Schlumberger

Case Study: Customized SHARC PDC and Rock Bit Save Apache 4 Days of Rig Time and USD 142,000

ROP improves 56% in 12 1/4-in section and 32% in 8 1/2-in borehole

Challenge: Reduce drilling time to TD for a 3,800-m directional well in Estación Fernandez Oro field, Argentina.

Solution: Improve 12 1/4-in rock bit hydraulics and redesign standard SHARC PDC bit cutters to increase durability and ROP.

Result: Saved 4.06 days of rig time and USD 142,100 when compared with the best average from five wells in the area.

Reduction in drilling time required

In the Estación Fernandez Oro field in Argentina, Apache typically drills wells in two sections—12 1/4-in borehole to 600 m and 8 1/2-in hole to TD at 3,800 m. All the wells are directional, with lateral displacement varying from 100 m to 500 m. The 12 1/4-in section is drilled with a roller cone drill bit. Three bit run are usually required to drill the 8 1/2-in section, which is particularly complex because of the wide range of formation types encountered: sandstone/claystone with conglomerates, limestone, sandstone, sandstone/claystone again, and more sandstone. Apache wanted to improve ROP in both sections, thus reducing the total drilling time.

Hydraulics improved, new bit designed, and cutters updated

For the 12 1/4-in section of well EFO 129, a hydraulics review of the roller cone bit resulted in changing the total flow area (TFA) to improve hydraulic horsepower per square inch (HSI) and impact force.

A Smith Bits design team produced a new and more dynamically stable SHARC high-abrasion-resistance PDC drill bit MSi519 for the first run in the 8 1/2-in section, with the goal of maximizing bit life. IDEAS integrated drillbit design platform enabled the team to virtually drill with a number of prototype designs, operating parameters, and BHA configurations before choosing the best combination.

For the second run in this section ONYX II premium PDC cutters were added to a fieldproven, 8 1/2-in MSi516 SHARC bit to reduce wear on the cutting structure and increase ROP. A third run was required to reach TD, due to a non-bit related trip.

Engineers used BHA data, directional profile, mud properties, and offset run information provided by Apache to analyze bit performance. They had several proprietary modeling and database tools at their disposal, including IDEAS integrated drillbit design platform, IDEAS platform analysis project for vibration analysis, DBOS drillbit optimization system for rock strength analysis, and DRS drilling record system, a collection of nearly 3 million bit runs.

Record ROP achieved and 4 days of rig time saved

The 600-m, 12 1/4-in section was drilled in 35.5 h, representing a 56% improvement in ROP. The 3,211 m, 8 1/2-in section was drilled in 294.75 h, which is 32% faster than the offset average. The SHARC bit with ONYX II cutters improved ROP in the 8 1/2-in section by 40% compared with the best offset well over the same interval. Based on comparison with the average of the five best offset wells in the area, total drilling time was reduced by 4.06 days, with a savings of USD 142,100 for Apache, setting a new record for drilling performance in this field.


Download: Customized SHARC PDC and Rock Bit Save Apache 4 Days of Rig Time and USD 142,000 (0.71 MB PDF)

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Drilling Time Reduced by 4 Days, New Drilling Record Set in Argentina

Record ROP achieved and 4 days of rig time savedRecord ROP achieved and 4 days of rig time saved
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