Reservoir Characterization using Acoustic Impedance Seismic Inversion Method and Seismic Attribute in the “RST” Field of the Taranaki Basin, New Zealand.

Abstract For estimation of petrophysical properties in industry, we are looking for a methodology which results in more accurate outcome and also can be validated by means of some quality control steps. To achieve that, an application of petrophysical seismic inversion for reservoir properties estimation is proposed. The main objective of this approach is to reduce uncertainty in reservoir characterization by incorporating well log and seismic data in an optimal manner. We use nonlinear optimization algorithms in the inversion workflow to estimate reservoir properties away from the wells. The method is applied at well location by fitting nonlinear experimental relations on the petroelastic cross-plot, e.g., porosity versus acoustic impedance for each lithofacies class separately. Once a significant match between the measured and the predicted reservoir property is attained in the inversion workflow, the petrophysical seismic inversion based on lithofacies classification is applied to the inverted elastic property, i.e., acoustic impedance or Vp/Vs ratio derived from seismic elastic inversion to predict the reservoir properties between the wells. Comparison with the neural network method demonstrated this application of petrophysical seismic inversion to be competitive and reliable.

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Application of model-based inversion technique in a field in the coastal swamp depobelt, Niger delta

International Journal of Advanced Geosciences ◽

10.14419/ijag.v6i1.10124 ◽

2018 ◽

Vol 6 (1) ◽

pp. 122

Author(s):

Okoli Austin ◽

Onyekuru Samuel I. ◽

Okechukwu Agbasi ◽

Zaidoon Taha Abdulrazzaq

Keyword(s):

Niger Delta ◽

Reservoir Characterization ◽

Seismic Inversion ◽

Inversion Method ◽

Seismic Reflection Data ◽

Model Based ◽

Reflection Data ◽

X 32 ◽

Niger Delta Basin ◽

Bypassed Oil

Considering the heterogeneity of the reservoir sands in the Niger Delta basin which are primary causes of low hydrocarbon recovery efficiency, poor sweep, early breakthrough and pockets of bypassed oil there arises a need for in-depth quantitative interpretation and more analysis to be done on seismic data to achieve a reliable reservoir characterization to improve recovery, plan future development wells within field and achieve deeper prospecting for depths not penetrated by the wells and areas far away from well locations. An effective tool towards de-risking prospects is seismic inversion which transforms a seismic reflection data to a quantitative rock-property description of a reservoir. The choice of model-based inversion in this study was due to well control, again considering the heterogeneity of the sands in the field. X-26, X-30, and X-32 were used to generate an initial impedance log which is used to update the estimated reflectivity from which we would obtain our inverted volumes. Acoustic impedance volumes were generated and observations made were consistent with depth trends established for the Niger Delta basin, inverted slices of Poisson impedances validated the expected responses considering the effect of compaction. This justifies the use of inversion method in further characterizing the plays identified in the region.

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Accuracy of wavelets, seismic inversion, and thin-bed resolution

Interpretation ◽

10.1190/int-2017-0023.1 ◽

2017 ◽

Vol 5 (4) ◽

pp. T523-T530

Author(s):

Ehsan Zabihi Naeini ◽

Mark Sams

Keyword(s):

Seismic Data ◽

Reservoir Characterization ◽

Low Frequency ◽

Seismic Inversion ◽

Inversion Method ◽

Frequency Content ◽

Frequency Model ◽

North West ◽

The North ◽

Well Data

Broadband reprocessed seismic data from the North West Shelf of Australia were inverted using wavelets estimated with a conventional approach. The inversion method applied was a facies-based inversion, in which the low-frequency model is a product of the inversion process itself, constrained by facies-dependent input trends, the resultant facies distribution, and the match to the seismic. The results identified the presence of a gas reservoir that had recently been confirmed through drilling. The reservoir is thin, with up to 15 ms of maximum thickness. The bandwidth of the seismic data is approximately 5–70 Hz, and the well data used to extract the wavelet used in the inversion are only 400 ms long. As such, there was little control on the lowest frequencies of the wavelet. Different wavelets were subsequently estimated using a variety of new techniques that attempt to address the limitations of short well-log segments and low-frequency seismic. The revised inversion showed greater gas-sand continuity and an extension of the reservoir at one flank. Noise-free synthetic examples indicate that thin-bed delineation can depend on the accuracy of the low-frequency content of the wavelets used for inversion. Underestimation of the low-frequency contents can result in missing thin beds, whereas underestimation of high frequencies can introduce false thin beds. Therefore, it is very important to correctly capture the full frequency content of the seismic data in terms of the amplitude and phase spectra of the estimated wavelets, which subsequently leads to a more accurate thin-bed reservoir characterization through inversion.

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Seismic Interpretation and Inversion Leading to an Accurate Reservoir Characterization in a Carbonate Environment

Journal of Biomedical Research & Environmental Sciences ◽

10.37871/jbres1376 ◽

2021 ◽

Vol 2 (12) ◽

pp. 1229-1230

Author(s):

Yasir Bashir ◽

Nordiana Mohd Muztaza ◽

Nur Azwin Ismail ◽

Ismail Ahmad Abir ◽

Andy Anderson Bery ◽

...

Keyword(s):

Seismic Data ◽

Acoustic Impedance ◽

Reservoir Characterization ◽

Rock Physics ◽

Seismic Inversion ◽

Seismic Interpretation ◽

And Inversion

Seismic data acquired in the field show the subsurface reflectors or horizon among the geological strata, while the seismic inversion converts this reflector information into the acoustic impedance section which shows the layer properties based on lithology. The research aims to predict the porosity to identify the reservoir which is in between the tight layer. So, the output of the seismic inversion is much more batter than the seismic as it is closer to reality such as geology. Seismic inversion is frequently used to determine rock physics properties, for example, acoustic impedance and porosity.

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Accelerating seismic fault and stratigraphy interpretation with deep CNNs: A case study of the Taranaki Basin, New Zealand

The Leading Edge ◽

10.1190/tle39100727.1 ◽

2020 ◽

Vol 39 (10) ◽

pp. 727-733

Author(s):

Haibin Di ◽

Leigh Truelove ◽

Cen Li ◽

Aria Abubakar

Keyword(s):

New Zealand ◽

Seismic Data ◽

Reservoir Characterization ◽

Seismic Survey ◽

Deep Convolutional Neural Networks ◽

Seismic Attribute ◽

Data Set ◽

Seismic Fault ◽

Attribute Analysis ◽

Specific Implementation

Accurate mapping of structural faults and stratigraphic sequences is essential to the success of subsurface interpretation, geologic modeling, reservoir characterization, stress history analysis, and resource recovery estimation. In the past decades, manual interpretation assisted by computational tools — i.e., seismic attribute analysis — has been commonly used to deliver the most reliable seismic interpretation. Because of the dramatic increase in seismic data size, the efficiency of this process is challenged. The process has also become overly time-intensive and subject to bias from seismic interpreters. In this study, we implement deep convolutional neural networks (CNNs) for automating the interpretation of faults and stratigraphies on the Opunake-3D seismic data set over the Taranaki Basin of New Zealand. In general, both the fault and stratigraphy interpretation are formulated as problems of image segmentation, and each workflow integrates two deep CNNs. Their specific implementation varies in the following three aspects. First, the fault detection is binary, whereas the stratigraphy interpretation targets multiple classes depending on the sequences of interest to seismic interpreters. Second, while the fault CNN utilizes only the seismic amplitude for its learning, the stratigraphy CNN additionally utilizes the fault probability to serve as a structural constraint on the near-fault zones. Third and more innovatively, for enhancing the lateral consistency and reducing artifacts of machine prediction, the fault workflow incorporates a component of horizontal fault grouping, while the stratigraphy workflow incorporates a component of feature self-learning of a seismic data set. With seven of 765 inlines and 23 of 2233 crosslines manually annotated, which is only about 1% of the available seismic data, the fault and four sequences are well interpreted throughout the entire seismic survey. The results not only match the seismic images, but more importantly they support the graben structure as documented in the Taranaki Basin.

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A Novel Approach for a better exploitation of a 3D seismic on a development field

10.5194/egusphere-egu21-9287 ◽

2021 ◽

Author(s):

Nasrine Medjdouba ◽

Zahia Benaissa ◽

Sabiha Annou

Keyword(s):

Reservoir Characterization ◽

Seismic Analysis ◽

Lower Triassic ◽

Seismic Inversion ◽

Reservoir Properties ◽

Seismic Attribute ◽

Amplitude Inversion ◽

Well Location ◽

Attribute Analysis ◽

Novel Approach

The main hydrocarbon-bearing reservoirover the study area is the lower Triassic Argilo-Gr&#233;seux reservoir. The Triassic sand is deposited as fluvial channels and overbank sands with a thickness ranging from&#160;10 to 20 m, lying unconformably on the Paleozoic formations. Lateral and vertical distribution of the sand bodies is challenging which makes their mapping very difficult andnearly impossible with conventional seismic analysis.&#160;In order to better define the optimum drilling targets, the seismic attribute analysis and reservoir characterization process were performed targeting suchthin reservoir level, analysis of available two seismic vintages of PSTM cubes as well as post and pre stack inversion results were carried out.The combination of various attributes analysis (RMS amplitude, Spectral decomposition, variance, etc.) along with seismic inversion results has helped to clearly identify the channelized feature and its delineation on various horizon slices and geobodies, the results were reviewed and calibrated with reservoir properties at well location and showed remarkable correlation.Ten development wells have been successfully drilledbased on the seismic analysis study, confirming the efficiency of seismic attribute analysis to predicted channel body geometry.Keywords: Channel, Attributes, Amplitude, Inversion, Fluvial reservoir.

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Poststack Seismic Inversion Using A Patch-based Gaussian Mixture Model

Geophysics ◽

10.1190/geo2020-0185.1 ◽

2021 ◽

pp. 1-102

Author(s):

Lingqian Wang ◽

Hui Zhou ◽

Hengchang Dai ◽

Bo Yu ◽

Wenling Liu ◽

...

Keyword(s):

Gaussian Mixture Model ◽

Mixture Model ◽

Acoustic Impedance ◽

Structural Information ◽

Gaussian Mixture ◽

Seismic Inversion ◽

Inversion Method ◽

Borehole Data ◽

Inversion Result ◽

Band Limited

Seismic inversion is a severely ill-posed problem, because of noise in the observed record, band-limited seismic wavelets, and the discretization of a continuous medium. Regularization techniques can impose certain characteristics on inversion results based on prior information in order to obtain a stable and unique solution. However, it is difficult to find an appropriate regularization to describe the actual subsurface geology. We propose a new acoustic impedance inversion method via a patch-based Gaussian mixture model (GMM), which is designed using available well logs. In this method, firstly, the non-local means (NLM) method estimates acoustic impedance around wells in terms of the similarity of local seismic records. The extrapolated multichannel impedance are then decomposed into impedance patches. Using patched data rather than a window or single trace for training samples to obtain the GMM parameters, which contain local lateral structural information, can provide more impedance structure details and enhance the stability of the inversion result. Next, the expectation maximization (EM) algorithm is used to obtain the GMM parameters from the patched data. Finally, we apply the alternating direction method of multipliers (ADMM) to solve the conventional Bayesian inference illustrating the role of regularization, and construct the objective function using the GMM parameters. Therefore, the inversion results are compliant with the local structural features extracted from the borehole data. Both synthetic and field data tests validate the performance of our proposed method. Compared with other conventional inversion methods, our method shows promise in providing a more accurate and stable inversion result.

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Depth-domain seismic reflectivity inversion with compressed sensing technique

Interpretation ◽

10.1190/int-2016-0005.1 ◽

2017 ◽

Vol 5 (1) ◽

pp. T1-T9 ◽

Cited By ~ 3

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.

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Assessment of updated low frequency model in delineating bypassed hydrocarbon reservoir: A 4D seismic study of ’X’ - field, offshore, Niger Delta, Nigeria

Indian Journal of Science and Technology ◽

10.17485/ijst/v13i36.770 ◽

2020 ◽

Vol 13 (36) ◽

pp. 3738-3753 ◽

Cited By ~ 1

Author(s):

Aniefiok Sylvester Akpan ◽

Keyword(s):

Acoustic Impedance ◽

Deterministic Model ◽

Low Frequency ◽

Seismic Inversion ◽

Fluid Replacement ◽

Inversion Method ◽

Frequency Model ◽

Hydrocarbon Reservoir ◽

Model Based ◽

4D Seismic

Aim/objectives: The aim of this research is, to use Time lapse (4D) seismic and investigate the influence of low frequency update in deterministic model-based seismic inversion employed in delineating a prospect saturated with bypassed hydrocarbon accumulation. Method: The dataset employed in this study incorporates 4D seismic volumes with fifteen (15) years production, interval between 2001 baseline and 2016 monitor seismic vintages. The inversion was carried out using full bandwidth of the updated low frequency and bandpass filtered low frequency approaches. The seismic vintages (baseline and monitor) were simultaneously inverted into acoustic impedance volumes for the two approaches. The formation fluid and lithology were discriminated through fluid replacement modelling (FRM) based on the colour separation between brine and gas saturation scenarios. Findings: The two inversion methods employed reveal six (6) zones suspected to be saturated with bypassed hydrocarbons. The delineated bypassed zones are masked in the full bandwidth approach,depicting the effect of the updated low frequency model. Meanwhile, the bandpass filtered approach result presents a better delineated bypassed reservoir as the zones are more pronounced when compared with the full bandwidth approach. Porosity estimate reveals that the bandpass filtered approach is characterized with excellent porosity in the suspected bypassed zones. The results equally gave more reliable and full delineated bypassed zones. Originality and novelty: The dataset employed in this study were obtained from a producing hydrocarbon field which, interest is to maximize the production of oil/gas. The study will bridge the inherent gab observed in using model-based seismic inversion approach to analyse and interpret seismic data in order to delineate hydrocarbon prospects. The research reveals that,the model-based seismic inversion method is still very effective in delineating hydrocarbon prospect when the updated low frequency is bandpass filtered to remove the model effect which influences the inverted acoustic impedance results. Keywords: Porosity; frequency; bypassed; reservoir and impedance

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