The Study on the Limit Extended Capacity for an Extended Reach Well

The limit extended capability is one of the key parameters in drilling design and drilling operation for an extended reach well, but people often overlook it. The study on this aspect is still rare at present. According to the practical drilling condition in extended reach well, the interstice element theory for the friction analysis of whole drill string was applied in building judging criteria and calculation model of the limit extended capability for an extended reach well in this paper. The established computer software for calculating the limit extended capability was used to calculate and analyze the influencing factors on the limit extended capability. We found out the main influencing factors and made an important conclusion that if it is considered from the degree of the influence on limit extended capability, the friction coefficient ranks first, the hole curvature ranks second, the threshold bit weight ranks third, and the rotary speed is the last one. This study provides a theory basis for the future drilling design and drilling operation in extended reach well.