Target-oriented data conditioning for prestack inversion in an unconventional reservoir: A Canadian case study

2016 ◽  
Vol 4 (2) ◽  
pp. SG11-SG18 ◽  
Author(s):  
Jorge Estrada ◽  
Peter Aaron ◽  
Richard Eden
Keyword(s):  
Reservoir Characterization ◽  
Synthetic Data ◽  
Real Data ◽  
Seismic Inversion ◽  
Prestack Inversion ◽  
Data Conditioning ◽  
Spatially Variant ◽  
Prestack Seismic Inversion ◽  
Background Trend

Target-oriented data conditioning is a key part of any reservoir characterization workflow. Data conditioning is used to optimize the match between the synthetic data, used in the prestack inversion, and the real data. When this is done correctly, the accuracy and confidence of inversion results may be greatly improved. This is proved on prestack seismic inversion results from a resource play in Canada. The flow is broken down into prestack gather conditioning, which improves the signal-to-noise and gather flatness, and poststack conditioning, which further improves the coherency prior to applying spectral balancing. As a final key step, spatially variant amplitude balancing is used to calibrate the angle stacks to the expected background trend from the well synthetics. The combination of all steps is demonstrated via [Formula: see text] and mu-rho versus lambda-rho crossplots, between the inverted results and the well measurements, to provide a significant improvement on the resolution and accuracy of the final prestack inversion.

Improving the quality of prestack inversion by prestack data conditioning

2015 ◽  
Vol 3 (1) ◽  
pp. T5-T12 ◽  
Author(s):  
Bo Zhang ◽  
Deshuang Chang ◽  
Tengfei Lin ◽  
Kurt J. Marfurt
Keyword(s):  
Reservoir Characterization ◽  
Incident Angle ◽  
Correlation Coefficients ◽  
Seismic Inversion ◽  
P Wave ◽  
Rock Properties ◽  
Prestack Inversion ◽  
Data Conditioning ◽  
Prestack Seismic Inversion ◽  
Hockey Sticks

Prestack seismic inversion techniques provide valuable information of rock properties, lithology, and fluid content for reservoir characterization. The confidence of inverted results increases with increasing incident angle of seismic gathers. The most accurate result of simultaneous prestack inversion of P-wave seismic data is P-impedance. S-impedance estimation becomes reliable with incident angles approaching 30°, whereas density evaluation becomes reliable with incident angles approaching 45°. As the offset increases, we often encounter “hockey sticks” and severe stretch at large offsets. Hockey sticks and stretch not only lower the seismic resolution but also hinder long offset prestack seismic inversion analysis. The inverted results are also affected by the random noises present in the prestack gathers. We developed a three-step workflow to perform data conditioning prior to simultaneous prestack inversion. First, we mitigated the hockey sticks by using an automatic nonhyperbolic velocity analysis. Then, we minimized the stretch at the far offset by using an antistretch workflow. Last, we improved the signal-to-noise ratio by applying prestack structure-oriented filtering. We evaluated our workflow by applying it to a prestack seismic volume acquired over the Fort Worth Basin, Texas, USA. The results inverted from the conditioned prestack gathers have higher resolution and better correlation coefficients with well logs when compared to those inverted from conventional time-migrated gathers.

Seismic reservoir characterization of Bone Spring and Wolfcamp Formations in the Delaware Basin — A case study: Part 1

2020 ◽  
Vol 8 (4) ◽  
pp. T927-T940
Author(s):  
Satinder Chopra ◽  
Ritesh Kumar Sharma ◽  
James Keay
Keyword(s):  
Reservoir Characterization ◽  
Rock Physics ◽  
Seismic Inversion ◽  
Delaware Basin ◽  
Seismic Reservoir ◽  
Data Conditioning ◽  
Inversion Analysis ◽  
Sweet Spots

The Delaware and Midland Basins are multistacked plays with production being drawn from different zones. Of the various prospective zones in the Delaware Basin, the Bone Spring and Wolfcamp Formations are the most productive and thus are the most drilled zones. To understand the reservoirs of interest and identify the hydrocarbon sweet spots, a 3D seismic inversion project was undertaken in the northern part of the Delaware Basin in 2018. We have examined the reservoir characterization exercise for this dataset in two parts. In addition to a brief description of the geology, we evaluate the challenges faced in performing seismic inversion for characterizing multistacked plays. The key elements that lend confidence in seismic inversion and the quantitative predictions made therefrom are well-to-seismic ties, proper data conditioning, robust initial models, and adequate parameterization of inversion analysis. We examine the limitations of a conventional approach associated with these individual steps and determine how to overcome them. Later work will first elaborate on the uncertainties associated with input parameters required for executing rock-physics analysis and then evaluate the proposed robust statistical approach for defining the different lithofacies.

scholarly journals Multidimensional scaling for the evaluation of a geostatistical seismic elastic inversion methodology

Geophysics ◽  
2014 ◽  
Vol 79 (1) ◽  
pp. M1-M10 ◽  
Author(s):  
Leonardo Azevedo ◽  
Ruben Nunes ◽  
Pedro Correia ◽  
Amílcar Soares ◽  
Luis Guerreiro ◽  
...  
Keyword(s):  
Multidimensional Scaling ◽  
Metric Space ◽  
Synthetic Data ◽  
Real Data ◽  
Seismic Inversion ◽  
Inversion Algorithm ◽  
Data Set ◽  
The Real ◽  
Geostatistical Inversion ◽  
Impedance Models

Due to the nature of seismic inversion problems, there are multiple possible solutions that can equally fit the observed seismic data while diverging from the real subsurface model. Consequently, it is important to assess how inverse-impedance models are converging toward the real subsurface model. For this purpose, we evaluated a new methodology to combine the multidimensional scaling (MDS) technique with an iterative geostatistical elastic seismic inversion algorithm. The geostatistical inversion algorithm inverted partial angle stacks directly for acoustic and elastic impedance (AI and EI) models. It was based on a genetic algorithm in which the model perturbation at each iteration was performed recurring to stochastic sequential simulation. To assess the reliability and convergence of the inverted models at each step, the simulated models can be projected in a metric space computed by MDS. This projection allowed distinguishing similar from variable models and assessing the convergence of inverted models toward the real impedance ones. The geostatistical inversion results of a synthetic data set, in which the real AI and EI models are known, were plotted in this metric space along with the known impedance models. We applied the same principle to a real data set using a cross-validation technique. These examples revealed that the MDS is a valuable tool to evaluate the convergence of the inverse methodology and the impedance model variability among each iteration of the inversion process. Particularly for the geostatistical inversion algorithm we evaluated, it retrieves reliable impedance models while still producing a set of simulated models with considerable variability.

scholarly journals SEISMIC TRAVELTIME TOMOGRAPHY IN THE DOM JOÃO FIELD, RECÔNCAVO BASIN, BRAZIL

2015 ◽  
Vol 33 (1) ◽  
pp. 89
Author(s):  
Naiane Pereira de Oliveira ◽  
Amin Bassrei
Keyword(s):  
Reservoir Characterization ◽  
New Technologies ◽  
Real Data ◽  
Seismic Inversion ◽  
P Wave ◽  
Gradient Algorithm ◽  
High Rate ◽  
Traveltime Tomography ◽  
Sonic Log ◽  
High Resolution Images

ABSTRACT. Tomography was incorporated in Exploration Geophysics with the intention of providing high-resolution images of regions in Earth’s subsurface that are characterized as potential reservoirs. In this work, seismic traveltime tomography in the transmission mode was applied to real data from the Dom João Field, Recôncavo Basin, State of Bahia, Brazil. This basin represents a landmark of oil exploration in Brazil and has been intensively studied since the 1950’s. Today, the Recôncavo Basin is still the principal oil producer in the State of Bahia, but there is a demand for new technologies, especially for mature fields, to improve hydrocarbon recovery. Acoustic ray tracing for the computation of traveltimes was used for forward modeling, and the conjugate gradient algorithm with regularization through derivative matrices was used as the inverse procedure. The estimated tomograms were consistent with available data from a sonic log near the acquisition area in terms of the layer geometry, as well as the P-wave velocity range. The results showed that traveltime tomography is feasible for the characterization of reservoirs with a high rate of vertical change, similar to the Dom Jo˜ao Field.Keywords: traveltime tomography, seismic inversion, regularization, reservoir characterization, Recˆoncavo Basin.RESUMO. A tomografia foi incorporada na Geofísica de Exploração justamente para fornecer imagens de alta resolução de regiões do interior da Terra, consideradas como potenciais reservatórios. Neste trabalho aplicamos a tomografia sísmica de tempos de trânsito no modo de transmissão em dados reais do Campo de Dom João, Bacia do Recôncavo, Estado da Bahia, Brasil. Esta bacia representa um marco da exploração de petróleo no Brasil e vem sendo exaustivamente estudada desde a década de 1950. Embora haja uma demanda por novas tecnologias, em especial para campos maduros, com o propósito de se aumentar a recuperação de hidrocarbonetos, a Bacia do Recôncavo é ainda a principal produtora do Estado da Bahia. Para o procedimento da modelagem direta foi utilizado o traçado de raios acústicos e para o procedimento inverso foi utilizado o algoritmo do gradiente conjugado com regularização através de matrizes de derivadas. Os tomogramas estimados foram consistentes com os dados provenientes do perfil sõnico de um poço próximo ao levantamento tomográfico analisado, tanto em termos de geometria de camadas, como também na faixa de velocidades da onda P. Os resultados mostraram que a tomografia de tempos de trânsito é viável para a caracterização de reservatórios com elevada taxa de variação vertical, que é o caso do Campo de Dom João.Palavras-chave: tomografia de tempos de trânsito, inversão sísmica, regularização, caracterização de reservatórios, Bacia do Recôncavo.

ANALOG RESERVOIR MODELLING OF CHANNEL SANDS

2005 ◽  
Vol 45 (1) ◽  
pp. 439
Author(s):  
D. Sherlock ◽  
G. Weir ◽  
K. Dodds
Keyword(s):  
Ground Truth ◽  
Real Data ◽  
Time Lapse ◽  
Seismic Inversion ◽  
Reservoir Modelling ◽  
Engineering Research ◽  
Seismic Properties ◽  
Before And After ◽  
Deepwater Channel

This paper outlines the results of analog modelling of a sandy deepwater channel reservoir to gain insight into issues of uncertainty in reservoir simulations and their seismic expression. The project is unique in that it integrates seismic and reservoir engineering research in a controlled laboratory environment. Unlike numerical modelling investigations, this laboratory-based modelling study provides real data that does not rely on assumptions and is, therefore, a useful case study for comparing the actual production and seismic response against numerical predictions.The 1 m2 model comprised two intersecting synthetic sandstone channels within a transparent acrylic matrix. The model was initially oil-saturated with irreducible water and was produced through waterflooding of the upper channel. Careful attention was paid to scaling of both the fluid dynamics and the seismic properties to ensure that the response of the model was representative of the field-scale environment. Scaled time-lapse seismic data was recorded before and after production and data such as water cuts, recovery rates and pressure drop between injector and producers were also recorded.Analog reservoir modelling (ARM) provides a new tool that allows seismic attributes to be evaluated against ground truth results and the performance of seismic inversion schemes to be critically assessed.

Depth-domain seismic reflectivity inversion with compressed sensing technique

2017 ◽  
Vol 5 (1) ◽  
pp. T1-T9 ◽  
Author(s):  
Rui Zhang ◽  
Kui Zhang ◽  
Jude E. Alekhue
Keyword(s):  
Compressed Sensing ◽  
Time Domain ◽  
Seismic Data ◽  
Reservoir Characterization ◽  
Synthetic Data ◽  
Seismic Inversion ◽  
Inversion Method ◽  
Depth Migration ◽  
Band Limited ◽  
The Time Domain

More and more seismic surveys produce 3D seismic images in the depth domain by using prestack depth migration methods, which can present a direct subsurface structure in the depth domain rather than in the time domain. This leads to the increasing need for applications of seismic inversion on the depth-imaged seismic data for reservoir characterization. To address this issue, we have developed a depth-domain seismic inversion method by using the compressed sensing technique with output of reflectivity and band-limited impedance without conversion to the time domain. The formulations of the seismic inversion in the depth domain are similar to time-domain methods, but they implement all the elements in depth domain, for example, a depth-domain seismic well tie. The developed method was first tested on synthetic data, showing great improvement of the resolution on inverted reflectivity. We later applied the method on a depth-migrated field data with well-log data validated, showing a great fit between them and also improved resolution on the inversion results, which demonstrates the feasibility and reliability of the proposed method on depth-domain seismic data.

Reservoir characterization through seismic inversion: A case study

2019 ◽  
Author(s):  
Binode Chetia ◽  
J. Nagaraju ◽  
Subhash Kr. Sharma ◽  
Anand Kumar
Keyword(s):  
Reservoir Characterization ◽  
Seismic Inversion
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