Review of Cementing Challenges in the WDDM Concession

By

 Arshad Waheed¹, Tarek Wahdan²

(1) Halliburton, Egypt, Cairo, Egypt (2) Rashpetco, Cairo, Egypt

 The WDDM is no exception to the challenge of shallow gas and water flow hazard seen in many of the deepwater projects worldwide. 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 loss of well, loss of template has been reported. Nor have shallow flows caused a safety threat to environment, personnel or equipment but in some instances contributed to non-productive time in the drilling operations. Nevertheless, efforts have been made to understand the flow mechanism and control these occurrences by having a shallow flow control contingency plan and designing cement slurries suitable for deepwater cementing challenges. 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 has particularly been effective in many cases except on one occasion. Flow control techniques such as using weighted mud to kill the well has also been tried for long term flow protection. This paper provides case histories in using foam cement to prevent losses while cementing low fracture gradient formation as well as controlling shallow water flows that were encountered unexpectedly.