The object of this paper is to present an integrated analysis of the information gathered on 3 different surveys in the Gulf of La Vela, an area of the Venezuelan continental shelf where some oil discoveries have already been made. A program of 34 geotechnical borings for foundation purposes was conducted in this area by Mc Clelland Engineers Inc. in the years 1972-1974. Prior to a second drilling exploratory phase, started in November 1978, INTEVEP (Instituto Tecnologico Venezolano del Petroleo) carried out a high resolution seismic survey over 6000 km2 with the collaboration of Mc Clelland Engineers, as well as a new geotechnical borings program with sophisticated push sampling and in-situ testing (vane shear, cone) in collaboration with Fugro-Gulf.
The integration of all these data allows a detailed description of the geology of the area, a definition of the geotechnical properties of the soils and a division of the area into zones of similar geological and geotechnical characteristics.
The Gulf of La Vela has been divided into two main areas. The eastern area has been highly affected by erosiona1 processes during past low stands of sea level, resulting in a very complex geological frame work. The main features encountered in this area are: erosion scarps, island-type relict features, prograding sedimentation and broad variations in stratigraphy geotechnical properties of the soils.
The western part is geologically more uniform and has been sub-divided into various zones with similar stratigraphy and geotechnical properties of the sediments. This division is associated with different types of soils (actual soft sediments, hard clays, cemented materials) and geological features that controlled the sedimentation such as deep-seated faults, erosion features and broad seafloor infilled paleochannels.
The Gulf of La Vela lies on the western part of the continental shelf of Venezuela, along the Caribbean Coast and East of the Paraguana Peninsula (Fig. 1). The exploration of hydrocarbons began in this area in 1972, and marked the first attempt to discover new reserves on the continental shelf of Venezuela. Prior to the first drilling exploratory phase, from 1972 to 1974, a program of 34 geotechnical borings was conducted by Mc Clelland Engineers Inc. The aim of this program was to define the stratigraphy and the geotechnical parameters of the soils up to 500 ft. below mud line in order to assist in the selection of a mobile drilling rig and to prepare a preliminary design of piles for fixed platforms.
The encouraging results of the first hydrocarbon exploration drilling program, during which oil and gas discoveries were made, led to a new exploratory phase initiated in November 1978. In order to assess safety of oil drilling exploration operations and placement of fixed permanent structures, INTEVEP, with the collaboration of Mc Clelland Engineers Inc., conducted a high-resolution seismic survey with seabed sampling. This survey consisted of a regional study that covered an area of 6000 km2 with 540 km of seismic lines and 37 seabed samples, and of site specific studies over 5 drilling and/or construction locations for a total of 870 km of seismic 1ines and 105 seabed samples.
