Schlumberger

Case Study: ECS Spectroscopy Sonde’s Petrophysical Analysis Finds Additional 250 ft of Productive Shale

Unconventional reservoirs discovered above and below limestone reservoir to also be completed, Midland basin

Challenge: Find bypassed reserves in shale and carbonate formations adjacent to a conventional limestone reservoir.

Solution: Run Platform Express integrated wireline logging tool in combination with the ECS elemental capture spectroscopy sonde to accurately determine clay content, mineralogy, and matrix properties to support robust, detailed petrophysical analysis.

Result: Identified 150 ft of productive unconventional shale reservoir above the currently produced limestone and another 100 ft below it.

Looking beyond the conventional reservoir

An operator’s target zone in the Midland basin is a conventional limestone bounded by shales. The reservoir varies from 100 to 150 ft in thickness and is produced from single-stage jobs designed to contain the stimulation. Because other wells in the area had mud logging shows, the operator wanted to know if additional producible formations were present.

Conducting fast, detailed petrophysical evaluation

The ECS elementary capture spectroscopy sonde was combined with the Platform Express integrated wireline logging tool for one-run measurement to support petrophysical analysis. The Platform Express tool provides high-resolution resistivity, density, and microresistivity measurements. The ECS sonde measures relative elementary yields for the determination of lithology, porosity, permeability, and fluid saturations and their producibility.

Finding bypassed pay in unconventional reservoirs

Petrophysical analysis found that the shales bounding the limestone reservoir are producible unconventional reservoirs, extending 150 ft above the limestone and 100 ft below it. The operator plans to reevaluate these bypassed reserves in completed wells and target them in new wells. The lithology from the ECS sonde’s measurements will be used to determine rock mechanical properties for stimulation design, including the identification of barriers to fracture propagation.


Download: ECS Petrophysical Analysis Finds Additional 250 ft of Productive Shale (2.30 MB PDF)

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