Abstract
Cementing technologies have advanced incrementally since the practice began in the early 1900's.While additives have been developed to meet specific downhole conditions and goals, the process by which cement is mixed has remained essentially unchanged beyond the initial development of mix-ing equipment specifically designed for oilfield operations.Equipment designed for "on the fly" mixing of dry cement on location has evolved and technological developments such as computer control have improved mixing factors such as den-sity control.However, the goal of delivering a homogenous slurry throughout the job has a finite limit when mixing on the fly no matter how much the mixing equipment is upgraded and is technology assisted.
Batch mixing cement is a commonly used method to average out slurry inconsistencies inherent to on the fly mixing opera-tions.Once mixed, however, the batch mixed cement must be placed immediately because the hydration process has begun and does not allow time to perform slurry performance testing to verify slurry properties and make adjustments.
Recent developments in cement technology have made it pos-sible to mix cement and keep it in a liquid state for extended periods of time.This means that the actual slurry to be pumped downhole can be mixed, tested and adjusted to meet the specific needs of the well.As reservoirs become depleted and exploration in increasingly more hostile environments at the surface and below becomes common, the delivery of a homogenous slurry to meet these conditions becomes a critical factor in the success of a well.
The chemical and mechanical processes involved to inhibit hydration have been described in the literature.[1,2,3] Using case studies, this paper illustrates how this technology has been applied in the Mid-Continent U.S.
