Anisotropic rock physics characteristics and patterns of pore-fracture type tight sandstone reservoirs

Exploration and development of tight gas reservoirs are pivotal in augmenting oil and gas reserves and production. Tight sandstone reservoirs, characterized by intricate geological environments, nuanced physical property variations, substantial fluid heterogeneities, and ambiguous seismic rock physi...

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Main Authors: Juncheng Dai, Yuanyuan Yan, Wei Wei, Cheng Xi, Guangguang Yang, Jun Yao
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-05-01
Series:Frontiers in Earth Science
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Online Access:https://www.frontiersin.org/articles/10.3389/feart.2025.1525693/full
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author Juncheng Dai
Yuanyuan Yan
Wei Wei
Cheng Xi
Guangguang Yang
Jun Yao
author_facet Juncheng Dai
Yuanyuan Yan
Wei Wei
Cheng Xi
Guangguang Yang
Jun Yao
author_sort Juncheng Dai
collection DOAJ
description Exploration and development of tight gas reservoirs are pivotal in augmenting oil and gas reserves and production. Tight sandstone reservoirs, characterized by intricate geological environments, nuanced physical property variations, substantial fluid heterogeneities, and ambiguous seismic rock physics responses, necessitate a departure from conventional isotropic reservoir sensitivity parameters. This study introduces an innovative lithofacies identification strategy and methodology grounded in anisotropic rock physics sensitivity parameters. The investigation revolves around 20 core samples from the fourth member of the Xujiahe Formation in Jianyang. A multi-scale approach, encompassing imaging logging, core analysis, porosity/permeability measurements, and cast thin section examinations, was employed to classify the samples into four distinct categories: dry and water-saturated pore types, alongside dry and water-saturated fractured pore types. Subsequently, an enhanced full-angle ultrasonic anisotropy testing system was utilized to conduct multi-directional acoustic wave measurements. The results revealed that gas-bearing fractured pore samples exhibit pronounced velocity and amplitude anisotropy, setting them apart from other lithofacies types. To quantify these distinguishing features, a rock physics template encompassing P-wave anisotropy (ε) and amplitude anisotropy (εA) parameters was established. By setting thresholds for ε and εA (>20%), the dry fractured pore lithofacies can be effectively discriminated. Moreover, leveraging the full-angle waveform similarity coefficient spectrum, we used a special parameter, εslow, for slowness anisotropy, along with its theoretical derivation. Notably, water-saturated pore types exhibited slowness anisotropy parameters consistently below 0.01. Integration of the (λρ-μρ) template and its thresholds (λρ < 60 & μρ < 30) further facilitated the selection and differentiation of all four lithofacies types. These research outcomes contribute significantly to advancing the prediction of tight sandstone reservoirs and fluid identification, offering a robust framework for future exploration endeavors.
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spelling doaj-art-e21f16a9f7904dae83626464ce7476832025-08-20T02:28:20ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632025-05-011310.3389/feart.2025.15256931525693Anisotropic rock physics characteristics and patterns of pore-fracture type tight sandstone reservoirsJuncheng Dai0Yuanyuan Yan1Wei Wei2Cheng Xi3Guangguang Yang4Jun Yao5PetroChina Southwest Oil and Gasfield Company, Chengdu, ChinaPetroChina Southwest Oil and Gasfield Company, Chengdu, ChinaPetroChina Southwest Oil and Gasfield Company, Chengdu, ChinaPetroChina Southwest Oil and Gasfield Company, Chengdu, ChinaPetroChina Southwest Oil and Gasfield Company, Chengdu, ChinaGuizhou Zhongkai Transportation Construction Co., Ltd., Guiyang, ChinaExploration and development of tight gas reservoirs are pivotal in augmenting oil and gas reserves and production. Tight sandstone reservoirs, characterized by intricate geological environments, nuanced physical property variations, substantial fluid heterogeneities, and ambiguous seismic rock physics responses, necessitate a departure from conventional isotropic reservoir sensitivity parameters. This study introduces an innovative lithofacies identification strategy and methodology grounded in anisotropic rock physics sensitivity parameters. The investigation revolves around 20 core samples from the fourth member of the Xujiahe Formation in Jianyang. A multi-scale approach, encompassing imaging logging, core analysis, porosity/permeability measurements, and cast thin section examinations, was employed to classify the samples into four distinct categories: dry and water-saturated pore types, alongside dry and water-saturated fractured pore types. Subsequently, an enhanced full-angle ultrasonic anisotropy testing system was utilized to conduct multi-directional acoustic wave measurements. The results revealed that gas-bearing fractured pore samples exhibit pronounced velocity and amplitude anisotropy, setting them apart from other lithofacies types. To quantify these distinguishing features, a rock physics template encompassing P-wave anisotropy (ε) and amplitude anisotropy (εA) parameters was established. By setting thresholds for ε and εA (>20%), the dry fractured pore lithofacies can be effectively discriminated. Moreover, leveraging the full-angle waveform similarity coefficient spectrum, we used a special parameter, εslow, for slowness anisotropy, along with its theoretical derivation. Notably, water-saturated pore types exhibited slowness anisotropy parameters consistently below 0.01. Integration of the (λρ-μρ) template and its thresholds (λρ < 60 & μρ < 30) further facilitated the selection and differentiation of all four lithofacies types. These research outcomes contribute significantly to advancing the prediction of tight sandstone reservoirs and fluid identification, offering a robust framework for future exploration endeavors.https://www.frontiersin.org/articles/10.3389/feart.2025.1525693/fulltight sandstoneanisotropyfluid identificationrock physicsquantitative interpretation
spellingShingle Juncheng Dai
Yuanyuan Yan
Wei Wei
Cheng Xi
Guangguang Yang
Jun Yao
Anisotropic rock physics characteristics and patterns of pore-fracture type tight sandstone reservoirs
Frontiers in Earth Science
tight sandstone
anisotropy
fluid identification
rock physics
quantitative interpretation
title Anisotropic rock physics characteristics and patterns of pore-fracture type tight sandstone reservoirs
title_full Anisotropic rock physics characteristics and patterns of pore-fracture type tight sandstone reservoirs
title_fullStr Anisotropic rock physics characteristics and patterns of pore-fracture type tight sandstone reservoirs
title_full_unstemmed Anisotropic rock physics characteristics and patterns of pore-fracture type tight sandstone reservoirs
title_short Anisotropic rock physics characteristics and patterns of pore-fracture type tight sandstone reservoirs
title_sort anisotropic rock physics characteristics and patterns of pore fracture type tight sandstone reservoirs
topic tight sandstone
anisotropy
fluid identification
rock physics
quantitative interpretation
url https://www.frontiersin.org/articles/10.3389/feart.2025.1525693/full
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