Skip to Main Content
Book Chapter

Observations from Exploration Drilling in an Active Mud Volcano in the Southern Basin of Trinidad, West Indies

By
Maria Henry
Maria Henry
Henry GeoConsulting Services, Inc., Littleton, Colorado, U.S.A
Search for other works by this author on:
Michael Pentilla
Michael Pentilla
Target Surveys, Westminster, Colorado, U.S.A
Search for other works by this author on:
Darrell Hoyer
Darrell Hoyer
Hoyer Petrophysics, Inc., Fort Collins, Colorado, U.S.A
Search for other works by this author on:
Published:
January 01, 2011

Abstract

The Trinidad Exploration and Development Company drilled the Habanero 1 well within Trinidad's southern basin in an area of surface mud volcano flows and vents. The well location is along a trend of mud volcanoes that extends across northern Venezuela and southern Trin-idad. The upper 3200 ft (975 m) of the well drilled through interbedded mud volcano layers as confirmed by palynology, paleontology, lithology, well log, and seismic information. Below 3200 ft (975 m), the well drilled primarily country rock deposits of the upper Miocene through Pliocene Cruse Formation. Paleontology and palynology data give an age range of Eocene through Miocene for the mud volcano material; the highest recovery of foraminifera and dino-cysts were from the Oligocene-Miocene Cipero and Lengua formations.

Several drilling problems were encountered, especially in the shallow, mudflow-rich part of the hole. Drilling issues included lost circulation intervals and the necessity for high mud weights (up to 17.5 ppg), to control high pressures. The well encountered numerous oil and gas shows, but no commercial hydrocarbons were tested.

Seismic data in the area illustrate a downward-tapering cone of disruption around mud volcano vents, with numerous faults providing conduits for the flow of mud. Drilling samples confirmed this interpretation, because the zones described as faulted commonly coincided with an influx of exotic mudflow material.

Subsurface logs measured decreased resistivity, lower density, and higher interval transit time (slower velocity) in mud volcano layers relative to intervals of country rock formations. These intervals are anomalous even when compared to log data for overpressured shale zones in neighboring wells. The Habanero 1 checkshot survey documents shallow mud volcano layers with velocities slower than the velocity of water, perhaps caused by the presence of entrained gases within the matrix of the mud. Refraction static velocities are also anomalously slow around Habanero 1 and along the trend of mud volcanoes.

You do not currently have access to this article.

Figures & Tables

Contents

AAPG Memoir

Shale Tectonics

Lesli J. Wood
Lesli J. Wood
Search for other works by this author on:
American Association of Petroleum Geologists
Volume
93
ISBN electronic:
9781629810089
Publication date:
January 01, 2011

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal