Analysis of BHA mechanical behavior of window cutting of herringbone multilateral wells

In the process of herringbone multilateral window cutting, BHA mechanical behavior in the bottom hole exerts direct effect on the trajectory shape of the branch hole. Improper control of the branch hole trajectory will be difficult to ensure the trajectory to go through the reservoir effectively, thereby will decrease the output of herringbone multilateral wells, the quality of the branch hole window will affect the safety of original hole completion string’s trip in the original hole. This paper establishes the finite element model of BHA of fishbone multilateral well window cutting, analyses BHA mechanical behavior of window cutting, calculates build-up ability of BHA, analyses the affect of BHA structure and TFO (tool face orientation) on the angle build-up ability. The application in XinJiang Oilfield shows that the calculating rate of build-up of fishbone multilateral well window cutting accords with the result of actual drilling, the error is less than 13%. The research lays sound basis for trajectory control of fish bone multilateral well window cutting.