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LETTERS TO THE EDITOR

Darwent's Trinidad well

I occasionally see reference to statements concerning the "first oil well by Col. Drake" in one or other oil field related magazine articles.
One such reference is to be found on p. 61 of the March 7 Oil & Gas Journal.
While one honors the pioneering work and achievements of Col. Drake in drilling the first oil well in the U.S.A., It is possibly time that the work of Capt Darwent in Trinidad should also be recognized. Capt. Darwent drilled a well, 280 ft deep, in the vicinity of the Pitch Lake in 1857, 2 years before the alleged first well of Col. Drake in 1859.
Due to the shifting pitch and the unstable geological conditions found around the Pitch Lake, the original well can no longer be found, as it must have long sunk beneath the ground.
At the same time, the second well, drilled in 1866, can still be seen and I should be pleased to submit a photograph of it, should you so desire.
Would someone more knowledgeable than me please advise why Capt. Darwent's well should not be regarded as "the first?"

Nigel P Boos
Aberdeen, Scotland.

EDITOR S NOTE: This letter was published in the April 25, 1988 issue of the Oil and Gas Journal The Editor of that Journal responded as follows: There are many claims to having drilled the first oil or gas well. For several years before 1859, oil was produced as a byproduct with brine from wells drilled in to saltwater deposits. Col. Drake's well, completed Aug.27 of that year with a production rate of 30 b/d, is credited with demonstrating that oil could be found in large volumes by drilling for it through rock.

Trinidad and Tobago Petroleum Atlas

I assume that the GSTT Executive occasionally likes to hear from their members. As Editor of the Newsletter you may wish to mention my suggestion in a future issue (after appropriate discussion with the society's executive level).
As a geologist, I have always found that a few good illustrations are worth many thousands of words. This is particularly true when it comes to describing complicated oil and gas accumulations.
I suggest, therefore, that the GSTT undertake a project to produce an Atlas of the Oil and Gas Accumulations of Trinidad and Tobago. I believe that production of such a document would be of benefit to the majority of GSTT members, and also potentially profitable via sales to overseas oil companies and university libraries.
Data on some (not all) Trinidadian oil fields are found in various publications. A great deal of this information is out of date and requires further refinement.
The Atlas format is very useful in that it allows for the presentation of key horizon maps, cross sections, seismic lines, type logs, production profiles, history of exploration/discovery, petrophysical data, etc., in a "user friendly" manner. This format is also useful for later addition of new pages should a new field be discovered after initial publication of the document.
The scope of this suggested project is such that GSTT may wish to consider joint publication with SPE. All of Trinidad's oil and gas accumulations (developed and undeveloped) should be included in the atlas.
Finally, I feel it would be highly commendable if the atlas were dedicated to the memory of Hans G. Kugler and to all the old "Oil Finders" who worked on exploration and development geology in Trinidad. I believe that an atlas would be a fitting tribute to their efforts and contributions.

Nicholas De Verteuil
Pennzoil International Company, Houston, Texas.

San Fernando Oil Seep

I read with much interest the news of the San Fernando oil seep reported in the press on consecutive days (2nd and 3rd November) and the request by the Mayor of San Fernando for assistance from a petroleum engineer in tracing the origin of the oil seep. As President of the Geological Society of Trinidad and Tobago, a professional body of practicing geologists with a membership of 90, I would like to take this opportunity to put the oil seep matter in some perspective and to enlighten the general public on the role of the geologist, especially the petroleum geologist, in these matters.
It is primarily the petroleum geologist who determines whether or not a well should be drilled for oil in an area, based on a geological evaluation of the available data, and based on a certain degree of extrapolation using a best-fit model. Petroleum exploration is the domain of the geologist as it is he who decides which rocks in the subsurface are likely to contain oil and where are these rocks best formed to result in an oil accumulation. The petroleum engineer, on the other hand, is involved in the mechanics of drilling the well, producing oil from the well and in evaluating the reservoirs from which oil is produced. Thus the assistance of a petroleum geologist, rather than a petroleum engineer, should be sought in attempting to understand the nature, and trace the origin, of the reported oil seep.
The San Fernando oil seep is not new and has been known for several decades. What probably caused it to be noticed once again are the very hot days we have been experiencing recently, resulting in the seeped oil, which had become semi-solid over the years, to flow once more as a very viscous, tarry and sticky liquid. In addition, the seep may be still active and would therefore intermittently extrude oil onto the surface. This oil seep is no different from one on Royal Road on parts of the San Fernando Hill, or from the numerous oil seeps in Penal, La Brea, Point Fortin, Guayaguayare, etc. Indeed the entire Pitch Lake can be considered a very large scale oil seep.
An oil seep is a surface manifestation of petroleum which is present at depth in the subsurface, so that, in a gross reconnaissance sense, an oil seep is a guide to the presence of oil in an area. Oil seeps were very significant in the early days of oil exploration when wells were located close to these seeps. However, with the advancement of technology, in particular reflection seismology (a method of x-raying the earth), emphasis was placed on defining the structures or containers for oil in the subsurface, and oil seeps were recognised for what they are a gross indication that oil has been generated in the area.
Basically 3 criteria must be met before petroleum can accumulate in commercial quantities in the subsurface. First, a rock capable of generating oil, termed the source rock, must be present. Secondly, the oil generated in the source rock must be able to migrate to reservoir rocks or containers. Thirdly, these containers must be so structured that oil can accumulate in them, rather than be lost to the surface.
The area south of the Central Range (called the Southern Basin in geologic terms) is covered with hundreds of oil seeps and is a known petroleum province, from which came almost all of Trinidad's 2.3 billion barrels of oil produced to date. Oil seeps are not confined to the land and numerous seeps are present off the east coast of Trinidad, as evidenced by the presence of tar balls on east coast beaches.
Thus the mere presence of an oil seep does not warrant the drilling of a well. The origin of the San Fernando oil seep is probably just a surface indication of oil generated from the source rock in the sub-surface, which migrated to the surface in different parts of southern Trinidad depending on the availability of migration pathways (faults or fractures in the earth) and following a vertically upward direction in accordance with the principles of buoyancy.
One of the objectives of the Geological Society of Trinidad and Tobago as enshrined in its constitution is the dissemination of geological knowledge to the general public. The Society, through its members, is always willing to offer advice and assist, where possible, in resolving matters of a geological nature.

Kirton Rodrigues President
Geological Society of Trinidad and Tobago.

Editors NOTE: This letter was published in the Trinidad Guardian on 8th November and in the Trinidad Express on 14th November; and is reproduced here for the benefit of GSTT members.

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