Today operators are forced to drill in increasingly challenging environments in an effort to meet a growing global demand for petroleum products. In Mexico, meeting this challenge requires more skills and innovative materials from oilwell cementing providers. Nowhere else in the world are the cementing requirements more difficult than those presented by Cantarell and other depleted zones and weaker formations present in Mexico. New ultra-light foamed cementing technology enables successful circulation and an effective seal, which can have a great impact on not only the cost of drilling a well, but on the productive life of the well. In addition to the easily quantified benefits from reduced water production, reduced remedial costs, decreased drilling days and increased hydrocarbon production, additional profitability stems from the more difficult to quantify areas such as delays in production delivery and early water production.
Traditionally, the lower limit for oilwell cementing has been 7.5 to 8.5 lb/gal. When the density of the cement slurry was reduced down to these light weights, it was still not low enough and the industry had to live with losses or attempt multi-stage cement jobs. In Cantarell, where a 7.3-lb/gal cement job was once attempted, these slurries were not light enough. Recent developments in ultra-light foam technologies have allowed the successful application of production quality foam cements delivered at downhole densities as low as 5 lb/gal.
This paper presents case histories from Mexican wells, which show how this ultra-lightweight foamed cement slurry technology was used to decrease costs and increase production, yielding more profitable wells for the operator.