Abstract

Distinguished participants, ladies and gentlemen. I am pleased and honored to be here today to address to you on the current status of petroleum activities in Thailand.

Each day at present, we are importing about 230,000 barrels of oil and refined products to meet our domestic needs. While energy is a crucial factor in sustaining our social and economic growth, its high cost of import has been a heavy burden on our foreign exchange reserves.

To add to this problem, too much reliance on foreign oil has put our social and development plans at great risk particularly with respect to both pricing and political uncertainties in the producing countries.

Hence, the government's first step toward alleviating this problem was to put greater emphasis on developing our own natural resources. But although we have made substantial progress in exploiting our offshore natural gas and onland crude oil in the past decade, Thailand is and will continue to be a net oil importing country in the foreseeable future.

Abstract

The Chum Saeng Formation of the Phitsanulok Basin, onshore Thailand, is an Early Miocene organic-rich lacustrine shale that provides good source rock and seal to existing conventional hydrocarbon accumulations. The Phitsanulok Basin is the largest onshore Tertiary rift basin and also the largest oil production for onshore Thailand. The basin is situated in the Lower part of the Northern Thailand, approximately 400 km north of Bangkok. The field was discovered in 1981 by ThaiShell and was put on production since 1983. The main hydrocarbon production is from structurally trapped fluvial
dominated lacustrine deltas of the Lan Krabu Formation and fluvial dominated Yom and Pratu Tao formations. Average thickness of the Chum Saeng Formation ranges from 50 to 400 m, with total organic carbon (TOC) ranging from 5 to 20 wt% There currently is no unconventional production from the Chum Saeng Formation. However, the Chum Saeng Formation is hypothesized to contain pervasive (also known as basin-center accumulation, continuous accumulation, and deep basin) oil and gas accumulations. Pervasive accumulation describes the extensive unconventional hydrocarbon
accumulations within a basin. Most pervasive accumulations are abnormally pressured (high or low), commonly lack a downdip water contact, and have low-permeability reservoir rocks. This study investigated the potential unconventional petroleum system of the Chum Saeng Formation. Petroleum system elements and processes were. used as tools to assess the petroleum potential of the Chum Saeng Formation. The subsurface work done included: (1) mapping thickness, (2) mapping organic richness, (3) mapping thermal mahlrity, (4) identifying the hydrocarbon generation window, (5) interpreting source rock depositional environment, (6) source rock analysis, (7) one-dimensional basin modeling, (8) analysis of formation pressure, and (9) analysis of significant gas shows from mud log. Producing oil and gas fields from the Greater Green River, Uinta, and Piceance basins in the Western United States were used as analogs. The conventional petroleum within the Phitsanulok Basin results from hydrocarbon migration from the thermally mature part of the basin ("kitchen") into structural traps. These accumulations occur updip and around the hydrocarbon generation window and feature normal to slightly overpressured. The conventional reservoir rocks are sandstones with good porosity and permeability. Pervasive oil and gas accumulations are identified in the center of the basin, the Sukhothai Depression, within both the oil and gas generation windows. Potential reservoir rocks occur within the Chum Saeng (source), Sarabop, Lan Krabu, Pratu Tao, and Yom formations, range from poor (less than 10 %porosity) to good (more than /0 %porosity) reservoir quality. The Chum Saeng Formation shares many similar properties to those of the currently producing pervasive oil and gas fields in the Greater Green River, Uinta and Piceance basins. However the rock units in the Phitsanulok Basin have lower pressures and reservoir rocks are expected to be less fractured, so there is a very low chance the rock will produce naturally; also the reservoir continuity is low. Reservoir enhancement (porosity and permeability) by hydraulic fracturing will play a crucial role in developing these potential pervasive accumulations. The study result provides new exploration opportunity to the
matured basin, by applying the unconventional thinking and using existing producing fields as analogs. Further investigations are including drilling unconventional exploration well to get the direct formation information.

Abstract

The main purpose of this short note is to introduce an onland area Where hydrocarbon potential is favorable, planning and exploration can be considered. The synthesis made was based on geological informations obtained during the geological mapping in southern Thailand, and by means of comparative study of all aspects with the known hydrocarbon accumulated areas in other parts of the country. The proposed sedimentary basin discussed here has all principal requirements for hydrocarbon potential. However, the surface and subsurface informations are not adequate and further detailed studies are required.

Abstract

During the past several years the Thai  Government has become increasingly interested in
finding oil deposits in Thailand that will supply her  ever-increasing need for petroleum and petroleum products. Simultaneously, some  foreign oil companies and various private interests in Thailand have also shown con-  siderable interest in oil exploration in Thailand.

With this in mind the Royal Thai Department of Mines and USOM/Thailand are commencing to gather and analyze basic geologic data that will aid and accellerate the search for oil in Thailand. This paper is an attempt to summarize the conclusions that I have reached regarding oil in Thailand on the basis of the very small amount of geologic information now available. It must be emphasized, however, that these opinions are based on scanty information, and that I may change them at any time as more geologic information is obtained.

First, however, it might be well to briefly outline the manner in which deposits of petroleum are formed in the rocks of the earth and to point out some of the difficul- ties in finding these hidden deposits.

Oil is a particular kind of hydrocarbon that is sometimes formed when the dead bodies of plants and animals are buried in muds and sands under conditions that prevent them from rotting completely. Usually, but not always, these muds are deposited in shallow marine bodies of water such as the Gulf of Thailand. Gradually and slowly this area sinks and more and more muds and sands are piled into it until the total thickness of sediments may be a thousand meters or more.

Abstract

Oil shale is commonly found in Tertiary intermontane basins throughout Thailand. They are thin bedded/laminated associated with Lacustrine shales and/or swamp-peat lignitic layers of Oligocene/Miocene age.

Exploration of oil shale in Thailand started in Mae Sot Basin, Northern of Thailand, more than 50
years ago. However, systematic exploration was carried out by the Department of Mineral Resources
after the oil crisis in 1973. Detail mapping and gravity survey were conducted and 156 holes ranging
in depth from 300-2,000 feet were drilled. Oil shale with thicknesses of 5-100 feet were found
interbedded with claystone, marl and siltstone. Distribution of these oil shale covers an area of about
200 km2.Geochemical analyses of over 10,000 samples indicates that the quality of these oil shale is
rather low. They contain average oil yield of 5% by weight or 12 gallons per ton which equivalent to
1,100 calories/gram of heating value and 60% ash content. High quality oil shale which has oil yield
more than 10% to a maximum of 26% by weight was also noted, but only small quantity. The total inplace reserve of oil shale in the Mae Sot Basin is approximately 18,000 million tons ( 6,000 million barrels of oil equivalent) which covers an area of about 54 km2.

Feasibility study was conducted by the Department of Mineral Resources in conjunction with the
Federal Republic of Germany and Japanese gevemment agency. They pointed out that the tendency
and potential ,for Mae Sot oil shale, could be developed by combining both direct burning and retorting for the purpose of electricity generation, raw material for cement factory and sync rude. For
the actual development scheme, it must be emphasized on an appropriate technology, economic situation and environmental impacts.

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