西南石油大学学报(自然科学版)

Previous Articles     Next Articles

Study on the Tooth Invasion Coefficient of Cone Bit and Penetration Rate
in Under-balance Drilling

Li Wei, Xu Xinghua, Yan Tie, Bi Xueliang   

  1. Li Wei, Xu Xinghua, Yan Tie, Bi Xueliang
  • Online:2013-06-01 Published:2013-06-01

Abstract:

The penetration rate rises rapidly in the under-balanced condition,but the intrusion mechanism of cone bit is unclear.
Based on rock intrusive theory and tasking the condition of under-balanced drilling into consideration,we explore intruding
rock and breaking rock of cone bit the intrusive coefficient equation of cone bit was derived,and the drilling rate model in the
condition of under-balanced drilling was built. The rock intrusive coefficient is a basic parameter which describes the intrusionresistant
ability of rock,which is not affected by tooth load and invasion depth. Taking Xushen Gas Field as an example,we
make theoretical analysis of the impact of angle of internal friction and bit angle on intrusive coefficient and penetration rate.
And the experiment results show that with the increase of effective normal stress of down-hole,and the increase of angle of
internal friction and bit angle,the intrusive coefficient increases;with the increase of effective normal stress,the penetration
rate decreases obviously,and with the increase of angle of internal friction and bit angle,the penetration rate decreases linearly

Key words: under-balance, under-balanced drilling, cone bit, intrusive coefficient, rock breaking mechanism