Geologic Setting of the Mad Dog Mooring System

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe Mad Dog prospect is located along the Sigsbee Escarpment in the southeastern portion of the Green Canyon Area. The Mad Dog mooring system straddles the Sigsbee Escarpment ( Figure 1). A total of eleven mooring piles arranged in three clusters were planned for this mooring system.Two clusters are situated along the Lower Continental Slope and one cluster is situated along the escarpment. The paper describes the complex surficial geologic setting as well as the geohazards present at the site and how they influenced the anchor locations of the chosen mooring pattern. The unique challenge of this project was the effort put forth to understand the mooring system in variable and complex areas at each anchor cluster.

Integrated Studies To Characterize the Mad Dog Spar Anchor Locations and Plan Their Installation

“…This layer is a regional feature prevalent at the Mad Dog site above and sometimes below the escarpment. This is consistent with observations by Berger et al (2006) where the shallow slump unit was observed to be blockier in nature at Cluster 3 than at Cluster 1 and therefore could be expected to be more consolidated. It has been discussed in-depth by Brand et al (2003).…”

“…However, the geotechnical properties of that top 13 ft of sediments were well understood from the work described in Al-Khafaji et al (2003), and Berger et al (2006). This stinger, enclosing the CPT rod, improved lateral support in the soft clays but prevented the measurement of cone parameters in the top 13 ft of sediments.…”

“…The geological setting of the Mad Dog anchoring system has been described by Berger et al (2006) and the details of the geotechnical investigation performed to design the anchors given by Liedtke et al (2006). This companion paper describes how the results of the geotechnical campaign were integrated with the high-resolution geophysical data to define the geotechnical and bathymetric constraints associated with the anchor locations and to provide input to the geotechnical design.…”

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TX 75083-3836, U.S.A., fax 01-972-952-9435.

AbstractThe geological setting of the Mad Dog anchoring system has been described by Berger et al (2006) and the details of the geotechnical investigation performed to design the anchors given by Liedtke et al (2006). This companion paper describes how the results of the geotechnical campaign were integrated with the high-resolution geophysical data to define the geotechnical and bathymetric constraints associated with the anchor locations and to provide input to the geotechnical design.

For Cluster 2, located on the Sigsbee Escarpment, the paper highlights the great care that was taken in positioning the anchors close to the location of the soil borings and Cone Penetrometer Tests (CPTs) and on seabed with acceptable slope angles.

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Laboratory Testing and Detailed Geotechnical Design of the Mad Dog Anchors

“…Reference is made to the accompanying papers (Berger et al 2006, Liedtke et al 2006and Jeanjean et al 2006 for details about the considerations made. The practical consequence was that one boring and one or two CPTs were performed at each of the two anchor Clusters on top of the Sigsbee Escarpment, while one boring and one CPT were performed at each anchor location in the slump area at Cluster 2 (in total 4 borings and 4 CPT's were performed at Cluster 2), see Field Architecture shown on Figure 1.…”