Halliburton has designed SentinelCem™ cement specifically to cure losses and enable further drilling. The solution is most applicable for severe-to-total losses that cannot be cured by particulate material additives. This cement system can be customized for low density to address situations where lost circulation is due to weak formations or having exceeded narrow pressure margins.
World Oil Awards 2014 Winner
"Best Drilling and Completions FLuids" Category
A unique property of SentinelCem cement is a thixotropic rheology that is shear-rate dependent: it remains fluid during pumping, begins to gel as pumping slows, gels quickly when pumping stops and can then regain fluidity multiple times, if and when needed, by applying shear. When the shear rate is high, the viscosity is low and the slurry flows easily for placement. Flow into formation openings reduces the shear rate. When the shear rate is reduced, as happens when it enters thief zones, the slurry thickens and gels, resisting slurry flow back, fall back or formation influx. This unique property of gaining early gel strength and compressive strength when the shear is reduced helps cure losses. The slurry will become liquid again, for a few cycles, if the shear is re-applied. The features such as thixotropy, bonding, and dynamic pumping time independent of temperature, increases the probability of curing the losses with this cement system. This solution helps manage operational costs by minimizing loss of fluids and allowing drilling to continue. Acid solubility enables optimally oriented perforations and stimulation treatments.
Lost circulation is a recurring, expensive challenge for the oil and gas industry. Losses range from seepage to complete; the financial impact involves non-productive time, remedial operations expenses, and material-replacement costs. Conventional solutions range from adjusting fluid rheology and pump rates to adding particulate materials to wellbore fluids; but these solutions do not always work and many severe-loss treatments have been designed on a trial-and-error basis.
SentinelCem cement is proven to help cure losses successfully, particularly severe losses.