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

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.

2009 ◽  
Vol 27 (5) ◽  
pp. 367-389 ◽  
Author(s):  
Chao Gao ◽  
Zhenliang Wang ◽  
Jie Deng ◽  
Jinghui Zhao ◽  
Xianchao Yang

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.


2015 ◽  
Vol 1092-1093 ◽  
pp. 1420-1423
Author(s):  
Lei Cao ◽  
Wei Sun ◽  
Rui Niu ◽  
Lei Huo ◽  
Fu Tao Qu ◽  
...  

By analyzing the thin sections, physical property and nuclear magnetic resonance, the petrology character, pore types and the movable fluid saturation distribution characteristics of Chang 6 reservoir in Banqiao-Heshui area were tested. The research shows that the main lithology of Chang 6 reservoir in study area is lithic arkose. The pore space of reservoir mainly include the solution pores and the primary residual intergranular pores. Fine pore-tiny throat is the main pore configuration. The physical properties of Chang 6 reservoir in Banqiao-Heshui area are weak and it belongs to low-permeability and porosity oil reservoir. There are two models of T2 spectrum, including bimodal and unimodal modes. Movable fluid saturation and fluid porosity varies a lot, the reservoir can be classified as many types by movable fluid saturation and for each of them, its movable fluid saturation differs obviously.


2017 ◽  
Vol 36 (3) ◽  
pp. 414-432 ◽  
Author(s):  
Baoquan Ma ◽  
Shaochun Yang ◽  
Hong Zhang ◽  
Qingdong Kong ◽  
Chunting Song ◽  
...  

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.


2015 ◽  
Vol 1092-1093 ◽  
pp. 1410-1415
Author(s):  
Yuan Kang ◽  
Wei Sun ◽  
Ting Shang ◽  
Jian Chao Shi ◽  
Jun Sheng

The Xishanyao reservoir in Niuquanhu area is a typical low permeability reservoir Diagenesis is very important for the physical property of reservoir. Through analyzed data of cast thin sections and scanning electron microscopy (SEM) data, analyzed the impact of main diagenesis on reservoir properties in Niuquanhu area. First, quantitative analyzed the various types of diagenesis on reservoir porosity contribution rate. Second, through restoring the original porosity, quantitative analyzed the pore evolution of reservoir caused by various types of diagenesis. Realized the quantitative analysis of porosity of each diagenesis stage. The quantitative calculation results agree well with the experimental analysis results, the error is 1.09%~1.51%, which showed the rationality of research method and the research results have certain reliability. The study of diagenesis has important significance for fine evaluation and favorable area prediction of Niuquanhu area reservoir.


Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Tongsheng Cao ◽  
Xianfeng Tan ◽  
Long Luo ◽  
Jingchun Tian ◽  
Dongping Tan ◽  
...  

Abstract The physical property heterogeneity of tight sandstones was mainly caused by complex alteration of various diagenesis combinations during burial process. However, diagenetic evolution of different diagenesis combinations which generally result in the strong difference and heterogeneity of physical property and pore structure is rarely well understood. The Middle Permian lower Shihezi Formation is one of the most important tight gas sandstone reservoirs in the Hangjinqi area of Ordos Basin, China. The reservoir heterogeneity of lower Shihezi Formation, which was caused by the differential diagenesis combination, is crucial to efficient exploration and development. Evolution mechanism of differential diagenesis combination and its effect on the reservoir quality in the tight lower Shihezi Formation sandstone in the Hangjinqi area of Ordos Basin was investigated by means of thin-section description, cathodoluminescence (CL) imaging, X-ray diffraction (XRD), scanning electron microscopy (SEM), and homogenization temperature of fluid inclusions. The lower Shihezi Formation sandstones can be divided into four diagenesis combination types according to the reservoir characteristics and diagenetic relationship. The main diagenetic sequence was mechanical compaction-chlorite rim-early pore-filling calcite cementation-dissolution-authigenic kaolinite-quartz cementation-late calcite cementation. Differential diagenesis combination was mainly controlled by the petrological characteristics, microfacies, and fault. Low content of rock fragment and high content of detrital quartz were beneficial to the compaction resistance and cementation. The moderate content of pore-filling calcite was conducive to pore space protection and feldspar dissolution. The faults control dissolution and differential diagenesis combination by influencing the migration of acid fluids. Moderate compaction-moderate cementation-moderate dissolution type (BBB type) and weak compaction-moderate cementation-strong dissolution type (CBA type) were in favour of high-quality reservoir development.


2011 ◽  
Vol 361-363 ◽  
pp. 51-54
Author(s):  
Hong Yan Yu ◽  
Hong Qi Li

As the result of its special structural feature and depositional setting, Ordos Basin formed large scale low-permeability reservoir. According to scanning electron microscope, casting sheet image, core observation, physical property analysis and core analysis testing, this paper summarized and analyzed ultra low permeability reservoir microscopic feature of Ordos Basin Baibao area Chang63. Reservoir microscopic feature is controlled by deposition and diagenesis. Deposition decided reservoir lithology, interstitial content and sizes of primary pores. Compaction and cementation of diagenesis destroyed primary pores, but denudation provided high range secondary pores, which improved storage space of the research area.


Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 470
Author(s):  
Yue Zhang ◽  
Jingchun Tian ◽  
Xiang Zhang ◽  
Jian Li ◽  
Qingshao Liang ◽  
...  

Diagenesis and pore evolution of tight sandstone reservoir is one of the most important issues surrounding clastic reservoirs. The tight sandstone of the Shanxi Formation is an important oil and gas producing layer of the Upper Paleozoic in Ordos Basin, and its densification process has an important impact on reservoir quality. This study determined the physical properties and diagenetic evolution of Shanxi Formation sandstones and quantitatively calculated the pore loss in the diagenetic process. Microscopic identification, cathodoluminescence, and a scanning electron microscope were used identify diagenesis, and the diagenesis evolution process was clarified along with inclusion analysis. In addition, reservoir quality was determined based on the identification of pore types and physical porosity. Results show that rock types are mainly sublitharenite and litharenite. The reservoir has numerous secondary pores after experiencing compaction, cementation, and dissolution. We obtained insight into the relationship between homogenous temperature and two hydrocarbon charges. The results indicated that there were two hydrocarbon charges in the Late Triassic–Early Jurassic (70–90 °C) and Middle Jurassic–Early Cretaceous (110–130 °C) before reservoir densification. The quantitative calculation of pore loss shows that the average apparent compaction, cementation, and dissolution rates are 67.36%, 22.24%, and 80.76%, respectively. Compaction directly affected the reservoir tightness, and intense dissolution was beneficial to improve the physical properties of the reservoir.


Author(s):  
Gao Zhanwu ◽  
Shi Jian ◽  
Xie Qichao ◽  
Zhou Yan ◽  
Zhou Shuxun

AbstractTight sandstone reservoirs dominated by are developed in the Chang 6 oil layer group of the Yanchang Formation in the central-western part of the Ordos Basin. Featuring the lacustrine delta facies, Chang 6 formation in the center-west area of Ordos Basin shows an increasing petroleum reserve expectation. Its exploitation practice, however, has many problems caused by tight sandstone reservoir features. According to diagenetic and pore analysis, the diagenetic facies in the study area are grouped into four types: chlorite-film-intergranular-pore, feldspar-dissolution, clay-cemented-micropore, carbonate-cemented-tightness for their obvious differences in mineral feature and pore evolution. By introducing the comprehensive classification parameter synthesized from 9 other parameters, the reservoir quality is divided up into four levels: I(Feci > 1), II(3 ≤ Feci ≤ 7), III(-2 ≤ Feci ≤ 3), IV(Feci ≤ -2). The reservoir quality division matches well with the diagenetic facies group. To decide the diagenetic type and reservoir quality division in all wells, the logging data are utilized with the Fisher discriminant method, which has obtained a good performance. The method enables the reservoir quality analysis expanding to all wells from samples, which is helpful for exploitation of the study area.


2014 ◽  
Vol 522-524 ◽  
pp. 1257-1261 ◽  
Author(s):  
Bing Xi Li ◽  
Yuan Ting Cao ◽  
Wen Zhong Ma

Micro-pore characteristics and its control factors are analyzed according to mercury penetration, physical property parameters, flake observation and scanning electron microscopy, etc. Studies show that Chang81 reservoir is ultra-low permeability, its main pore types are intergranular pore and feldspar dissolved pore, its main pore throat types are low porosity, fine throat to micro-fine throat. Diagenesis stage of Chang 81 reservoir is situated in the diagenetic stage B. compaction mainly reduce the pore space, while the micro-cracks caused by compaction can be good reservoir space; ferrocalcite cement, Chlorite coating and kaolinite would destroy the reservoir space by filling in the primary pores and secondary pores; hydration of feldspar would destroy the reservoir space, while dissolution of feldspar would improve the reservoir space; dissolution of feldspar is the most favorable diagenesis.


Author(s):  
Yubin Bai ◽  
Jingzhou Zhao ◽  
Delin Zhao ◽  
Hai Zhang ◽  
Yong Fu

AbstractThis study applied vacuum-impregnated casting thin sections, fluorescence slices, scanning electron microscopy (SEM), pressure-controlled mercury porosimetry (PCP), rate-controlled mercury porosimetry (RCP), X-ray diffraction of clay minerals, overburden pressure, and conventional physical property strategies to determine the microscopic characteristics of the Chang 6 member, a typical tight sandstone reservoir in the Jingbian oilfield in the Ordos Basin, China. We also analyzed the controlling effects of pore structure on reservoir quality and oiliness. The results showed that the pore types of the Chang 6 sandstone reservoir can be divided into four categories: residual intergranular pores, dissolution pores, intercrystalline pores between clay minerals, and microfractures. The pore size of the Chang 6 sandstone reservoir ranged from 20 to 50 μm. We employed PCP and RCP strategies to characterize the pore structure of the Chang 6 reservoir. The pore radius was less than 2 μm, and on average, the throat radius was less than 0.3 μm. The reservoir physical properties were affected by diagenesis, particularly compaction, and the average porosity failure rate was 56.3%. Cementation made the reservoir more compact, dissolution improved the physical properties of the reservoir locally, and fracturing effectively improved the reservoir seepage ability; however, its influence on porosity was limited. The pore structure controlled the quality of the reservoir. The physical properties of the reservoir were closely related to the oil-bearing properties. The lower limits of porosity and permeability of industrial oil flow in the reservoir were 7.5% and 0.15 mD, respectively. These results provide an additional resource for the exploration and development of tight oil in the Ordos Basin.


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