PDC bit hydraulics design, profile are key to reducing balling
- Univ. of California, Berkeley, CA (United States)
- Univ. of Tulsa, OK (United States)
Polycrystalline diamond compact (PDC) bits with a parabolic profile and bladed hydraulic design have a lesser tendency to ball during drilling of reactive shales. PDC bits with ribbed or open-face hydraulic designs and those with flat or rounded profiles tended to ball more often in the bit balling experiments conducted. Experimental work also indicates that PDC hydraulic design seems to have a greater influence on bit balling tendency compared to bit profile design. There are five main factors that affect bit balling: formation type, drilling fluid, drilling hydraulics, bit design, and confining pressures. An equation for specific energy showed that it could be used to describe the efficiency of the drilling process by examining the amount of energy spent in drilling a unit volume of rock. This concept of specific energy has been used herein to correlate with the parameter Rd, a parameter to quantify the degree of balling.
- OSTI ID:
- 415673
- Journal Information:
- Oil and Gas Journal, Vol. 94, Issue 50; Other Information: PBD: 9 Dec 1996
- Country of Publication:
- United States
- Language:
- English
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