Page 53: of Offshore Engineer Magazine (Sep/Oct 2014)

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The PDC bits with conical diamond (recommendation: HSI > 2.5hp/in ) to elements in new concepts of drill bit cut-

Drilling

Stinger element design drilled the second ensure good bottom hole cleaning, better ting structures. We are also investigating the use of different shapes in Stinger insert part of the 8 ½-in. section with excel- cutter refrigeration and cutting structure to further improve side impact resistance lent performance, presenting minimal durability.

Bit design: over conical Stinger inserts while main- wear after drilling 234m at an average The center-placed Stinger taining aggressiveness and also the use of

ROP of 15.4m/h. Vibration levels were element has proven to increase stability high frequency downhole measurements kept within an acceptable range through- and reduce vibration levels; The CDE for the next iterations. Reducing the devel- out the run. The changes in lithology also has proven to improve drilling eff- opment cycle and identifying optimum encountered were effectively drilled at ciency at bit center, increasing the ROP; parameters and procedures are also neces- high rates, since bit cutting structure was All versions tested presented minimum sary along with working to improve the kept sharp until the end of the run. The wear in the cone area.

Cuttings: durability on Nose/Shoulder area.

PDC bits with conical diamond Stinger Good cuttings size genera- element design was used with a rotary tion confrming that the conical diamond steerable BHA and the following param- element was crushing the rock into João Pedro Tocantins eters were used: larger-than-normal fragments (desirable is a Senior Product

WOB: 9 – 52klbs, average 37klbs; feature for geology evaluation). Engineer for Smith •

RPM: 45 – 180, average 136 RPM; The PDC bits with conical Bits, a Schlumberger • S&V:

Flow rate: 580 – 650, average 645GPM; diamond Stinger element design clearly company, located in •

Drilling ROP: 15.4m/h. showed better dynamical behavior than Brazil.  His focus • conventional PDC bits. includes continuous Impact damage was the main product development

OE: What were the lessons learned from Cutters: drilling with the bits in Brazil and how failure mode, therefore bigger bevels and for Brazil, drilling optimization and have operators reacted to the results?

cutters with more resistance to frontal technical support for all bit types. He

The main lessons were related to hydrau- impact load should be considered. joined Schlumberger in 2006.  João Pedro lics, bit design, cuttings quality, stability Tocantins earned his Bachelors in Civil

OE: What future developments do you and vibration (S&V) and the need for Engineering from Pontifícia Universidade foresee in PDC bits with conical diamond more impact resistant cutters. The most Católica do Rio de Janeiro (PUC-Rio) and

Stinger element technology and its uses?

important knowledge gained from drill- his Post Graduate Diploma in Petroleum

Currently there is an ongoing project ing runs can be summarized as: Engineering from Pontifícia Universidade

Hydraulics: Maximize HSI Católica do Rio de Janeiro (PUC-Rio).

to investigate different uses of Stinger 052_0914_D&C2_presalt bits.indd 55 8/21/14 4:16 PM

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