Schlumberger

Case Study: PDC Completes First Single-Run Drilling of 12 1/4-in Section in Ghana’s Challenging Jubilee Field

Challenge: In one run, drill an entire 12 1/4-in section through a reservoir in Ghana’s Jubilee Field, which has taken at least four bit runs to complete.

Solution: Run 12 1/4-in MDSi816LBPX PDC drill bit optimized with ONYX premium PDC cutters.

Result: The bit completed the section in one run: reducing the time per interval by eliminating multiple trips, saving two drilling days equaling USD 2 million in costs.

Bit with advanced durability and ROP that can transition from a soft to hard formation

An operator drilling sections in Ghana’s Jubilee Field was suffering high-bit consumption rates. The resulting number of trips was threatening the economic viability of the operation. However, completing sections in this area was difficult. It required drilling through a soft shale and claystone formation measured at 1 to 10 kpsi with an average interval length of 1,000 m. Following this, drilling transitions into a hard and abrasive sandstone composition measuring 10 to 25 kpsi with an average interval of up to 400 m.

Previous drilling in this area of the Jubilee field resulted in bit failures that forced at least four bit trips to complete a single section. Bits used on these offsets were usually characterized by poor dull condition: RO and WT. The operator wanted to reduce the trips needed to replace bits and, ideally, drill the proposed reservoir intervals in one run.

Application-specific bit design

To design a bit that could complete these sections, in one run, a Smith Bits engineering design team used modeling software, surface parameter optimization, drilling road map graphs and correlation studies between adjacent wells. This included several proprietary modeling and database tools:

  • IDEAS integrated dynamic design and analysis platform
  • i-DRILL integrated dynamic system analysis service design for BHA modeling
  • DBOS drillbit optimization system
  • DRS drilling record system, a collection of nearly 3 million bit runs

Using a Schlumberger PowerDrive rotary steerable system, the design team tested several 12 1/4-in PDC-bit designs. The bit that proved to have the best and most consistent performance was the 12 1/4-in MDSi816LBPX with ONYX cutters.

USD 2 million saved on a single section

The optimized PDC was the first bit to drill an entire 12 1/4-in section from shoe to TD in Ghana’s Jubilee field in one run. The bit’s performance saved two days of drilling time, which equals USD 2 million dollars. The bit’s single-run capability has subsequently been recognized by several other customers, and it has become the standard design for applications in this area where it continues to prove its value.


Download: PDC Completes First Single-Run Drilling of 12 1/4-in Section in Ghana's Challenging Jubilee Field (0.68 MB PDF)

Related services and products

 
 
 
 
Request More Information

USD 2 Million in Cost and
Two Drilling Days Saved

Jubilee Field 12 1/4-in bit performance12 1/4-in section distance drilledCost of 12 1/4-in section and estimated savings
PrevNextZoom1 of 3