Wyniki badań objawów bituminów w otworze Maczki IG-1

Zdzisław Dembowski, Andrzej Różkowski




From February 21, 1963 to February 25, 1965, a deep key well Maczki IG-1 was drilled in the Upper Silesian Coal Basin. Drilling process was accompanied by manifold geophysical measurements. The bore hole pierced a 24 m thick series of Quaternary deposits and encountered Carboniferous formations, 2131 m in thickness. The formations were represented by the Ruda, saddle, Grodziec, Flora, Sarnów and Malinowice beds, developed as siltstone-claystone rocks and sandstones, with seams and intercalations of coal in the Upper part of the section (to the Sarnów beds inclusive).
A 28 m thick series of marls and marly clays referred by K. Bojkowski to the lower part of the Upper Visean, has been found to occur under the Malinowice beds. Beneath, there rest fine-crystalline, pelitic, locally detrital limestones containing, down to a deplth of 2388 m, some amphipores (according to M. Pajchlowa the series from 2388 moo 2907 m represents Frasnian–Givetian).
The uppermost part of the carbonate serias (2183–2388 m.) has not so far been stratigraphically subdivided, and may comprise both the lowermost stages of the Lower Carboniferous and the uppermost ones of the Devonian.
During drilling works, traces of bitumens were observed in both drill mud and drill core (Fig. 1); the greatest oil manifestations and a strong gas escape from the mud were observed after piercing the carbonate series.
On the basis of the observations made during drilling operations, and on interpretations of logging curves (Fig. 2) these intervals were distinguished for examinations at a depth from 2270 m to 2183 m (table 1). Both perforation and acidizing of the well gave, generatly speaking, negative results only.
The lowermost interval (2270–2260 m) gave a feeble amount of bringe (35–90 l/day), the higher intervals being completely unproductive. Before the well was abandoned shooting operations were made at the depths from 2207 to 2203 m and from 2199 to 2195 m, resulting in a small outflow of brine and in distinct oil traces.
Laboratory examinations of the carbonate series (Table 2) demonstrated a minimum porosity of limestones and almost no permeability. It should, however be stressed here that the rocks, though compact, are fractured and ,their permeability is of fissure character; practically, this character can hardly be determined on the basis of drill core samples (at places 10% core recovery only).
Gas manifestations, observed in drill mud during drilling, have been examined, and the results are presented in Table 3. An analysils of oil and brine taken from the welle after shooting have been made, too.
After the carbonate series was pierced, a distinct increase in mineralization of drill mud appeared. The mineralization increased gradually with depth (Fig. 1).
A rapid increase dn mineralization degree of drill mud was accompanied also by a dilution of the mud, observed at a depth of 2805 m. The investigations show here a different degree of water content in the carbonate complex, the top portion of the complex being only scarcely water-saturated. Chemical properties of water  (Table 4) and character of the coefficients Na/Cl = 0,834, Cl/HCO3 = 328 and SO4+HCO3/ Cl = 0,0045 point to a considerable metamorphic process of the waters and to their occurrence in a stagnation zone as isolated waters.
Bitumen manifestations, ascertained in the well Maczki IG-1 in a carbonate series isolated by the Upper partly also by the Lower Carboniferous deposits, corroborate a thesis that the shows of liquid bitumens observed in the deposits of productive Carboniferous (J. Kuhl, T. Milecki, 1957; A. Kotas, W. Malczyk, 1964) are connected with the migration from the deposits overlain by the productive Carboniferous.
Thus, a virtual possibility exists to search for bitumen deposits in the formations discussed above, however, additional researches should be made, too, since a lack of positive effects of the tests made in the well Maczki IG-1 might be a result of deep clagging of fissures with drill mud and with cementing material responsible for a failure during perforation or acidizing works necessary for opening prospective oil-bearing horizons.


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