Low-Temperature Dispersant Improves Cement Slurry Properties in Deepwater Operations | Schlumberger
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Gulf of Mexico, United States, North America
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Low-Temperature Dispersant Improves Cement Slurry Properties in Deepwater Operations


The cementation of tophole sections in deepwater operations is very challenging due to the conditions in which those jobs take place. Tophole sections in deepwater operations often have a narrow margin between the pore and fracture gradients and shallow hazards, such as gas or water flow, associated with them. The low temperature found at seabed results in high fluid viscosities, slow gel strength development, and delayed early compressive strength development of the slurry. To optimize the low-temperature slurries currently used, a novel low-temperature dispersant was developed that enables designing the slurry to meet the required properties. The new dispersant has several main benefits in slurry design and properties. The dispersant enables the slurry to develop faster gel strength and has no retarding effect compared to conventional dispersants. The new dispersant will provide a flat rheology over time, allowing better control of the circulating pressures during placement. Laboratory tests show less gelation and an improvement in static gel strength development as compared to current dispersants. The dispersant also provides better rheological properties, often at lower concentrations, thereby facilitating a simplified slurry design. Following laboratory testing, the low-temperature dispersant was introduced in Gulf of Mexico operations with very good results. Operationally, the dispersant is easy to handle. It is compatible with all typical cementing additives and can be used with conventional cementing equipment and liquid additive systems. The low-temperature dispersant has been used in various types of deepwater slurries such as lightweight, conventional, and foamed slurry system, using drill water or seawater as the base fluid, often requiring less concentration and improving key slurry properties to achieve successful cementing operations in challenging low-temperature conditions.

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