Wettability of Carbonate Reservoir Rocks: A Comparative Analysis

Faramarzi-Palangar, Mohsen; Mirzaei‐Paiaman, Abouzar; Ghoreishi, Seyyed Ali; Ghanbarian, Behzad

doi:10.3390/app12010131

Cited by 11 publications

(6 citation statements)

References 74 publications

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“…In the saturated oil stage, sample 1 had a peak contact angle range of 65-70 degrees, different from the usual understanding. Generally, the reservoir's wettability in the original state should be oil wettability [70,91]. This difference may be due to no aging treatment after saturated oil.…”

Section: Wettability Variation Of Different Mineralmentioning

confidence: 99%

Effects of Wettability and Minerals on Residual Oil Distributions Based on Digital Rock and Machine Learning

Zhang

Lin

et al. 2022

Lithosphere

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The wettability of mineral surfaces has significant impacts on transport mechanisms of two-phase flow, distribution characteristics of fluids, and the formation mechanisms of residual oil during water flooding. However, few studies have investigated such effects of mineral type and its surface wettability on rock properties in the literature. To unravel the dependence of hydrodynamics on wettability and minerals distribution, we designed a new experimental procedure that combined the multiphase flow experiments with a CT scan and QEMSCAN to obtain 3D digital models with multiple minerals and fluids. With the aid of QEMSCAN, six mineral components and two fluids in sandstones were segmented from the CT data based on the histogram threshold and watershed methods. Then, a mineral surface analysis algorithm was proposed to extract the mineral surface and classify its mineral categories. The in situ contact angle and pore occupancy were calculated to reveal the wettability variation of mineral surface and distribution characteristics of fluids. According to the shape features of the oil phase, the self-organizing map (SOM) method, one of the machine learning methods, was used to classify the residual oil into five types, namely, network, cluster, film, isolated, and droplet oil. The results indicate that each mineral’s contribution to the mineral surface is not proportional to its relative content. Feldspar, quartz, and clay are the main minerals in the studied sandstones and play a controlling role in the wettability variation. Different wettability samples show various characteristics of pore occupancy. The water flooding front of the weakly water-wet to intermediate-wet sample is uniform, and oil is effectively displaced in all pores with a long oil production period. The water-wet sample demonstrates severe fingering, with a high pore occupancy change rate in large pores and a short oil production period. The residual oil patterns gradually evolve from networks to clusters, isolated, and films due to the effects of snap-off and wettability inversion. This paper reveals the effects of wettability of mineral surface on the distribution characteristics and formation mechanisms of residual oil, which offers us an in-deep understanding of the impacts of wettability and minerals on multiphase flow and helps us make good schemes to improve oil recovery.

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Section: Wettability Variation Of Different Mineralmentioning

confidence: 99%

Effects of Wettability and Minerals on Residual Oil Distributions Based on Digital Rock and Machine Learning

Zhang

Lin

et al. 2022

Lithosphere

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“…Despite the extensive literature on intra-dense intervals and K v /K h for explaining these phenomena, the effect of capillary forces is often underestimated, particularly in numerical simulations where reliable experimental data is lacking (Feng D et al, 2018;Pandey V K et al, 2023;Fabbri C et al, 2021). Given that most carbonate reservoirs are of mixed or oil-wet nature, detailed research on the impact of Frontiers in Energy Research frontiersin.org negative capillary forces is crucial (Arif M et al, 2020;Nowrouzi I et al, 2020;Faramarzi-Palangar M et al, 2021;Feng D et al, 2021;Ekechukwu G K et al, 2021;Siyal A et al, 2021;Esfandyari H et al, 2021;AlZaabi A et al, 2023;Boampong L O et al, 2023;Siyal A et al, 2023;Samani M K et al, 2023). Current methods to improve water sweep efficiency involve wettability alteration through low salinity water flooding and optimizing perforation intervals (Vermolen, E et al, 2014;He, E et al, 2015;Xinmin, S et al, 2018;Lee, Y et al, 2019;Snosy M F et al, 2022;Feng D et al, 2022b;Khurshid, I et al, 2022;Tackie-Otoo, B N et al, 2022a;Souayeh, M et al, 2022;Nascimento, F P et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

Research on water-out mode and differential perforation in thick carbonate reservoir

Junshuai,

Peiyuan,

Jian

et al. 2024

Front. Energy Res.

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The development of anti-rhythmic carbonate reservoirs in the Middle East often encounters challenges such as water hold-up and reverse coning during the water injection process, leading to premature water breakthrough and various water-out issues. The unclear understanding of these phenomena, attributed to strong reservoir heterogeneity, results in a relatively low recovery degree in water injection development. This paper investigates the mechanisms behind water hold-up and reverse coning phenomena, offering detailed solutions. Numerical models of the oil reservoirs were developed, and an extensive study of influencing factors, including reservoir types, Kv/Kh, water injection pressure differential, wettability, and perforation position, was conducted to unveil the underlying mechanisms. Key findings indicate that the water hold-up phenomenon is influenced by capillary force barriers due to wettability and high-perm streaks, while the reverse coning phenomenon depends on the combined forces of gravity, capillary force and downward production differential among which downward production differential is the dominant factor compared to capillary force and gravity. The study also proposes a differential perforation principle tailored to different water-out types to enhance vertical sweep efficiency. The differential perforation principle is as follows: the optimal perforation position is at top layer and the optimal perforation length approximately accounts for 1/4 of the total oil layer thickness for water-out in bottom; the avoidance perforation height in top accounts for 1/6 of the total oil layer thickness and the optimal perforation length approximately accounts for 1/2 of the total oil layer thickness for water-out in top; the avoidance perforation height in top and bottom accounts for 1/5 and 2/5 of the total oil layer thickness respectively for water-out in both top and bottom.

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“…Traditional approaches for assessing wettability include but are not limited to contact angle measurements using the sessile drop/captive drop procedure, spontaneous imbibition method, Amott–Harvey, U.S. Bureau of Mines (USBM) methods, capillary rise method, and nuclear magnetic resonance (NMR) method. Relative permeability and capillary pressure curves are also used to provide insights into the wettability values of the reservoir rocks. − Of all of the wettability measuring methods, the Amott–Harvey and the USBM are the industry standard and most reliable methods for determining wettability . The A–H index, I AH , is related to the imbibition characteristics of the rock, and the USBM index is related to the area under the capillary pressure curves.…”

Section: Introductionmentioning

confidence: 99%

“…Relative permeability and capillary pressure curves are also used to provide insights into the wettability values of the reservoir rocks. 15 − 17 Of all of the wettability measuring methods, the Amott–Harvey and the USBM are the industry standard and most reliable methods for determining wettability. 3 The A–H index, I AH , is related to the imbibition characteristics of the rock, and the USBM index is related to the area under the capillary pressure curves.…”

Section: Introductionmentioning

confidence: 99%

Standardization of Particle Size for Floating Particle Wettability Measurement for Carbonate Rocks

et al. 2023

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Misrepresentation of the wettability of a reservoir can lead to potentially low ultimate hydrocarbon recovery resulting in substantial economic losses. At the same time, it is impossible to determine the wettability of a reservoir across its length and breadth on a continuous basis using standard procedures. This work presents the development and standardization of a quick, easy, and low-cost wettability measurement method using the adherence tendency of rock particles in the oil or aqueous phase. The most important aspect of this study was establishing the optimum particle size for sustained floatation and balancing the buoyancy and gravity effect. The results show that the particles sink with a larger than optimum particle size because of the gravity effect. Similarly, the particles would float if they are smaller than optimum due to buoyancy and viscosity advantages. A new scale is designed, and the midpoint analysis shows that a 63−90 μm particle size is the ideal size range for the carbonate reservoir's wettability measurements, as the midpoint of the size distribution coincides with the standard Amott−Harvey (A−H) index. However, this size range is found to be wider for oil-wet particles. The floating particle method has several advantages over the established methods once standardized against a reliable process. Not only is the process fast but it can be performed with basic laboratory tools and does not require a high skill set. Most importantly, reliable wettability information can be obtained from drill cuttings and core fragments, enabling the determination of reservoir wettability on a continuum basis and not as a point basis, thus providing a more reliable average value, particularly for heterogeneous and unconsolidated reservoirs.

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Wettability of Carbonate Reservoir Rocks: A Comparative Analysis

Cited by 11 publications

References 74 publications

Effects of Wettability and Minerals on Residual Oil Distributions Based on Digital Rock and Machine Learning

Effects of Wettability and Minerals on Residual Oil Distributions Based on Digital Rock and Machine Learning

Research on water-out mode and differential perforation in thick carbonate reservoir

Standardization of Particle Size for Floating Particle Wettability Measurement for Carbonate Rocks

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