Prehydrating High-strength Microspheres in Lightweight Cement Slurry Creates Value for Offshore Malaysian Operator

Abstract

Abstract Casing cementation across depleted reservoirs can be challenging because conventionally weighted cement slurries can induce losses and damage the permeability of formations caused by the higher associated hydrostatic pressure they exert on the wellbore. Therefore, when such pressure-related concerns exist, lighter-weight cement slurries are often preferred. For an offshore Malaysia operator, a lightweight cement slurry was proposed to reduce hydrostatic pressure and prevent losses and formation damage. However, instead of a water-extended lightweight cement slurry, a high-performance, lightweight (HPLW) cement slurry consisting of high-strength, hollow microspheres was designed. Special bulk blending and transportation are normally required for these HPLW slurries because of the large bulk volume and low specific gravity (SG) of high-strength, hollow microspheres. In this case, because of limitations related to the rig’s storage capacity, the microspheres could not be stored conventionally and used as a dry additive to the slurry during mixing. Instead, an alternative solution involving prehydrating the high-strength microspheres with liquid additives and mix water in the mixing pits was implemented. This paper discusses the procedures used during cementing operations and details the value of using this mixing method.