Relationship Between Near Seafloor Seismic Amplitude, Impedance, and Soil Shear Strength PropertIes and Use in Prediction of Shallow Seated Slope Failure

Abstract

The movement of petroleum exploration and production to the frontier deepwater and ultra-deepwater of the Gulf of Mexico presents a variety of engineering challenges. One such challenge is the placement of seafloor production infrastructure on or near the base of steep slopes associated with the Sigsbee Escarpment. As a result, the potential hazards associated with shallow seated slope failures have become a legitimate concern. These types of failures can result in the formation of debris flows and turbidity currents capable of damaging or destroying seafloor structures in their path. The potential for significant damage or loss of seafloor facilities from such an event merits a comprehensive understanding of the factors that influence shallow slope failures. However, total field coverage with geotechnical cores to assess these factors is neither logistically or economically feasible nor practical. We present a new method for integrating these factors with available geotechnical core data and 3D seismic to quantitatively extrapolate and predict the location of critical areas of potential shallow seated slope failure.

Sedimentation in the Vicinity of the Sigsbee Escarpment during the Last 25,000 yrs

“…The purpose of the coring was to characterize the various types of sediment deposits, morphologic and structural features, and to ground-truth seafloor backscatter amplitudes and subbottom seismic reflectors (1,3,4,5,6,9). A total of 95 cores were collected and their lengths ranged from several to nearly 20 m. In addition, 8 borings were also collected to investigate deeper sediments.…”

>b<Caracterização física de sedimentos quaternários na Plataforma Continental Sul Brasileira>/b<

“…Desde os estudos pioneiros levados a cabo por Shumway (1960), Nafe & Drake (1961), Hamilton (1963Hamilton ( ), (1971 e Hamilton & Bachman (1982) foi se desenvolvendo um largo campo de aplicação sobre propriedades físicas, notadamente a velocidade de propagação do som (vp) e a densidade γ de sedimentos marinhos inconsolidados, com estudos relacionados a reconstruções paleoclimáticas (Chi & Mienert, 1996;Presti et al, 2003), classificação de unidades sísmicas e sedimentares (Narantsetseg et al, 2014;Kim et al, 2019), elaboração de modelos geoacústicos vinculados a propriedades texturais dos sedimentos (Kim et al, 2011;Bae et al, 2014;Tian et al, 2019) ou a análises de risco geológico (Brand et al, 2003).…”