Geotechnical Engineering


GEMS performs geotechnical engineering for the offshore oil and gas worldwide. Our client base include all the Majors and the Independents, and the many service companies worldwide. In continued growth since the inception as geoscience consultants in 1997, we began offering the geotechnical engineering services in 2002. We take great pride in providing sound, effective and efficient engineering solutions across all offshore geotechnical areas. We specialize in an integrated (geophysical and geotechnical) approach to the engineering-of-the-seabed. We work closely with our clients throughout  a project, whether it be Concept, Pre-FEED, FEED or Detailed Design phase. To date, we have participated, contributed and or completed over 500 projects across many geographical locations worldwide.

Primary areas of services:

  • Site Investigation
  • Site Characterization
  • Geotechnical Analysis and Design
  • Other Services

Site Investigations and Project Management

Our engineers have extensive experience with planning and managing geotechnical site investigations for both shallow and deepwater locations involving some of the most complex soil conditions. Our team uses all available data to optimize the scope of geotechnical data acquisition and laboratory testing. Our team has  completed typical offshore/industry certifications and trainings such as TWIC, HUET, SafeGulf, RigPass, UKOOA, etc.

  • Professional project management and contract services
  • Planning field investigations and sampling/testing programs
    • Sampling methods: soil boring, jumbo piston core (JPC), piston core (PC), box core (BC), gravity core (GC) and In situ testing methods: cone penetration testing (CPT), field vane (FV) and T-bar testing
    • Onboard lab testing methods: moisture content, unit weight, pocket penetrometer (PP) shear strength, Torvane (TV) shear strength, miniature vane (MV) shear strength, T-bar tests,  etc.
  • Onboard technical QA/QC client representation
  • Interpretation of field soil data
  • Field reports with field core logs
  • Lab test assignments and lab oversight
    • Standard laboratory testing program: moisture content, unit weight of soil, Atterberg limits, specific gravity, Hydrometer particle size analysis, grain size sieve analysis, carbonate content, organic content, salt content, remolded miniature vane (MVr) shear strengths, unconsolidated undrained (UU) triaxial shear strength, thermal conductivity, electrical resistivity, etc.
    • Advanced laboratory testing program: direct simple shear (DSS) test, constant rate of strain (CRS) consolidation test, anisotropically consolidated undrained (CK0U) triaxial  test, tilt table test, interface shear box (ISB) test, core photography, x-ray radiographs, core CT scan, multi-sensor core logging (MSCL), radio carbon age dating, etc.
  • Geotechnical data reports with core/photo logs, graphical and tabular data plots and summaries

Site Characterization & Integrated Study

Our engineers interpret seabed conditions and soil parameters for use in geotechnical foundations design by analyzing all available data from field and laboratory testing programs and existing databases. Depending on analysis type, importance of subsea structures and/or client’s requests as well as data availability, we integrate  geological/geophysical data to better understand the soil history, stratigraphy and geohazards when developing the design profiles of soil parameters. Our team specializes in using Geographical Information Systems (GIS) to manage all data spatially, and to integrate all geologic, geotechnical, and other data into a single database.  

  • Interpretation and spatial interpolation of soil parameters
  • Integration of geotechnical and geological investigation results
  • Recommendation of soil design parameters for different subsea structures
  • Risk assessment and reliability-based studies


 

Foundation Design and Analyses

Our engineers have extensive experience with planning and managing foundation installation for both shallow and deepwater locations involving some of the most complex soil conditions. Our team uses all available data to optimize the scope of geotechnical data acquisition and laboratory testing. We follow the industry codes and standards for analyses: API RP 2A/2GEO; API RP 2SK; ISO 19901-4; ISO 19901-8; DNV-CN30-4; DNV-RP-E303; DNV-RP-F109; DNV-OS-F101; DNV-OS-C101; DNV-RP-C207; and others.

  • Pipelines and risers
    • Pipe-soil interaction analysis for flowlines
    • Dynamic soil stiffness analysis for risers
    • Pipeline crossings
  • Shallow foundations
    • Jack-up rig footing penetration and punch-through analysis
    • Mudmat bearing capacity, sliding resistance and settlement
    • Concrete mattresses
  • Deep foundations
    • Suction pile penetration and holding capacity analysis
    • Driven pile penetration and holding capacity analysis
    • Conductors (drilled & grouted, jetted)
    • Load-deformation responses (p-y, t-z, q-z), axial and lateral capacities
    • Pile driving analysis
    • Existing pile re-analysis
    • Advanced and novel foundation concepts and installation recommendations
  • Hybrid foundations and anchors
    • Hybrid or pin-piled mudmat
    • Various anchors
  • Slope stability and run-out analyses
    • Slope stability analysis
    • Risk index approach for candidate sites of run-out analysis
    • Run-out analysis
    • Probability of a run-out impacting a structure
  • Other special analyses
    • Fracture pressure study for well conductors
    • Subsea dropped object protection study
    • Finite element analysis and simulations