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P. G. Ranjith - One of the best experts on this subject based on the ideXlab platform.

  • Laboratory Simulation of Flow through Single Fractured Granite
    Rock Mechanics and Rock Engineering, 2015
    Co-Authors: K. K. Singh, D. N. Singh, P. G. Ranjith
    Abstract:

    Laboratory simulation on Fluid flow through fractured rock is important in addressing the Seepage/Fluid-in-rush related problems that occur during the execution of any civil or geological engineering projects. To understand the mechanics and transport properties of Fluid through a fractured rock in detail and to quantify the sources of non-linearity in the discharge and base pressure relationship, Fluid flow experiments were carried out on a cylindrical sample of granite containing a ‘single rough walled fracture’. These experiments were performed under varied conditions of confining pressures, σ _3 (5–40 MPa), which can simulate the condition occurring about 1,000 m below in the earth crust, with elevated base pressure, b _p (up to 25 MPa) and by changing fracture roughness. The details of the methodologies involved and the observations are discussed here. The obtained results indicate that most of the data in the Q verses b _p plot, fall on the straight line and the flow through the single fracture in granite obeys Darcy’s law or the well-known “cubic law” even at high value of b _p (=4 MPa) and σ _3 (=5 MPa) combination. The Reynolds number is quite sensitive to the b _p, σ _3 and fracture roughness, and there is a critical b _p, beyond which transition in flow occurs from laminar to turbulent. It is believed that such studies will be quite useful in identifying the limits of applicability of well know ‘cubic law’, which is required for precise calculation of discharge and/or aperture in any practical issues and in further improving theoretical/numerical models associated with Fluid flow through a single fracture.

Xiaolin Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Modified model of porosity variation in Seepage Fluid-saturated porous media under elastic wave
    Journal of Petroleum Exploration and Production Technology, 2015
    Co-Authors: Liming Zheng, Xu Jiaxiang, Jing Liu, Xiaolin Zhao
    Abstract:

    As an unconventional method, low-frequency vibration production technology is applied for oil recovery enhancement in amounts of oil fields. Petro-physic properties in Seepage Fluid-saturated porous media with are revealed to be influenced seriously by elastic wave in substantial researches. With an assumption of static Fluid-saturated, porosity variation equation in Biot’s model is not appropriate to interpret the percolating in low-frequency vibration production technology, there exists an obvious error from the actual experimental data. Based on the function mechanisms and factors controlling the porosity in Seepage Fluid-saturated porous media, a modified model of porosity variation under vibration is developed to improve the accuracy. Different coefficients for porosity increase are derived. The factors include the compaction of matrix and Fluid, proportion of Seepage interconnected pores, change of adhesive layer in capillary tube as well as transport of particle under vibration. Furthermore, a comparison with experimental result in artificial sandstone cores is carried out to verify the validity. An error of about 4–21 % is reduced by the modified porosity variation compared with that in Biot’s model. As a critical basis of wave equation, the modified porosity is helpful to illustrate the concrete change of percolation in low-frequency vibration production technology.

Pei-yuan Qian - One of the best experts on this subject based on the ideXlab platform.

  • Changing composition of microbial communities indicates Seepage Fluid difference of the Thuwal Seeps in the Red Sea
    Antonie van Leeuwenhoek, 2015
    Co-Authors: Bo Yang, Weipeng Zhang, Renmao Tian, Yong Wang, Pei-yuan Qian
    Abstract:

    Cold seeps are unique ecosystems that are generally characterized by high salinity and reducing solutions. Seepage Fluid, the major water influx of this system, contains hypersaline water, sediment pore water, and other components. The Thuwal cold seeps were recently discovered on the continental margin of the Red Sea. Using 16S rRNA gene pyro-sequencing technology, microbial communities were investigated by comparing samples collected in 2011 and 2013. The results revealed differences in the microbial communities between the two sampling times. In particular, a significantly higher abundance of Marine Group I (MGI) Thaumarchaeota was coupled with lower salinity in 2013. In the brine pool, the dominance of Desulfobacterales in 2011 was supplanted by MGI Thaumarchaeota in 2013, perhaps due to a reduced supply of hydrogen sulfide from the Seepage Fluid. Collectively, this study revealed a difference in water components in this ecosystem between two sampling times. The results indicated that the seawater in this cold seep displayed a greater number of characteristics of normal seawater in 2013 than in 2011, which might represent the dominant driving force for changes in microbial community structures. This is the first study to provide a temporal comparison of the microbial biodiversity of a cold seep ecosystem in the Red Sea.

K. K. Singh - One of the best experts on this subject based on the ideXlab platform.

  • Laboratory Simulation of Flow through Single Fractured Granite
    Rock Mechanics and Rock Engineering, 2015
    Co-Authors: K. K. Singh, D. N. Singh, P. G. Ranjith
    Abstract:

    Laboratory simulation on Fluid flow through fractured rock is important in addressing the Seepage/Fluid-in-rush related problems that occur during the execution of any civil or geological engineering projects. To understand the mechanics and transport properties of Fluid through a fractured rock in detail and to quantify the sources of non-linearity in the discharge and base pressure relationship, Fluid flow experiments were carried out on a cylindrical sample of granite containing a ‘single rough walled fracture’. These experiments were performed under varied conditions of confining pressures, σ _3 (5–40 MPa), which can simulate the condition occurring about 1,000 m below in the earth crust, with elevated base pressure, b _p (up to 25 MPa) and by changing fracture roughness. The details of the methodologies involved and the observations are discussed here. The obtained results indicate that most of the data in the Q verses b _p plot, fall on the straight line and the flow through the single fracture in granite obeys Darcy’s law or the well-known “cubic law” even at high value of b _p (=4 MPa) and σ _3 (=5 MPa) combination. The Reynolds number is quite sensitive to the b _p, σ _3 and fracture roughness, and there is a critical b _p, beyond which transition in flow occurs from laminar to turbulent. It is believed that such studies will be quite useful in identifying the limits of applicability of well know ‘cubic law’, which is required for precise calculation of discharge and/or aperture in any practical issues and in further improving theoretical/numerical models associated with Fluid flow through a single fracture.

Jiang Shaoyong - One of the best experts on this subject based on the ideXlab platform.

  • Sr and Nd isotopes of cold seep carbonates from the northern South China sea as proxies for Fluid sources
    'Elsevier BV', 2020
    Co-Authors: Chen Wei, Bi Zhu, Fan Meitong, Yang Tao, Jiang Shaoyong
    Abstract:

    In this study, Sr isotopes combined with Nd isotopes of modern cold seep carbonates were studied to provide reliable proxies for sources and pathways of seep Fluids. We presented Sr and Nd isotopes together with stable carbon and oxygen isotope data of cold seep carbonates recovered from the northern continental slope of the South China Sea (SCS). Based on the evidence for negligible detrital contamination and diagenetic alteration, carbonate samples are considered dependable archives which record Sr and Nd isotope signals of the original pore waters from which carbonates have precipitated. Excellent correlation between Sr-87/Sr-86 ratios and 1/Sr observed in carbonate samples indicates two end-members with distinct Sr isotopic signatures, including modern seawater as a major source and a lesser contribution from methane-rich seep Fluid driven from a deep source. Besides these two end-members, release of Nd from organic matter and Fe-Mn oxyhydroxide is an additional contribution to pore water Nd. Furthermore, Sr and Nd isotopic compositions suggest water-rock interactions between upward seep Fluid and detrital component in sediments, which resulted in the isotopic shift towards pronounced Nd-143 depleted and slightly Sr-87 enriched in the Fluid phase. This study provides insight into the knowledge for tracing Seepage Fluid circulation by Sr-Nd isotope system at modern seep systems