Field results

Drilling basement rock

New, counterforce assisted XC-AST Reveal Hard Rock Potential with PDC Bits

Objective

The cost of hard rock drilling grows exponentially with depth. The exponent is the individual drill-bit footage. Tomax took on a full-scale drilling test to demonstrate what could be done to PDC performance when the self-excited axial vibrations in a stiff system are replaced by the controlled motions of a purpose-built regulator.

Results

A 6 ¾” XC-AST tool was made up in the BHA with a new, API class M333 PDC bit from Halliburton DBS. On bottom, the energy to drill, or Mechanical Specific Energy (MSE), was continuously monitored to look for wear and to compare against a reference run.

mse-vs-time

The new XC-AST produced a continuous ROP at 1.6 m/hr in South Scandinavian basement rock. There was no sign of wear from the MSE data.

Value

The PDC technology represents the most energy-efficient kind of drill-bits. When the risk from axial impact is eliminated, these bits can drill practically any rock.

Leached PDC cutters unharmed by the basement rock. The actual strength of each cutter is 20 times the rock. The only way these cutters fail is through impact or over-heating.

More images:

Tool

6 3/4” XC-AST

Country

Norway

Rig

Ullrigg

Section

8 ½”

BHA

PDC and AST

Time

November 2015

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