scholarly journals Variations in vitrinite reflectance values for the Upper Cretaceous Mesaverde Formation, southeastern Piceance Basin, northwestern Colorado; implications for burial history and potential hydrocarbon generation and The Fryingpan Member of the Maroon Formation; a Lower Permian(?) basin-margin dune field in northwestern Colorado

1989 ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 58
Author(s):  
Yohanes Ardhito Triyogo Varianto ◽  
Sugeng Sapto Surjono ◽  
Salahuddin Salahuddin

Akimeugah Basin in the western part of Aru Trough is included as a Paleozoic Basin which is one of the potential hydrocarbon-producing basins in Eastern Indonesia. Tectonic evolution in Akimeugah Basin during Cambrian to present has produced a very significant erosion that affected the hydrocarbon generation process. ‘ARD’ Block study uses three exploratory well data including well report and 26 lines of 2D seismic data with a total length of 5,812.55 kilometers and the distance between seismic lines ranging from 10 to 15 kilometers. Seismic data is processed with IHS Kingdom software for tectonostratigraphy analysis, while calculation and erosion analysis are performed by combining well data consisting of sonic, vitrinite reflectance and seismic. To get a burial history model and generation & expulsion period, this study utilizes Petromod software. Five phases of the tectonic evolution led to four times of erosional period with a sediment thickness of 290 – 3,370 feet were loss. The erosion of the sedimentary rocks causes the maturation process delayed more than 200 million years. Burial history in the study area with the erosion absence assumption results a hydrocarbon generation starting from around 210 million years ago. Meanwhile, by considering the loss of eroded sedimentary rocks during four tectonic phases, hydrocarbon generation time just occurred 3.1 million years ago.


1997 ◽  
Vol 37 (1) ◽  
pp. 505 ◽  
Author(s):  
M.M. Mitchell

The Otway Basin formed during the Mesozoic separation of Antarctica and Australia. A study of apatite fission track (FT) analysis and vitrinite reflectance (VR) data from borehole samples in the western Otway Basin was initiated to elucidate some of the thermal and structural complexities of this region.Interpretation of results suggest that some areas experienced regionally elevated palaeotemperatures, however, much of the region is at present-day maximum temperatures. Where cooling from maximum palaeotemperatures is observed, the timing may be grouped over three main intervals as follows; mid-Cretaceous, Late Cretaceous to Early Tertiary, and Tertiary. Cooling was facilitated by a decline in geothermal gradient, uplift and erosion, or both. Evidence for a decline in geothermal gradient from values >55°C/km in the mid- Cretaceous is recognised in several wells. Elevated mid- Cretaceous palaeogeothermal gradients (50−60°C/km) have been reported for the eastern Otway Basin, suggesting that these high temperatures were a regional phenomena. Cooling by uplift and erosion at this time was minimal throughout the western Otway Basin in contrast to the kilometre scale uplift and erosion reported for the eastern Otway Basin and adjacent basement inland of this section of the rift.The relative early maturation of the Otway Supergroup during mid-Cretaceous regionally elevated geothermal gradients, and subsequent basin restructuring, are key factors affecting hydrocarbon preservation in the western Otway Basin. Strategies for identification of prospective areas include identification of regions that have remained at moderate temperatures during the Early Cretaceous, and have not undergone burial under a thick Upper Cretaceous to Tertiary section.


2012 ◽  
Vol 63 (4) ◽  
pp. 335-342 ◽  
Author(s):  
Paweł Kosakowski ◽  
Magdalena Wróbel

Burial history, thermal history and hydrocarbon generation modelling of the Jurassic source rocks in the basement of the Polish Carpathian Foredeep and Outer Carpathians (SE Poland)Burial history, thermal maturity, and timing of hydrocarbon generation were modelled for the Jurassic source rocks in the basement of the Carpathian Foredeep and marginal part of the Outer Carpathians. The area of investigation was bounded to the west by Kraków, to the east by Rzeszów. The modelling was carried out in profiles of wells: Będzienica 2, Dębica 10K, Góra Ropczycka 1K, Goleszów 5, Nawsie 1, Pławowice E1 and Pilzno 40. The organic matter, containing gas-prone Type III kerogen with an admixture of Type II kerogen, is immature or at most, early mature to 0.7 % in the vitrinite reflectance scale. The highest thermal maturity is recorded in the south-eastern part of the study area, where the Jurassic strata are buried deeper. The thermal modelling showed that the obtained organic matter maturity in the initial phase of the "oil window" is connected with the stage of the Carpathian overthrusting. The numerical modelling indicated that the onset of hydrocarbon generation from the Middle Jurassic source rocks was also connected with the Carpathian thrust belt. The peak of hydrocarbon generation took place in the orogenic stage of the overthrusting. The amount of generated hydrocarbons is generally small, which is a consequence of the low maturity and low transformation degree of kerogen. The generated hydrocarbons were not expelled from their source rock. An analysis of maturity distribution and transformation degree of the Jurassic organic matter shows that the best conditions for hydrocarbon generation occurred most probably in areas deeply buried under the Outer Carpathians. It is most probable that the "generation kitchen" should be searched for there.


2021 ◽  
Author(s):  
H. Lazuardi

One-dimensional and two-dimensional basin modeling can be used to infer the burial history, hydrocarbon generation, and migration of hydrocarbon. In this paper, the study focuses on 1D and 2D basin modeling in North Sumatera Offshore as one of the prolific deep-water basins in Indonesia. The data consists of 5 exploration wells and 2D seismic data that are vitrinite reflectance, rock-eval data, and bottom-hole temperature. Well data’s have been used to calibrate heat flow and thermal evolution of the basin, while 2D seismic data have been used to support the basin modeling. Based on the result, the basin formed by the collision of the Australian Plate with the Eurasian Plate evolved due to block faulting that caused a pull-apart basin. In the Early Oligocene, changes in the movement of the Indian plate also changed tectonics from subduction to strike-slip fault resulting in Andaman Sea rifting. The southern part of the research area was affected by the Andaman Sea rifting, which caused unconformities in the Middle Miocene. The main generating source rock is the Bampo, Belumai, and Baong Formation, which is predominantly consist of Type III kerogen (gas prone) in the north and Type II/III (mix oil and gas prone) in the South. The timing of petroleum generation may have occurred is in the Early Pliocene. The Early oil generation which occurred simultaneously with the seal rock and may have been migrated to the Middle and Late Miocene reservoir through the faults as a vertical migration pathway. The results of this study allow us to improve the hydrocarbon prospect and reduce exploration risks.


Author(s):  
A., C. Prasetyo

Overpressure existence represents a geological hazard; therefore, an accurate pore pressure prediction is critical for well planning and drilling procedures, etc. Overpressure is a geological phenomenon usually generated by two mechanisms, loading (disequilibrium compaction) and unloading mechanisms (diagenesis and hydrocarbon generation) and they are all geological processes. This research was conducted based on analytical and descriptive methods integrated with well data including wireline log, laboratory test and well test data. This research was conducted based on quantitative estimate of pore pressures using the Eaton Method. The stages are determining shale intervals with GR logs, calculating vertical stress/overburden stress values, determining normal compaction trends, making cross plots of sonic logs against density logs, calculating geothermal gradients, analyzing hydrocarbon maturity, and calculating sedimentation rates with burial history. The research conducted an analysis method on the distribution of clay mineral composition to determine depositional environment and its relationship to overpressure. The wells include GAP-01, GAP-02, GAP-03, and GAP-04 which has an overpressure zone range at depth 8501-10988 ft. The pressure value within the 4 wells has a range between 4358-7451 Psi. Overpressure mechanism in the GAP field is caused by non-loading mechanism (clay mineral diagenesis and hydrocarbon maturation). Overpressure distribution is controlled by its stratigraphy. Therefore, it is possible overpressure is spread quite broadly, especially in the low morphology of the “GAP” Field. This relates to the delta depositional environment with thick shale. Based on clay minerals distribution, the northern part (GAP 02 & 03) has more clay mineral content compared to the south and this can be interpreted increasingly towards sea (low energy regime) and facies turned into pro-delta. Overpressure might be found shallower in the north than the south due to higher clay mineral content present to the north.


2019 ◽  
Vol 56 (4) ◽  
pp. 365-396
Author(s):  
Debra Higley ◽  
Catherine Enomoto

Nine 1D burial history models were built across the Appalachian basin to reconstruct the burial, erosional, and thermal maturation histories of contained petroleum source rocks. Models were calibrated to measured downhole temperatures, and to vitrinite reflectance (% Ro) data for Devonian through Pennsylvanian source rocks. The highest levels of thermal maturity in petroleum source rocks are within and proximal to the Rome trough in the deep basin, which are also within the confluence of increased structural complexity and associated faulting, overpressured Devonian shales, and thick intervals of salt in the underlying Silurian Salina Group. Models incorporate minor erosion from 260 to 140 million years ago (Ma) that allows for extended burial and heating of underlying strata. Two modeled times of increased erosion, from 140 to 90 Ma and 23 to 5.3 Ma, are followed by lesser erosion from 5.3 Ma to Present. Absent strata are mainly Permian shales and sandstone; thickness of these removed layers increased from about 6200 ft (1890 m) west of the Rome trough to as much as 9650 ft (2940 m) within the trough. The onset of oil generation based on 0.6% Ro ranges from 387 to 306 Ma for the Utica Shale, and 359 to 282 Ma for Middle Devonian to basal Mississippian shales. The ~1.2% Ro onset of wet gas generation ranges from 360 to 281 Ma in the Utica Shale, and 298 to 150 Ma for Devonian to lowermost Mississippian shales.


2021 ◽  
Vol 9 ◽  
Author(s):  
Jia Wang ◽  
Xianfeng Tan ◽  
Jingchun Tian ◽  
Long Luo ◽  
Xuanbo Gao ◽  
...  

Diagenetic evolution is an important controlling factor of shale gas reservoirs. In this study, based on field outcrop and drilling core data, analytical techniques including X-ray diffraction (XRD), field emission scanning electron microscope combined with a focused ion beam (FIB-FESEM), and energy-dispersive spectroscopy (EDS) analyses were performed to determine the diagenetic evolution of the Longmaxi Formation shale and reveal the effect of diagenetic evolution on the shale gas exploration and development in the Sichuan Basin, Southwest China. The eodiagenesis phase was subdivided into two evolution stages, and the mesodiagenesis phase was subdivided into three evolution stages in the basin margin and center. Absorbed capacity and artificial fracturing effect of the Longmaxi Formation shale gas were related to mineral composition, which was influenced by sedimentary characteristics and diagenetic evolution. The diagenetic system in the basin margin was more open than that in the basin center due to a different burial history. The more open diagenetic system, with more micro-fractures and soluble constitute (e.g., feldspar), was in favor for the formation and preservation of secondary dissolved pores and organic pores in the basin margin. The relatively closed diagenetic system with stronger compaction resulted in deformation of pore space in the central basin.


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