This paper covers the 7-year history of drilling-fluids application in a reservoir drilling campaign offshore Abu Dhabi, from the early use of a solids-free, brine-/water-based mud to the recent application of nondamaging, nonaqueous fluids (NAFs) with micronized acid-soluble ilmenite. The complete paper provides details about the integration of filter-cake breakers with various types of drilling fluids, from dormant drilling-fluid additives to delayed, pH- and temperature-activated breakers. The paper describes the steps taken to achieve these performance goals, including changes to the oil/water ratio (OWR), internal phase composition [heavier calcium briomide (CaBr2) instead of calcium chloride (CaCl2)], and a micronized, acid-soluble ilmenite as a weighting agent.
Development Highlights
A key objective for the offshore Abu Dhabi project was to drill longer horizontal 8½-in. intervals while retaining zero-skin completions.
