Direct XCD Drillable Alloy Casing Bit | Schlumberger

Direct XCD

Drillable alloy casing bit

Construct vertical wells while casing in one run

The Direct XCD drillable alloy casing bit is specially designed for drilling vertical or tangential wells to TD in one run. This PDC bit drills on standard casing that is rotated at the surface.

Eliminate dedicated drillout runs

The bit’s sub is composed of durable oilfield-grade steel, and its body is a copper bronze alloy. This unique composition allows it to be drilled out by any standard PDC bit after the Direct XCD casing bit has drilled to TD and the casing has been cemented. After drillout, the drillout PDC bit can continue drilling the next interval, eliminating the need for a dedicated drillout run.

The cutting structure of the Direct XCD casing bit can be fitted with 13-, 16-, or 19-mm PDC cutters, which are available in standard or premium grades.

TDDirect casing-drilling and liner-drilling technology
The bit’s sub is composed of durable oilfield-grade steel, and its body is made of a copper bronze alloy. This unique alloy allows it to be drilled out by any standard PDC bit after the Direct XCD bit has drilled to TD and the casing has been cemented in place.
TDDirect casing-drilling and liner-drilling technology
Drilling with conventional drillpipe (left) allows a larger annulus, while drilling with casing (right) minimizes annulus size; rotating casing smears cuttings into the borehole wall, sealing pores in the formation to reduce fluid losses and producing a stronger borehole for improved cementing.

Increase wellbore strength

Drilling with the Direct XCD casing bit smears cuttings into the borehole wall, resulting in an action termed the plastering effect, which strengthens wellbores for improved cementing. The plastering effect process has proved to reduce NPT resulting from borehole-related problems, such as

  • sloughing shales

  • tight holes

  • borehole bridges

  • lost circulation

  • large-diameter surface hole resulting in hard-to-remove cuttings from the annulus

  • damaged producing zones

  • stuck pipe.

In a field case, lost circulation resulted in two unsuccessful attempts to reach bottom using conventional drillstrings. On the third attempt, the operator used a Direct XCD casing bit. Its signature plastering effect eliminated lost circulation issues and produced a high-quality wellbore.

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