Estimating rock mechanical properties of the Zubair shale formation using a sonic wireline log and core analysis

Abbas, Ahmed K.; Flori, Ralph E.; Alsaba, Mortadha

doi:10.1016/j.jngse.2018.03.018

Cited by 47 publications

(11 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If only the P wave time difference is available, the S wave time difference can be obtained by eq where X , Y , and Z are conversion coefficients, which are different in different regions, and X = 0.0077, Y = 73.58, and Z = −102.298 in our study area.…”

Section: Results and Discussionmentioning

confidence: 99%

“…Method of Calculating Rock Brittleness Using Well Logging Data. In this study, a new model of rock brittleness is established based on the energy evolution characteristics in the rock failure process, and several rock mechanical experiments are needed to obtain the elastic modulus E, the peak strength σ B , the peak strain ε f , and the postpeak modulus M. 43,54 If some mechanical parameters have been obtained in experiments, evaluating the brittleness with easily accessed logging data is feasible, thereby reducing the workload. How to obtain the parameters in brittleness evaluation and calculate the brittleness indexes by logging data are illustrated as follows.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Shale Brittleness Index Based on the Energy Evolution Theory and Evaluation with Logging Data: A Case Study of the Guandong Block

Zhou²,

Li³

et al. 2020

ACS Omega

View full text Add to dashboard Cite

Shale brittleness is a key index that indicates the shale fracability, provides a basis for selecting wells and intervals to be fractured, and guarantees the good fracturing effect. The available models are not accurate in evaluating the shale brittleness when considering the confining pressure, and it is necessary to establish a new shale brittleness model under the geo-stress. In this study, the variation of elastic energy, fracture energy, and residual elastic energy in the whole process of rock compression and failure is analyzed based on the stress–strain curve in the experiments, and a shale brittleness index reflecting the energy evolution characteristics during rock failure under different confining pressures is established; a method of directly evaluating the shale brittleness with logging data by combining the rock mechanic experiment results with logging interpretation results is proposed. The calculation results show that the brittleness decreases as the confining pressure increases. When the confining pressure of the Kong-2 member shale of the Guandong block is less than 25 MPa, the brittleness index decreases significantly as the confining pressure increases, and when the confining pressure is greater than 25 MPa, the brittleness index decreases slightly. It is shown that the shale brittleness index is more sensitive to the confining pressure within a certain range and less sensitive to the confining pressure above a certain value.

show abstract

Section: Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Shale Brittleness Index Based on the Energy Evolution Theory and Evaluation with Logging Data: A Case Study of the Guandong Block

Zhou²,

Li³

et al. 2020

ACS Omega

View full text Add to dashboard Cite

show abstract

Section: Discussionmentioning

confidence: 99%

“…When the indenter entered into the shale sample in the nanoindentation tests, the mechanical properties of the shale sample were affected by many factors, such as the clay content, the brittle mineral content, and the TOC content. 43 Therefore, to determine the relationships between the mechanical parameter and these influencing factors, the mechanical parameters of six shale samples with various mineral compositions were measured using the nanoindentation tests (Table 4). The plots of the elastic modulus and hardness versus hard mineral content (siliceous and carbonate minerals combined), clay content, TOC, and soft component content (clay and TOC combined) are shown in Figures 16 and 17, respectively.…”

Section: Mineral Compositions and Organicmentioning

confidence: 99%

Assessment of the Multiphase Mechanical Properties of the Longmaxi Formation Shale Using Nanoindentation Tests

et al. 2021

View full text Add to dashboard Cite

Mechanical properties are some of the most important parameters for understanding well drilling and hydraulic fracturing designs in unconventional reservoir development. As an effective tool, nanoindentation has been used to determine the mechanical properties of rocks at the nanoscale. In this study, the Longmaxi Formation shale samples from the Yibin area of China were collected and analyzed to obtain the multiphase mechanical properties. The mineral compositions and organic geochemistry of the shale samples were studied using X-ray diffraction, energy-dispersive X-ray spectrometry, and a carbon/sulfur analyzer. The pore structures of the shale samples at the micro- and nanoscales were characterized by field-emission scanning electron microscopy. The mechanical parameters of the shale samples, such as the hardness and elastic modulus, were investigated using the nanoindentation method to identify three mineral phases: brittle minerals, soft matters, and complex minerals at the interfaces between brittle minerals and soft matters. The uncertainty characteristics of the mechanical parameters of the three mineral phases were evaluated using the Weibull model, and the factors interfering with the mechanical parameters were analyzed for the different shale samples. The results showed that the brittle minerals had the largest recovered elastic deformations and the smallest residual deformations, while the soft matters had the largest residual deformations and the smallest recovered elastic deformations. The analysis results of the coefficients of variation and the Weibull modulus both confirmed that the scatter of the hardness was higher than that of the elastic modulus because of the uncertain contact area, and the hardness and elastic modulus of the soft matters had the highest uncertainty among the three mineral phases. The elastic modulus increased nonlinearly with increasing hardness according to a power function for the whole shale sample. The elastic modulus and hardness both had a favorable linear relationship with the total organic carbon (TOC) content, illustrating that the TOC content was one of the significant factors that affected the mechanical parameters of the shale samples.

show abstract

“…Predominated by dark-grey argillaceous-lime dolostone, lime dolostone, dolomitic limestone and calcareous mudstone, some anhydrite-rich beds and halite beds develop in the upper part. Eocene Paleocene Lower E2-3xg 1 Brown-red mudstone with some grey-white fine sandstone and calcareous mudstone interbeds.…”

Section: Xiaganchaigoumentioning

confidence: 99%

Impact of Lithologic Heterogeneity on Brittleness of Cenozoic Mixed Fine-grained Sedimentary Rock Reservoirs in Western Qaidam Basin

Li¹,

Wu²,

Wang³

et al. 2022

Preprint

View full text Add to dashboard Cite

In order to understand the impact of lithologic heterogeneity of continental mixed fine-grained sedimentary rocks on reservoir brittleness in western Qaidam basin, the mechanical properties of the rocks and their correlation with mineral composition and petrographic characteristics were studied by measns of mineralogy, petrography and triaxial stress test. The results show that the reservoir rocks can be divided into 5 different types according to the mechanical properties of the reservoir (characteristics of stress-strain curves), among them Type I and III belong to similar elastoplastic failure model, type II shows a special pulse failure mode for plastic material, type IV shows a failure mode of mixed characteristics, and type V exhibits a typical plastic failure model. The correlation between minerals and mechanical properties indicates that quartz and feldspar, which are often considered brittle minerals, do not contribute much to the brittleness of continental fine-grained sedimentary rocks. The main minerals affecting reservoir brittleness are dolomite and clay minerals, and their contributions to reservoir brittleness are positive and negative, respectively. The petrographic analysis results prove that the abnormal correlation between rock mechanical properties and quartz and feldspar is caused by the different rock fabrics. When dolomite forms a rock skeleton, it typically exhibits greater strength, brittleness and physical properties than other minerals. Based on the results, a brittleness evaluation standard for continental fine-grained sedimentary rock reservoir is proposed, and the validity of the standard is verified by the spatial correlation between the lithology probability model and the micro-seismic monitoring data, indicating that the spatial heterogeneity of dolomite-rich rock is the main controlling factor for the development of ‘sweet spot’ in the Cenozoic continental fine-grained sedimentary rock reservoir in the Western Qaidam Basin.

show abstract

Estimating rock mechanical properties of the Zubair shale formation using a sonic wireline log and core analysis

Cited by 47 publications

References 27 publications

Shale Brittleness Index Based on the Energy Evolution Theory and Evaluation with Logging Data: A Case Study of the Guandong Block

Shale Brittleness Index Based on the Energy Evolution Theory and Evaluation with Logging Data: A Case Study of the Guandong Block

Assessment of the Multiphase Mechanical Properties of the Longmaxi Formation Shale Using Nanoindentation Tests

Impact of Lithologic Heterogeneity on Brittleness of Cenozoic Mixed Fine-grained Sedimentary Rock Reservoirs in Western Qaidam Basin

Contact Info

Product

Resources

About