Geophysics

This course addresses the problem of accurate seismic interpretation in deep-water and the delicate construction of seismic maps in the deep-water realm. It is intended to all petroleum professionals involved in exploration and production, geophysicists, geologists, rock physicists, reservoir engineers and drilling engineers.

Seismic interpretation is covered with a series of practical examples that focuses on the deepwater realm, with emphasis on proximal, intermediate and distal marine reservoirs. Acquisition and processing of 2D and 3D data is also discussed in what concerns the practical use of the rather extensive growing database libraries in deepwater.

The distinct data challenges in deepwater are examined in detail so that it would lead to practical problem of drilling locations and the finding and development of deepwater deposits.. Issues in the drilling of deep-water wells such as thickness of the overburden, pore-pressure prediction and geo-steering, are discussed. Practical workshops involve understanding of the main techniques in the seismic section interpretation and in precise structural contouring mapping in deep-water, with focus on the continental slope bathymetry correction and its effect upon time and depth maps. Handling of seismic velocities, depth conversion, comparisons of 2D vs. 3D data, and the principles of 4D and of 4C seismology are also briefly discussed. Time-slice of 3D datasets, seismic interpretation of attributes of amplitude and phase are applied to the mapping exercises for the purpose of better reservoir characterization and possible occurrence of fluid effects.

COURSE OBJECTIVES are the practical understanding of aspects concerning the precise deep-water seismic interpretation fundamental for successfully drilling oil and gas wells in the deep-water realm. Correct estimates of seismic velocities and map contouring techniques in deep-water are essential for achieving ideal vertical and deviated well locations and to the geo-steering of horizontal wells upon reservoir development.

The course covers the essentials of offshore seismic data from acquisition to processing and interpretation. To this effect it examines seismic tape formats, data libraries, design of seismic proprietary and spec surveys, data processing workflows in deepwater and the utilization of interpretation software in workstations Methodologies for correct interpretation of seismic sections and the techniques applied in the architecture details of map contouring are discussed in connection with suites of exercises that apply these techniques in offshore data of passive and compressive continental margins, covering the outer shelf, slope, rise and basin.

Focus is given to the interpretation of deep-water reservoirs, mainly proximal, intermediate and distal turbidites. The main differences between hand-drawn interpretation and computer workstation mapping are discussed so that the principles of interpretation may be utilized to quality control computer section interpretation and computer mapping. This is particularly important in deep-water due to the effect of bathymetry over contouring and depth conversion.

Comparisons between hand contouring and computer contouring are carried out for the purpose of understanding the subtleties of subjective hand contouring versus grid algorithm contouring. Special emphasis is therefore given to hand contouring map interpretation comparisons with modern workstation software grid interpretation mapping for 2D and 3D data sets. Comparative interpretation of the main prospective deep-water regions of the world such as Gulf of Mexico, Offshore Brazil, West Africa, North Sea and Southeast Asia are effected with suite of comprehensive exercises covering structural and stratigraphic interpretation and the use of seismic attributes. Rift and compressional mapping exercises cover normal and reverse faults handling, the understanding of paleo-lows and paleo-highs and flattening of bathymetry for re-construction of basin tectonism. Handling of seismic velocities in deep-water are made with specific exercises of depth conversion. Attendees are daily given hands-on mapping problems and exercises that cover geophysical exploration and development mapping in deep-water. Salt tectonics models over distinct basins are examined and comparisons made for basin architectures and hydrocarbon plays of autochthonous salt vs allochtonous salt.

Fractured reservoirs such as tight carbonates and basements set complex challenges to appraisal and development teams due to their high degree of heterogeneity and hard-to-predict reservoir quality. A multi-disciplinary approach that draws on sedimentology, diagenesis, structural geology, rock mechanics and reservoir engineering techniques has to be applied.

This course provides geologists and reservoir engineers with the essential knowledge needed in the real-world business context where management of risk and reduction of uncertainties is important. The objective is to present the key technical issues in geology, geomechanics and engineering and illuminate the range of tools and techniques available to tackle them (along with their limitations). A constant theme is to illustrate these issues with case histories from the industry. 

The course is intended to be interactive in that delegates are encouraged to participate in discussions so that key points are openly scrutinised.

A constant theme of the course is to apply ‘first principles’ from geological science to the results generated by reservoir characterisation tools, techniques and modelling softwares. With due attention to these principles the technical and commercial risks associated with fractured reservoir hydrocarbon developments can be mitigated.