Burial History and Porosity Evolution of Brazilian Upper Jurassic to Tertiary Sandstone Reservoirs

1997 ◽  
pp. 79-89
Keyword(s):  
Upper Jurassic ◽  
Burial History ◽  
Porosity Evolution ◽  
Sandstone Reservoirs ◽  
Tertiary Sandstone

scholarly journals Physical Property and Origin of Lowly Permeable Sandstone Reservoir in Chang 2 Division, Zhang-Han Oilfield, Ordos Basin

2009 ◽  
Vol 27 (5) ◽  
pp. 367-389 ◽  
Author(s):  
Chao Gao ◽  
Zhenliang Wang ◽  
Jie Deng ◽  
Jinghui Zhao ◽  
Xianchao Yang
Keyword(s):  
Pore Space ◽  
Ordos Basin ◽  
Physical Property ◽  
Asymmetric Distribution ◽  
Porosity Evolution ◽  
Key Factor ◽  
Northern Shaanxi ◽  
Sandstone Reservoirs ◽  
Diagenetic Facies ◽  
Pore Types

Lowly permeable sandstone reservoirs play an important role in the exploration and exploitation of natural gas and petroleum in China. The reservoirs are major lowly permeable sandstone reservoirs in Chang 2 division, Yanchang Formation, Upper Triassic in Zhang-Han oilfield, which located in the northern Shaanxi slope of Ordos Basin. According to the distribution and composition of sand beds, integrated measured physical properties, micro-pore structure analysis, cast thin section observation, scanning electron microscopy, the impacts of deposition and diagenesis on porosity evolution are analyzed. The essential diagenesis causing the porosity loss is evaluated quantitatively, and finally the origin mechanisms of low permeability reservoir in Zhang-Han oilfield are discussed. The results show: (1) Fine particle and low compositional maturity arkose are the material foundation of the formation of poor physical property sandstone; (2) The main pore space of reservoir is secondary pores. There are two types of combined pores that including dissolve-residual pores and dissolve-micropores. The porosity values display an approximately normal distribution, and permeability values are asymmetric distribution of the logarithm in lowly permeable sandstones. Their correlation coefficient becomes more and more worse with the decrease of permeability; (3) There are four diagenetic facies, in which three diagenetic facies belong to extra-lowly permeable and ultra-lowly permeable reservoir sandstones and widely distributed, and they are diagenetic lithofacie background of lowly permeability sandstone; (4) In low compositional maturity arkose, its initial porosity is 1/4 lower than conventional reservoir, the secondary and dissolved pores are main pore types of lowly permeable reservoir rocks. It is also a key factor of effective oil-bearing of lowly permeability sandstone.

PALAEOTECTONIC EVOLUTION AND HYDROCARBON GENESIS OF THE CENTRAL EXMOUTH PLATEAU

1982 ◽  
Vol 22 (1) ◽  
pp. 131 ◽  
Author(s):  
Peter M. Barber
Keyword(s):  
Lower Triassic ◽  
Geothermal Gradient ◽  
Upper Jurassic ◽  
Source Rocks ◽  
Burial History ◽  
Exmouth Plateau ◽  
Mature Phase ◽  
Gas Source ◽  
Cenozoic Era ◽  
Block Structures

In the wake of high industry optimism for the discovery of commercially viable hydrocarbons on the Exmouth Plateau, drilling of three wells by the Phillips Group revealed the presence of noncommercial quantities of gas. Expectations were originally based on the generation of oil from Upper Jurassic and Neocomian shales in the Kangaroo Trough and subsequent migration into Triassic and Jurassic tilted fault blocks on the Exmouth Plateau High, tested by the Jupiter 1 and Mercury 1 wells. In both these wells, and at the Saturn 1 location subsequently drilled in the Kangaroo Trough, the Upper Triassic, Jurassic and Cretaceous sections were found to be immature and incapable of generating hydrocarbons. Most hydrocarbon shows on the Exmouth Plateau possibly originated from a deep (5.5 km) overmature gas source, probably Lower Triassic and Permian shales. Deep tapping of the source beds by faults bounding the tilted fault block structures has enabled gas to migrate.Integrated palaeotectonic and thermal maturation studies indicate a direct link between the hydrocarbon grade and its subsequent expulsion and entrapment. The absence of much of the Jurassic cover due to erosion and/or non-deposition allowed early and mature phase hydrocarbons being generated from the Permian and Lower Triassic to escape. With increasing depth of burial and concomitant overmature hydrocarbon genesis during the Cenozoic era, further leakage was caused by upward perpetuation and regeneration of the fault conduits, breaching the Lower Cretaceous and younger sealing units. Effective trapping usually occurs only where overmature gas is trapped by fault-independent closure immediately beneath the Callovian break-up unconformity, such as at Jupiter 1 and Saturn 1.The lack of major liquid hydrocarbons is attributed to unfavourable source rocks, inadequate burial history and an historically low geothermal gradient, the effect of which is further compounded by the cooling effect of water depths greater than 1000 m.

Investigation of the geological, technical and economical obstacles for large-scale utilization of geothermal energy from Danish sandstone reservoirs

2020 ◽  
Author(s):  
Mette Olivarius ◽  
Niels Balling ◽  
Jesper P. M. Baunsgaard ◽  
Esben Dalgaard ◽  
Hanne Dahl Holmslykke ◽  
...  
Keyword(s):  
Large Scale ◽  
Oil And Gas ◽  
Gas Permeability ◽  
Business Case ◽  
Depositional Environments ◽  
Heat Extraction ◽  
Geothermal Resource ◽  
Burial History ◽  
Reservoir Properties ◽  
Sandstone Reservoirs

<p>The Triassic–Jurassic sandstone reservoirs in the Danish subsurface at c. 1–3 km depth contain an enormous geothermal resource that is currently utilized in only three geothermal plants due to a number of geological, technical and commercial barriers. These barriers have been addressed in the GEOTHERM project funded by Innovation Fund Denmark and recommendations for overcoming the obstacles have been made. Some of the methods that are used in the oil and gas sector have successfully been introduced in the geothermal reservoir evaluations to reduce the risk associated with new exploration wells. Quantitative seismic interpretation proved capable of giving a reliable reservoir characterization with regards to estimation of porosity and sand/clay distribution. Diagenesis modelling gave good estimates of reservoir quality by utilizing the knowledge obtained about depositional environments, petrography, reservoir properties and burial history. Relationships between fluid and gas permeability have been established such that the regularly measured gas permeability can be recalculated to fluid permeability giving a better representation of the reservoir. The composition of the formation water in the three geothermal plants has been measured and used for geochemical modelling to evaluate the risk of scaling, where especially barite showed a tendency to precipitate upon cooling of the brine. Simulations of the thermal development of the reservoirs during long-term geothermal exploitation demonstrate significant heat extraction from the layers present above and below each reservoir, which ensures that only a small decrease in production temperature occurs over several decades. The regional geothermal resource estimation has been updated based on a new comprehensive 3D temperature model of the subsurface, confirming the presence of a huge geothermal resource with wide geographical extend covering most of the country. The causes of injection problems have been investigated including corrosion and scaling processes, showing that careful choice of well-lining and tubing materials besides cautious operation of plants are of utmost importance to prevent problems. A geothermal business case has been developed to give a lifetime assessment of geothermal plants including feasibility, design, drilling, construction, production and abandonment, showing that the operational costs are closely linked to the existing infrastructure and to the choices made when designing the geothermal plant. In conclusion, the new scientific results and best-practice manuals provide a significantly higher chance of success of new geothermal projects when including the recommended measures to minimize the geological uncertainties and prevent problems during drilling and production.</p>

Cementation and porosity evolution of tight sandstone reservoirs in the Permian Sulige gas field, Ordos Basin (central China)

2019 ◽  
Vol 103 ◽  
pp. 276-293 ◽  
Author(s):  
Aiping Fan ◽  
Renchao Yang ◽  
Nils Lenhardt ◽  
Meng Wang ◽  
Zuozhen Han ◽  
...  
Keyword(s):  
Ordos Basin ◽  
Central China ◽  
Tight Sandstone ◽  
Gas Field ◽  
Porosity Evolution ◽  
Sandstone Reservoirs
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