SEISMIC INTERPRETATION AND CLASSIFICATION OF

MUD VOLCANOES OF THE SOUTH CASPIAN BASIN,

OFFSHORE AZERBAIJAN

A Thesis by MEHDI YUSIFOV

Submitted to the Office of Graduate Studies of

Texas A&M University

in partial fulfillment of the requirements for the degree of

MASTER OF SCIENCE

August 2004

Major Subject: Geology

ABSTRACT

Seismic Interpretation and Classification of Mud Volcanoes of the South Caspian Basin, Offshore Azerbaijan.

Mehdi Yusifov, B.S., Azerbaijan State Oil Academy

Understanding the nature of mud volcanism, mechanisms of formation, types of eruptions and their relationship to the hydrocarbon systems provides important information about subsurface conditions and geological processes within the South Caspian Basin.

A 2D seismic grid in southeastern offshore Azerbaijan is used to define the areal distribution of mud volcanoes and to make a classification of the mud volcanoes based on characteristic seismic features. A detailed database for each determined mud volcano is constructed. Analysis of different parameters from this database shows that there is a high concentration of mud volcanoes in the southern part of the study area that coincides

with subsurface structures within the basin. Mud volcanoes with low relief (several tens of meters) are mainly concentrated in the northeast. Mud volcanoes with large vertical relief (greater than 200 m) are clustered in the southwest part of the basin. Mud volcano development in the South Caspian Basin is generally linked to faults, which in some instances are detached at the basement level.

By using interpreted seismic surfaces the relative time of mud flows has been determined from the mud volcanoes. The cycles of mud volcano activity in the South Caspian Basin coincides with the time of high sedimentation rate, a regional contraction episode, and major stage for hydrocarbon generation.

Mud volcano activity initiated in the Sabunchi-Syrakhany (lower Pliocene) and has increased in activity in upper Apsheron-Quaternary time.

Previous studies of the onshore mud volcanoes in Azerbaijan and the results from current work conclude that mud volcano formation within the South Caspian Basin is mainly controlled by tectonic forces and overpressured sediments.

Mud volcano activity is not always related to the Maykop organic rich shale succession. It can occur at shallow depths by pressure breakthrough from any stratigraphic zone.