Evaluate reservoir with significant TOC and mineralogical variations

An operator drilling a lateral well in Pennsylvania needed to evaluate rock and fluid heterogeneity along the planned trajectory targeting the Marcellus Shale. The well was planned to target a section of the Marcellus Shale with a high total organic carbon (TOC) concentration of up to 20%. The operator needed to analyze the mineralogical and geochemical composition of the formation to precisely steer the horizontal well within the target zone and optimize the fracturing strategy.

Accurately evaluate formation at surface from cuttings

Schlumberger recommended characterizing the mineralogy, elemental composition, and TOC of the reservoir with the LithoFlex service from Geoservices, a Schlumberger company. This wellsite laboratory-quality evaluation method provides accurate and repeatable evaluation of cuttings immediately after they reach the surface, avoiding conveyance issues and exposure to additional operational risk.

Provided information critical to optimizing fracturing design

Through analysis of cuttings samples, the LithoFlex service identified lateral variations in mineralogy and TOC and revealed zones of superior production potential. Logs from the LithoFlex service confirmed that the lateral was landed in the target zone. Providing further proof that the well was landed in the Marcellus Shale, TOC concentration exceeded 10%, and the concentration of redox proxies, such as molybdenum and uranium, increased.

Measurements of brittleness from the LithoFlex service identified brittle zones that the operator can use to optimize the fracturing strategy of this well. Additionally, the LithoFlex service identified intervals where the lateral was drilled out of zone. The changes in formation are indicated by spikes in calcite, as shown in the log, and provide valuable information for optimizing completion design.