Stochastic simulation of porosity and acoustic impedance conditioned to seismic data and well data

1997 ◽  
Author(s):  
Alfhild L. Eide ◽  
Bjorn Ursin ◽  
Henning Omre
Keyword(s):  
Stochastic Simulation ◽  
Seismic Data ◽  
Acoustic Impedance ◽  
Well Data

scholarly journals Seismically detected porous Zechstein carbonates in Southern Jutland, Denmark

1995 ◽  
Vol 42 ◽  
pp. 34-46
Author(s):  
Kim Gunn Maver
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Seismic Reflection ◽  
Synthetic Seismograms ◽  
Lateral Distribution ◽  
Seismic Modelling ◽  
Seismic Sections ◽  
Well Data ◽  
Impedance Models

Zechstein carbonates in Southern Jutland, Denmark, have been explored by 10 wells since 1952, and a total of more than 2000 km of 2D seismic data has been acquired by various contractors. Seismic modelling, based on all the well data, is used as an aid to predict the lateral distribution of porous Zechstein carbonate intervals from the seismic data. ID seismic modelling is used to define the maximum number of intervals detected by the seismic sections at well locations. The ID seismic modelling results are also used to derive 2D acoustic impedance models and corresponding synthetic seismograms. The seismic modelling results illustrate a number of diagnostic reflection patterns associated with the porous carbonate intervals. The predicted distribution of porous carbonate intervals is, however, found to be uncertain, as thickness and porosity variations of each interval cannot be distinguished. Furthermore, thin porous carbonate intervals are not detected by the seismic sections, and the seismic reflection patterns indicating the presence of porous carbonate intervals can be associated with other lithologies. Porous Ca-la, Ca-lb, Ca-2 and Ca-3 carbonate intervals are found to be detected by the seismic sections only in the Zechstein platform area, and only the porous Ca-2 carbonate interval can be mapped

scholarly journals Reservoir Characterizarion Using Acoustic Impedance Inversion and Multi-Attribute Analysis in Nias Waters, North Sumatra

2019 ◽  
Vol 34 (1) ◽  
Author(s):  
Fathkhurozak Yunanda Rifai ◽  
Tumpal Bernhard Nainggolan ◽  
Henry Munandar Manik
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Source Rocks ◽  
Time Migration ◽  
Attribute Analysis ◽  
Impedance Inversion ◽  
Acoustic Impedance Inversion ◽  
Well Data ◽  
North Sumatra ◽  
Rock Lithology

Seismic method is one of the most frequently applied geophysical methods in the process of oil and gas exploration. This research is conducted in Nias Waters, North Sumatra using one line 2D post-stack time migration seismic section and two wells data. Reservoir characterization is carried out to obtain physical parameters of rocks affected by fluid and rock lithology. Seismic inversion is used as a technique to create acoustic impedance distribution using seismic data as input and well data as control. As final product, multi-attribute analysis is applied to integrate of inversion results with seismic data to determine the lateral distribution of other parameters contained in well data. In this research, multi-attribute analysis is used to determine the distribution of NPHI as a validation of hydrocarbon source rocks. In that area, there is a gas hydrocarbon prospect in limestone lithology in depth around 1450 ms. Based on the results of sensitivity analysis, cross-plot between acoustic impedance and NPHI are sensitive in separating rock lithology, the target rock in the form of limestone has physical characteristics in the form of acoustic impedance values in the range of 20,000-49,000 ((ft/s)*(g/cc)) and NPHI values in the range of 5-35 %. While the results of the cross-plot between the acoustic impedance and resistivity are able to separate fluid-containing rocks with resistivity values in the range about 18-30 ohmm. The result of acoustic impedance inversion using the model based method shows the potential for hydrocarbons in the well FYR-1 with acoustic impedance in the range 21,469-22,881 ((ft/s)*(gr/cc)).

scholarly journals Time-Lapse Seismic Monitoring of Onshore Reservoirs in Niger Delta, Field ‘K’ as a Case Study

2017 ◽  
Vol 1 (1) ◽  
pp. 23-27 ◽  
Author(s):  
A. Ogbamikhumi ◽  
T. Tralagba ◽  
E. E. Osagiede
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Niger Delta ◽  
Rock Physics ◽  
Time Lapse ◽  
Seismic Survey ◽  
Impedance Change ◽  
Data Set ◽  
Reservoir Fluid ◽  
4D Seismic

Field ‘K’ is a mature field in the coastal swamp onshore Niger delta, which has been producing since 1960. As a huge producing field with some potential for further sustainable production, field monitoring is therefore important in the identification of areas of unproduced hydrocarbon. This can be achieved by comparing production data with the corresponding changes in acoustic impedance observed in the maps generated from base survey (initial 3D seismic) and monitor seismic survey (4D seismic) across the field. This will enable the 4D seismic data set to be used for mapping reservoir details such as advancing water front and un-swept zones. The availability of good quality onshore time-lapse seismic data for Field ‘K’ acquired in 1987 and 2002 provided the opportunity to evaluate the effect of changes in reservoir fluid saturations on time-lapse amplitudes. Rock physics modelling and fluid substitution studies on well logs were carried out, and acoustic impedance change in the reservoir was estimated to be in the range of 0.25% to about 8%. Changes in reservoir fluid saturations were confirmed with time-lapse amplitudes within the crest area of the reservoir structure where reservoir porosity is 0.25%. In this paper, we demonstrated the use of repeat Seismic to delineate swept zones and areas hit with water override in a producing onshore reservoir.

scholarly journals Characterizing Seismo-stratigraphic and Structural Framework of Late Cretaceous-Recent succession of offshore Indus Pakistan

2018 ◽  
Vol 10 (1) ◽  
pp. 174-191 ◽  
Author(s):  
Majid Khan ◽  
Yike Liu ◽  
Asam Farid ◽  
Muhammad Owais
Keyword(s):  
Seismic Data ◽  
Late Eocene ◽  
Indian Plate ◽  
Processing Scheme ◽  
Structural Growth ◽  
Seismic Records ◽  
Exploratory Wells ◽  
Well Data ◽  
Seismic Reflection Profiles ◽  
Push Up

Abstract Regional seismic reflection profiles and deep exploratory wells have been used to characterize the subsurface structural trends and seismo-stratigraphic architecture of the sedimentary successions in offshore Indus Pakistan. To improve the data quality, we have reprocessed the seismic data by applying signal processing scheme to enhance the reflection continuity for obtaining better results. Synthetic seismograms have been used to identify and tie the seismic reflections to the well data. The seismic data revealed tectonically controlled, distinct episodes of normal faulting representing rifting during Mesozoic and transpression at Late Eocene time. A SW-NE oriented anticlinal type push up structure is observed resulted from the basement reactivation and recent transpression along Indian Plate margin. The structural growth of this particular pushup geometry was computed. Six mappable seismic sequences have been identified on seismic records. In general, geological formations are at shallow depths towards northwest due to basement blocks uplift. A paleoshelf is also identified on seismic records overlain by Cretaceous sediments, which is indicative of Indian-African Plates rifting at Jurassic time. The seismic interpretation reveals that the structural styles and stratigraphy of the region were significantly affected by the northward drift of the Indian Plate, post-rifting, and sedimentation along its western margin during Middle Cenozoic. A considerable structural growth along the push up geometry indicates present day transpression in the margin sediments. The present comprehensive interpretation can help in understanding the complex structures in passive continental margins worldwide that display similar characteristics but are considered to be dominated by rifting and drifting tectonics.

Seismic-to-well tie of a field of the Nigerian Delta

2021 ◽  
Vol 19 (3) ◽  
pp. 125-138
Author(s):  
S. Inichinbia ◽  
A.L. Ahmed
Keyword(s):  
Seismic Data ◽  
Processing Parameters ◽  
Seismic Inversion ◽  
Seismic Wavelet ◽  
Statistical Measures ◽  
Convolution Model ◽  
Data Driven Approach ◽  
Well Data ◽  
Seismic Reflectors ◽  
Matching Techniques

This paper presents a rigorous but pragmatic and data driven approach to the science of making seismic-to-well ties. This pragmatic  approach is consistent with the interpreter’s desire to correlate geology to seismic information by the use of the convolution model,  together with least squares matching techniques and statistical measures of fit and accuracy to match the seismic data to the well data. Three wells available on the field provided a chance to estimate the wavelet (both in terms of shape and timing) directly from the seismic and also to ascertain the level of confidence that should be placed in the wavelet. The reflections were interpreted clearly as hard sand at H1000 and soft sand at H4000. A synthetic seismogram was constructed and matched to a real seismic trace and features from the well are correlated to the seismic data. The prime concept in constructing the synthetic is the convolution model, which represents a seismic reflection signal as a sequence of interfering reflection pulses of different amplitudes and polarity but all of the same shape. This pulse shape is the seismic wavelet which is formally, the reflection waveform returned by an isolated reflector of unit strength at the target  depth. The wavelets are near zero phase. The goal and the idea behind these seismic-to-well ties was to obtain information on the sediments, calibration of seismic processing parameters, correlation of formation tops and seismic reflectors, and the derivation of a  wavelet for seismic inversion among others. Three seismic-to-well ties were done using three partial angle stacks and basically two formation tops were correlated. Keywords: seismic, well logs, tie, synthetics, angle stacks, correlation,

WARROON GAS DISCOVERY SUPPORTS EXPLORATION OF ANTICLINES

1981 ◽  
Vol 21 (1) ◽  
pp. 85
Author(s):  
B. R. BROWN
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Gas Condensate ◽  
Seismic Survey ◽  
Seismic Surveys

Warroon, a small gas condensate discovery in the western Surat Shelf, was mapped as a faulted anticline from seismic data shot in April 1979. The discovery well was drilled in August 1979 on the then highest known point of the mapped closure. The well flowed up to 8 MMcf/D from about 2.4 m (eight feet) of Showgrounds Sandstone over the gross interval 2 048 to 2 060 m (6 720 to 6 760 ft). Subsequently, two small seismic surveys comprising 62 km and including experimental shooting and acoustic impedance processing have been shot over the anticline. A step-out will be considered in the 1981 drilling program.The discovery of gas and condensate in Warroon, and in the Glen Fosslyn discovery in an adjacent permit, optimistically suggests that the prospective area of the Wunger Ridge may be extended. A major seismic survey comprising over 450 km of 12-fold 96 channel recording was shot in the Spring of 1980. The interpretation of the data could lead to proposals to drill a number of wildcats on structures similar in appearance to Warroon.

Colored and linear inversions to relative acoustic impedance

Geophysics ◽  
2019 ◽  
Vol 84 (2) ◽  
pp. N15-N27 ◽  
Author(s):  
Carlos A. M. Assis ◽  
Henrique B. Santos ◽  
Jörg Schleicher
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Computational Cost ◽  
Synthetic Data ◽  
Seismic Source ◽  
Alternative Methods ◽  
Well Log ◽  
Linear Inversion ◽  
Amplitude Inversion ◽  
Band Limited

Acoustic impedance (AI) is a widely used seismic attribute in stratigraphic interpretation. Because of the frequency-band-limited nature of seismic data, seismic amplitude inversion cannot determine AI itself, but it can only provide an estimate of its variations, the relative AI (RAI). We have revisited and compared two alternative methods to transform stacked seismic data into RAI. One is colored inversion (CI), which requires well-log information, and the other is linear inversion (LI), which requires knowledge of the seismic source wavelet. We start by formulating the two approaches in a theoretically comparable manner. This allows us to conclude that both procedures are theoretically equivalent. We proceed to check whether the use of the CI results as the initial solution for LI can improve the RAI estimation. In our experiments, combining CI and LI cannot provide superior RAI results to those produced by each approach applied individually. Then, we analyze the LI performance with two distinct solvers for the associated linear system. Moreover, we investigate the sensitivity of both methods regarding the frequency content present in synthetic data. The numerical tests using the Marmousi2 model demonstrate that the CI and LI techniques can provide an RAI estimate of similar accuracy. A field-data example confirms the analysis using synthetic-data experiments. Our investigations confirm the theoretical and practical similarities of CI and LI regardless of the numerical strategy used in LI. An important result of our tests is that an increase in the low-frequency gap in the data leads to slightly deteriorated CI quality. In this case, LI required more iterations for the conjugate-gradient least-squares solver, but the final results were not much affected. Both methodologies provided interesting RAI profiles compared with well-log data, at low computational cost and with a simple parameterization.

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