Wyniki wyszukiwania - BazTech

1

Study on selection and direct inversion method of brittleness index for shale reservoir

Qin Ziyu, Wen Xiaotao, Pan Shulin, Chen Jing-yi, Gou Qiyong

Acta Geophysica

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2023

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Vol. 71, no. 2

757--768

EN

The brittleness index can be indirectly converted by elastic parameters which are obtain by pre-stack amplitude variation with offset inversion and extended to the whole work area. However, indirect conversion will bring cumulative errors. In order to improve the accuracy of obtaining the brittleness index, the exact Zoeppritz equation including different brittleness indices is derived. Before inversion, we analyzed the characteristics of the brittleness index under the changes of brittle minerals, porosity and organic matter content through rock physics model, and selected the brittleness index most suitable for the work area. Based on the Bayesian framework, we introduce the Limited-memory Broyden–Fletcher–Goldfarb–Shanno (L-BFGS) method to invert theoretical and actual data. Theoretical data inversion results demonstrate this method can achieve good results in both PP- and PS-wave joint inversion as well as only PP-wave inversion. To further verify the effectiveness of the algorithm, the brittleness index of actual data is directly inverted by using the studied algorithm and process. The inversion results of the borehole-side trace are in good agreement with the brittleness index calculated by log data. Both theoretical and practical data prove the feasibility of our proposed method.

2

Bayesian seismic AVO inversion with a group optimization strategy

Li Chuanhui, Liu Xuewei

Acta Geophysica

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2023

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Vol. 71, no. 6

2733--2746

EN

The seismic amplitude-versus-offset (AVO) inversion based on the Bayesian framework is effective for obtaining the elastic parameters of the stratum from observed seismic data. Usually, this algorithm is used to obtain sparse reflectivity levels of elastic parameters through a proper long-tailed prior probability distribution. Considering the high correlation between underground parameters, a group optimization strategy was used for Bayesian AVO inversion, where the model parameters were inverted in groups at reflection interfaces. A group Cauchy constraint consisting of Cauchy constraint and l2-norm was designed. In the constraint, the Cauchy constraint is executed between groups to promote the sparsity of model parameters, and l2 regularization is executed within each group for constraining uniformity. The new Bayesian AVO inversion algorithm based on the group optimization strategy can help estimate the reflectivity levels of elastic parameters with desired sparsity. Additionally, even in the absence of the covariance matrix, the algorithm can still ensure the correlation of resulting solutions. It has been demonstrated that good results have been obtained from both numerical and field examples.

3

3C seismic data processing and interpretation: a case study from Carpathian Foredeep basin

Szymańska-Małysa Żaneta, Dubiel Paweł

Acta Geophysica

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2019

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Vol. 67, no. 6

2031--2047

EN

Chałupki Dębniańskie seismic profile 2D–3C is located in Carpathian Foredeep basin, Poland, and is an object of interest for geologists and geophysicists due to the presence of gas-bearing layers. Multicomponent seismic plays a significant role in supporting reservoir analysis related to accumulations of crude oil and natural gas. The purpose of the research was the optimal processing workflow design, which integrated seismic images of three-component 2D seismic line (2D–3C seismic). A complete processing flow for vertical and both horizontal components was conducted to obtain stacks and prestack gathers with preserved amplitude relations (RAP processing). The main issue of the research was the interpretation of S-wave velocity, which was not provided by well log data. The obtained results increased the reliability of seismic interpretation within Chałupki Dębniańskie area. The research provided valuable information regarding amplitude anomalies and helped in the verification of the potential gas accumulations. Several reservoir analysis tools were tested, including seismic attributes and AVO analysis. Conducted research confirmed the existence of reservoir which is characterized by good reservoir parameters.

4

Key preprocessing technology and its application for CBM AVO analysis

Liu Z., Si G., Chen X., Wang Q., Deng S.

Acta Geophysica

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2017

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Vol. 65, no. 5

1069--1079

EN

The hazards of amplitude versus offset (AVO) technique mostly applied in seismic explorations for predicting coalbed methane (CBM) content mainly derive from multi-stage amplitude modifications during seismic signal preprocessing. The modifications are undoubtedly necessitated by improving high signal-to-noise ratio (SNR) and high resolution, and achieve high fidelity to some extent; and nevertheless lead to an unfavorable possibility to implement CBM AVO analysis. Similar to sand-stone reservoir with gas, AVO analysis preprocessing for CBM reservoir strictly abides by a relative amplitude preserved (RAP) principle and particularly emphasizes on preserving the evanescent class IV AVO anomaly. As for those indispensable dealings with linear noise attenuations, near-surface variety compensations and time/depth spatial imaging, the key technologies adapted to CBM AVO preprocessing should use radial trace (RT) filter, refined surface-consistent amplitude compensation (SCAC), and RAP Kirchhoff prestack time migration (PSTM). The theoretical analysis and one real 3D example in this paper demonstrate that three key technologies compliant to RAP principle in CBM AVO preprocessing can preserve the class IV AVO anomaly and benefit an operation of CBM AVO analysis and an improvement of CBM evaluation.

5

Oprobovanie AVO-analiza, akusticeskoj i uprugoj inversij dla prognozirovania petrofiziceskih svojstv porod na primere ozemlinskogo i uzno-ozemlinskogo mestorozdenij pripatskogo progiba

Konusenko A. S.

Prace Naukowe Instytutu Nafty i Gazu

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2012

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nr 182 wyd. konferencyjne

337--342

EN

The effective hydrocarbon exploration activity depends largely on the quantitative estimate of reservoir characteristics of promising intervals of the cross-section. Today the main task of seismologists is not only determination of the collector position in section, but also of fluid primer-sealer type, quantitative estimate of porosity, fracturing and other petrophysical parameters. The necessary data are tightness and velocities of Р- and S-waves. Such problems solving is in the detailed survey of dynamic properties of wave field. The author of this report used one of the most advanced methods of studying of the dynamic wave field — AVO-analysis for the first time on the territory of the Prypyatsky depression. We obtained preliminary positive results for predicting reservoir properties in the target interval. In spite of numerous contradictions concerning implementation of these methods and rather complex seismic and geological conditions of Prypiat downfold, this work illustrates applicability of AVO-analysis and shows good results.

6

Razrabotka metodiki uglublennoj odbrabotki sejsmiceskih dannyh dal’neisego prognozirovania geologiceskogo razreza s ispol’zovaniem AVO-analiza i inversii

Kuz'menko P. N.

Prace Instytutu Nafty i Gazu

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2008

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nr 150 wydanie konferencyjne

383--388

EN

The problems of the dynamic seismic data processing for further prediction of geologic section using AVO-analysis and inversion are described in the article. The seismic data processing technique with "true" amplitudes preserving is developed. The efficiency of this technique application on the real 2D seismic data acquired in the Black Sea area is shown.

7

Analiza zmienności amplitudy względem offsetu w systemie ProMAX

Leginowicz A.

Nafta-Gaz

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2008

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R. 64, nr 10

661-671

PL

W artykule przeanalizowano zmienność amplitudy względem offsetu, na danych pre-stack, przy użyciu systemu ProMAX. W Zakładzie Sejsmiki INiG wykonano sekwencje procedur AVO na wybranych modułach systemu oraz podjęto próbę określenia parametrów elastycznych ośrodka w oparciu o analizę zmienności amplitudy względem offsetu. Za główny parametr, charakteryzujący właściwości elastyczne ośrodka i przydatny do wytypowania anomalnych stref złożowych, przyjęto współczynnik Poisson’a, którego skalowaną zmianę można otrzymać w postaci wynikowej sekcji atrybutu AVO. Ponadto wykonano analizę przy użyciu crossplotów na wytypowanej potencjalnej anomalii złożowej, widocznej na sekcjach atrybutów AVO (Intercepr, Gradient, Zmiana Współczynnika Poisson’a). Analiza ta pozwoliła na rozróżnienie miejsc interesujących złożowo od innych anomalii nieperspektywicznych.

EN

The aim of this work was amplitude variation versus offset analysis of pre-stack data with ProMAX system. Seismic data processing for AVO interpretation was discussed. ProMAX system AVO interpretation was presented and feasibility study of elastic parameters qualification based on AVO – amplitude variation versus offset. Poisson Ratio was chosen as main parameter characterizing elastic property of solid. This analysis has allowed discrimination between interesting and unperspective anomalys.

8

Wykorzystanie atrybutów bazujących na danych sejsmicznych przed składaniem do oceny stopnia nasycenia gazem warstw złożowych, NE część zapadliska przedkarpackiego

Pietsch K., Tatarata A.

Geologia / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

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2008

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T. 34, z. 2

301-320

PL

Dla poszukiwań naftowych w NE części zapadliska przedkarpackiego interesująca jest odpowiedź na pytanie, czy można na podstawie rejestrowanych przekrojów sejsmicznych opracować wskaźniki, które pozwoliłyby na ocenę stopnia nasycenia gazem przestrzeni porowej warstw zbiornikowych. Równoczesna zależność sejsmicznego obrazu złoża od wielu parametrów petrofizycznych powoduje, że ocena wpływu tych parametrów oparta została na wielowariantowych modelowaniach sejsmicznych. Modelowania (system Hampson-Russell (CGGVeritas)) wykonano dla modelu aproksymującego wielohoryzontowe złoże gazu "Łukowa" (profil sejsmiczny T0152005 zrealizowany przez Geofizykę Toruń Sp. z o.o, (Pomianowski et al. 2005) oraz dane geofizyki wiertniczej z otworu Ł-2). W niniejszym artykule przedstawiono wyniki testów procedur interpretacyjnych, które bazują na danych sejsmicznych przed składaniem (AVO Product, Fluid Factor, lambdap i microp, impedancja elastyczna). Potwierdzeniem poprawności opracowanych kryteriów jest zestawienie przypływów, wg próbnika złoża, ze zinterpretowanym przekrojem sejsmicznym.

EN

The question, whether it is possible to create such indicators that would allow to assess a saturation degree of reservoir pore space directly from seismic response, is interesting for hydrocarbon prospecting in the NE part of the Carpathian Foredeep. The dependence of seismic image of gas reservoir upon plenty of petrophysical parameters causes that the analysis of their influences on seismic response were based on seismic multi-variant modelling. Seismic model approximating "Łukowa" gas reservoir was constructed with Hampson-Russell System (CGGVeritas) accordingly with a geometry of profile no T0152005 acquired by Geofizyka Toruń Ltd. and additionally supported by log data from Ł-2 well. This paper presents results of the tests of interpretative procedures based on pre-stack seismic data such as AVO Product, Fluid Factor, lambdap and microp, elastic impedance. The correctness of established criteria was confirmed by a juxtaposition of an inflow rate obtained from a drill-stem tester and the interpreted seismic profile.