Zintegrowana analiza anomalii sejsmicznych wraz z interpretacją danych geofizyki otworowej dała podstawy do odtworzenia środowiska sedymentacji osadów mioceńskich zapadliska przedkarpackiego. Zmienność wykształcenia osadów, zarówno pionową, jak i poziomą, prześledzono na podstawie szczegółowej korelacji międzyotworowej, a następnie, wykorzystując dodatkowo analizę charakteru wykształcenia krzywych geofizyki otworowej, dokonano próby określenia zarysu architektury depozycyjnej. W celu odtworzenia środowiska sedymentacji na większym obszarze, posłużono się szczegółową interpretacją zdjęcia sejsmicznego 3D. Analiza form geoanomalii i badanie spójności zapisu sejsmicznego zaowocowało wydzieleniem różnych elementów paleomorfologii, takich jak: koryta, wały przybrzeżne, stożki i litosomy.
EN
Integrated analysis of seismic anomalies together with well logging data interpretation was a basis for reconstruction of processes of depositional environment of the Miocene succession, in the Carpathian Foredeep. Vertical and lateral variability of sediments was analysed using detailed wells correlation. Then, using the analysis of a shape of well logs, the outline of depositional architecture was determined. In order to determine the sedimentology environment in a larger area, the detailed 3D seismic data results interpretation was used. The analysis of geoanomalies forms and coherence of seismic record resulted in differentiation of various paleomorphology elements such as: channels, subaqueous levees, fans and lithosom.
Reprocessing of 3D seismic data from the Carpathian Foreland and new interpretation techniques enabled more accurate mapping of structure and facies distribution of Miocene series and their bedrock. The reprocessing of a part of Sokołów Małopolski–Smolarzyny, 2001 3D seismic survey carried out in 2006 was focused on the Pogwizdów structure. Application of GeoProbeŽ software and the detailed analysis of seismic trace attributes along with the structural interpretation gave new information on morphology of the pre-Miocene bedrock and Miocene series. The area of erosional channels (paleovalleys), where anhydrite sediments and probably the Baranów Beds were distinguished, is particularly interesting as it is characterized by some distinctive anomalies of the analyzed seismic attributes. The evidence for presence of anhydrite within the so-called anhydrite-less island significantly enhances probability of discovering new gas fields with the Baranów Beds as reservoirs and anhydrites as a seal. The number of potential gas fields should compensate for their small reserves.
The Miocene Carpathian foredeep basin in Poland (CFB) developed in front of the Outer Carpathian fold-and-thrust belt, at the junction of the East European craton and the Palaeozoic platform. 3D seismic data, cores and well logs from Sokołów area (vicinity of Rzeszów) were used in order to construct new depositional model of the Miocene succession of the Carpathian foredeep. The gas-bearing Miocene infill of the CFB is characterized by a shallowing-upward trend of sedimentation and consists of hemipelagic, turbiditic and deltaic and nearshore-to-estuarine facies associations. Lowermost part of the Miocene infill seems to has been deposited from the North. Such direction of sediment supply was related to influence of existing relief of the pre-Miocene basement, where very deep (up to 1,5 km) erosional valleys cut into the pre-Miocene (Precambrian) basement due to inversion and uplift of the SE segment of theMid-Polish Trough are located. Upper part of theMiocene infill reflects sediment progradation from the South, from the Carpathian area into the foredeep basin. In the Rzeszów area existence of the so-called anhydrite-less island, i.e. relatively large area devoid of the Badenian evaporitic cover caused by the post-Badenian uplift and widespread erosion of evaporites,has been postulated for many years. Interpretation of 3D seismic data showed that such model should be abandoned. In the studied part of the CFB, Late Badenian evaporitic sedimentation was restricted to the axial parts of deep paleovalleys. Evaporites deposited in these valleys have been rarely encountered by exploration wells as such wells were almost exclusively located above basement highs separating erosional paleovalleys, hence giving incorrect assumption regarding regional lack of evaporitic cover. It is possible that in axial parts of these valleys important gas accumulations might exist, charged from the South and sealed by the Badenian evaporites.
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Do rozpoznania elementów geomorfologii sejsmicznej na zdjęciach 3D osadów miocenu rejonu Dębica—Rzeszów—Sokołów Małopolski zapadliska przedkarpackiego wykorzystano szereg atrybutów sejsmicznych oraz przestrzenną wizualizację 3D. Uzyskane wyniki wskazują na obecność w utworach dolnego sarmatu dwóch systemów podmorskich koryt. Lokalnie rozwinięty system poprzeczny ma części proksymalne ukryte pod nasunięciem stebnicko-karpackim, a w kierunku NE łączył się z systemem osiowym o rozciągłości co najmniej 40 km i przepływie w kierunku E-SE. Koryta w obu systemach wykazują niską krętość, lokalnie anastomozującą lub meandrową geometrię, a ich szerokość wynosi 0,1-0,7 km. Wypełnienia koryt i ich amalgamaty, wykazują miąższości około 5-100 m i prawdopodobnie głównie heterolitowy charakter.
EN
A number of seismic attributes derived from five, partly overlapping 3D seismic datasets, were analyzed in order to get an insight into depositional elements of Miocene strata in SE part of the Carpathian Foreland Basin. Results point out the presence of two, major submarine channel systems in lower Sarmatian deposits. A locally developed transverse system has its proximal reaches hidden beneath the Stebnik-Carpathian thrust and it merges towards NE into an axial system, min. 40 km in extent, which drained to the E-SE. Channels show generally low sinuosity, locally anastomosing to meandering patterns, and their width varies between 0.1 and 0.7 km. Channels' fills, 5-50 m thick, are probably largely heterolithic in character.
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Tematem pracy jest wykorzystanie najnowszych metod inwersji sejsmicznej dla osadów czerwonego spągowca w obszarze zdjęcia sejsmicznego 3D Parzęczewo—Czarna Wieś. Wcześniejsze badania sejsmiczne przeprowadzone na wspomnianym terenie umożliwiły odkrycie złóż gazu typu litologicznego i strukturalno-litologicznego (Ujazd, Paproć—Cicha Góra). Analizy sedymentologiczne i geologiczne oparte na danych z głębokich odwiertów, wskazały na możliwość istnienia złóż związanych z wyklinowaniami serii osadowej czerwonego spągowca na północnym skłonie wału wolsztyńskiego [2]. Wykrycie pułapek strukturalno-litologicznych i określenie linii zasięgu piaskowców saksonu wymaga szczegółowych analiz amplitudowych odbicia od stropu serii osadowej czerwonego spągowca. Autor wykonał kompleksową analizę wspomnianego refleksu w oparciu o zapis sejsmiczny przygotowany z zachowaniem rzeczywistych relacji amplitud. W ramach ww. badań wykonano modelowanie syntetycznych kolekcji CDP oraz inwersję symultaniczną (inwersję sejsmiczną przed składaniem), której parametry oparte zostały na licznych krzywych karotażowych. Przygotowania do projektu oraz rezultaty inwersji zostaną szczegółowo przedstawione w czasie prezentacji.
EN
This paper describes the up-to-date seismic inversion methods that were utilized in the area of 3D seismic project Parzęczewo—Czarna Wieś. The previous 3D seismic investigation in this region enabled to discover the presence of gas reservoirs in the form of structural- stratigraphic and stratigraphic traps (Ujazd, Paproć—Cicha Góra gas field). Numerous geological and sedimentological investigations based on well data indicated that the area in question is still highly prospective. In order to outline stratigraphic traps, a careful amplitude analysis of top reservoir reflection is required. On the basis of pre-stack seismic data, processed with preserved true relative amplitudes, author performed comprehensive study of the Zechstein Base reflection. Within the scope of the project an extensive synthetic gather generation and simultaneous prestack inversion was carried out. The preparations and results will be thoroughly discussed during presentation.
TThe Polish Carpathian Foredeep Basin (PCFB) is the northern compartment of a foreland basin system that surrounds the Carpathian orogenic belt. The axis of the eastern part of the PCFB plunges gently towards SE, where the Miocene basin-fill succession exceeds 2000 metres in thickness. The Miocene succession developed in shallow marine ramp settings and is subdivided into 3 lithostratigraphic units: sub-evaporitic (onshore-to-nearshore), evaporitic, and supra-evaporitic (offshore-to-estuarine). The upper unit includes a siliciclastic series (Upper Badenian–Sarmatian), which constitutes the main segment of the succession. It displays an asymmetric, shallowing-up trend, expressed by the following sequence: hemipelagic-turbiditic-deltaic-low-energy nearshore-to-estuarine facies associations. Sediment accummulation in the basin has been significantly overprinted by higher-frequency cyclicity and encloses several genetic stratigraphic sequences bounded by MFS surfaces. An early phase of the basin development was characterised by high-rate subsidence and slow-rate sedimentation (hemipelagic facies). The turbiditic facies association identified within the Sieniawa–Rudka area resulted from southward progradation of a submarine fan/prodeltaic depositional system, mainly fed from the northern and north–western continental margins of the basin. An overall SE–ward palaeoslope inclination controlled the main phase of the deltaic progradation, which had gradually replaced the turbiditic systems. The late deltaic phase was characterised by ENE palaeotransport directions. The final phase of the basin filling took place in shallow-water, low-energy, nearshore-to-estuarine environments. In the early stage of the basin development, a complex system of NW–SE elongated basement pop-ups and flower structures in the Miocene succession were produced by reactivation and inversion of Mesozoic basement faults. The growth of these positive structures modified local subsidence patterns and affected the organisation of depositional systems of the siliciclastic series. A narrow elevation of the RyszkowaWola High (RWH) gradually grew above one of the pop-up structures. Complex structural-stratigraphic hydrocarbon traps developed along the RWH, due to interaction between the growth of local faults and the development of the successive depositional systems. Tidally-modified delta-top and estuarine facies are the most common hydrocarbon hosts within individual sequences of the „deltaic” segment of the succession..
The Miocene Carpathian Foredeep Basin in Poland (CFB) developed in front of the Outer Carpathian fold-and-thrust belt, at the junction of the East European craton and the Palaeozoic platform. Within the upper Badenian through Sarmatian deposits of its eastern part, the CFB hosts numerous gas fields. The gas-bearing Miocene succession is characterised by a shallowing-upward trend of sedimentation and consists of offshore hemipelagic, turbiditic and deltaic and nearshore-to-estuarine facies associa-tions. The foredeep basin formation was largely controlled by the structure of its Neoproterozoic–Early Cambrian basement, especially by NW–SE trending faults inherited from Mesozoic tectonic history of SE Poland (subsidence and inversion of the Mid-Polish Trough). Several NW–SE-elongated, narrow basement pop-up structures developed in the northeasternmost part of the CFB, one of them being the Ryszkowa Wola block. The uplift of the pop-up basement block involved Miocene reactivation of older fault zones and resulted in the formation of a narrow, NW–SE elongated Ryszkowa Wola horst (RWH) above it, within the Miocene strata. A complex system of right-stepping, en-echelon, mainly normal faults of predominantly E–W trend, branching off from the NW–SE-striking boundaries of the RWH, has developed around and above the horst, leading to compartmentalisation of the Miocene succession into numerous, mutually displaced and rotated fault blocks. Such an association of deformation structures recognised from the 3D seismics was interpreted in terms of transpressive conditions with the horizontal maximum tectonic compression axis directed š E–W and a sinistral strike-slip displacements on NW–SE striking faults in the basement. The structural interpretation of the Ryszkowa Wola structure proposed here is in line with published results of analogue modelling of fault patterns in sediments overlying active strike-slip discontinuities in a rigid basement. The basement-cover interaction within the Ryszkowa Wola structure in the area of Sieniawa–Rudka was partly coeval with the Miocene deposition of the CFB infill. The uplift and horizontal displacements of the Ryszkowa Wola basement block modified the local subsidence pattern and the organisation of Miocene depositional systems. The syn-depositional strike-slip fault activity in the basement of the CFB resulted in differential movements and rotations of kinematically linked fault-blocks in the Miocene succession around and above the RWH, leading to the formation of numerous gas traps.
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Poziom wapienia cechsztyńskiego stał się jednym z najbardziej perspektywicznych poziomów zbiornikowych z punktu widzenia poszukiwań w Polsce. Rejon paleoelementu zwanego wałem wolsztyńskim był na początku transgresji morza cechsztyńskiego naturalnym miejscem sedymentacji typu rafowego na lokalnych paleopodniesieniach szelfu. Rafy te w wyniku gry naftowej stały się pułapkami akumułującymi gaz migrujący z utworów wieku karbońskiego. Dane sejsmiki 3D integrowane z pozostałymi rodzajami danych pozwalają na wydzielenie ciał rafowych-pułapek w procesie interaktywnej, komputerowej interpretacji opartej na czynniku litofacjalnym. Wykorzystuje ona informacje dostarczane przez geofizykę otworową i elementy paleogeografii możliwe do pozyskania z danych sejsmiki 3D. Wydzielenie pułapek umożliwia przejście do następnego etapu, polegającego na określeniu ich geometrii i porowatości. Pozwala to obliczyć zasoby złoża. Zastosowane procedury interpretacyjne zostały potwierdzone rezultatami 12 otworów odwierconych na rafie Kościan i czteroma następnymi na rafach Bonikowo, Białcz, Brońsko i Kokorzyn. Ich efektem jest osiągnięcie, niespotykanej w polskiej praktyce poszukiwań węglowodorów, skuteczności wierceń.
EN
The Zechstein LHmestone formation became one of the most perspective reservoirs as far as the to exploration carried out in Poland is concerned. The region ofpalaeoelement, referred to as the Wolsztyn ridge, used to be a natural sedimentation place of the reef type on the local palaeoelevation of the shelf at the beginning of the Zechstein sea transgression. As a result of hydrocarbon play, these reefs became accumulation traps for the migrating gas that takes it origin in the strata of the Carboniferous age. The 3D seismic data integrated with other types of data allow for the selection of reefs-traps in the process of interactive, computer analysis based on the lithofacies factor. It makes use of the information supplied by well logging and elements ofpalaeogeography which can be acquired from 3D seismic data. The selection of traps open the possibility of passing to the next stage which consists in determining geometry and porosity. The determination of the said allows to calculate reservoir reserves. The applied interpretation procedures have been confirmed by the results received in 12 wells in the Kościan reef and four others in the Bonikowo, Białcz, Brońsko and Kokorzyn reefs. The effect is the efficiency of drilling unprecedented so far in Polish practice of exploration.
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