Five Years Experience Deepwater Drilling
Authors: Hammett Dillard S. 
Published: December 2007

This paper presents the past, present and future of deepwater exploration drilling (600 to 8,000'). Specifically presented are the technical achievements that were necessary to move beyond 600' water depths and to provide the capability to drill in 8,000' of water. Also presented are several examples of these technical achievements which have been experienced by operating exploration drilling units in the deepwater environment during the past 5 years.

Introduction

The trend in offshore exploration clearly shows that the industry will and can move to deeper water environments to drill and explore for oil and gas (Figure 1). Records show that it took the industry 20 years to move floating drilling from 100' water depths to 1,300', yet in the past 5 years we have extended the water depth an additional 2,200', from 1,300' to 3,500'. We have now drilled more than 160 exploration wells in the water depths of 600' to 3,500'. The future indicates we will be drilling in over 4,000' water depths this year and 8,000' by 1980.

PAST PAST Floating drilling started in the period from 1953 to 1956 in water depths of 100 to 300' utilizing converted ship hulls and subsea systems. SUBMAREX and CUSS I were the first two units and were closely followed by WODECO I in 1958 and NOLA III in 1959. In 1961, the first semi-submersible designed for rougher water, BLUEWATER I, went into operation followed by OCEAN DRILLER in 1963. Coring (one bit run holes) was conducted in 11,672' of water from the CUSS I (temporarily equipped with dynamic stationing equipment) in 1961 for the purpose of coring the earth's crust. In 1962, the EUREKA and in 1964 the CALDRILL dynamically stationed vessels were put in service for the specific purpose of coring the ocean floor, searching for oil purpose of coring the ocean floor, searching for oil and gas reserves. In 1969, the GLOMAR CHALLENGER started a worldwide coring survey of the ocean floor in water depths up to 20,000' for earth crust research.

The world's oceans have challenged man's imagination, fortitude and technological capabilities for centuries on end, dating back to the days of Columbus, Magellan and including more recently highly sophisticated operations such as the GLOMAR CHALLENGER project.

These challenges for the most part have posed grave danger but man has invariably prevailed to reap rewards of the oceans, potential of which even today has not been fully evaluated.

Engineers who have built careers around designing bridges, buildings and dams have found that the world's oceans offer many more challenges and rewards.

Technology of drilling a hole and the equipment needed to drill a hole has been perfected for inland operations for the past 70 years. This same technology and equipment has for the past 25 years been extended offshore. First on small platforms, then on barges, jackups and mobile platforms.

As water depths increased, floating drilling became necessary. This required three major technological extensions of knowhow and innovation. These include:

Motion. The rig no longer has bottomsupport. Mooring. The floating unit must be held against environments. Subsea. The blowout preventer is now below water.

In the years 1953 through 1964, the oil industry was developing the technology and equipment to work from floating vessels while drilling exploration wells. All of the above major technological extensions required many hours of engineering, new types of equipment, and years of operating experience to achieve the confidence of the oil industry that exploration from floating drilling was safe and practical. These advances are now routine.

Motion. We continue drilling operations in 40' waves and 60 knot winds. Mooring. We have drilled successfully in 3,500' water depths and have stayed on location in 92' waves and 100 knot winds.