PRINCIPLE RESULTS OF THE MAJOR SCIENTIFIC

INVESTIGATIONS FOR hydrocarbons IN THE

SWEDISH DEEP GAS EXPLORATION PROJECT

 

 

J. F. Kenney

Gas Resources Corporation, 11811 North Freeway, fl. 5, Houston, TX 77060, U.S.A.;

Institute of Earth Physics, Academy of Sciences, Bolshaya Gruzinskaya 10, 123.810 Moscow, RUSSIA..

 

 

          The Swedish deep gas exploration project involved the drilling of two deep wells in the granite environment of the Siljan meteorite impact structure.  Although the preliminary scientific investigations which preceded the drilling of the deep wells were conducted with competency, the subsequent exploration activities delivered almost no value scientifically and none commercially.  The drilling of the first well, Gravberg 1, was an engineering fiasco, and many of the most important of its scientific investigations were badly mishandled.  The project for drilling the second well, Stenberg 1, in December 1991 degenerated into an "opera buffa" accompanied by financial chicanery.

            The scientific information generated by the Swedish deep gas project has previously been mishandled particularly such connected with the observations of hydrocarbons.  The drilling of the Swedish deep gas exploration project did not discover either natural gas or oil in more than trace amounts and has been a commercial failure.  Regrettably there has been heretofore considerable misunderstanding concerning the scientific information generated by the Swedish deep gas project, particularly such connected with the observations of hydrocarbons.  Specifically to clear up misunderstandings of such, here are reported the following:

 

1.)     The observations and measurements of the full suite of light hydrocarbon gases from Methane through n-Hexane from the granite basement while drilling the second well, Stenberg 1, with pure fresh water;

2.)     The determination, through application of the technique of second-derivative absorptive spectroscopy, that the oil pumped from the well Gravberg 1 incontrovertibly contained a component of unrefined, native, formation oil;

3.)     The measurement of mantle markers of the Group VIII Platinide series in the formation oil observed during the drilling of the first well, Gravberg 1;  and

4.)     The observation of thermophilic, chemo-synthesizing, hydrocarbon-metabolizing bacteria at depths in the granite exceeding 3,000 meters.

 

1.)     The observations and measurements of the full suite of light hydrocarbon gases from Methane through n-Hexane from the granite basement while drilling the second well, Stenberg 1, with pure fresh water.

          Here follows a table which records typical measurements of the hydrocarbon gases liberated from the pure water drilling fluid upon return from the hole being drilled during part of an approximate three day period between 17-19 September 1991.  On those dates, the depth at which the well was drilling was approximately 3,300 m.  These particular sample data have been chosen primarily because they are typical of the hydrocarbon fluids observed in course of the scientific testing which was carried out during the course of drilling;  many, many similar sets of data could be given.

          These fluids may be considered "headspace" gases because they were broken out of water from the return line and allowed to collect in a enclosed chamber where they displaced water which had previously filled it.  The gases were taken from their collecting chamber in stainless steel canisters of volumes between 150-3,800 cm³ equipped with stainless steel valves;  the canisters had been previously cleaned and charged with Nitrogen.  The canisters were shipped by air to the laboratory Geochemische Analyzen GmBH in Lehrte, Germany, where their contents were analyzed by mass spectrometer.  The major component of the gas samples was always Nitrogen for which the volume percentage varied between 78%-97%;  the Oxygen volume percent varied between 1.8%-4.04%, and the same of Carbon Dioxide and Argon between 0.01-0.02% and 0.87-1.07%, respectively.  Measurement of the hydrocarbon gases is in parts per million (ppm).

 

 

          In order to exclude data which might contain contamination, particular attention has been given in the selection of this data for samples with no cis-Butene or Ethine at the ppm level.  Although the drilling process was circulating several thousand gallons of pure water containing no drilling fluid additives of any sort whatever, the mass spectrometer analysis was sensitive to detect trace amounts of hydrocarbon gases attributable to small amounts of pipe and collar dope used making up the drill string.  Specific among these was cis-Butene whose presence was recognized as an indicator for trace contamination by pipe or collar dope.  The pipe and collar dope used had previously been analyzed thoroughly to ascertain its chemical constituency.  Monitoring of the hydrocarbon fluids in both the circulating water and the headspace gases established that those contaminants were removed from the system after 1-3 "bottoms-up" circulations following either the addition of a new stand of drill pipe or a trip into the hole.

          The presence of the full suite of saturated Alkane hydrocarbons from Methane through Hexane is observed at once in this data.  Present also are the Alkenes from Ethene through Butene, in lesser abundance than the Alkane of equal Carbon weight.  The dominant component in all samples is Methane.  The distribution of hydrocarbon gases is characteristic of the same as observed in petroleum reservoirs.

          These observations of hydrocarbon gases in the well Stenberg 1 are not significantly different from the same made during the drilling of the first well, Gravberg 1.  However, during the drilling of Gravberg 1, there was never maintained proper control over the use of chemical additives in the drilling fluid;  nor was there ever proper analysis and characterization of those additives.  Such lack of control generated uncertainty concerning the origin of the hydrocarbon gases when such were observed during the drilling of Gravberg 1.  Consequently there developed much argument over whether the hydrocarbon gases observed in Gravberg 1 had originated from the granite environment or had resulted from some alteration of drilling fluid chemicals during the drilling process.

          The stringent controls maintained during the drilling of Stenberg 1 have removed all of the uncertainty associated with the origin of the hydrocarbon gases observed during the drilling of both those wells:  The full suite of hydrocarbon gases from Methane through Hexane have been observed in both wells;  and their observation during the drilling of Stenberg 1 under conditions which admit no suggestion of contamination by chemical drilling fluids has determined that those gases entered the well bore and the drilling fluid from the granite environment at depth.

 

2.)     The determination, through application of the technique of second-derivative absorptive spectroscopy, that the oil pumped from the well Gravberg 1 incontrovertibly contained a component of unrefined, native formation oil.

          During the final stages of drilling the first well, Gravberg 1, a pump was run into the well to a depth of approximately 4,500 ft., and a substantial amount of oil was withdrawn from the hole during a six week testing period.  Unfortunately, there had been an attempted hydraulic fracturing test carried out on the well using diesel oil as the frac fluid several weeks prior to the pumping operation.  Inevitably, there arose again contention over whether the pumped oil was simply, and solely, the diesel frac fluid or contained any component of a native, formation oil.  In order to resolve that uncertainty, the technique of second-derivative absorptive ultra-violet spectroscopy was borrowed from the aerospace industry and applied to several samples of the oil pumped from Gravberg 1.

          The particular method of second-derivative absorptive spectroscopy applied measured the relative abundances of the trace components Benzene, Toluene (Methylbenzene), Ethylbenzene and Xylene (Dimethylbenzene), - the so-called BTEX analysis.  These compounds are all very volatile, the lightest being Benzene and the others consecutively heavier.  The Gibbs chemical potential, , of these compounds increases by approximately 2 Kcal/mole, with Benzene possessing the lowest chemical potential and Xylene the highest.  The combination of the effects of these properties of mass and chemical potential produce distinct, and immediately recognizable, differences in any sample of hydrocarbon material depending upon whether such might be a refined product:  Because Benzene is the compound with the lowest chemical potential, in a natural, unrefined mixture of hydrocarbons, there will be almost always be more Benzene than Toluene, more Toluene than Ethylbenzene, and more Ethylbenzene than Xylene.  However, in a sample of refined hydrocarbon material, because Benzene is the lightest and the most volatile, the preceding progression of abundances in reversed;  and there will be less Benzene than Toluene, less Toluene than Ethylbenzene, and less Ethylbenzene than Xylene.  Thus in any sample which has been collected carefully and for which the BTEX analysis has been carried out properly, there is usually an immediately recognized pattern which establishes whether the hydrocarbons have been refined.  Furthermore, the BTEX analysis has been developed into a highly sensitive tool such that it can be used to distinguish one or more components of a sample into refined products and natural hydrocarbons.  The BTEX analysis of the oil pumped from Gravberg 1 was performed by Exploration Technologies of Houston, Texas.  The results of those analyses established that much of the oil pumped from Gravberg 1 was indeed the diesel frac fluid which had previously been put into the well;  and those same BET analyses established incontrovertibly that there was also in that pumped oil a component of native, unrefined indigenous crude oil.

 

3.)     The measurement of mantle markers of the Group VIII Platinide series in the formation oil observed during the drilling of the first well, Gravberg 1.

          A mantle marker is any entity, - nuclear isotope, atom, molecule or even crystal structure, - which by either its presence or its relative abundance demonstrates an origin in the mantle of the Earth.  The atoms of the rare, siderophilic Group VIII Platinide metals,which include, in addition to Platinum and Palladium, the rare elements Iridium, Rhodium, and Osmium can serve as mantle markers.

          A heavy petroleum fluid was observed on several instances during the drilling of Gravberg 1, once during the Summer of 1986 and again during the Winter of 1989.  The material was a heavy, black petroleum fluid characterized by a strong, pungent smell, and became popularly known as the Gravberg 1 "Black Gunk".  As with the observations of hydrocarbon gases and in absence of proper controls or monitoring, there arose almost at once argument over the origin of the so-called "Black Gunk" material.  Among other hypotheses was offered a suggestion that the petroleum material might have resulted from some extraordinary transformation of such as soy bean oil or organic alcohols as are found in such drilling fluid additives as "Torque Trim".  In order possibly to eliminate such uncertainties, we had several samples of the Gravberg 1 "Black Gunk", taken respectively from the well depths 18,900 ft. and 22,781 ft., analyzed for unusual presence of the mantle marker Iridium.  The results of the Iridium abundance measurements, which were carried out by Dr. Frank Asaro and Dr. Helen Michels at the Lawrence Berkeley Laboratory using neutron activation techniques, are described in part in the following table.

 

 

          As the data reflects, the Iridium content in the Gravberg 1 "Black Gunk" from both depths manifested very high abundances of Iridium.  The abundances of Iridium at both depths was greater by at least two orders of magnitude from such found in crustal rock and was greater even than the measured values for Ir in MORB available at the time.  As a cross check, particularly in light of the fact that the Siljan Ring is a meteorite impact structure, several measurements of the Iridium abundance were made in local rocks.  Those measurements established that the local rocks from the Siljan Ring do not contain unusual abundance of Iridium and that the Iridium in the Gravberg 1 "Black Gunk" could not have originated either from shallow local rock or from any drilling fluid chemical additive.

 

Printed in: Proceedings of the VII^th International Symposium on the Observation of the Continental Crust through Drilling, 1994, DOSECC, Santa Fe, NM, 25-28