Pipeline laying and embedment in soft fine-grained soils: Field observations and numerical simulations

Z. J. Westgate, D. J. White, M. F. Randolph, P. Brunning

Research output: Chapter in Book/Conference paperConference paper

23 Citations (Scopus)

Abstract

The as-laid embedment of offshore pipelines governs several aspects of pipeline design and lay route architecture. The observed as-laid embedment in soft soils is greater than would be predicted based on the static penetration resistance of the seabed using the in situ soil strength. Empirical 'dynamic embedment factors' are used to scale up this calculated embedment to estimate the as-laid value. The source of this discrepancy is dynamic lay effects, including the form and duration of any dynamic vessel and pipeline movements, and the seabed soil conditions. This study presents data to support an improved methodology to estimate the likely range of as-laid pipeline embedment. Existing theoretical models are reviewed, using aslaid pipeline survey data from five pipelines across two soft fine-grained soil sites. It is shown how the dynamic embedment in the field can be estimated by accounting separately for (i) a reduction in soil strength due to pipeline motions in the touchdown zone and (ii) an increase in the pipeline catenary bearing pressure due to vessel and pipeline dynamics. This represents a more robust methodology than the common industry practice of applying an empirical dynamic embedment factor to the calculated static embedment. Guidance on the pipeline embedment that occurs when the usual lay process is interrupted is also provided, for example at sleeper crossings and during weather-related downtime, in-line tee connections, abandonment and recovery activities, and pipeline termination assembly connections.

Original languageEnglish
Title of host publicationOffshore Technology Conference 2010, OTC 2010
Pages326-340
Number of pages15
Volume1
Edition1
Publication statusPublished - 1 Dec 2010
EventOffshore Technology Conference 2010 - Houston, TX, United States
Duration: 3 May 20106 May 2010
https://www.infield.com/otc10_houston_2010.htm

Publication series

NameProceedings of the Annual Offshore Technology Conference
Number1
Volume1
ISSN (Print)0160-3663

Conference

ConferenceOffshore Technology Conference 2010
Abbreviated titleOTC 2010
CountryUnited States
CityHouston, TX
Period3/05/106/05/10
OtherThe Offshore Technology Conference (OTC) is where energy professionals meet to exchange ideas and opinions to advance scientific and technical knowledge for offshore resources and environmental matters.
Founded in 1969, OTC’s flagship conference is held annually in Houston. OTC has expanded technically and globally with the Arctic Technology Conference, OTC Brasil, and OTC Asia.
OTC ranks among the largest 200 trade shows held annually in the United States and is among the 10 largest meetings in terms of attendance.
OTC is sponsored by 13 industry organizations and societies, who work cooperatively to develop the program each year. OTC also has two endorsing organizations and ten supporting organizations.
Internet address

Fingerprint

Dive into the research topics of 'Pipeline laying and embedment in soft fine-grained soils: Field observations and numerical simulations'. Together they form a unique fingerprint.

Cite this