Case Study: NeoScope Sourceless LWD Service Delivers High-Quality Formation Evaluation Data for Apache

Eliminating chemical nuclear source in West Kanayes exploration concession saves 7 days of rig time

Challenge: Acquire full suite of petrophysical measurements in directional exploration well where poor borehole conditions prevented wireline tools from reaching the entire interval of interest.

Solution: Use NeoScope sourceless formation-evaluation-while-drilling service for faster deployment by eliminating the need for a chemical nuclear source and geoVISION imaging-while-drilling service for quantitative petrophysical and formation images analysis.

Result: Saved the time and expense of shipping a chemical nuclear source to the wellsite—7 days and USD 200,000—while providing high-quality formation evaluation measurements and high-resolution images.

Evaluation of field with poor borehole conditions

While running an exploration program to evaluate the West Kanayes concession in the western desert of Egypt, Apache Corporation contacted Schlumberger to provide complete petrophysical and geological data. Poor borehole conditions in a directional well prevented wireline tools from reaching the entire interval of interest. The NeoScope sourceless LWD service was selected to acquire the full suite of petrophysical measurements because it could be mobilized to the wellsite faster than a chemical nuclear source service, saving valuable rig time.

Acquisition of quality data with sourceless LWD technology

Using pulsed neutron-porosity and neutron-gamma-density measurements, the NeoScope service provided 1,774 ft of high-quality data, including the oil-bearing sandstone reservoir section of approximately 5% porosity. These measurements were compared to measurements of porosity and density from conventional chemical nuclear sources. The sourceless neutrongamma density data and other measurements correlated along the interval, which allowed Apache to complete the formation evaluation across the well.

Laterolog resistivity measurements were also acquired using the geoVISION service to provide quantitative, high-resolution array resistivities in addition to high-quality images. The images were used to pick bedding plans and identify natural and drilling-induced fractures and faults.

Time savings through elimination of chemical nuclear source

Combining NeoScope measurements and quantitative geoVISION laterolog resistivities and images provided Apache with a unique solution that could be quickly mobilized. The Schlumberger LWD services provided detailed formation evaluation across the full openhole section despite the well’s poor borehole conditions. Using the NeoScope service saved Apache the time and expense of deploying a chemical nuclear source to the wellsite—7 days and USD 200,000. Eliminating the time to load and unload the source saved 6 hours of rig time per well. In addition, all measurements were available in the first 16 ft of a single 25-ft collar position close to the bit.

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