scholarly journals Diagenetic facies quantitative evaluation of low-permeability sandstone: A case study on Chang 82 reservoirs in the Zhenbei area, Ordos basin

2017 ◽  
Vol 36 (3) ◽  
pp. 414-432 ◽  
Author(s):  
Baoquan Ma ◽  
Shaochun Yang ◽  
Hong Zhang ◽  
Qingdong Kong ◽  
Chunting Song ◽  
...  
Keyword(s):  
Quantitative Evaluation ◽  
Ordos Basin ◽  
Physical Property ◽  
Reservoir Quality ◽  
Low Permeability ◽  
Data Envelopment ◽  
Reservoir Evaluation ◽  
Diagenetic Facies

Quantitative characterization of diagenetic facies has great significance for reservoir evaluation and prediction. In order to find out the method to evaluate diagenetic facies, the author took Chang 82 reservoir low-permeability sandstone in Zhenbei area of Ordos basin as research object and divided the reservoir into six types of diagenetic facies by analysis of casting thin section, scanning electron microscope, cathode luminescence, and physical property. According to 14 quantitative evaluating parameters which were related with petrology characteristic, diagenesis strength, pore structure, etc. quantitative evaluation of diagenetic facies of low-permeability sandstone reservoir was done by data envelopment analysis. The result showed that in the Chang 82 reservoir low-permeability sandstone in Zhenbei area of Ordos basin, quantitative representative indexes of diagenetic facies ranged from 0 to 1.00. Various diagenetic facies and their indexes had interval corresponding relation. The diagenetic facies of weak corrosion with chlorite mat and the diagenetic facies of corrosion of unstable components had the best reservoir quality. Their diagenetic facies indexes ranged from 0.66 to 1.00. The reservoir quality of the diagenetic facies filled with kaolinite was not as good as the former. The indexes ranged from 0.50 to 0.66. The diagenetic facies of quartz secondary enlargement and the diagenetic facies of clay mineral cementation replacement had poor reservoir quality. Their diagenetic facies indexes ranged from 0.30 to 0.40. The diagenetic facies of carbonate cementation had the poorest reservoir quality. It hardly possessed fluid storage capability. After comparing diagenetic facies indexes, absorption strength and remaining oil saturability, the perfect corresponding relation between quantitative evaluation results and reservoir quality could be verified.

Research on Diagenetic Facies Based on Diagenetic Effect in the Low Permeability Sandstone Reservoir - A Case from C81 Reservoir in Huanjiang Region, Ordos Basin

2014 ◽  
Vol 522-524 ◽  
pp. 1274-1279
Author(s):  
Chun Wang ◽  
Zhi Guo Jin ◽  
Cheng Zhi Liu
Keyword(s):  
Physical Properties ◽  
Ordos Basin ◽  
Physical Property ◽  
Low Permeability ◽  
Thin Sections ◽  
Diagenetic Minerals ◽  
Calcite Cementation ◽  
Diagenetic Facies ◽  
Pore Types ◽  
Feldspar Dissolution

The research is carried out on diagenetic minerals, pore types and its impact on the physical properties in Huanjiang C81reservoir of Ordos basin, which is based on reservoir physical property test, thin sections observation and scanning electron microscopy. Several minerals closely associated with reservoir physical properties are identified from diagenetic effect views. It results in that a classification is proposed for the diagenetic facies, consisting of four kinds of diagenetic facies: ferroan calcite cementation facies, hydromica/kaolinite cementation facies, chlorite coating facies and feldspar dissolution facies. The study of C81reservoir in Huanjiang region shows that this scheme is favorable to estimate low permeability reservoir, the result shows fairly good consistency with the distribution of physical property of wells.

Research on Diagenetic Facies of Low Permeability Reservoir: A Case Study of the Yanchang Formation in Longdong Area, Ordos Basin

2012 ◽  
Vol 616-618 ◽  
pp. 145-150
Author(s):  
Jing Fu ◽  
Sheng He Wu
Keyword(s):  
Ordos Basin ◽  
Low Permeability ◽  
Yanchang Formation ◽  
Significant Difference ◽  
Local Medium ◽  
Intensity Calculation ◽  
Diagenetic Facies

Based on data of cast thin section, cathode luminescence and scanning electron microscope, the present paper comprehensively investigated the types and quantitative intensity of reservoir diagenesis of the Upper Triassic Yanchang Formation in Longdong area of Ordos Basin, distinguished the types of diagenetic facies from the aspect of quantitative index. The intensity calculation and classification of compaction, cementation and dissolution indicates that the Yanchang Formation of Longdong area experienced strong compaction including medium to strong compaction and extremely strong compaction locally for the high contents of matrix. There is great difference in cementation intensity which presents mainly in weak cementation with local medium to strong cementation. Dissolution is strong in study area mainly in medium to strong. The reservoir could be divided into eight types of diagenetic facies, including medium compaction with strong dissolution face, medium compaction with medium dissolution face, medium compaction with medium cementation and medium dissolution face, strong compaction with strong dissolution face, strong compaction with medium dissolution face, medium compaction with strong cementation face, strong compaction with strong cementation face and extremely strong compaction face. The reservoir quality of different diagenetic facies has a significant difference.

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.

scholarly journals The Cavendish Field, Block 43/19, UK North Sea

2020 ◽  
Vol 52 (1) ◽  
pp. 131-141 ◽  
Author(s):  
N. Wasielka ◽  
J. G. Gluyas ◽  
H. Breese ◽  
R. Symonds
Keyword(s):  
Grain Size ◽  
Continental Shelf ◽  
North Sea ◽  
Water Depth ◽  
Reservoir Quality ◽  
Low Permeability ◽  
Gas Field ◽  
Upper Carboniferous ◽  
Northern Margin

AbstractThe Cavendish Field is located in UK Continental Shelf Block 43/19a on the northern margin of the Outer Silverpit Basin of the Southern North Sea, 87 miles (140 km) NE of the Lincolnshire coast in a water depth of 62 ft (18.9 m). The Cavendish Field is a gas field in the upper Carboniferous Namurian C (Millstone Grit Formation) and Westphalian A (Caister Coal Formation) strata. It was discovered in 1989 by Britoil-operated well 43/19-1. Production started in 2007 and ceased in 2018. Gas initially in place was 184 bcf and at end of field life 98 bcf had been produced. The field was developed by three wells drilled through the normally unmanned platform into fluvio-deltaic sandstone intervals that had sufficiently good reservoir quality to be effective reservoirs. The majority of the formation within closure comprises mudstones, siltstones and low permeability, non-reservoir-quality feldspathic sandstones. The quality of the reservoir is variable and is controlled by grain size, feldspar content and diagenesis. The field is a structural trap, sealed by a combination of intra-Carboniferous mudstones and a thick sequence of Permian mudstones and evaporites.

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