Modern Deepwater Site Investigation: Getting It Right the First Time

Abstract

Deepwater site investigation for petroleum production facilities requires much more than the simple one-boring approach that has been common at many continental shelf sites. Instead, because foundation-zone soil and geologic conditions found at many deepwater sites can be complex, a multi-phased approach that integrates and analyzes various geoscience and geotechnical data is required to optimize deepwater siting, geohazard risk assessment, and foundation design. This paper summarizes best practices for planning and executing a modern deepwater site investigation. The paper is based on our experience in carrying out various aspects of more than 100 deepwater site investigations over some 20 years. Although others have documented case histories illustrating specific deepwater site investigations, described various data acquisition tools, and discussed geohazards risk assessment in some detail, to our knowledge no generic, public summary exists that: 1) explains the numerous considerations and significance of each in planning and executing a deepwater site investigation; 2) describes the range and significance of geoscience and geotechnical components that can be required; 3) gives the generic phases and sequence of execution required to optimize the process; and 4) provides guidance on the cost and schedule time required to carry out a deepwater site investigation.The paper outlines a methodology for efficient, effective deepwater site investigation that is a useful explanation and guide for anyone responsible for this activity. The methodology will help operators optimize the planning and execution of deepwater site investigations, including geohazard risk assessments, and deliver results to project design teams in a timely manner. Unlike major operators, most independent operators and facilities designers/ constructors do not have site investigation and geohazard specialists on staff who are experts in the methodology presented. This paper is written principally for these organizations and provides them with a practical methodology for planning and executing effective deepwater site investigations.

Concept Stage Site Assessments, Deepwater Development Risks, and Long-Term Value Preservation: Why Getting it Right the First Time is More Important Than Ever

“…Skip critical steps in site characterization protocols such as that recommended by Campbell et al (2008) in the hope of saving time or money. Skip critical steps in site characterization protocols such as that recommended by Campbell et al (2008) in the hope of saving time or money.…”

“…Site investigation protocols such as that proposed by Campbell et al (2008) include a prescribed sequence of work in which each step makes use of information and conclusions from previous steps in order to maximize the value of the information. Concept stage investigations are necessary to properly specify and scope subsequent high-resolution geophysical and geotechnical data collection programs, as well as to inform activities such as field layout that might otherwise be conducted without the benefit of any geological or geotechnical information.…”

An Expert Panel Review of Geotechnical Site Investigation Regulations and Current Industry State of Practice

“…By conducting the work in phases (see Figure 1) as described by Campbell et al 4,5 , all data needed to define the potential subsurface variability and geohazard risks can be confidently acquired. By conducting the work in phases (see Figure 1) as described by Campbell et al 4,5 , all data needed to define the potential subsurface variability and geohazard risks can be confidently acquired.…”