Distribution characteristics and oil mobility thresholds in lacustrine shale reservoir: Insights from N2 adsorption experiments on samples prior to and following hydrocarbon extraction

Bai, Longhui; Liu, Bo; Du, Yijing; Wang, Boyang; Tian, Shansi; Wang, Liu; Xue, Zhiqiang

doi:10.1016/j.petsci.2021.10.018

Cited by 72 publications

(48 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… 43 The hysteresis loops of untreated and reacted PR and PP shale were small, and the isotherms increased to infinity when P / P 0 = 1, which further reflected the existence of macropores and mesopores in these shales. 44 Based on the IUPAC recommendation, the isotherm shapes and the hysteresis loops of the unreacted and reacted shale samples belonged to type IV and H2, respectively. The characteristics of N 2 adsorption–desorption isotherms indicated that the PR and PP shale possessed a continuous and open nanometer pore system, and pores in these shales were mainly slit pores and ink-bottle pores.…”

Section: Resultsmentioning

confidence: 99%

“…The characteristics of N 2 adsorption–desorption isotherms indicated that the PR and PP shale possessed a continuous and open nanometer pore system, and pores in these shales were mainly slit pores and ink-bottle pores. 44 , 45 …”

Section: Resultsmentioning

confidence: 99%

“…The hysteresis loops in N 2 isotherms were observed when the relative pressure ( P/P 0 ) was higher than 0.45, reflecting that the capillary condensation occurred in the macropores (>50 nm) and mesopores (2–50 nm) . The hysteresis loops of untreated and reacted PR and PP shale were small, and the isotherms increased to infinity when P / P 0 = 1, which further reflected the existence of macropores and mesopores in these shales . Based on the IUPAC recommendation, the isotherm shapes and the hysteresis loops of the unreacted and reacted shale samples belonged to type IV and H2, respectively.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Impact of Pyrite Oxidation on the Pore-Structure Characteristics of Shale Reservoir Rocks under the Interaction of Fracturing Fluid

Sun

et al. 2022

ACS Omega

View full text Add to dashboard Cite

Hydraulic fracturing combined with horizontal drilling is widely used to develop shale gas resources, and huge amounts of fracturing fluid are injected into shale reservoirs. However, the fracturing fluid is ineluctably retained in reservoir rocks after fracturing, resulting in the alteration of shale pore systems and further affecting the hydrocarbons production efficiency. In this work, two types of shales with different pyrite contents, namely, pyrite rich (PR, Niutitang Formation) and pyrite poor (PP, Xiamaling Formation), were emphasized to illustrate the effect of pyrite oxidation on pore structure after fracturing operation. Slickwater fracturing fluid was used to treat the shale samples for a period of 3 days, under the condition of 100 °C and 50 MPa. The field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) were utilized to determine the surface morphology and mineral composition. The low-temperature N 2 adsorption was performed to quantify the pore structure. The results showed that the pyrite oxidation induced the dissolution of both the pyrite and calcite and generated many dissolution pores for the pyrite-rich shale after slickwater treatment. The mineral dissolution led to an increase in the number of mesopores, enlarged the total specific surface area (TSSA) and total pore volume (TPV), and strengthened the pore-structure complexity. On the other hand, the pyrite-poor shale only experienced clay swelling after slickwater treatment. Its pore surface roughness and pore-structure complexity degraded with the loss of nanopores and the reductions in TSSA and TPV. The results of this study enhance the understanding of the impact of pyrite oxidation on the pore structure and provide new insight into the optimization of fracturing operation conditions based on shale’s mineral composition characteristics.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Impact of Pyrite Oxidation on the Pore-Structure Characteristics of Shale Reservoir Rocks under the Interaction of Fracturing Fluid

Sun

et al. 2022

ACS Omega

View full text Add to dashboard Cite

show abstract

“…More research is needed in order to increase the validity of the interpretations from this work; for samples with high organic matter contents and in mature windows, oil washing is needed to obtain more accurate information of fullspectrum pore size distribution and connectivity among differently sized pores [21,68].…”

Section: Discussionmentioning

confidence: 99%

“…Because of the multiscale pore size distribution of shale and variable resolution limitation of each experimental technique, it is necessary to combine the advantages of each method to investigate the full-spectrum pore distribution and determine the pore connectivity of shales [19,20]. Meanwhile, shales are fine-grained sedimentary rocks with a wide range of lithologies, and the study of complex lithological controls on shale oil accumulation and movement is critical for different lithofacies and facies [21][22][23]. Thus, the representativeness of experimental samples and methodologies for different facies was the key to successful research of shale oil exploration and production [24].…”

Section: Introductionmentioning

confidence: 99%

Quantitative Characterization of Full-Spectrum Pore Size and Connectivity for Shale with Different Sedimentary Facies from the Dongying Depression, Bohai Bay Basin, East China

Yin

et al. 2022

Geofluids

View full text Add to dashboard Cite

Working with shales in the fourth member of Shahejie Formation in the Dongying Depression in Bohai Bay Basin of East China, this study examines the facies classification, petrological characteristics, pore size distribution, and pore connectivity of oil-producing shale. The studied shales could be classified into five sedimentary facies according to a three-step classification criterion that consists of total organic carbon (TOC), sedimentary structure, and mineral composition. Among them, the “low TOC massive siliceous mudstone” and “low TOC layered clayey mudstone” facies have similar distributions from low-pressure N2 physisorption, and the incremental volume within the 3-30 nm pore size range is much higher than the “high TOC laminated clayey marlstone” and “low TOC layered siliceous marlstone” facies. The T 2 spectra of nuclear magnetic resonance tests for the “high TOC laminated clayey marlstone” facies which contains abundant calcite laminae and organic matter-hosted pores commonly show three peaks, with a dominant peak at less than 300 nm in diameter and good pore connectivity. The T 2 spectra of three other facies are both characterized by two peaks, and the main peak of the “low TOC layered siliceous marlstone” and “low TOC layered clayey mudstone” facies has a similar range at 2-500 nm, in contrast with 1-17 nm for the “low TOC massive siliceous mudstone” facies. Pores in these four facies are mainly at nanoscales with predominant pore-throat diameters at less than 50 nm; however, the “high TOC laminated clayey marlstone” facies has the largest peak in the range of >1 μm, possibly because of its interlaminar structure and microcracks. The spontaneous imbibition experiments using two distinct fluids indicated that all of four facies have a much better pore connectivity towards the hydrophilic fluid than these experienced by the hydrophobic fluid.

show abstract

Micro- to nano-scale areal heterogeneity in pore structure and mineral compositions of a sub-decimeter-sized Eagle Ford Shale

Wang

Zhao

et al. 2022

Preprint

View full text Add to dashboard Cite

To improve the understanding of spatial heterogeneity in fine-grained shale, methods of microscale X-ray fluorescence (μ-XRF) mapping, (ultra-) small-angle x-ray scattering [(U)SAXS] and wide-angle X-ray scattering were used to determine elemental and pore structure variations in sizes up to ˜10 cm on two samples prepared at circular (8 cm×8 cm×0.8 mm in width×length×thickness) and rectangular (5 cm×8 cm×0.8 mm) orientations from a piece of Eagle Ford Shale outcrop in South Texas. Thin section petrography and field emission-scanning electron microscopy, X-ray diffraction (XRD), total organic carbon, and pyrolysis were also utilized to investigate the potential spatial heterogeneity of pore types, mineral and organic matter compositions for both samples. Overall, the siliceous-carbonate mineral contents in these carbonate-rich Eagle Ford Shale vary between laminations at mm scales. For the circular sample, porosity and surface area variations range from 0.82 to 3.04% and 1.51 to 14.1 m 2 /g, respectively. For the rectangular sample, values for porosity and surface area vary from 0.93 to 2.50% and 3.95 to 10.8 m 2 /g. By analyzing six selected sub-samples on each of two samples with X-ray scattering and XRD techniques, nm-sized pores are mainly interparticle ones in the higher calcite regions, where the porosity is also relatively lower, while the lower calcite regions consist of both interparticle and intraparticle pore types with higher porosity. Finally, the μ-XRF and (U)SAXS are combined to generate porosity distribution maps to provide more insights about its heterogeneity related to the laminations and fractures at our observational scales.

show abstract

Distribution characteristics and oil mobility thresholds in lacustrine shale reservoir: Insights from N2 adsorption experiments on samples prior to and following hydrocarbon extraction

Cited by 72 publications

References 41 publications

Impact of Pyrite Oxidation on the Pore-Structure Characteristics of Shale Reservoir Rocks under the Interaction of Fracturing Fluid

Impact of Pyrite Oxidation on the Pore-Structure Characteristics of Shale Reservoir Rocks under the Interaction of Fracturing Fluid

Quantitative Characterization of Full-Spectrum Pore Size and Connectivity for Shale with Different Sedimentary Facies from the Dongying Depression, Bohai Bay Basin, East China

Micro- to nano-scale areal heterogeneity in pore structure and mineral compositions of a sub-decimeter-sized Eagle Ford Shale

Contact Info

Product

Resources

About