| This paper mainly investigates the applicability of PDC bit in Futai Oilfield of Shengli exploratory region.On the basis of collection and tests of geological information, rock sample and drilling information, this paper carries out research and analysis about the formation drilling features of Futai Oilfield as well as the PDC bit design theory such as crown profile, cutting structure, hydraulic structure and stability etc. Rock failure mechanism is analyzed through lab tests of mini diamond bit, providing basic data ant theoretical support for bit design. PDC bit crown profile, consisting of single circular arc parabola profile or dual cone profile with deeper inner taper is introduced. Cutter arrangement for various bits is determined. The bit is improved by the application of hybrid cutting structure and detailed analysis of hydraulic structure. Simultaneously, bit stability is enhanced using multiple bit stable structure design techniques such as deep inner taper, force balance and hybrid cutter arrangement etc.Based on the field tests and the theoretical research, a new PDCbit is developed. Compared with the roller cone bit at the same interval of the same area, the new bit shows significant economical and social benefits by an increase of 290% for average footage and a rise of 77.8% for average ROP. |
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