The impact of diagenesis precipitation on fracture permeability in naturally fractured carbonate reservoirs

Aljuboori, Faisal Awad; Lee, Jang Hyun; Elraies, Khaled Abdalla; Stephen, Karl Dunbar

doi:10.1007/s13146-020-00664-8

Cited by 9 publications

(8 citation statements)

References 45 publications

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“…Evidence for these structures acting as barriers is that: (1) limestone stringers are present proximal to fractures (Figure 9c,d), which would have otherwise been fully replaced if fractures and E‐W faults were dolomitising fluid conduits, and (2) the location of larger scale E‐W / NE‐SW faults correlates with the lateral termination of the main dolostone geobody towards the south of Serra Esparreguera (Figure 3). Furthermore, thin calcite cemented fractures separate dolostone from the unreplaced host limestone (Figure 10c) creating sharp dolomitisation fronts, suggesting that they control replacement and acted as fluid barriers, which is observed in other diagenetically altered carbonates (Aljuboori et al, 2021; Bauer et al, 2016; Coalson et al, 1994).…”

Section: Discussionmentioning

confidence: 95%

Depositional and structural controls on a fault‐related dolostone formation (Maestrat Basin, E Spain)

et al. 2022

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Fault‐related dolomitisation is responsible for the development of numerous hydrocarbon reservoirs hosted in diagenetically‐altered carbonates and is therefore critical to hydrocarbon exploration, subsurface storage (i.e. CO2), the formation of associated mineralisation (i.e. MVT‐deposits) and for understanding the key controls on subsurface fluid flow. Multiple dolomitised outcrop analogues have been characterised in recent years, but uncertainty still remains as to the controls on dolomitisation in terms of dolostone geobody size and geometries, their distribution and how they impact reservoir quality. Late Tithonian shallow‐marine carbonates at Serra Esparreguera in the Maestrat Basin (E. Spain) were partially dolomitised on the seismic scale, resulting in a spectrum of geobodies with varying degrees of spatial connectivity. Dolostone predominantly replaces Polpís Fm wackestones and packstones, and bioclastic grainstones of the Bovalar Fm. Dolostone geobodies transition through vertical stratigraphy from being massive and spatially extensive to localised stratabound bodies as textural heterogeneity increases. Irregular dolostone geometries occur in the Polpís Fm, which is texturally homogenous relative to the overlying Bovalar Fm, cross‐cutting bedding in areas with high abundance of faults. Faults occur adjacent to dolostone and constrain its lateral extent across the outcrop. Dolomitisation fronts are typically sharp with morphologies affected by small‐scale faults and bedding‐parallel stylolites. Dolomitisation occurred under burial conditions and dolostones were later overprinted by phases of calcite and saddle dolomite cementation. The spatial distribution of dolostone is strongly influenced by the depositional heterogeneity and faults, while smaller structures (i.e. metre‐scale fractures and stylolites) and bedding surfaces controlled the dolomitisation front geometry. Dolostone geobodies at Serra Esparreguera provide new insights into the structural, depositional and diagenetic controls on dolomitisation at a seismic scale, which can be used as a predictive guide to improve the understanding of carbonate reservoirs with complex paragenetic histories.

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Section: Discussionmentioning

confidence: 95%

Depositional and structural controls on a fault‐related dolostone formation (Maestrat Basin, E Spain)

et al. 2022

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“…The oil and gas in carbonate reservoirs play an extremely important role in the world’s oil and gas resources. , Acidizing is a conventional measure for carbonate reservoir stimulation . For the carbonate reservoir, the main purpose of acidizing is to dissolve some formation rock minerals and plug the materials into pores (fractures) and form acid wormholes with high permeability to communicate between the wellbore and the oil storage medium. , With the continuous exploration and development of carbonate reservoirs, the reservoir conditions faced by acid stimulation become more and more complex, and the shortcomings of traditional acidizing technology become increasingly obvious.…”

Section: Introductionmentioning

confidence: 99%

“…The oil and gas in carbonate reservoirs play an extremely important role in the world’s oil and gas resources. 1 , 2 Acidizing is a conventional measure for carbonate reservoir stimulation. 3 For the carbonate reservoir, the main purpose of acidizing is to dissolve some formation rock minerals and plug the materials into pores (fractures) and form acid wormholes with high permeability to communicate between the wellbore and the oil storage medium.…”

Section: Introductionmentioning

confidence: 99%

Self-Generated Organic Acid System for Acid Fracturing in an Ultrahigh-Temperature Carbonate Reservoir

Zhang¹,

Liu

Xiong³

et al. 2023

ACS Omega

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As an important part of acid fracturing technology for the carbonate reservoir, the performance of the acid system directly affects the stimulation effect. In view of the current problems of an acid fluid system in an ultrahigh-temperature carbonate reservoir, such as fast acid–rock reaction, short effective action distance, and difficulty maintaining the conductivity of acid etching fractures, an experimental study on the self-generated organic acid system was carried out. The results showed that acetic anhydride and ethyl acetate, which had a strong acid generating ability, were suitable for the parent acid types of self-generated organic acids. Preferably, the peak temperature of 25% acetic anhydride is 160 °C, while the peak temperature of 30% ethyl acetate is 180 °C. The acid–rock reaction kinetics experiment shows that the order of activation energy is ethyl acetate > acetic anhydride > cross-linked acid. The reaction rate is arranged as follows: ethyl acetate < acetic anhydride ≪ cross-linked acid. The self-generated organic acid of ethyl acetate has the largest activation energy, the smallest reaction rate, and the best retarding effect. Acetic anhydride forms a strong nonuniform pitting morphology on the surface of the rock plate, with an initial conductivity of 225.4 μm2·cm. Ethyl acetate forms an uneven pitting morphology, and the initial conductivity is 53.1 μm2·cm. However, the ability of acid etching fracture formed by ethyl acetate to maintain fracture conductivity is stronger than that of acetic anhydride. Ethyl acetate is more suitable for a deep ultrahigh-temperature carbonate reservoir.

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“…The tight carbonate reservoir controlled by various geological factors [1], such as the lithofacies paleogeographic environment [2][3][4][5][6], karst paleomorphology [7][8][9][10][11][12][13][14], diagenesis and diagenetic facies [15][16][17][18][19], and tectonic movement [7,20], is complex in rock structure with diverse reservoir pores and strong heterogeneity. However, different factors are controlling the reservoir distribution in various depths from the surface to the bottom; for example, the upper Majiagou formation may be greatly affected by karst palaeogeomorphology, while the lower Majiagou formation is highly influenced by lithofacies and the paleogeographic environment [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Tight Dolostone Reservoir and Its Main Controlling Factors in the Submember Ma55 of Majiagou Formation in the Western Ordos Basin

Zhou

et al. 2023

Geofluids

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The tight carbonate reservoir was controlled by various geological factors, and such factors played different roles in buried depths and formations. Therefore, studies related to the factors controlling carbonate reservoir distribution are of great significance for the prediction and evaluation of high-quality dolostone reservoirs. In this paper, we focus on the controlling factor of the submember Ma55 dolostone reservoir in the western Ordos Basin. The main rock types, reservoir pores, physical properties, and pore structure characteristics of the reservoir were analyzed by thin section identification, physical property analysis, and mercury injection, respectively. Then, the main controlling factors of reservoir development were comprehensively analyzed from the perspectives of palaeostructure, lithofacies palaeogeography, diagenesis, and diagenetic facies. The results show that two kinds of dolostone reservoirs in the submember Ma55 developed in the western Ordos Basin, including intercrystalline pore-type and dissolution pore-type. The former reservoir is primarily characterized by powder-fine dolostone with residual structure, dolomite intercrystalline pore, and micropore with porosity ranging from 2% to 11%. There are three types of pore structures developed in it, such as macropore-medium throat-single peak (MAMS), macropore-fine throat-single peak (MAFS), and medium pore-fine throat-single peak (MEFS). The latter reservoir is mainly featured by powdery crystalline dolostone with gypsum and halite dissolution, moldic pore, and dissolved pore between breccias with a porosity greater than 5%. It consists of two types of pore structures, such as macropore-fine throat-single peak (MAFS) and medium pore-coarse throat-multipeak (MECM). The intercrystalline pore-type dolostone reservoir is mainly controlled by the lithofacies palaeogeographic environment and diagenesis. In specific, the shoal microfacies at the edge of the platform and the active reflux seepage dolomitization are the basic sedimentary environment conditions for reservoir formation and the key to reservoir formation, respectively. The dissolution pore-type dolostone reservoir is primarily influenced by both paleostructure and diagenesis. The relatively high part of the paleostructure provides favorable conditions for the formation of evaporate minerals, and early freshwater dissolution is the key to reservoir formation. This research will provide a theoretical basis for forecasting the favorable distribution areas of different types of dolostone reservoirs.

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The impact of diagenesis precipitation on fracture permeability in naturally fractured carbonate reservoirs

Cited by 9 publications

References 45 publications

Depositional and structural controls on a fault‐related dolostone formation (Maestrat Basin, E Spain)

Depositional and structural controls on a fault‐related dolostone formation (Maestrat Basin, E Spain)

Self-Generated Organic Acid System for Acid Fracturing in an Ultrahigh-Temperature Carbonate Reservoir

Characteristics of Tight Dolostone Reservoir and Its Main Controlling Factors in the Submember Ma55 of Majiagou Formation in the Western Ordos Basin

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