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A field method for assessing borehole friction for directional well casing

1988; Elsevier BV; Volume: 1; Issue: 4 Linguagem: Inglês

10.1016/0920-4105(88)90007-1

1873-4715

Eric Maidla, Andrew K. Wojtanowicz,

Hydraulic Fracturing and Reservoir Analysis

A field procedure to evaluate the borehole friction factor between a pipe string and a borehole was developed. The primary concern of this research was to investigate and mathematically describe the drag associated with casing runs in directional wells through the use of the two-dimensional approach. The borehole friction factor was found, through an iterative procedure, by matching the calculated hook load to the measured one at the surface. The borehole friction factor was calculated as the unique value for the match. This study shows the necessary precision requirements for the hook load measurement instrumentation and presents three different types of equipment that meet accuracy demands. The significance of the mechanical friction effect on hook load was also addressed, by introducing the drag-weight ratio concept. It was found out that to assure accuracy of the method, the minimum required value of the drag-weight ratio should be 25%. The statistical analysis revealed that one single value of the borehole friction factor can represent the well. It was concluded in the study that the model can be used for prediction of tensional load of a casing string in a directional well.