Foam Cementing Controls Deepwater Shallow Flow in the East Mediterranean

Abstract

Abstract Deepwater drilling, though relatively new in the Nile Delta region of the Eastern Mediterranean, has increased operating water depths to over 4,000 ft within a year from a record depth of 1,900 ft in the fall of 1999. The deepwater extension of the ancient Nile delta has been divided into six major operating licenses granted by the Egyptian government. This paper will primarily focus on the knowledge gained from experience by Rashpetco (JV between BG, Edison and Egyptian General Petroleum Company) in the West Delta Deep Marine (WDDM) development block (Fig. 1). The WDDM is no exception to the common challenges encountered in deepwater projects around the world, including shallow gas and waterflow hazards.1,2 The obvious consequence of an unexpected shallow fluid flow is an uncontrolled blowout situation with no drilling-control equipment in place. In some reported cases, even after the flow was controlled prior to running casing, fluid flow occurred after cementing the surface pipe. To date, the shallow flows witnessed in the WDDM have not resulted in any severe loss of capital, unlike other areas where the loss of wells and templates has occurred.3,4 Nor have shallow flows in the WDDM caused a safety threat to environment, personnel, or equipment; however, in some instances, they may have contributed to non-productive time in drilling operations. Nevertheless, efforts have been made to understand the flow mechanism and control these occurrences by developing shallow flow-control contingency plans and designing cement slurries suited to the challenges of deepwater cementing. Foam cement and other lightweight, high-strength cement slurries have been used to balance cement slurry weight between the low margins of the fracture gradients and the flow potentials of the drilled section. Foam cementing especially has been effective in many cases. This paper provides case histories in the control of unexpected shallow water flows and discusses the suitability of foam cement technology in deepwater situations.