scholarly journals Appalachian Basin Low-Permeability Sandstone Reservoir Characterizations

1993 ◽  
Author(s):  
Ray Boswell ◽  
Susan Pool ◽  
Skip Pratt ◽  
David Matchen
Keyword(s):  
Appalachian Basin ◽  
Low Permeability ◽  
Sandstone Reservoir

scholarly journals Impact of Diagenesis on the Low Permeability Sandstone Reservoir: Case Study of the Lower Jurassic Reservoir in the Niudong Area, Northern Margin of Qaidam Basin

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 453
Author(s):  
Wenhuan Li ◽  
Tailiang Fan ◽  
Zhiqian Gao ◽  
Zhixiong Wu ◽  
Ya’nan Li ◽  
...  
Keyword(s):  
Physical Properties ◽  
Oil And Gas ◽  
Qaidam Basin ◽  
Isotope Analysis ◽  
Lower Jurassic ◽  
Low Permeability ◽  
Hydrocarbon Generation ◽  
Northern Margin ◽  
Pore Evolution ◽  
Sandstone Reservoir

The Lower Jurassic reservoir in the Niudong area of the northern margin of Qaidam Basin is a typical low permeability sandstone reservoir and an important target for oil and gas exploration in the northern margin of the Qaidam Basin. In this paper, casting thin section analysis, scanning electron microscopy, X-ray diffraction, and stable isotope analysis among other methods were used to identify the diagenetic characteristics and evolution as well as the main factors influencing reservoir quality in the study area. The predominant types of sandstone in the study area are mainly feldspathic lithic sandstone and lithic arkose, followed by feldspathic sandstone and lithic sandstone. Reservoir porosity ranges from 0.01% to 19.5% (average of 9.9%), and permeability ranges from 0.01 to 32.4 mD (average of 3.8 mD). The reservoir exhibits robust heterogeneity and its quality is mainly influenced by diagenesis. The Lower Jurassic reservoir in the study area has undergone complex diagenesis and reached the middle diagenesis stage (A–B). The quantitative analysis of pore evolution showed that the porosity loss rate caused by compaction and cementation was 69.0% and 25.7% on average, and the porosity increase via dissolution was 4.8% on average. Compaction was the main cause of the reduction in the physical property of the reservoir in the study area, while cementation and dissolution were the main causes of reservoir heterogeneity. Cementation can reduce reservoir space by filling primary intergranular pores and secondary dissolved pores via cementation such as a calcite and illite/smectite mixed layer, whereas high cement content increased the compaction resistance of particles to preserve certain primary pores. δ13C and δ18O isotopes showed that the carbonate cement in the study area was the product of hydrocarbon generation by organic matter. The study area has conditions that are conductive to strong dissolution and mainly occur in feldspar dissolution, which produces a large number of secondary pores. It is important to improve the physical properties of the reservoir. Structurally, the Niudong area is a large nose uplift structure with developed fractures, which can be used as an effective oil and gas reservoir space and migration channel. In addition, the existence of fractures provides favorable conditions for the uninterrupted entry of acid fluid into the reservoir, promoting the occurrence of dissolution, and ultimately improves the physical properties of reservoirs, which is mainly manifested in improving the reservoir permeability.

Characteristics of Nano-Micro Pore Networks and Petroleum Microscopic Occurrence State in Ultra-Low Permeability (Tight) Sandstone Reservoir

2017 ◽  
Vol 17 (9) ◽  
pp. 6039-6050 ◽  
Author(s):  
Juncheng Qiao ◽  
Jianhui Zeng ◽  
Xiao Feng ◽  
Zhifeng Yang ◽  
Yongchao Zhang ◽  
...  
Keyword(s):  
Low Permeability ◽  
Tight Sandstone ◽  
Pore Networks ◽  
Occurrence State ◽  
Sandstone Reservoir

Research on Stress Sensitivity of Low Permeability Sand Stone Reservoir

2011 ◽  
Vol 317-319 ◽  
pp. 2432-2435
Author(s):  
Yu Xue Sun ◽  
Fei Yao ◽  
Jing Yuan Zhao
Keyword(s):  
Plastic Deformation ◽  
In Situ Stress ◽  
Stress Sensitivity ◽  
Oil Field ◽  
Low Permeability ◽  
High Permeability ◽  
Permeability Changes ◽  
Loading And Unloading ◽  
Sandstone Reservoir

In the process of low-permeability sandstone reservoir exploitation, stress sensitivity takes place with the effective stress rises gradually, which will cause permeability decline. Allowing to the condition of in-situ stress, the study and experiment on the rock core in Jilin oil field Fuxin326 oil layer are presented. The experimental results show that the stress sensitivity of this oil layer is small; the regularity of permeability changes is in accordance with exponential function. The stress sensitivity of high permeability core is larger than that of low permeability core. Moreover, experimental and theoretical analysis shows that low permeability core has a larger permeability loss than high permeability core in loading and unloading process where elastic plastic deformation of rock will happen, which is the major reason that permeability loss can not return completely.

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