The dissertation was delivered in two parts. Part 1 dealt with the locality, type, placement and where possible the quality and quantity of the non-petroleum rock resources. This was given by Mr. Kenrick Haynes of the Ministry of Energy and Natural Resources. Part 11 sought to develop a technical model for the studying of each main type of rock resource leading to the development of resource inventories and resource allocation maps. This was presented by Mr. W. Taddius Rajpaulsingh.

In Part 1, the author prefaced his delivery by indicating that very little is known indepth of these resources. He further pointed out that no attempt has been made over the last sixteen (16) years to make an inventory of these resources. The author of Part 11, reiterated these sentiments and indicated that compiled work on these resources are of 1952 to 1960 in the form of "The General and Economic Geology of Trinidad B.W.1 , by H. H. Suter, Ph.d - Second Edition, with revisionary Appendix by G.E. Higgins." The Economic Geological Map of this publication is herewith included. This Economic Geological Map was updated and revised in 1966 by the then Government Geologist - Kevin M. Marshall. This revised edition of the Economic Geological Map (1966) was used as the base for the map included herewith and as presented in the Draft Publication of Ministry of Finance (Planning and Development) - Town and Country Planning Division - National Physical Development Plan Trinidad and Tobago - Vol. I - Survey and Analysis.

Mr. Kenrick Haynes systematically dealt with the type, locality, placement, quality, quantity and overall historical, economic and political development of these resources as seen in the maps included.

Mr. W. Taddius Rajpaulsingh chose two types of resources, - one - the metamorphosed, dense, hard, bluePrey, crystalline limestone of the Northern Range, and two - the sand and gravel deposits of the east and north eastern areas of the Northern Basin. He then catagorised the available data in facets of Historical Geology, and Applied Geology, thereby forging a Technical Model which was married to the known economic uses. From the melting pot arose inventories of amount, quality and best use.

In its continuing effort to provide its members with the forum for discussing the latest concepts and techniques in various aspects of petroleum exploration and development, The Geological Society of Trinidad and Tobago held another Advanced Petroleum Short Course at the Trinidad Hilton from March 22nd to March 26th, 1982.  The course entitled 'Subsurface Techniques in Relation to Basin Analysis and Resource Appraisal' was conducted by Professor Garrison of the University of California, Santa Cruz.

In pointing out the geologic importance of Sedimentary Basins, Prof. Garrison stated that of the 600 sedimentary basins recognized in the world today, only 160 produce hydrocarbons in commercial quantities.  Halbouty (1978) estimated that another 240 may have little or no potential, with the remaining 200 being slightly or completely unexplored.  In addition, up to 70% of the world's undiscovered hydrocarbon reserves may be found in already explored basins through additional exploration and development.  Thus it is imperative that a full understanding of the development of sedimentary basins be undertaken in order that their resource potential can be determined.

A Sedimentary Basin, as described by Professor
Garrison, represents an 'entity of depositional and structural characteristics, such as sedimentary facies, unconformities and geologic history, all of which bear on the resource potential of petroleum and other commodities. Over the years there have been several attempts to classify sedimentary basins based on either tectonic setting, tectonic history, basement type, plate tectonics or resource potential.  However, perhaps the most important aspect of sedimentary basin analysis is the fact that though most sedimentary basins display similar development characteristics, each basin, be it regional or local, is unique and must be examined within that framework.  Of added importance is the realization that all the depositional systems, rivers, deltas or turbidite fans operating within any sedimentary basin are systematically related and dependent on each other.

The first phase in the examination of any sedimentary basin must involve analysis of surface outcrops and where possible seismic data.  However,  Subsurface information such as cores, cuttings and well logs is critical not only in exploration but in development studies. Each of the case histories presented by Professor Garrison underscored this fact in that all of his findings were supported by maps, correlations between wells and reservoir analysis.  Where possible these were supplemented by petrographic analysis of rock samples, lithologic descriptions and analysis of sedimentary structures.

Included in the course was a one day field trip to several areas throughout the south of Trinidad.  The
primary purpose of this trip was to examine the surface outcrops of formations, such as the Herrera's, that are productive in several areas in Trinidad and relate those findings to the subsurface information that is already available.

In general, the course provided an excellent opportunity for all present to appreciate the need for co-operative work between geologists, engineers and geophysicists in understanding basin development.  For whereas the geologist may be able to locate porous rocks, the engineers may be able to understand porosity and permeability variations all in determining resource potential.  In reviewing the manner in which Professor Garrison presented his data, we were all reminded of the importance of detailed investigation and in depth research, which is often overlooked in our day to day studies.

One other noteworthy aspect of the course was the discussion generated among the participants.  It was truly encouraging, to listen to the ideas being forwarded The discussion showed that geologists in Trinidad are facing up to the challenge, as outlined by Professor Garrison, of trying to understand the development of the sedimentary basin within which are located the productive and potential horizons in Trinidad and Tobago.

In its search for its own supply of hydrocarbons, the Petroleum Corporation of Jamaica has initiated a program of exploratory drilling. At the same time, the University of the West lndies at Mona, is conducting source rock studies of the Jamaican sediments.

Mr. Kirton Rodrigues who is currently persuing a doctorate in Geochemistry at U. W. 1. was guest speaker of the GSTT in April 1982.

In his presentation on the Petroleum Source Rock Potential of Jamaica, Mr. Rodrigues outlined the methods utilized in the evaluation of source rock potential and maturation viz.  Total Organic content; Kerogen analysis; spore coloration index and vitrinite reflectance.

Table I is a summary of findings on source rock potential.  These findings are based on geochemical studies of outcrop samples from a cross section of source-type sediments (cf Fig. 1).  From the summary, it can be seen that most of the organic matter studied is of humic type, which would, at best, produce dry gas and/or waxy crudes.  In addition, potential reservoirs lie in carbonate formations or sands derived from volcanic flows.  Volcanics usually produce poor reservoir sands.

On the whole, the study indicates condition for finding commercial hydrocarbons are not of the best.

The Geological Society of Trinidad and Tobago and Premier Consolidated Oilfields Limited jointly sponsored a seminar entitled "THE PETROLEUM INDUSTRY - 1981 REVIEW/ 1982 FORECAST."

This was held at the Trinidad Hilton on Wednesday 7th April 1982.

The sponsors found that in view of the pivotal role played by the Petroleum Industry on the national economy' it was important that current timely information on the industry be available to people in all sectors of the economy. The seminar was designed to fill this vacuum. Premier Consolidated Oilfields Limited, sanctioned by the Ministry of Energy and Natural Resources will publish a monthly newsletter on the Petroleum Industry entitled "TRINIDAD PETROLEUM' This publication will keep participants and subscribers up to date on activities in the industry.

The seminar was attended by approximately 80 people which included senior management from the Petroleum Industry and Related Service Industry, Trade Unions, members from the Banking and Financial Communities, Construction Industry Personnel, various International Organizations and the Press. Various aspects of the petroleum were reviewed (Production, revenue, incentives, forecast etc.).

The seminar was opened by the Minister of Energy and National Resources, The Hon. Patrick Manning, who gave an over view of the International Petroleum climate. He said he foresaw a permanent stabilization in World Oil Prices because of high conservation and increased use of alternative energy. He further stated that the dependence for oil and its products is not as price inelastic as previously believed. On the local scene, the Minister indicated that Texaco had 500,000,000 barrels of heavy oil reserves but needed greater tax incentives for secondary recovery. Finally, the Minister indicated that natural gas production was rising and that this resource could play a critical role in National Development in the future.

A Review of 1981 Activity was done by Dr. K. Persad, Manager Exploration and Production at Premier. Dr. Persad gave a review of Oil and Gas Production/ utilization, drilling and completion statistics, exploration and development activity, refining, and important Caribbean Highlights. His talk revealed that 1981 daily average of 189, 487 barrels/day was a 10% decline from 1980's figure of 212, 066 barrels/day, with offshore fields accounting for 76.9% of production. Gas production was 537.32 mmcf/day. He also revealed that although there was a decline in production more wells were completed in 1981 than 1982.

In a forecast of the Industry for 1982, Mr. H. Hinds, Chief Petroleum Engineer at the Ministry of Energy and Natural Resources indicated that Trinidad and Tobago expected to produce 68 Million barrels of oil this year, a 1.6% decline on 1981. He also stated that $1 10 million will be spent by Oil Companies on exploration drilling and $125 million on development drilling. A total of 26 Exploratory Wells and 217 Development Wells would be drilled. Mr. H. Hinds also explored the point that oil could be found at greater depths if deep drilling was initiated by Companies.

In his presentation 'Present Oil Prices and their expected impact on the Industry,' Mr. R. Powers, President and General Manager of Amoco Trinidad Oil Company Limited gave a comprehensive discourse on market dynamics as related to the laws of supply and demand. He showed that the fall and possible stabilization of oil prices was related to laws of supply and demand. Mr. Powers' talk was divided into four (4) main sections: fundamentals of Crude Oil economics, a review of the international oil scene over the last 12 years, an assessment of the current oil situation and projections for the future.

In a very stimulating discussion, Mr. L. Scotland, Corporate Manager, Royal Bank of Trinidad and Tobago Limited, outlined the "Impact of the Reduced Revenue on the National Economy." He predicted a "worst case" reduction in Oil Tax Revenue of over $ l billion, this prediction being based on a 25% drop in oil prices. The resultant effect, he said, would be a sharp reduction in surplus available to the state and a money-supply drop, which would be a welcome development in the fight against inflation. The first victims of this loss in Government Revenue would be Subsidies and Welfare Program and Public Sector employment. Mr. Scotland concluded that the "real problem may not surface in 1982, but in the years beyond."

Responding to the call for practical solutions, Mr. A. Chow, Independent Senator, spoke on "Tax incentives to increase Production." The main objective of his talk examined the principal instrument of fiscal policy as they concern the oil industry and suggested methods by which the variable factors can be manipulated to exert maximum beneficial effect upon the long term future of the oil industry." Along the same lines Mr. B. Abdullah, Manager Information and Resources at Premier, outlined the use of micro computers as a tool in increasing the productivity of the Petroleum worker.

The seminar concluded on a very stimulating note with a panel discussion.

The Maracaibo Basin accommodates the Bolivar Coastal Field, one of the world's largest oilfields, with production from horizons of Miocene, Eocene, -P2laeocene and Cretaceous ages. On April 21, 1982, a party of six (6) geologists from Trinidad, set out to Maracaibo with the purpose of visiting - outcrops of stratigraphic units in the Maracaibo Basin representing the time interval from the Triassic up to the Miocene. The 5-day trip was planned as a follow-up to the Eastern Venezuelan expedition, made a year previously, and was once again led by the ever able Alton Ferrell of Texaco.

Joined by two (2) Maraven geologists, the party traveled south from Maracaibo, across the 8 Km bridge over Lake Maracaibo, around the towering Andes (with brief excursions up as far as the blanketing clouds would allow) through well guarded villages and into the city of San Cristobal, nestled in the lap of the Andes.

Magnificent exposures of the units cropped out at road cuts along the way and facies changes could be followed both vertically and laterally. Outstanding examples of characteristics of the various depositional environments were on display, from the deep water shales of the Eocene Pauji to the migrating channel of the Mirador Sands and lignite beds of the wide - spread Carbonera. The relationship between the units observed and their reservoir and source rock characteristics in the producing areas were discussed at the stops. In addition, many units were sampled, some to be analysed for paleontological and geochemical information. Visits were also paid to the huge tarseep at Mene Grande, the Mene Grande Field and the Bolivar Coastal Field.

Consideration was also given to the ethnic and indigenous cultures encountered along the route. The most memorable experience was a visit to an Indian Commune. Here some of the descendants of the original inhabitants survive, their livelihood coming from handicraft, making souvenirs, and primitive weapons for sale to visitors.

The geological features, brief encounters with the various aspects of the Venezuelan society and culture, all folded into a knee buckling, breath-taking Andean setting, presented an experience which should be grasped at any future opportunity.

The sediments exposed at Galeota Point and the adjacent beaches all belong to the Mayaro and Gros Morne Formations, but for the unconformable veneer of Pliocene clay (Globorotalia Margaritae Zone) belonging of the to the Palmiste formation. At the south end of Mayaro beach the sediments good are arranged in a broad anticline. The axial trace runs and approximately east-west. The crest is poorly defined, tectonically disrupted by a mish-mash of faults. It is tempting to suggest that this fault zone It is the eastern continuation of the Marcel Main Fault. (Figs. 1 + 2)

THE POINT

Galeota Point is the south eastern most tip of the island. The beds here, dip to the south, and are thus ex, posed along strike. This section can be subdivided into 6 sedimentological units. The sequence coarsens upwards, shales (mudstones) at the base, to medium-fine to fine grained-sands at the top of the cliff.

UNIT VI Starting at the base;

The shales (mudstones) at the base; these are moderately hard, fissile, dark - yellow - brown to moderate - yellow - brown, typical of the shales Gros Morne Formation. This section has yielded fauna, suggestive of Gros Morne age. Poor preservation inhibits paleoecological definition, but all samples had brackish, littoral, inner neritic to very shallow marine species. Small isolated ripples, migrating ripples, isolated low amplitude channels, become increasingly frequent up-sequence. Compaction and dewatering structures are commonly seen adjacent, or within, sandy bodies. The sandy material is sedimentologically organized into thin beds and lamellae which show a variety of structures, (mentioned above). This sporadic occurrence of coarse material implies that this unit was subjected to strongly fluctuating conditions, or geologic events, interspersed with periods of quiescent, slow mudstone deposition. The coarser beds/lamellae show vestiges of having been reworked by the east to west flow. The mudstones were also reworked, but their internal organization is only revealed if they are washed in a fine spray of water.

UNIT V

Abundant trace fossils are peculiar to this unit. Small finger to pencil-sized borings and grazing trails riddle this grey, silty sandstone over about 1 metre. The borings show little organization. This unit was deposited under unique conditions, and these conditions must have been biologically quite restrictive.

UNIT IV

This, and the overlying unit show spectacular sedimentological features. The features are strongly contrasting and evoke a wide spectrum of geologic interpretations. ' First a description of this unit; sands and silty sands form the two distinctive lithological units. First, the yellow, cleaner sand units are seen, imbricated within the silts. Second, the yellow sands and grey silty sands are parallelly interbedded. The contrast between the two 'bed' forms within this unit provokes two schools of thought; one that suggests that these are contemporaneous depositional features, and the other which prefers penecontemporaneous deformation, to best explain what is seen here. It is unequivocal that some beds have been disrupted. Was it erosion and redeposition, or was it dewatering combined with differential compaction that disorganized the bedding?

UNIT III

This unit is spectacular. 200' (along strike) (25m wide, 3-5m deep) of symmetrical troughs of similar orientation, all with strongly eroded bases. The troughs are unlevied, without channel-log deposits. They are filled by a sequence of progressively less-concave, graded laminations. The top of the trough may show ripplemarks of remarkable symmetry with their crests, curiously oriented, parallel to the axis of the troughs. 'Channel' deposits filled by layers conforming to the channel shape with concavity upward with layers thinning towards the sides are typical of completely submerged channels. These sand filled 'channels' are not simple channels. It may be best to consider them later, in relation to the section as a whole.

UNIT II

Here sands and silty sands are interlaminated over a thickness of 25 ft. At the eastern end of the section, there is an erosional base, at the western end the base is gradational conforming with the top of the channels. Individual beds range between 4-10 cm. Only loading and dewatering structures are common. This rapid and repeated fluctuation in the sedimentary record is worthy of note.

UNIT I

The sands which are high on the cliff are difficult of access, but fallen blocks show them to be friable, with large calcitic pods which may be distinguished in the cliff face by their proud aspect. These massive sands may be festoon bedded (cross-bedding< 140 ) . Locally oxidised root imprints, and red-stained bifurcating borings, heamatitic clay nodules, suggest highly aerobic conditions. Occasionally, feathered vertical biogenic structures are seen, these are thought to be the result of borings made by Pelecypods (Mya) (Reineck 1958). The large borings with iron-rich modular skins are thought to belong to small shrimp-like crustacae, e.g. Callianassa, commonly found in the foreshore environment (Howard and Reineck 1972b).

DISCUSSION:

The paleontology suggests that these units were deposited in a marine environment; both the microfauna and the megatrace fossils have marine affinities. The mode of transport was indisputably fluvial, and thus, subsequently deltaic (angularity of sand and presence of carbonaceous material). The presence of carbonaceous material is not distinctive, but it does imply that the source of terrigenous material was not distant. There are no indications of deep water conditions prevailing, while this unit was being deposited. This is a paralic sequence (Selley, 1978).

The shales (mudstones) at the base, are as fine as any seen in any local outcrop; and the sands are not unlike others in this basin. There are no major hiatuses, thus, this must represent part of a single depositional cycle.

The mudstones show tranquil conditions, interspersed with sand deposition in higher energy conditions. Some units show evidence of strong turmoil ( a geologist once suggested, in broken English, "It's a Tornado"). The top most sand has not been studied in detail, but the cross-bedding suggests that it too, was deposited under highly energetic conditions.

This exposure coarsens upwards, and thus probably represents a progradation. Within the outcrop there are vestiges of erosional events, distinctly expressed in the channels. The direction of 'flow' was clearly along the channel axis. However, the ripple marks imply that the oscillatory environment in which they developed was oblique to the erosional flow in the channel. It is also clear that subsequent to the channel being eroded, sporadic deposition produced the peculiar laminate and symmetrical channel-fill seen here.

The two prevalent coastal (paralic) depositional environments are deltas and barrier bars. Deltas are the consequence of a variety of affecting and effecting deposition, which combine to produce diverse sedimentary records. Many contemporary deltas are rapidly reworked in wave or current dominated environments. Should the delta be reworked the sedimentary record stores, not the vestige of deltaic accumulation but the hallmarks of the final, conclusive mode of deposition.

This section has been reworked. Its sedimentary features indicate that deposition was effected under high energy, shallow water, littoral conditions. This sequence probably evolved in a prograding wave dominated beach/barrier bar environment, possibly, with strong longshore currents, not distant from a distributary fluvial system.

CONCLUSION:

It is presumptions, but interestingly provocative to imply so much from one strike section. It is critical to discover what happens in space, i.e. along strike and dip. Nothing is known of the sands dimensions or geometry. This section could be unique in the basins sedimentary record. Any inferences on a regional scale, from a single exposure, are sure to be misleading.

There are two possible avenues of further investigation. The first is to work the exposures along the south coast to determine paleocurrent directions and to check for lithologic consistency. The second route involves looking at the seismic profiles and the log motifs to best determine whether a thoroughly reworked delta or barrier bar/beach environment as proposed, fits what is seen in the north eastern part of the basin.

---

CONYBEARE, C.E.B.9

"LITHOSTRATIGRAPHIC ANALYSIS

OF SEDIMENTARY BASINS:'

1979, ACADEMIC PRESS INC.

1 ST EDITION

This book is a general review and commentary on the fundamental concepts and methodology of tectonics and sedimentation which are the bases for lithostratigraphic analysis. The book reviews a vast field of information, has very practical application and is well illustrated.

The text reviews the direct methods of lithostratigraphic analysis of sedimentary basins such as surface geological mapping and examination of subsurface drill cuttings and cores; indirect methods such as geophysical surveys and petrophysical logging of grain characteristics, physical and chemical properties, and the geometry of stratigraphic rock bodies. The author discussed the implications of these various methods to structural and lithostratigraphic aspects of basin analysis.

Other areas of interest covered in the text include concepts which are necessary for an analysis of sedimentary basins. These concepts involve principles of stratigraphy and sedimentation and the influence of tectonism.

(The author comments on some of the criteria involved in the construction of maps and sections and emphasizes the need to use all data in making a final, comprehensive interpretation). In the text, examples of application of lithostratigraphic analysis to concepts of exploration for hydrocarbons, coal, minerals, subsurface water resources, potential storage reservoirs for natural gas, and strata suitable for disposal of chemical waste are given.

The reading of the text on lithostratigraphic analysis of sedimentary basins in highly recommended for all practicing geologists, since such analysis is the basis for interpreting geologic history of sedimentary basins, which is the corner stone of exploration studies.

AMOCO The most encouraging news in the Oil Industry so far in 1982 has been Amoco's oil discovery in their Galeota Ridge III well situated approximately six and one half kilometers from Tesoro's Galeota Field and nine (9) kilometers from Amoco's Poui Field. The well which was drilled to total depth of 8005 feet in a water depth of 18 fathoms, flowed 900 BPD of 43 API oil and 0.3 million cubic ft. of natural gas on 24/64 inch choke from a sand at 3200 feet. Amoco plans to follow up this successful discovery with another well approximately six and one half miles to the north east. Further tests are being carried out in other sands.

TEXACO The Rowan Forthworth jackup drilling rig is expected in Trinidad late May, 1982 to drill Texaco's Iguana - 1 well in the Gulf of Paria. The well is proposed to a total depth of 12,500 feet. After drilling for Texaco, the rig will be contracted to Trintoc and Trinmar for drilling several wells in the Gulf of Paria over the next two years. Texaco has contracted a new rig from Well Services to drill three deep wells in their Barrackpore Lease. The rig which is capable of drilling to 12000 - 15000 feet is already drilling the first well.

TRINMAR Trinmar is presently gearing up for its next development Platform (No. 24) which will be installed in the North Soldado Field. Twelve (12) firm and seven (7) dependent infill locations will be drilled from this platform to depths of 6500 - 9500 feet. Effective spud date is third quarter, 1982. The drilling contractor is Skinner while Go International has acquired the logging contract for openhole logs.

TRINTOC Trintoc plans to operate four (4) rigs at least on a part time basis, on exploration activity for the rest of 1982. Well Services Rig - 1, which is capable of drilling to 6,500 feet and Skinner Rig 17 capable of drilling to 10,000 feet will be operated in Penal and Point Fortin areas. Skinner Rig 18 which will be coming to Trinidad from Barbados can drill to 15000 feet. It will be operating in the Penal and Ortoire fields. Off-shore drilling will be done by the Rowan Forthworht rig in Trintoc's NM-5 and S-1 blocks in the Gulf of Paria. Trintoc may run some seismic in ' the North Coast Marine Area in conjunction with Tenneco Oil Co.

TRINIDAD-TESORO is due to spud Platform "D" in its Galeota Field Area in July 1982. Seventeen (17) wells are planned to be drilled from this Platform two (2) of which will be semi-exploratory. The average depths of the semi-exploratory wells is approximately 7500' while the development well will be drilled to depths ranging from 1500 to 3000 feet. Once again Well Services slant rig will be used in the drilling of these shallow holes as was the case with Platforms B and C.

VENEZUELA

Conventional cores from surface to T. D.! Eight to nine days of open hole logging! Twenty-six logging services! Six months of computer processing. These are super wells 1 and 2.

A Joint venture between the government of Venezuela and Schlumberger, the wells were drilled in the heavy oil belt of Eastern Venezuela, Faja Petrolifera, to depths of approximately 5000 feet. The companies, Meneven and Maraven were the operators and were each responsible for the drilling of one well. From the gathering of both direct [conventional cores) and indirect (open hole logs) information, one can only assume that when the processing is completed and the data assimilated, more accurate information and innovative and useful interpretations can be obtained from the use of open hole surveys.