Optimization of Deepwater Template Drilling

Abstract

This paper describes the methods and technologies employed during the drilling of the Jolliet Development wells. The Jolliet development wells were drilled from a subsea drilling template in water depth of 1760 feet. INTRODUCTION The field is currently producing from the first Tension Leg Well Platform (TLWP) in the Gulf of Mexico which was installed after completion of the drilling phase. Jolliet development drilling operations were conducted between July 1987 and May 1989 after installation of the drilling template. The drilling performance attained on this project was outstanding when compared with other wells drilled in this type of frontier environment. This paper presents an overview of the methods and equipment used to optimize deepwater drilling from a template and therefore ultimately realize substantial savings. Key elements of the successful Jolliet drilling program were a result of THOROUGH PRE-PLANNING through superior teamwork between operations and engineering personnel and the inclusion of state of the art. The detailed drilling rig specification, steerabledirectional drilling motors, MWD tools with downhole torque and bit weight capabilities, development of an All oil Mud System utilizing LVT base oil, implementation ofimproved hole cleaning techniques areindicative of the detailed approach taken throughout the drilling program. Personal computing capabilities played a major part in the ability to thoroughly analyze and optimize drilling. Each of these elements were continually fine tuned and adjusted through a detailed system of concurrent critique. TEAM ORGANIZATION The Jolliet drilling team was formed well in advance of drilling template installation. Personnel from many different departments within the company were pulled together to form the team. Company management made a committment to ensure that the expertise ofindividuals within the company was utilized to the fullest. The team was organized with a central point of focus around the DrillingSupervisor. All planning and optimization was funnelled to and from the DrillingSupervisor for implementation as illustrated in Figure 1. PROJECT OBJECTIVES The first step in assurance of a successful drilling program was to clearly define the MISSION of the drilling team and the program. Clear and concise objectives were defined. Safety From the outset safety was identified ag the team's most important priority. The safety of the drilling operation and all team members was considered first when planning and executing all operations. Protection of the environment and compliance with governmental regulations were addressed and included within the umbrella of the "Safety Objective". Well Productivity Maximum well productivity, as a result of minimum exposure to formation damage during drilling operations, was considered paramount. Drilling practices as well as the mud system and additives were closely scrutinized to ensure minimum formation damage. Primary cementation Good primary cement jobs were identified as an absolute requirement for the efficient depletion of the Jolliet reservoirs. Primary cementation techniques were fined tuned for integration with subsea wellheads. This of course resulted in a minimum requirement for remedial cement jobs both during and after drilling operations.