Geoscience Techniques for Engineering Assessment of Oman to India Pipeline Route
Authors: Baerenwald Paul D. , Mullee J.E. , Campbell Keny J. 
Published: October 2008

A variety of geoscience techniques were used to define soil conditions and evaluate geologic process in order to develop design criteria for complex segments of the proposed Oman toIndia pipeline route. Geophysical survey data, seafloor cores, ROV observation of the seafloor, and oceanographicmeasurements were the principal field data collected. Geotechnical soil testing, and x-ray radiography, detailed geologic logging, and C-14 age dating of cores were earned out. The diverse sets of field data and lab test results wereintegrated by a multi-disciplined team of geoscientists and engineers to develop geologic and soil models, soil design criteria, a turbid flow model, and seafloor stability models. The integrated approach used here is applicable to other complex areas where seafloor stability needs to be assessed or design criteria need to be developed for active geologic processes.

Introduction

Geophysical, geotechnical, ROV, and oceanographic surveys of potential pipeline routes were carried out in 1994 and 1995 to assess the technical feasibility of installing, operating, and maintaining a submarine gas pipeline from Oman to India. A detailed description of most of the survey activities and equipment used is given in Mullee (1995).

The results of these survey indicated that, although a workable pipeline route appeared to have been identified, potentially constraining conditions exist along six complex sections of the proposed route. These six sections comprise approximately 453 km or about 40 percent of the 1135 km-long route, and include portions of the Oman continental slope, the Dalrymple Trough, three submarine channels on the Indus Fan, and the Indian continental slope rig. 1). Maximum water depth along the route is -3500 m.

Detailed examinations of geophysical, geological, geotechnical, ROV, and seismological (earthquake) data were undertaken in order to define and assess conditions along the six complex portions of the proposed route, and to model seafloor stability and possible fan-channel turbid flows. This paper presents the approach used to analyze and integrate the diverse sets of data to provide information for optimum routing and design.

Project Contributors

There were several major contributors to this large and complex project, Decca Survey Overseas Limited (DSOL), Abu Dhabi, carried out all geophysical and coring operations in the field, and provided basic geophysical data interpretation. Seafloor Surveys International, Seattle, and Williamson and Associates, Seattle, provided specialized urvey and data presentation service as subcontractors to DSOL. Selantic Subsea Technology was subcontracted by DSOL to provide coring equipment and personnel. Geotechnical testing was carried out by Foundation Engineering of Dubai under contract to DSOL. Oceanographic data collection and analysis was done by Wimpey Environmental, U.K. ROV setiees were provided by Oeeaneenng International, Houston. Details of most survey operations are given in Mulle (1995).

An international team of geoscience experts was assembled to carry out the complex analysis and synthesis of data.