Paper: IMPROVING CEMENT BOND WITH A FORMULATED SILICATE PREFLUSH

A high quality cement bond between casing and wellbore is an environmental and economic imperative for the duration of a well. A strong cement bond provides zonal isolation and prevents gas migration, gas entrapment and excessive water production. The growing public concern about possible gas migration to fresh water or to the atmosphere has further highlighted the importance of achieving the best possible cement bond. A chemical preflush prior to primary cementing is an inexpensive and effective method to help ensure a quality primary cement job. Ideally, the chemical preflush should be multi-functional and not only remove drilling fluid residue but also provide other features such as: improve fluid loss control, improve water wetting of surfaces prior to cementing, and prevent or aid in the prevention of cement fallback. To achieve all these features, it is common practice to run a sequence or blend of chemicals to adequately prepare the wellbore for cementing. This paper discusses a single-component product built on sodium silicate that can provide all of the aforementioned benefits. Specific focus is directed towards the interactions between surfactants and sodium silicate in a flush