Operator Improves Formation Evaluation in Unconventional Shale Using LithoFlex Service, USA

Improve formation evaluation in an unconventional shale play

An operator needed to drill a lateral well within organic-rich shale in the USA, with >10% TOC. To place the well within the target zone and enhance completion design, the operator needed to identify and analyze key parameters, such as shale lithofacies, organic richness, and kerogen content, as well as obtain more accurate porosity evaluation than those derived from LWD measurements.

Porosity is a fundamental parameter for oilfield formation evaluation yet is challenging to determine in shale formations, especially in horizontal wells. Conventional methods for obtaining porosity measurements are based on analyzing core samples using gas immersion or liquid saturation. However, these techniques are time-consuming and limited to evaluation in the laboratory, and— for wells drilled laterally—core is typically not recovered. In lateral wells, porosity is assessed through LWD measurements, and the main challenge is the abundance of kerogen that is part of the solids matrix but has log responses similar to or indistinguishable from pore fluids. Without accurately characterizing the kerogen content, it is difficult to estimate porosity in shale.

Determine key rock properties in near-real time

Schlumberger recommended using DRIFTS, a cost-efficient component of the LithoFlex service. The LithoFlex service provides near-real-time formation evaluation in water- and oil-based mud for both wellsite and remote data monitoring and interpretation. Using the LithoFlex service, key measurements can be obtained from cuttings, including kerogen density, for improved porosity calculations derived from bulk density measurements.