SS - Visualization and Collaboration: Keys to Optimal Platform Placement
Authors: Cristancho Jairo Hernando , Peters Ron , Denham Waitus W. , Algu Devendra , Daley Paul , Njoku Chinonyerem 
Published: July 2010

Determining the optimal location for a new platform in offshore deepwater environments is one of the more challenging and complex exercises that an operator must negotiate. Engaging multidisciplined stakeholders, who often have disparate objectives or constraints in determining an ideal site location, can easily become a time-consuming and inefficient process.

To be effective, numerous scenarios must be modeled in a rigorous and efficient manner to determine the optimal location. For one such complex task, Shell elected to use the latest technologies in well planning and visualization. To ensure a successful project, the definitive solution needed to accelerate the well planning process while considering information from all necessary disciplines.

This project had its own particular set of challenges, including abundant hazards and obstacles lying on the seafloor, a complex salt body to be avoided, and a wide range and uncertainty of geological targets. All of these challenges were modeled in a visualization system composed of surface maps, geological targets, and geophysical data. Upon completion of the initial model, a collaborative well planning session enabled a quick evaluation of the risks and drivers observed by each discipline. This process led to an understanding across disciplines of the dependent activities that must occur in the correct order, which established the work scope and avoided unnecessary tasks.

After this initial meeting, four possible locations were proposed. Using the 3D visualization and well planning software, each proposed surface location was then planned to reach the pre-defined targets. The plans were later statistically analyzed to show the drillability of each location and reviewed by the team. Using the same model and constraints, multiple iterations generated and optimized new plans to a series of updated targets. Approximately 400 potential wellpaths were considered and risked across several scenarios until the final location was determined.

This paper describes the procedure used to determine the optimal surface location for the platform using a 3D visualization and well planning application. This application is intended for all personnel (including drilling, completions, and geological and geophysical disciplines) involved in the well planning process and field development projects.

Introduction

The area described in this paper refers to a multi-block location in the Gulf of Mexico that the operator discovered in the mid- 1980s and that has been in production since the early 1990s. Most of the development wells were drilled using a 24-slot tension leg platform (TLP), which has been in service for more than 10 years.

In recent years, newer prospects have been identified within the field that have either been impossible to reach from the existing platform rig or that have pushed the existing rig capability to its limits, resulting in the need to drill expensive and difficult extended reach wells. This scenario, combined with the lack of available slots on the platform, makes the planning and development of future prospects prohibitive in the short and medium term. In addition, continued exploration has shown that the field still holds a significant amount of reserves, and because of a strong desire to extend the overall field life, it has become obvious that new infrastructure must be built in the field to meet these objectives.

With this scenario in mind, the operator formed an experienced team comprising geologists, geophysicists, and drilling and completions engineers, who were assigned the task of designing a new platform development. Each discipline had its own set of data, constraints, and concerns. Challenges from various perspectives were examined, including shallow hazards, seabed faulting, seafloor hazards, existing infrastructure, existing subsea wells, and how to access the extended reach geological targets.