Cement-Slurry Design To Prevent Destabilization of Hydrates in Deepwater Environment

Abstract

Hydrates present challenges to drilling, cementing, and producing in deepwater environments. If the hydrates are destabilized during well operations, gas or solids could rise to the surface and create problems. Therefore, there is a compelling need to prevent destabilization of hydrates from drilling to producing operations in the life of the well.The volume of cement slurry in the surface casing is great because of the large annulus, and this slurry volume results in a great amount of heat generated during slurry hydration. Further, during production, hydrocarbons could increase the temperature of the surrounding formation. These factors could destabilize the hydrates.Cement slurries are designed to lower the heat of hydration while meeting or exceeding the other properties needed for successful deepwater cementing. Heat of hydration is reduced by a factor of more than two when compared to the conventional cement-slurry design. The improved cement-slurry designs lower considerably the thermal conductivity of the set cement sheath.Laboratory tests designed to measure and optimize the heat of hydration are discussed and field implementation of these slurries and results are presented. Results presented in this paper should help the industry construct and produce wells without destabilizing the hydrates, thus, promoting well safety and economics.

Investigation of the Hydraulic Integrity of Cement Plug: Oilwell Cementitious Materials

“…It is suspected that the slurry volume plays a major role in how the cementitious material cures, thereby influencing its shrinkage and bonding with the casing. Slurries of different volumes may also cure slightly differently, this is because the amount of heat generated during the hydration of larger volumes of slurry is higher than that in smaller volumes (Ravi et al, 2009). There is also a need to point out that temperature influences the hydration kinetics and early-age shrinkage of cementitious materials (Elkhadiri et al, 2009;Lura et al, 2001;Maltais and Marchand, 1997).…”

Heat Control Effect of Phase Change Microcapsules upon Cement Slurry Applied to Hydrate-Bearing Sediment

“…In this section, the effects of MPCM-1, low-heat inorganic materials, and as-purchased microcapsules upon the comprehensive properties of cement stone are studied. As GHBS is soft and the pressure window between fracture and formation-pore pressure gradients is narrow, a low-density cement slurry system is usually used to cement the well to prevent loss of circulation [45][46][47]. As shown in Table 5, the reduction effect of MPCM-1 upon the initial density of cement slurry was more notable than other low-heat materials.…”

Study on preparation and properties of polyurethane modified epoxy resin lotion cementing slurry

“…have already become important energy reserve areas in China (Wang et al 2011, Wang et al 2009, Luo et al 2017, Bu et al 2020. However, the complexity of the deepwater environment, especially the brittle failure of the cement sheath and the sinking of the wellhead (Ravi et al 2009), has brought huge challenges to the exploration and production of deepwater resources (Lv et al 2021, Tian et al 2022, Zheng (2023). This is because the deep-water and shallow strata are very fragile and mostly composed of loose sandstone structures (Wang et al 2023), which can extend several hundred meters below the mud line, easily reducing the bonding quality between the cementing interface and the well.…”