Shale pore characteristics and their impact on the gas-bearing properties of the Longmaxi Formation in the Luzhou area

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: July 23, 2024

Abstract Deep shale has the characteristics of large burial depth, rapid changes in reservoir properties, complex pore types and structures, unstable production. The whole-rock X-ray diffraction (XRD) analysis, physical property parameter testing, scanning electron microscopy (SEM) high-pressure mercury intrusion CO 2 adsorption experimentation, low-temperature nitrogen adsorption–desorption testing were performed to study structure marine reservoirs southern Sichuan Basin. results show that deep Wufeng Formation Longyi 1 sub-member Luzhou area is superior Weiyuan terms factors controlling gas enrichment, such as organic matter abundance, gas-bearing thickness. SEM utilized identify six pores (mainly pores). porosities pyrobitumen reach 21.04–31.65%, while solid kerogen pores, siliceous mineral dissolution carbonate are low at 0.48–1.80%. mainly micropores mesopores, with a small amount macropores. total volume ranges from 22.0 36.40 μL/g, an average 27.46 specific surface 34.27 50.39 m /g, 41.12 /g. positively correlated TOC content, minerals, clay minerals. key period for which matches evolution process hydrocarbon generation, capacity, direct indirect cap rocks, Middle Late Triassic present. Areas late structural uplift, uplift amplitude, high formation pressure coefficient favor preserving content production levels.

Language: Английский

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Quantitative Analysis of Pore Complexity in Lacustrine Organic-Rich Shale and Comparison to Marine Shale: Insights from Experimental Tests and Fractal Theory

Energy & Fuels, Journal Year: 2024, Volume and Issue: 38(17), P. 16171 - 16188

Published: Aug. 14, 2024

Continental shale gas enrichment is significantly influenced by pore structure, yet research on this topic remains limited compared to marine shale. This study investigates the complex structure of lacustrine Da'anzhai (DAZ) from YB area, employing X-ray diffraction (XRD), scanning electron microscope (SEM), and low-temperature N2 adsorption. The fractal dimension (FD) calculated using Frenkel–Halsey–Hill (FHH) model, revealed two distinct dimensions: D1 (2.3438–2.7933) D2 (2.5235–2.82). Both exhibited positive correlations with total organic matter (TOC) content, thermal maturity, other parameters, micropores exhibiting strongest influence. Results indicate that DAZ comprises quartz (28.1%–42%), clay (41.5%–60%), carbonate minerals (0.7%–11.2%), TOC content ranging 0.32% 1.74%, indicating low high maturity. Total volume (PV) varies 0.0105 0.0193 cm3/g, specific surface area (SSA) 3.14 11.33 m2/g. While mesopores dominate size distribution, contributing most SSA, macropores influence overall PV. Interestingly, regular morphology, primarily associated well-sorted rounded terrigenous quartz, negatively correlated D2. Conversely, feldspar contributed macropore formation, a negative correlation both FD. Clay minerals, compacted over time, contribute reduced increased micropore abundance, resulting in between intricate morphology Compared Longmaxi (LMX) shale, exhibits lower (OM) but higher mineral content. Furthermore, types are dominated intergranular pores within development OM than LMX These key differences result complexity FD comparative analysis provides valuable insights into structures offers framework for different sedimentary facies.

Language: Английский

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Critical depth prediction based on in-situ stress and gas content model of deep coalbed methane in Liupanshui Coalfield in China

Scientific Reports, Journal Year: 2025, Volume and Issue: 15(1)

Published: Jan. 2, 2025

In-situ stress plays a pivotal role in influencing the desorption, adsorption, and transportation of coalbed methane. The reservoir gas content represents physical parameter, encapsulating both methane enrichment capacity underlying law reservoir. This investigation collates, computes, consolidates data concerning pore pressure, breakdown closure triaxial principal stress, content, lateral pressure coefficient, other pertinent variables from coal reservoirs within several coal-bearing synclines Liupanshui coalfield, China. study elucidates characteristics longitudinal development area, their interrelationships. area is situated middle-high zone, exhibiting discernible evolution patterns reverse fault mechanism to strike-slip normal mechanism, progressing shallow deep. In deeper stratigraphy, strike-slip-normal emerges. relationship between burial depth subjected linear regression, resulting proposal simplified model for vertical in-situ stress. hyperbolic regression algorithm was employed order derive envelope median formulas coefficient (k values). k value displays discrete behavior along axis depths, gradually converging strata ultimately stabilising at approximately 0.65 with increasing depth. A comprehensive examination substantiates efficacy axis, offering profound insights into interrelationships evolving stresses. mean found be 11.89 m³/t, general increase depth, followed by subsequent decrease. (Pp) positive correlation content. comprehensively developmental field, attributes ratio (KH, kh, k), corresponding transformative relationships coupled geostress field parameters conversion inversion are delineated, accompanied detailed exposition definition process, significance, interrelations. Within estimated range 450 500 m, while critical 670 m. Moreover, falls 700–800 It noteworthy that deep coalfield has been identified as 800 Subsequently, "in-situ stress-gas mode" formulated, thereby providing structured framework understanding dynamic interactions

Language: Английский

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Experimental Study on the Characteristics and Diagenetic Processes of Typical Tight Oil Reservoirs

Chemistry and Technology of Fuels and Oils, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 18, 2025

Language: Английский

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Tracking CO2 migration and accumulation in the Subei Basin using geochronology and fluid inclusion quantitative analysis

Scientific Reports, Journal Year: 2025, Volume and Issue: 15(1)

Published: March 4, 2025

In petroliferous sedimentary basins, the interplay between CO2 and hydrocarbons exerts a notable influence on hydrocarbon generation accumulation. This research focuses Huangqiao oil gas reservoir, which is known for hosting largest reserves in China. U-Pb isotopic dating of calcite veins fractures, carbon oxygen isotope analyses, along with rare earth element (REE) analysis were applied to elucidate chronology origin inorganic organic fluids studied area. Petrographic observations revealed presence various components fluid inclusions, including gaseous CO2, CH4, CH4-CO2 mixtures, fluids. Besides, through Raman quantitative measurements thermodynamic simulations, density, composition, pressure, temperature characteristics CH4 bearing inclusions calculated. Based entrapment conditions results, two stages charging identified: an early-Jurassic stage (approximately 200-185 Ma) characterized by mid-maturity early-Eocene 61-41 marked high-maturity CH4. accumulation events divided into stages: high-density activity during early Eocene 59-39 low-density Tertiary-Quaternary 23-4 Ma). Moreover, deep influx reservoirs led hydrothermal alteration, as evidenced anomalously high homogenization temperatures vitrinite reflectance. has extraction effect crude oil, where its late entry primarily results removal lighter components, especially When high-temperature enters it accelerates cracking alters fluid's composition. thermal event also speeds up source rock's evolution, leading extraction, pyrolysis, displacement throughout reservoir's development process. study presents comprehensive approach quantitatively studying geological basins this nature.

Language: Английский

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Hygroscopic effect of high clay-content shale under temperature and humidity conditions and its impact on mechanical properties

PLoS ONE, Journal Year: 2025, Volume and Issue: 20(3), P. e0319672 - e0319672

Published: March 7, 2025

High clay-content shale, containing hydrophilic clay minerals, is highly sensitive to environmental temperature and humidity. It readily absorbs moisture from the air, leading increased water content reduced mechanical strength, which poses challenges for underground structures, such as mining roadways, tunnels, storage chambers. This study investigates influence of humidity on high shale during its hygroscopic process examines evolution properties under variations in content, aiming reveal effects behavior shale. Hygroscopic experiments were conducted using a chamber, with quartz sand non-clay mineral control groups, strength performed reconstituted samples varying content. Results showed that equilibrium (EWC) decreases lower higher temperature. When decreased 100% RH 80% RH, average EWC dropped 15.88% 7.53%. Under high-humidity conditions (100% RH), 11.92% only after 30°C. Within experimental conditions, reducing was found be more effective than increasing EWC. Based test results, can decrease loss uniaxial compressive (UCS) caused by absorption approximately 50% 15.48%. The results indicate primary factor influencing Reducing significantly mitigate absorption, while plays supplementary role. These findings provide scientific basis controlling engineering enhance structural stability.

Language: Английский

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A Method for Predicting Different Types of Natural Fractures in Tight Sandstone Based on the Secondary Rescaled Range Analysis of Logging Curves: A Case Study From the Chang 7 Member in Huaqing Oilfield, Ordos Basin, China

Energy Science & Engineering, Journal Year: 2025, Volume and Issue: unknown

Published: March 12, 2025

ABSTRACT Currently, there are various methods for predicting natural fractures using logging data, however these primarily the number and location of fractures. This is making it difficult to determine fracture types. paper introduces R/S‐FD method, combined with development pattern in study area, secondary R/S analysis was introduced construct Secondary method. method overcomes limitations traditional that can only predict cannot type After eliminating systematic errors, prediction accuracy bedding high‐angle reaches 73% 74%, respectively. By analyzing characteristics 23 wells research provided insights into oil layers within region. The a precise, fast, cost‐effective approach different types next step involves leveraging large cases as data foundation, based on big machine learning techniques, establish correlation between F value enabling more accurate predictions quantities

Language: Английский

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Investigating Enhanced Oil Recovery Techniques in Ultratight Reservoirs Through Coreflooding Experiments

International Journal of Energy Research, Journal Year: 2025, Volume and Issue: 2025(1)

Published: Jan. 1, 2025

This study explores the efficacy of various enhanced oil recovery (EOR) techniques, including water alternating gas (WAG), (GAW), alkaline surfactant polymer (ASP), and chemical WAG (CWAG) injections. Through coreflooding tests analysis, we assess their effectiveness in mobilizing displacing trapped reservoirs. Our findings reveal significant novelty methods developed, particularly CWAG injection strategies, which achieved remarkable factors. Specifically, demonstrated superior performance, with a maximum factor 64.5%, attributable to water’s higher displacement efficiency. ASP injections also emerged as promising method, achieving 69.5%, offering comparable traditional techniques while enhancing sweep Furthermore, advanced strategies showcased improvements, CWAG1, CWAG2, CWAG3, CWAG4 factors 73.5%, 76%, 82%, 93%, respectively. These insights highlight critical role formulation, sequence, optimization maximizing recovery, thereby, contributing sustainable resource management economic viability.

Language: Английский

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Characterization of shale pore heterogeneity and its controlling factors: A case study of the Longmaxi Formation in Western Hubei, China

Energy Science & Engineering, Journal Year: 2024, Volume and Issue: 12(7), P. 2899 - 2917

Published: July 1, 2024

Abstract To quantitatively characterize the complexity of shale pore structures and their controlling factors in Longmaxi Formation Western Hubei, our study focused on organic‐rich outcrops Yidu‐Hefeng compound anticline. We conducted tests for organic content, maturity, whole‐rock mineral composition, along with employing high‐pressure mercury injection low‐temperature gas adsorption experiments. Utilizing V‐S, FHH, sponge models, we calculated fractal dimensions micro‐, meso‐, macropores. In region, is characterized by calcium‐rich shales that are abundant matter. Our analysis samples revealed a total carbon (TOC) ranging between 1.04% 4.24%, an average 2.5%. The Ro values fluctuate 2.98% 3.57%, mean value 2.845%, indicating over‐mature stage from early to late thermogenesis. Constituents such as quartz span 39.8% 51.3%, median 44.3%, while feldspar oscillates 3.8% 12.4%, averaging at 8.48%. Clay minerals constitute 24.3% 41.7% samples, 34.16%. Shale porosity exhibits segmented nature. For instance, D 1 varies 2.1278 2.4056, 2.2767; 2 fluctuates 2.4995 2.7492, 2.6309; 3 ranges 2.6835 2.9427, centering around 2.8111. These variations indicate intricacies macropore structure. Positive correlations TOC maturity evident, whereas negative association observed 3. collaborative interplay siliceous organics mirrors relationship content its dimensions, akin TOC. transformations, due accumulation dehydration, predominantly contribute macro‐porosity, weakly aligning negatively but positively Variations carbonate role primarily yielding dissolution macropores manifest subtle link enhancing Pore volume correlates 2, no conspicuous 3, trends negatively. compaction transformation processes clay seem favor generation macropores, mildly

Language: Английский

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Shale reservoir characterization and implications for the exploration and development of the upper Permian Wujiaping Formation, Longmen–Wushankan area, eastern Sichuan Basin

Frontiers in Earth Science, Journal Year: 2024, Volume and Issue: 12

Published: Sept. 13, 2024

Recent exploration efforts have revealed significant industrial gas flow from the Wujiaping Formation marine shale in Longmen–Wushankan area of eastern Sichuan Basin, underscoring its considerable potential. In this study, reservoir characteristics and potential are further evaluated. On basis well rock electrical properties, experimental analyses, depositional structural patterns region, we characterize properties identify primary factors controlling accumulation. The results indicate that is characterized by a high organic matter content, favorable pore types, porosity, content brittle minerals, which conducive to subsequent development fracturing. A positive correlation observed between total carbon (TOC) mineral content. TOC strongly correlated with (the coefficient 0.75). yield attributed combination sedimentary environments, conditions, roof floor fracturing capabilities. However, compared Longmaxi lower thinner shale, deeper burial, posing challenges for development. criteria evaluating established, four areas identified. Overall, Permian holds promising Further an enhanced understanding formation will provide valuable guidance future area.

Language: Английский

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