Novel Cementing Technology for Deepwater Hydrate Layer

Methane Hydrates is an ice-like crystalline substance formed by methane and water under high pressure and low temperature environment. Each 1 unit methane hydrates contains about 170 units (converted in standard conditions) of methane gas. The low temperature and high pressure environment in deep water leads to the existence of hydrate layer in the shallow formation, which poses a significant challenge to cementing. The conventional cement slurry systems have limitations when applied in such well condition, since the heat of hydration during cement setting is high and there is a high risk of gas liberation from methane hydrates, easily causing severe well security issues. The low temperature environment, unconsolidated formation and narrow safety window also increased the complexity of the cementing jobs by a high performance requirement of the cement slurry. A low hydration heat cement slurry and an indoor cementing simulation evaluation method were developed in order to ensure effective isolation of the hydrate layer. This paper will describe in detail about the cement slurry development, performance and evaluation process in the lab with a novel method in the industry. This technology was proven as a solution for deep water hydrate layer well cementing, which is a great reference for cementing industry.