Novel Cohesive Cement Sealant System

This paper documents development of a unique sealant that has strong cohesive properties. The cohesive nature of this system allows it to stay together as a complete fluid without being diluted by the fluids surrounding it. This is accomplished through a combination of stimulation and cementing chemicals and techniques. The properties of this cohesive sealant are applicable for lightweight system stability, plug and abandonment cement plug cohesiveness, balanced plug stability, and situations where the sealant must migrate through another fluid before it sets. This fluid is particularly useful in applications requiring a lightweight sealant to float above another fluid. Traditional lightweight cement systems will disperse, allowing their particulates to separate from the system. The cohesive system developed is capable of holding its particulates in the system. In addition, this system develops higher compressive strengths than traditional lightweight systems. The cohesive cement system was originally designed to be injected into a brine filled cavern, rise through the brine, and seal the top of the cavern. This was the reasoning for the cohesive nature of the system, its low density, and its high strength. The cohesive system was successful for this field application. The novelty of this system spurred further developments including expanded density ranges and mechanical property improvements, thereby broadening the range of utility for this system.