Seismic velocity deviation log: An effective method for evaluating spatial distribution of reservoir pore types

Shirmohamadi, Mohamad; Kadkhodaie, Ali; Rahimpour‐Bonab, Hossain; Faraji, Mohammadali

doi:10.1016/j.jappgeo.2017.03.001

Cited by 16 publications

(1 citation statement)

References 16 publications

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“…Mid-to high-angle fractures dominate the upper Deng-4 zone, whereas low-to mid-angle fractures dominate the lower Deng-4 zone (Li Y. et al, 2014). Fracture systems with vuggy pores/caves provide a good reservoir pore system (Shirmohamadi et al, 2017;Abdlmutalib et al, 2019), but these features tend to cause a high degree of seismic anisotropy, and current seismic data at present lack high-quality azimuthal information. This poses a challenge to interpret the anisotropy and identify the reservoir pore types and fluid producibilities using the seismic data.…”

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confidence: 93%

Anisotropic Rock Model-Guided Post-Stack Attribute Analysis With Pore Type and Production Data for a Carbonate Gas Reservoir

Huang

et al. 2021

Front. Earth Sci.

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The Moxi area in the Sichuan Basin is dominated by carbonate gas reservoirs, where gas productivity is most strongly influenced by their pore types. Fractured caves are the most favorable pore structure type for reservoir productivity, followed by cave and vuggy pore structures, and interparticle pore structures are the least productive. The spatial discrimination of these three pore types is important for cost-effective development. However, the pore type identification remains difficult owing to poor-quality azimuthal seismic data. A practical approach is to understand the seismic signatures of the different pore types and the related productivities from the post-stack data. In this work, seismic forward modeling is conducted using a constructed theoretical model of Hudson's anisotropic representation, and the pre-stack and post-stack anisotropy signatures are analyzed for different pore types. The rock model is further calibrated using log data, and forward modeling is performed based on the calibrated logs. We propose a new attribute of these signatures: namely, the ratio of the absolute peak and the absolute trough immediately below the peak, which is applied to the three-dimensional seismic data in the Moxi area. In contrast with other conventional attributes, this ratio effectively correlates with pore type, which allows the pore types in wells to be differentiated. This attribute also reasonably correlates with open flow gas rate of the well. The results demonstrate that this attribute from the post-stack data is a promising indicator of pore type and gas productivity and can also be readily mapped spatially for the selection of new drilling locations.

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confidence: 93%

Anisotropic Rock Model-Guided Post-Stack Attribute Analysis With Pore Type and Production Data for a Carbonate Gas Reservoir

Huang

et al. 2021

Front. Earth Sci.

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Integrated Petrophysical and Heterogeneity Assessment of the Karstified Fahliyan Formation in the Abadan Plain, Iran

2023

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A new insight to access carbonate reservoir quality using quality factor and velocity deviation log

Larki,

Jaffarbabaei,

Soleimani

et al. 2023

Acta Geophys.

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Estimating wave damping in carbonate rocks is complex due to their heterogeneous structure. For this reason, further research in this area is still necessary. Since the identification and evaluation of reservoir quality play an essential role in the optimal use of hydrocarbon resources, efforts are made to provide new solutions to achieve this goal by managing knowledge and accessing information from new tools such as the Vertical Seismic Profile (VSP). Seismic waves are deformed in frequency content and amplitude as they pass through the earth's layers. Part of the reduction in wavelength is related to the nature of the wave propagation and part to the geological properties, including porosity and fracture. Anisotropy and velocity model analysis, rather than the direct connection between reservoir parameters and seismic absorption coefficient, have received the majority of attention in earlier studies on the impact of reservoir parameters and fractures on changes in the quality factor. In this study, the correlation of the quality factor with parameters such as velocity deviation, fracture density, and permeability has been investigated, and an attempt has been made to define the quality factor as a tool to assess the quality of the reservoir. The statistical study using the multiple linear regression method found that fracture density is the most important parameter that follows the trend of the quality factor value. In the analysis, the quality factor showed a relatively good correlation with the permeability of the core data, so in the periods with maximum permeability, the quality factor had the lowest values. According to K-Means Clustering Analysis, 18% of the studied reservoir interval was evaluated as good quality, 33% as medium, 36% as poor, and 12% as hydrocarbon-free. This work provides insight into accessing reservoir quality using quality factor and velocity deviation logs and would be valuable for the development of reservoir quality prediction methods. Based on the study's results, it is recommended to apply this technique for modeling reservoir heterogeneity and assessing 2D and 3D seismic data to predict the reservoir quality of gas fields prior to drilling operations and reduce exploration risks.

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Seismic velocity deviation log: An effective method for evaluating spatial distribution of reservoir pore types

Cited by 16 publications

References 16 publications

Anisotropic Rock Model-Guided Post-Stack Attribute Analysis With Pore Type and Production Data for a Carbonate Gas Reservoir

Anisotropic Rock Model-Guided Post-Stack Attribute Analysis With Pore Type and Production Data for a Carbonate Gas Reservoir

Integrated Petrophysical and Heterogeneity Assessment of the Karstified Fahliyan Formation in the Abadan Plain, Iran

A new insight to access carbonate reservoir quality using quality factor and velocity deviation log

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