Centralization of casings in wells

Abstract

Centralization of casings is very important in order to ensure a high quality well. Poor centralization of casing is often the main reason for bad cement jobs, which forces the operators to perform remedial cementing. This increases the costs and delays the completion of wells. By ensuring proper spacing between centralizers, a good primary cement job can be achieved. The “do it right the first time” principle cannot be stressed enough. This thesis focus on the use of the OptiCem™ module included in the WELLPLAN™ software. The module have been used to do simulations on proper distribution of centralizers along the casing in order to achieve good standoff values. Several well profiles have been investigated, as well as the DLS’, radius’ and casing-weight’s effect on centralizer density. Results of the simulations shows that distribution rates from 1,5-3 centralizers per 100 ft. of casing is sufficient in order to meet the industrial standoff requirement of 70%. This coincides well with today’s current practice.