Major Controls on the Evolution of the Cambrian Dolomite Reservoirs in the Keping Area, Tarim Basin

2013 ◽  
Vol 734-737 ◽  
pp. 377-383
Author(s):  
Qing Li ◽  
Xue Lian You ◽  
Wen Xuan Hu ◽  
Jing Quan Zhu ◽  
Zai Xing Jiang
Keyword(s):  
Tarim Basin ◽  
Significant Contribution ◽  
Oil And Gas ◽  
Geochemical Data ◽  
Acid Dissolution ◽  
High Quality ◽  
Secondary Porosity ◽  
Oil And Gas Exploration ◽  
Reservoir Evolution ◽  
Major Factors

The Cambrian dolomite reservoir is an important target in oil and gas exploration. The Penglaiba section in the Keping area is typically examined in studies dealing with the Cambrian dolomite reservoirs of northwestern Tarim Basin. Based on sedimentological, petrographic, and geochemical data, lithofacies and fluids are identified as the major factors that control the dolomite reservoir in the study area. Lithoacies are fundamental to reservoir evolution because they provide suitable channels for dolomitization and dissolution of fluids that, in turn, facilitate the formation of high quality reservoirs. The lithofacies which could form high-quality reservoirs in the study area are: slope slip (collapse) facies, gypsum related facies, and algae dolomite facies. The sources of fluids include seawater, meteoric freshwater, diagenetic/hydrocarbon fluid, and hydrothermal fluid. These fluids lead to dolomitization, penecontemporaneous meteoric dissolution, hypergene dissolution, organic acid dissolution and hydrothermal dissolution that result in secondary porosity, and as such, they have a significant contribution to reservoir evolution.

Discovery of the lower Cambrian high-quality source rocks and deep oil and gas exploration potential in the Tarim Basin, China

AAPG Bulletin ◽  
2018 ◽  
Vol 102 (10) ◽  
pp. 2123-2151 ◽  
Author(s):  
Guangyou Zhu ◽  
Feiran Chen ◽  
Meng Wang ◽  
Zhiyao Zhang ◽  
Rong Ren ◽  
...  
Keyword(s):  
Tarim Basin ◽  
Lower Cambrian ◽  
Oil And Gas ◽  
Source Rocks ◽  
High Quality ◽  
Oil And Gas Exploration

scholarly journals Formation environments and mechanisms of multistage paleokarst of Ordovician carbonates in Southern North China Basin

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haitao Zhang ◽  
Guangquan Xu ◽  
Mancai Liu ◽  
Minhua Wang
Keyword(s):  
Carbonate Rocks ◽  
North China ◽  
Oil And Gas ◽  
Carbonate Reservoir ◽  
Carbonate Reservoirs ◽  
Geochemical Data ◽  
Near Surface ◽  
Oil And Gas Exploration ◽  
Pore Types ◽  
North China Basin

AbstractWith the reduction of oil and gas reserves and the increase of mining difficulty in Northern China, the carbonate rocks in Southern North China Basin are becoming a significant exploration target for carbonate reservoirs. However, the development characteristics, formation stages, formation environments and mechanisms of the carbonate reservoirs in Southern North China Basin are still unclear, which caused the failures of many oil and gas exploration wells. This study focused on addressing this unsolved issue from the Ordovician carbonate paleokarst in the Huai-Fu Basin, which is located in the southeast of Southern North China Basin and one of the key areas for oil and gas exploration. Based on petrology, mineralogy and geochemical data, pore types, distribution characteristics, and formation stages of the Ordovician paleokarst were analyzed. Then, in attempt to define the origins of porosity development, the formation environments and mechanisms were illustrated. The results of this study showed that pore types of the Ordovician carbonates in the Huai-Fu Basin are mainly composed of intragranular pores, intercrystalline (intergranular) pores, dissolution pores (vugs), fractures, channels, and caves, which are usually in fault and fold zones and paleoweathering crust. Furthermore, five stages and five formation environments of the Ordovician paleokarst were identified. Syngenetic karst, eogenetic karst, and paleoweathering crust karst were all developed in a relatively open near-surface environment, and their formations are mainly related to meteoric water dissolution. Mesogenetic karst was developed in a closed buried environment, and its formation is mainly related to the diagenesis of organic matters and thermochemical sulfate reduction in the Permian-Carboniferous strata. Hydrothermal (water) karst was developed in a deep-buried and high-temperature environment, where hydrothermal fluids (waters) migrated upward through structures such as faults and fractures to dissolve carbonate rocks and simultaneously deposited hydrothermal minerals and calcites. Lastly, a paleokarst evolution model, combined with the related porosity evolution processes, nicely revealed the Ordovician carbonate reservoir development. This study provides insights and guidance for further oil and gas exploration in the Southern North China Basin, and also advances our understanding of the genesis of carbonate paleokarst around the world.

Redefined Distribution of the Permian Volcanic Rocks in the Tarim Basin: Based on Logging and Seismic Data

2013 ◽  
Vol 448-453 ◽  
pp. 3723-3727 ◽  
Author(s):  
Yun Pan ◽  
Zong Xiu Wang ◽  
Mao Pan
Keyword(s):  
Tarim Basin ◽  
Seismic Data ◽  
Oil And Gas ◽  
Volcanic Rocks ◽  
Oil Field ◽  
Shielding Effect ◽  
Underlying Structure ◽  
Oil Exploration ◽  
Oil And Gas Exploration ◽  
The North

There are a lot of Permian volcanic rocks which are widely distributed in Tarim Basin. Because of the shielding effect of the volcanic rocks to the underlying structure, the distribution of the volcanic rocks in Tarim Basin is very important to the deep oil and gas exploration. However, with the progress of oil exploration in Tarim oil field in recent years, much more logging and seismic data is available. Based on the model of logging-seismic integrated identification, the distribution of the Permian volcanic rocks is revised by using the drilling, logging and seismic data. It shows that the rhyolite is mainly distributed in the north basin, and the basalt is widely distributed in the basin. Moreover, the basalt has larger area than which delineated by other people.

Origin of organic matter in the Eagle Ford Formation

2015 ◽  
Vol 3 (1) ◽  
pp. SH27-SH39 ◽  
Author(s):  
Kenneth S. Boling ◽  
Stephen I. Dworkin
Keyword(s):  
Organic Matter ◽  
Oil And Gas ◽  
Major And Trace Elements ◽  
Geochemical Data ◽  
Eagle Ford ◽  
Seawater Chemistry ◽  
Total N ◽  
High Productivity ◽  
Oil And Gas Exploration ◽  
Economic Significance

The Upper Cretaceous Eagle Ford Formation is an organic-rich mudrock of economic significance for oil and gas exploration. In order to facilitate a better understanding of paleoceanographic conditions during Eagle Ford deposition, this study integrates the isotope chemistry of bulk organic matter with inorganic geochemical data. Measurements of total organic carbon (TOC), total N, [Formula: see text], [Formula: see text] and inorganic major, and trace elements were taken from 166 Eagle Ford and Pepper Formation outcrop samples from McLennan County, central Texas. These data reveal the chemostratigraphic character and the evolution of Cretaceous seawater chemistry on the Texas shelf and allowed the identification of six distinct chemofacies that are useful for correlation purposes. Based on these data, changing paleoredox conditions were documented ranging from normal marine (oxic) conditions associated with the Pepper Formation, anoxic conditions associated with the Lower Eagle Ford Formation, suboxic conditions associated with most of the upper Eagle Ford, and then a return to normal marine conditions at the top of the Eagle Ford Formation. The high TOC content of the Lower Eagle Ford was most likely caused by high productivity that in turn drove conditions to anoxia. Geochemical data that correlate well with TOC were used to identify intervals of potential organic enrichment.

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