Application of Modern NMR Logging for Mixed-Lithology Carbonate Reservoirs (A Case Study)

Syngaevsky, Pavel E.; Khafizov, S.F.

doi:10.2118/2003-016

Cited by 1 publication

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“…All correlations were within the average porosity range for the Falher sandstone, which does not exceed 15% (Harris 2014). Previous methods for determining porosity in formations of complex lithology have required multiple types of log porosity combinations (Syngaevsky and Khafizov 2003). Analyzing a zone with mixed lithology indicates a large range in porosity values for the Onyia, Sarda, and Erfourth methods (Fig.…”

Section: Fig 8-shale Porosity Comparison Between the Cedola Shale Comentioning

confidence: 99%

Evaluating Multiple Methods to Determine Porosity from Drilling Data

Cedola

Atashnezhad

Hareland

2017

SPE Oklahoma City Oil and Gas Symposium

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Porosity can be obtained from drilling data by using different correlations that relate the porosity to the unconfined compressive strength (UCS), which is obtained from drill bit inverted rate of penetration (ROP) models. Knowing the porosity at a given depth can benefit in helping to define the formations being penetrated and to characterize variations in a reservoir, thereby benefitting in selective stimulation. In this paper, previous studies that present methods for calculating porosity from UCS values will be compared and evaluated with sections of porosity that have been calculated from log data taken from three wells in Alberta, Canada. The correlations that will be compared include: Onyia, Sarda, Erfourth, and the UCS-gamma ray methods. The Onyia, Sarda, and Erfourth correlations are previously published while the UCS-gamma ray method correlates UCS in conjunction with the gamma ray at the bit. The porosity values that are found through these correlations are then plotted and their trends compared to each other as well as to the porosity obtained from log data in different sections from the well in Alberta, Canada. This process will help to determine what formation types are best correlated to the individual correlation. Typical drilling data is used in an inverted ROP model to obtain UCS. The UCS and gamma ray values are then taken and related to the porosity through the correlations presented in this paper and compared to the porosity determined from log data. Examining the different correlations that have been analyzed in various types of formations yield information indicating which correlation is best correlated to a specific formation type. The comparison's show that the predictability for some correlations are reasonable for limited datasets and sections of the well. To reasonably predict porosity values for mixed lithologies or shale formations, the integration of gamma log data is necessary. The trends exhibited from the correlations show that the comparison between porosity in shale is better seen when using the integrated UCS-gamma ray correlation. Utilizing the new UCSgamma ray model seemingly indicates that this useful new method can more accurately predict porosity variations in mixed lithologies and in shale reservoir sections. Bettering stimulation placement as well as minimizing logging in the reservoir can greatly reduce the overall cost of the operation. The improved selective stimulation process could also allow for higher production rates and/or potential reduced stimulation cost, thus increasing overall profit. This template is provided to give authors a basic shell for preparing your manuscript for submittal to an SPE meeting or event. Styles have been included to give you a basic idea of how your finalized paper will look before it is published by SPE. All manuscripts submitted to SPE will be extracted from this template and tagged into an XML format; SPE's standardized styles and fonts will be used when laying out the final manuscript. Links will be added to your manuscript for r...

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Section: Fig 8-shale Porosity Comparison Between the Cedola Shale Comentioning

confidence: 99%