This paper describes the successful use of eccentric tools to solve a variety of complex down hole problems associated with drilling through flowing salt formations in the Gulf of Suez. The tool allows simultaneous reaming and drilling with steerable assemblies (SRWD).
The SRWD technology was applied in two intervals on well A-19, East Zeit Bay Field, as insurance against hole problems caused on the previous wells by salt mobilization and saltwater flows. On well A-19, the operator had to decide either to drill with a large casing program or use the under reaming technology while still drilling an economic well. Additional problems involved drilling through large salt sections, possible saltwater flows, interbeded hard limestone/anhydrite sections and an aggressive directional wellbore design.
Without SRWD technology, the operator would have to drill a well using a large hole design, which was complicated due to the platform considerations, casing inventories available, and the higher costs associated with the increases of mud volumes, and decreased penetrations rates. The operator was able to steer the 14-inch SRWD tool to keep the wellbore on track at 38 degrees to the planned casing point. The lower 12–1/4" build section was drilled from 38 degrees to 67 degrees while turning the hole from an azimuth of 108 degrees to 123 degrees with no major problems associated with the SRWD tools.
The authors will discuss the optimization of the well design, the technology of the SRWD and the close cooperation between all the service companies required to help the operator drill the longest horizontal well in the Gulf of Suez without sacrificing cost per foot, and making a successful well.
Introduction
The East Zeit field, is located in the Gulf of Suez, Egypt, Figure 1. The company has operated the East Zeit field since 1996 and drilled two of the 19 wells (Figure 2) on the platform. The major geologic structures are the same throughout the Gulf of Suez with regards to the Kareem, Nukhul, and the Nubia formations as depicted in a generalized stratigraphic section, Figure 3. The majority of the production from the 19 wells is from the Nubia and Nukhul formations. The Kareem formation is productive in the area, but had not been drilled due to its limited economic potential near the platform. However, geological mapping indicated economic pay could be located southeast of the platform if drilled horizontally, Figure 4.
Challenges
The challenge was to drill a commercial horizontal well in the Kareem formation from the East Zeit A Platform starting the horizontal section 5000 ft away from the surface location. Drilling in the East Zeit area had been difficult due to platform constraints, lost circulation problems, saltwater flows, plastic formations, and hard interbeded formations. Additionally, due to the complex regional geology, the well design had to be flexible to allow for directional changes as the well was drilled. Drilling in the Gulf of Suez, Egypt presents operational challenges due to equipment availability and logistics.
