Wyniki wyszukiwania - BazTech

1

Changes in the physico-chemical properties of topsoil in a landslide-affected area (western part of the Transylvanian Basin, Romania)

Bălc Ramona, Roba Carmen, Rosian Gheorghe, Costin Dan, Horvath Csaba, Zglobiu Octavia Raluca, Chirtos Diana

Geological Quarterly

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2020

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Vol. 64, No. 4

931--941

EN

Landslides determine increases and decreases in specific soil compounds which is affecting soil fertility. The recovery of soil fertility is a long process and may be used as an indicator of the landslide age and can contribute to the management plan of the affected area. In order to add to data about soil properties affected by landslides, the current study focuses on a young and shallow landslide from the western part of the Transylvanian Depression. Soil samples were analysed from a physico-chemical point of view (pH, organic matter - OM, total organic carbon - TOC, major cations, and iron content) in two places, at between 0 and 60 cm depth (inside and outside the landslide). The results obtained showed lower values of pH inside the landslide, low values of TOC and rock fragments in both places studied (inside and outside the landslide) and no differences in soil texture between disturbed and undisturbed soil. The ammonium, magnesium and calcium content was higher outside the landslide, the sodium level was slightly higher outside the landslide, while the potassium concentration was higher inside the landslide. This study offers new data regarding recovery of soil fertility and highlights the importance of gaining knowledge on soil properties of relevance to future measures to increase the fertility of agricultural soils.

2

Palaeoenvironmental changes in the Transylvanian Basin during the Early Miocene revealed by the foraminifera assemblages

Székely S. F., Beldean C., Bindiu R., Filipescu S., Săsăran E.

Geological Quarterly

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2016

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Vol. 60, No. 1

167--180

EN

The evolution of the Transylvanian Basin during the Early Miocene has been restored from the succession of palaeoenvironments inferred from the sedimentological trend and succession of specific foraminifera assemblages from Lower Miocene Tihău section in northwestern Transylvanian Basin. Planktonic foraminifera suggest a Burdigalian age and recorded sea-level changes, climatic and productivity events. Benthic foraminifera offered valuable data on the palaeoenvironmental evolution, with a large-scale progradational (coarsening up) sedimentary succession influenced by regional tectonics. The succession of depositional events include: i) transgressive coarse grained deposits with typical mediterranean assemblages of bivalves in beach environments; ii) the glauconitic facies which can be associated to the maximum flooding surface of the transgression; iii) the sedimentation continued on a narrow shelf influenced by deltas during the highstand; iv) influence of regional tectonics and subsequent filling with turbidites associated to fan deltas.

3

Noninvasive stimulation opportunities in a marginal gas field

Stefanescu D. P., Nitulete A.

AGH Drilling, Oil, Gas

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2016

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Vol. 33, no. 2

507--514

EN

The Laslau Mare field is a brown gas field in the Transylvanian Basin. The field was developed in the 1970s and the production consists of more than 99% methane gas and low WGR (average of 0.03 m3/kscm). Current reservoir pressures are at a less than a third of initial values. As in any mature field with increasing water production and reservoir pressure depletion, several degrees of formation damage and tubular obstructions have been observed. Mud invasion, plugged perforation, water blockage and scale precipitation at the near wellbore region are factors impairing wells to produce at potential. Adding to the above the fact, the reservoir is water sensitive (low reservoir pressures and water wet reservoir). Severe constraints on production were seen when performing any sort of operation requiring the use of water based fluids, as severe losses occur. These procedures have always given post-job challenges to production engineers. Skin induced by mud or liquid losses is highly affecting wells post job performance. Long recovery times have been observed following workovers’ operations in Laslau Mare (0.5 to 2.5 years recovery for workovers and one to three months for wash treatments). Perforation and re-perforation operations are one of the best way to overcome the formation damage, bypass the invaded zones and open new production zones. Historically, perforation was done with casing guns in overbalanced condition. This practice induces immediately a skin created by fluids losses and prolong the flow back periods making the stimulation much less effective. Another methodology is to run through tubing guns and perforate in underbalanced conditions with smaller guns being limited by the completion size. In the latter case, the perforation performance are much less than the casing gun ones. In both cases, the full potential of the well is not achieved. A newer methodology is introducing re-perforation/perforation with casing guns in underbalanced, dry conditions, within snubbing operations. The methodology allows instantaneous gain of production and maximizes well recovery factor in the long term. Two pilot operations were executed with very good results and promising opportunities arise for candidate wells in the field.

4

New steps in finding the potential prospects for unconventional gas reservoirs in Transylvanian Basin (Romania)

Stefanescu D. P., Piteiu M. A., Vlasin I.

AGH Drilling, Oil, Gas

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2012

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Vol. 29, no. 1

285-292

EN

The present paper is considered a result of the Romgaz managerial team preoccupation for identifying unconventional gas resources and reserves in Transylvanian Basin and is also designed as a continuation of our last year assessments, In this respect was initiated a complex project in which we were involved. Because the recent studies have proved an insufficient maturity degree of the organic matter in Transylvanian Basin, so in this stage we can not speak about "shale gas", only "tight gas" category has been approached. The methodology applied in our study preparation included more steps which are briefly presented in the paper. After the inventory of our whole data base, with all the productive fields and also the areas between them, we performed a filtering of the collected data and information, focusing mainly on the new zones, inside the known structures and also on the isolated wells, located between fields. The main selection criterions were the Badenian formations, with low permeability and porosity, based on the cores analyses, located deeper at more than 2000 m, and tested with low gas flow rates. gas shows or even no flow (dry tests). For each selected packages and the individual isolated wells, we estimated the petrophysical parameters (porosity, gas saturation), geometrical ones in terms of area and net pay and energetical (the volume factor), in order to go further to computing the initial geological resources by volumetric method. Due to the uncertainty of each parameters involved, beside the computation in deterministic way, was applied the statistical method by Monte Carlo simulation, taking into account the minimum and maximum values of the parameters. The conclusions derived from our estimations, allowed to define a play associated with the deep zone of Basin "Deep Basin Center" and to propose few prospects, based on the most attractive selection criterions, in terms of volumes, net pay, cores and logs, 3D seismic, etc. As a result of our assessment, we hope to be implemented in the near future a pilot project.

PL

W artykule przeanalizowano wyniki badań ekipy menedżerskiej Romgazu nad określeniem niekonwencjonalnych złóż i zasobów gazu ziemnego w Basenie Transylwanii. Jednocześnie jest to kontynuacja ubiegłorocznych obliczeń szacunkowych. W ten sposób też został zainicjowany złożony projekt nad którym obecnie pracują autorzy pracy. Dotychczasowe badania wykazały niewystarczający stopień dojrzałości materii organicznej na terenie Basenu Transylwanii, dlatego na tym etapie trudno mówić o "gazie łupkowym", można jedynie o gazie uwięzionym w skale. Metodologia zastosowana w pracy została powiększona o kolejne etapy, które opisano w artykule. Po przeanalizowaniu bazy danych, wszystkich produktywnych złóż i obszarów pomiędzy nimi, zgromadzone dane i informacje przefiltrowano koncentrując się jedynie na nowych strefach, wewnątrz znanych struktur oraz na pojedynczych otworach w strefie między złożami. Głównie, na podstawie analizy rdzeni pobranych z głębokości z ponad 2000 m oraz badań gazu o małych prędkościach lub praktycznie zerowych przepływach (suche testy) wybrano badeńskie formacje o niskiej przepuszczalności i porowatości. Dla wybranych pakietów i pojedynczych, wyizolowanych otworów oszacowano parametry petrofizyczne (porowatość, nasycenie gazem), geometryczne pod kątem powierzchni i wydajności oraz energetyczne (współczynnik objętości), w celu dalszego obliczenia zasobów początkowych z wykorzystaniem metody objętościowej. Ze względu na niepewny charakter każdego z parametrów, poza deterministycznymi obliczeniami komputerowymi zastosowano statystyczną metodę Monte Carlo, uwzględniającą wartości minimalne i maksymalne parametrów. Z przeprowadzonych badań wynika możliwość określenia gry związanej z głęboką strefą Basenu, tj. "Głębokie Centrum Basenu" i zaproponowania kilku potencjalnych rozwiązań na podstawie najbardziej korzystnych kryteriów, np. objętości, opłacalności, rdzeni i profili, seismiki 3D. Opierając się na przeprowadzonych szacunkach mamy nadzieję wdrożyć projekt pilotażowy w niedalekiej przyszłości.

5

Origin of mineral waters from Someseni, Transylvanian Basin, Romania

Berdea P., Cuna S. M., Balas G., Hauer E.

Geological Quarterly

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2005

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Vol. 49, No. 2

145-150

EN

Analysis of the stable isotope composition of the mineral waters from Someseni, Transylvanian Basin, Romania has been made to constrain their origin. The mineral-rich aquifer islocated on the western border of the Neogene Transylvanian Basin. The isotopic study (18 O, D) of mineral waters from Someseni Spa was carried in order to rehabilitate them as natural curative waters. Water samples from five springs (1, 2, 3, 8 and 15), from Becas Brook and from River Somes were collected monthly from October 2003 to March 2004. The quantity of precipitation and the mean temperature in the area were monthly recorded. The deuterium vs. 18 O investigations of the springs indicate a meteoric provenance with deep circulation, having the deuterium content of meteoric water, but shifted to a higher 18 O content as result of isotopic exchange with coun try rock. The δ D and δ18 O values for springs 3 and 8 in February 2004 and March 2004 respectively, suggest some in fluence of surface waters derived from melting of the snow cover.