Session 1 - Oral 14
Design of Well Cement Slurry System for Shallow-Hydrate under Deep Water：The Development and Application of New Energy Storage Microspheres
Meihua HUO，Huajie LIU，Hui YIN，Yuhuan BU，Rui MA
School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, PR China
Abstract：Deep-water shallow formations are characterized by low temperature, high pressure and low fracture pressure, and are often associated with natural gas hydrates. In deep-water cementing, the stability of natural gas hydrate is destroyed due to heat release from hydration of cement slurry and temperature rise around well bore. The decomposition of substances destroys the cementing quality between cement ring and formation. Therefore, how to reduce the low hydration heat release without affecting the performance of cement is one of the keys of deep water cementing technology.
The design of low hydration exothermic oil well cement slurry mainly includes three steps. Firstly, design and develop high strength hollow microspheres and test their effect on cement slurry performance. Secondly, apply high strength hollow microspheres to paraffin encapsulation to form energy storage microspheres. Finally, the influence of energy storage microspheres (ESM) on the hydration heat release performance of cement was tested, and the influence of ESM on the strength and other basic properties of cement (density, settlement stability, rheology, etc.) was evaluated.
The results show high-strength metakaolin-based hollow microspheres has strong liquid absorption capacity in cement slurry, its shell has large pores and stable liquid absorption capacity. Porous hollow ceramic microspheres show excellent adsorption capacity, which can adsorb additives to the inner hollow of microspheres. The new microspheres can carry both hydrophobic and hydrophilic materials. Energy storage microspheres can be prepared by adsorbing paraffin. Energy storage microspheres can significantly reduce the hydration heat release of oil well cement, and have no negative impact on the density and settlement stability of cement. Furthermore, the properties of energy storage microsphere cement could be improved by optimizing additives.
In this paper, a cementing slurry with good early strength and low hydration heat dissipation was developed by adding energy storage microspheres and optimizing additives, which can be used for cementing gas hydrate reservoirs in deep water.
Keywords：well cement slurry; low hydration exothermic; natural gas hydrate reservoir; Deep Water; Energy Storage Microsphere.