Sedimentary Feature Identification and Textural Analysis | SLB

Sedimentary Feature Identification and Textural Analysis

Detailed borehole resistivity image data and interpretation

Interpretation of Deep-reading EM Data

High-resolution resistivity and acoustic images can reveal important attributes of sedimentary rocks. Using sedimentary features, we can deduce the processes and conditions at the time of deposition and derive the overall geologic depositional environment. Basal scour and fill features are highly visible and can be interpreted to provide highly useful channel orientation. Massive sands versus laminated intervals or conglomerates can be easily identified with borehole images as well as revealing if bioturbation has taken place. With advanced resistivity-based technologies, we can detect sand laminations as thin as 0.2 in and provide an accurate net pay count. All of these attributes can be used to corroborate and validate the production selection of one reservoir interval with respect to another one.

Sedimentary Feature Identification and Textural Analysis
The hydrocarbon saturation calculated from vertical resistivity and resistivity anisotropy measured with Rt Scanner service clearly indicates the presence of hydrocarbon that otherwise would have been overlooked using classic resistivity measurement of only horizontal resistivity.
Sedimentary Feature Identification and Textural Analysis
In highly laminated sediments, the image log from the FMI fullbore formation microimager clearly shows the net pay zones that can contribute to production. Laminations as thin as 0.2 in can be resolved on the images. Here, sand is distinguished from shale laminations with a resistivity cutoff (far right track).

Paleocurrent indication

Very high-resolution images can be acquired with advanced tools such as the FMI-HD high-definition formation microimager or the MicroScope HD resistivity- and high-definition imaging-while-drilling service. Our experienced petrotechnical experts can carefully analyze these images and reveal important information from them, characterize cross-bedded intervals, and indicate the direction of depositional currents, which can lead to more successful offset wells and more efficient field development.

Porosity analysis in carbonates

Many productive carbonates have complex dual-porosity systems with widely varying proportions of primary and secondary porosity. High-resolution borehole electrical images, such as those acquired with the FMI-HD microimager, can be used to quantify the porosity distribution and determine the importance of vugs to the overall effective porosity and permeability. A better understanding of the drivers of reservoir production can be gained in complex heterogeneous carbonate reservoirs through image interpretation, especially when the natural fractures are linked to matrix and vuggy porosity.