Deepwater Pipelines: East Break Area, Offshore Texas

ABSTRACT Union Oil Company of California recently installed 27 miles of deepwater pipelines in the East Breaks Area, Offshore, Texas. The 6", 8" and 10" pipelines were laid in water depths of 200–1000 ft. These lines are a combination of rigid and flexible pipe and will transport crude oil and natural gas. This paper provides an overview of the project with discussion on the feasibility study, engineering and design, installation and support equipment, and the procedures implemented. INTRODUCTION Union Oil Company of California and its co-owners, Amoco Production Company and Mobil Producing Texas and New Mexico, became involved in the East Breaks Area with the acquisition of federal leases in 1974. The four blocks are located about 100 miles south of Galveston, Texas (Figure 1). Exploratory drilling began in 1975 and by 1978 several wells proved adequate reserves to justify the high cost of field development. Construction of the first platform, Cerveza, began in the fall of 1979. The single piece jacket was installed in East Breaks Block 160 in the summer of 1981 in 935 ft. of water. In 1982, the second platform needed for field developement, Cerveza Ligera, was installed in East Breaks Block 159 in 925 ft. of water. The results of initial well completions warranted full gas and oil processing on both platforms. Production estimates for the field are 100 MMCFD of gas and 12000 BPD of oil. Plans were made for a crude oil pipeline to be laid into the High Island Area to connect with an existing line. Plans for a gas sales pipeline are still pending. Infield flowlines between the two platforms were required to transport oil and gas to the departing sales pipelines. Drilling and production schedules for the field warranted installation of three pipelines during the same time period. Initial plans and cost estimates called for a total of 27 miles of 6", 8", and 10" pipe to be laid for approximately $25.5 million. TASKS AND ENGINEERING The first phase of pipeline installations in the East Breaks Field involved a means of transporting the crude oil from both platforms to an existing platform in the High Island Area. In the arly stages of planning, a decision was made to run a 10" crude oil pipeline from East Breaks 160A platform (EB 160A) to High Island A-536C platform (HI 536C). This platform is producing oil and shipping into a 10" pipeline that is a segment of the High Island Pipeline System (HIPS)