Digital studies of rock cuttings contribute to save funds during oil extraction

The study of cuttings—drilled rock carried by the drilling fluid from the bottom of the well to the surface—and obtaining logging data helps reconstruct the chemical, mineralogical composition, reservoir parameters of rocks and the characteristics of the fluid that saturates the reservoir. A publication saw light in Journal of Petroleum Science and Engineering.

Core drilling is one of the most expensive operations in the oil industry. Partially abandoning core extraction allows the widespread use of geophysical methods for studying wells.

But for petrophysical data calibration, it is still necessary to extract and examine the core, especially from the productive part of the sedimentary stratum. When developing large deposits, dozens and hundreds of wells are drilled. Of course, oil companies would like to have a core from each drilled well, but this could lead to a significant increase in the cost of projects.

A potential alternative that can open up the possibility of creating detailed spatial models of a productive reservoir may be an approach based on digital analysis of drill cuttings. The main objective was to assess the possibility of using tomographic and geochemical analysis of sludge to create a digital petrophysical and geochemical model of oil reservoir rocks.

Vice-Rector for Earth Sciences Danis Nurgaliev comments, "KFU's World-Class Research Center in Liquid Hydrocarbons owns a technology for oil extraction optimization. We call it Pseudo Drill Cutting. It's essentially a new oilfield service for companies."

Oil and gas companies produce millions of tons of drilling waste. A small amount of cuttings can provide information on the composition and structure of the reservoir, which can complement and in some cases replace core studies.

"The cuttings have great potential for low-cost extraction of reservoir data, and the availability of effective technology for its analysis will significantly reduce the cost and time of drilling. The potential use of cuttings for assessing reservoir and petrophysical properties is possible when taking into account the factors of changing the structure of the cuttings, the representativeness of samples, as well as optimizing the drilling process," says co-author, Research Associate Rail Kadyrov.

Core and cuttings samples were taken simultaneously from the same intervals when drilling directional wells in the Carboniferous layers of an oil field in the Republic of Tatarstan.

More information:
Digital rock physics: Defining the reservoir properties on drill cuttings

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Provided by Kazan Federal University