Investigation of Hook Load Behavior while Tripping Through Tight Wellbores

Abstract

Recognizing different HKL response patterns while tripping through different restrictions in the well can be a huge advantage in the sense that it can reduce downtime and stuck pipe incidents as it allows for right means of removing the restriction.

There can be different reasons for restriction of moving the drillstring in the wellbore. In this thesis restrictions are divided into keyseat, dogleg, borehole closure and ledges. Mathematical and physical HKL response models are presented for the 3 latter restrictions. For ledges and borehole closure, type curve models are presented. For tripping through a dogleg a stiff string model was derived based on deflection of steel beams.

Field data from a well was evaluated with the use of the presented restriction models. The HKL response from tripping through the doglegs in the well was calculated, and different HKL abnormalities were identified with the different restriction models.

Several over-pulls and took weights were identified with ledge type curve, which can be confirmed from lithology and comparison of HKL response for other runs at the same depth. Generally the doglegs in this well did not cause major overpulls or took weight as a result of the overall extra friction created in doglegs. Tripping through doglegs, does however causes, abnormal HKL response in relation to keyseating as a result of the string tension that is pulling the drillstring towards the borehole wall