from three stratigraphic wells. The integration of these results synthesizes the petrophysical behavior of the units. It defines intervals with clay volumes of less than 30%, effective porosity around 20%, which means favorable characteristics as reservoir rocks that need to be considered in future exploratory projects.

CARPENTARIA BASIN: A REGIONAL ANALYSIS WITH REFERENCE TO HYDROCARBON POTENTIAL

1984 ◽  
Vol 24 (1) ◽  
pp. 7 ◽  
Author(s):  
I. R. Burgess
Keyword(s):  
Regional Analysis ◽  
Northern Territory ◽  
Primary Objective ◽  
Western Boundary ◽  
Hydrocarbon Generation ◽  
The West ◽  
Clastic Sediments ◽  
Oil Expulsion ◽  
Reservoir Potential ◽  
Territory Border

The Carpentaria Basin is an epeirogenic intracratonic downwarping which formed during the Mesozoic. It is the northernmost of three main Jurassic-Cretaceous downwarps forming the Great Australian Artesian Basin. The basin is filled with clastic sediments, predominantly derived from Precambrian ridges on the flanks of the basin, which thicken gradually from the basin margins towards the depocentre.The Carpentaria Basin is analogous to the Eromanga Basin immediately to the south, and several rock units were deposited contemporaneously in both basins so that they can be mapped in the subsurface from one basin to the next. There is no change in sedimentary style or lithology.The character of the Base Mesozoic Unconformity, over which the Carpentaria Basin was deposited, changes abruptly from east to west. East of a point approximately coincident with the Queensland-Northern Territory border the unconformity surface is flat and featureless but to the west it becomes very rugged and irregular. This rugged horizon is believed to reflect either ancient karst topography or extensive reefal build-up equivalent to dolomite intersected in Burketown 1. Based on correlations with the McArthur and Georgina Basins it is probably Cambrian or Proterozoic in age. These rocks are known elsewhere to be porous and permeable.The unconformity shelves to the west towards Groote Island and the Northern Territory mainland and sediments of the Carpentaria Basin onlap a shallowing ancient landscape. The western boundary of the basin believed to be prospective for hydrocarbons is taken as the limit of deposition of the Cretaceous Gilbert River Formation.Lithologies and the existence of aquifers in the onshore Carpentaria Basin indicate that suitable reservoirs are present. Sandstones in the Cretaceous Gilbert River Formation, the Jurassic Eulo Queen Group and the Hutton Sandstone have the best reservoir potential. The Gilbert River Formation is the primary objective because it was extensively deposited throughout the basin, whereas Jurassic sandstones are restricted to topographic lows.The Gilbert River Formation is sourced and sealed by shales of the Wallumbilla Formation. Onshore this formation is too shallow to be mature but seismic indicates that offshore it is sufficiently deeply buried to be producing and expelling hydrocarbons.The hydrocarbon prospects of the Carpentaria Basin have in the past been considered low because the Mesozoic sequence onshore is thin and even offshore the total thickness of Mesozic and Cainozoic sediments is only about 1760 m at its maximum. This judgement ignored the fact that, although no economic hydrocarbon discoveries have been recorded from the Carpentaria Basin and/or the underlying Palaeozoic Basins, several shows have been reported. Shows reported in onshore wells suggest hydrocarbon generation within the basin. Geochemical and palynological studies carried out on samples from onshore wells and bores indicate the basal Mesozoic sequence is within geochemical Zone II, where the actual generation of hydrocarbons occurs but where significant mobilization and effective oil expulsion do not take place. These data suggest the deeper offshore portion of the basin should be within the oil window.

Stratigraphic Intervals for Oil and Tar Sand Deposits in the Uinta Basin, Utah

2017 ◽  
Vol 54 (4) ◽  
pp. 227-264
Author(s):  
Ronald Johnson ◽  
Justin Birdwell ◽  
Paul Lillis
Keyword(s):  
Brackish Water ◽  
Source Rocks ◽  
Uinta Basin ◽  
Green River ◽  
Reservoir Rocks ◽  
Stratigraphic Framework ◽  
Two Samples ◽  
The Rich ◽  
And Migration ◽  
Almost All

To better understand oil and bitumen generation and migration in the Paleogene lacustrine source rocks of the Uinta Basin, Utah, analyses of 182 oil samples and tar-impregnated intervals from 82 core holes were incorporated into a well-established stratigraphic framework for the basin. The oil samples are from the U.S. Geological Survey Energy Resources Program Geochemistry Laboratory Database; the tar-impregnated intervals are from core holes drilled at the Sunnyside and P.R. Spring-Hill Creek tar sands deposits. The stratigraphic framework includes transgressive and regressive phases of the early freshwater to near freshwater lacustrine interval of Lake Uinta and the rich and lean zone architecture developed for the later brackish-to-hypersaline stages of the lake. Two types of lacustrine-sourced oil are currently recognized in the Uinta Basin: (1) Green River A oils, with high wax and low β-carotane contents thought to be generated by source rocks in the fresh-to-brackish water lacustrine interval, and (2) much less common Green River B oils, an immature asphaltic oil with high β-carotane content thought to be generated by marginally mature to mature source rocks in the hypersaline lacustrine interval. Almost all oil samples from reservoir rocks in the fresh-to-brackish water interval are Green River A oils; however four samples of Green River A oils were present in the hypersaline interval, which likely indicates vertical migration. In addition, two samples of Green River B oil are from intervals that were assumed to contain only Green River A oil. Tar sand at the P.R. Spring-Hill Creek deposit are restricted to marginal lacustrine and fluvial sandstones deposited during the hypersaline phase of Lake Uinta, suggesting a genetic relationship to Green River B oils. Tar sand at the Sunnyside deposit, in contrast, occur in marginal lacustrine and alluvial sandstones deposited from the early fresh to nearly freshwater phase of Lake Uinta through the hypersaline phase. The Sunnyside deposit occurs in an area with structural dips that range from 7 to 14 degrees, and it is possible that some tar migrated stratigraphically down section.

scholarly journals Fluid inclusions in buried quartz of the Yanchang sandstone in the Jiyuan area, Ordos Basin, China: Implications for basin evolution and petroleum accumulation

2020 ◽  
pp. 014459872097451
Author(s):  
Wenqi Jiang ◽  
Yunlong Zhang ◽  
Li Jiang
Keyword(s):  
Fluid Inclusions ◽  
Ordos Basin ◽  
Homogenization Temperature ◽  
Burial Depth ◽  
Hydrocarbon Generation ◽  
Rock Interaction ◽  
Yanchang Formation ◽  
Reflection Data ◽  
And Migration ◽  
Vitrinite Reflection

A fluid inclusion petrographic and microthermometric study was performed on the sandstones gathered from the Yanchang Formation, Jiyuan area of the Ordos Basin. Four types of fluid inclusions in quartz can be recognized based on the location they entrapped. The petrographic characteristics indicate that fluid inclusions in quartz overgrowth and quartz fissuring-I were trapped earlier than that in quartz fissuring-IIa and fissuring-IIb. The homogenization temperature values of the earlier fluid inclusions aggregate around 80 to 90°C; exclusively, it is slightly higher in Chang 6 member, which approaches 95°C. The later fluid inclusions demonstrate high homogenization temperatures, which range from 100 to 115°C, and the temperatures are slightly higher in Chang 9 member. The calculated salinities show differences between each member, including their regression characteristics with burial depth. Combining with the vitrinite reflection data, the sequence and parameters of fluid inclusions indicate that the thermal history of the Yanchang formation mostly relied on burial. Salinity changes were associated with fluid-rock interaction or fluid interruption. Hydrocarbon contained fluid inclusions imply that hydrocarbon generation and migration occurred in the Early Cretaceous. The occurrence of late fluid inclusions implied that quartz cement is a reservoir porosity-loose factor.

scholarly journals The Cambrian Henson Gletscher Formation: a mature to postmature hydrocarbon source rock sequence from North Greenland

1987 ◽  
Vol 133 ◽  
pp. 141-157
Author(s):  
F.G Christiansen ◽  
H Nøhr-Hansen ◽  
O Nykjær
Keyword(s):  
Source Rock ◽  
Source Rocks ◽  
Hydrocarbon Generation ◽  
Hydrocarbon Source Rock ◽  
Reservoir Rocks ◽  
Potential Source ◽  
Potential Reservoir ◽  
Field Season ◽  
North Greenland

During the 1985 field season the Cambrian Henson Gletscher Formation in central North Greenland was studied in detail with the aim of evaluating its potential as a hydrocarbon source rock. The formation contains organic rich shale and carbonate mudstone which are considered to be potential source rocks. These are sedimentologically coupled with a sequence of sandstones and coarse carbonates which might be potential reservoir rocks or migration conduits. Most of the rocks exposed on the surface are, however, thermally mature to postrnature with respect to hydrocarbon generation, leaving only few chances of finding trapped oil in the subsurface of the area studied in detail.

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