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Case Study: MicroScope Azimutally Focused Resistivity Images Enable PetroChina to Exceed Production Goal

Identification of structural features in thin tight gas reservoir allows accurate well placement in one run with 91% in zone

Challenge: Develop a well in a thin tight gas reservoir with structural variations and fractures along the horizontal section.

Solution: Identify structural features of the reservoir using MicroScope resistivity- and imaging-while-drilling service to place well in the target zone and optimize completion design.

Result: Drilled the 1,095-m horizontal section in one run with 91% in zone and initial gas production of 120,000 m3/d, which exceeded the operator’s goal.

Thin tight gas reservoir development in China

When PetroChina SWOGC planned to drill a long horizontal well in the thin dolomite gas reservoir of the Sichuan basin in eastern China, the company faced a variety of challenges in the planning stages of development. In addition to the thin target zone—expected to only be between 1 and 2 m thick—the challenges included uncertainties regarding lateral property and stratigraphic thickness and high local structural dip. There were also no control wells in this thin tight gas reservoir.

Azimutally focused resistivity images for horizontal well optimization

MicroScope service provided azimutally focused resistivity image that clearly identified and defined the dips, faults, and fractures along the horizontal section. Even with the local structural undulations, variations in target zone thickness, and lateral property changes along the horizontal section, these images helped to accurately geosteer the well and place it within the target zone.

MicroScope service also provided valuable fracture information to design the hydraulic staging designs and segmentations for completion optimization. The borehole images provided by MicroScope service, combined with teamwork and communication, enabled successful drilling and precise placement of a long horizontal well in this complex, thin, dolomite gas reservoir.

Accurate well placement and completion optimization

The 1,095-m horizontal section was drilled with 91% in zone—exceeding the minimum requirement of 80%—and good trip gas readings throughout the section. The well was completed in one run and a total of 151 drilling hours, with initial gas production of 120,000 m3/d, which exceeded the operator’s production goal for the well.


Download: MicroScope Azimutally Focused Resistivity Images Enable PetroChina to Exceed Production Goal (2.25 MB PDF)

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"MicroScope service helped us significantly in making accurate real-time decisions in this challenging environment and opened more opportunities to develop thin target tight-gas reservoirs."
Peng Hai Run
Chief of G&G
PetroChina SWOGC ShuNan