SUBSEA PRODUCTION FOR WELLS DRILLED FROM JACKUP DRILLING UNITS

Abstract

Subsea production systems have been an accepted method of developing offshore oil and gas fields since the installation of the first subsea trees in the early 1960s offshore California. Generally subsea completions have been done from floating drilling vessels on wells with subsea wellhead equipment. A number of wells have been completed subsea by bottom supported jackup rigs on wells drilled using mudline suspension equipment. The subsea completion equipment and methods utilised to adapt mudline suspension wells for a subsea production tree are described. This method of completion offers important benefits as it allows completion of wildcat or delineation wells, it can be used in areas of small, scattered reservoirs, and it can be used in conjunction with floating production systems. The cost associated with these subsea completions is roughly equivalent to those of standard subsea completions from floating vessels. An overview of a typical completion system is presented and compared.