Schlumberger

Case Study: SHARC Bits Save Operator 17 Days Drilling Ultrahard Interbedded Formation

Bits deliver over 70% higher ROP than nearest offset

Challenge: Drill 12 1/4-in, 2,765 m section through interbedded formations with unconfined compressive strength (UCS) that ranges from below 2,000 psi up to 42,000 psi, with two bits, in less than 30 days.

Solution: Run the 12 1/4-in MSi616 SHARC high-abrasion-resistance PDC drill bit with ONYX PDC cutters.

Result: The SHARC bits collectively drilled the 12 1/4-in, section in 15.1 days saving 17.12 days compared to the previous best completion time in the same field.

High drillbit durability required

PDO working in North West field of Oman faced a challenge drilling 12 1/4-in 2,765 m section at depth of 1,276 to 4,041 m in 30 days. The formations to be drilled, Natih to Middle Khuff representing the top part of the section and Khuff the lower, have a lithology that includes limestone, dolomites, shale, and sands with a UCS range between 2,000 psi and 42,000 psi. For operators working in this field, these conditions have resulted in unacceptable ROP, chronic bit replacement, and lost BHAs or assembley components.

Application-specific bit designed

Smith Bits assembled a team of product engineers, design engineers, and hydraulics experts to analyze the application and select a bit for the operator that would drill the entire 12 1/4-in 2,765 m section with an ROP above 15 m/h using two bits. The team had access to several proprietary modeling and database tools:

  • IDEAS integrated drillbit design platform
  • i-DRILL engineered drilling system design for BHA modeling
  • DBOS drillbit optimization system
  • DRS drilling record system, a collection of nearly 3.5 million bit runs

Upon completion of their application analysis the team recommended that the operator to use two 12 1/4-in MSi616 SHARC high-abrasion resistant PDC drill bits with ONYX cutters. ONYX cutters stay sharp longer in both hard carbonates and abrasive sand formations to provide superior drilling performance. An IDEAS design platform, the bit’s cutting structure layout ensures the stability and durability necessary to efficiently drill through hard, interbedded, and abrasive formations.

17 days saved drilling 2,765 m ultrahard section

The first 12 1/4-in MSi616 SHARC bit drilled the top part of the section from the Natih to Middle Khuff formations from a depth of 1,276 m to 3,506 m for a total of 2,230 m. The overall ROP for the first bit was 16.28 m/h, which is 78% higher than the closest offset drilled in that part of the formation. The second SHARC bit drilled through the Khuff formation to complete the lower section from a depth of 3,506 m to 4,041 m for a total of 535 m. The overall ROP for this second run was 10.31 m/h, which is 65% higher than the closest drilled in that formation. This performance by the two SHARC bits resulted in 12 1/4-in section being completed in 15.1 days. A savings of 17.12 days compared to the fastest 12 1/4-in section drilled by other manufacturers’ bits in the same field.


Download: SHARC Bits Save Operator 17 Days Drilling Ultrahard Interbedded Formation (0.68 MB PDF)

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North West Field of Oman
12 1/4-in Section Run Details

North West field of Oman 12 1/4-in section run details
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