Matrix-fluid decoupling-based joint PP-PS-wave seismic inversion for fluid identification

Geophysics ◽  
2019 ◽  
Vol 84 (3) ◽  
pp. R477-R487 ◽  
Author(s):  
Bing-Yi Du ◽  
Wu-Yang Yang ◽  
Jing Zhang ◽  
Xue-Shan Yong ◽  
Jian-Hu Gao ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Reservoir Characterization ◽  
Joint Inversion ◽  
Rock Physics ◽  
Seismic Inversion ◽  
New Method ◽  
Converted Wave ◽  
Fluid Identification ◽  
Fluid Factor ◽  
Fluid Detection

Seismic fluid identification is the main goal of current prestack seismic inversion. Various kinds of fluid indicators are used for fluid detection in industry today. However, the existing methods cannot always provide reliable fluid prediction owing to the insensitivity to fluid response and the lack of converted wave constraints. The equivalent fluid bulk modulus is an effective fluid factor based on matrix-fluid decoupling, which can provide persuasive evidence for fluid detection. Combining poroelasticity theory and matrix-fluid decoupling theory, we have deduced a new PS-wave linear amplitude versus offset approximation equation that provides estimations of equivalent fluid bulk modulus, rigidity, porosity, and density. Then, the joint inversion of PP- and PS-waves based on matrix-fluid decoupling was executed in a Bayesian framework with constraints from rock physics and well-log data obtaining elastic parameter estimation of high precision directly. We tested the new method on a synthetic example and field multicomponent data, and the results indicated that the estimated fluid factor matched with well-data interpretation and geology information because of adding converted wave information and avoiding indirect inversion error. This demonstrated that the new method can enhance the quality of fluid detection and provide reliable geophysical evidence for reservoir characterization.

Introduction to this special section: Rock physics

2019 ◽  
Vol 38 (5) ◽  
pp. 332-332
Author(s):  
Yongyi Li ◽  
Lev Vernik ◽  
Mark Chapman ◽  
Joel Sarout
Keyword(s):  
Reservoir Characterization ◽  
Model Building ◽  
Seismic Analysis ◽  
Focal Point ◽  
Special Section ◽  
Rock Physics ◽  
Seismic Inversion ◽  
Reservoir Properties ◽  
Model Studies ◽  
Experimental Rock

Rock physics links the physical properties of rocks to geophysical and petrophysical observations and, in the process, serves as a focal point in many exploration and reservoir characterization studies. Today, the field of rock physics and seismic petrophysics embraces new directions with diverse applications in estimating static and dynamic reservoir properties through time-variant mechanical, thermal, chemical, and geologic processes. Integration with new digital and computing technologies is gradually gaining traction. The use of rock physics in seismic imaging, prestack seismic analysis, seismic inversion, and geomechanical model building also contributes to the increase in rock-physics influence. This special section highlights current rock-physics research and practices in several key areas, namely experimental rock physics, rock-physics theory and model studies, and the use of rock physics in reservoir characterizations.

scholarly journals Integrated Well Data And 3D Seismic Inversion Study For Reservoir Delineation And Description

2020 ◽  
Vol 70 (1) ◽  
pp. 209-220
Author(s):  
Qazi Sohail Imran ◽  
◽  
Numair Ahmad Siddiqui ◽  
Abdul Halim Abdul Latif ◽  
Yasir Bashir ◽  
...  
Keyword(s):  
Reservoir Characterization ◽  
Rock Physics ◽  
Seismic Inversion ◽  
Depositional Environments ◽  
Well Log ◽  
Reservoir Properties ◽  
Rock Physics Modeling ◽  
Physics Modeling ◽  
And Performance ◽  
Well Log Analysis

Offshore petroleum systems are often very complex and subtle because of a variety of depositional environments. Characterizing a reservoir based on conventional seismic and well-log stratigraphic analysis in intricate settings often leads to uncertainties. Drilling risks, as well as associated subsurface uncertainties can be minimized by accurate reservoir delineation. Moreover, a forecast can also be made about production and performance of a reservoir. This study is aimed to design a workflow in reservoir characterization by integrating seismic inversion, petrophysics and rock physics tools. Firstly, to define litho facies, rock physics modeling was carried out through well log analysis separately for each facies. Next, the available subsurface information is incorporated in a Bayesian engine which outputs several simulations of elastic reservoir properties, as well as their probabilities that were used for post-inversion analysis. Vast areal coverage of seismic and sparse vertical well log data was integrated by geostatistical inversion to produce acoustic impedance realizations of high-resolution. Porosity models were built later using the 3D impedance model. Lastly, reservoir bodies were identified and cross plot analysis discriminated the lithology and fluid within the bodies successfully.

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

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.

scholarly journals Rock Physics Models and Seismic Inversion in Reservoir Characterization, “MUN” Onshore Niger Delta Field

2019 ◽  
Vol 10 (11) ◽  
pp. 981-994
Author(s):  
James Mwendwa Munyithya ◽  
Chukwuemeka Ngozi Ehirim ◽  
Tamunonengiyeofori Dagogo
Keyword(s):  
Niger Delta ◽  
Reservoir Characterization ◽  
Rock Physics ◽  
Seismic Inversion

scholarly journals Seismic characterization of geothermal sedimentary reservoirs: A field example from the Copenhagen area, Denmark

2020 ◽  
Vol 8 (2) ◽  
pp. T275-T291 ◽  
Author(s):  
Kenneth Bredesen ◽  
Esben Dalgaard ◽  
Anders Mathiesen ◽  
Rasmus Rasmussen ◽  
Niels Balling
Keyword(s):  
Reservoir Characterization ◽  
Energy Resource ◽  
Rock Physics ◽  
Seismic Inversion ◽  
Amplitude Variation With Offset ◽  
Seismic Characterization ◽  
Rock Physics Modeling ◽  
Physics Modeling ◽  
Physics Model ◽  
Rock Physics Model

We have seismically characterized a Triassic-Jurassic deep geothermal sandstone reservoir north of Copenhagen, onshore Denmark. A suite of regional geophysical measurements, including prestack seismic data and well logs, was integrated with geologic information to obtain facies and reservoir property predictions in a Bayesian framework. The applied workflow combined a facies-dependent calibrated rock-physics model with a simultaneous amplitude-variation-with-offset seismic inversion. The results suggest that certain sandstone distributions are potential aquifers within the target interval, which appear reasonable based on the geologic properties. However, prediction accuracy suffers from a restricted data foundation and should, therefore, only be considered as an indicator of potential aquifers. Despite these issues, the results demonstrate new possibilities for future seismic reservoir characterization and rock-physics modeling for exploration purposes, derisking, and the exploitation of geothermal energy as a green and sustainable energy resource.

De-risking Appraisal Phase in the Recent Gas Discovery in Banggai-Sula Basin, Central Sulawesi: Application of AVO Analysis and Pre-stack Inversion in the Sub-ophiolite Reef Carbonate Play

2021 ◽  
Author(s):  
M. Ahmad
Keyword(s):  
Reservoir Characterization ◽  
Linear Trend ◽  
Rock Physics ◽  
Seismic Inversion ◽  
Added Value ◽  
Quality Data ◽  
Water Contact ◽  
Avo Analysis ◽  
Amplitude Versus Offset ◽  
Avo Attributes

Following the success in the exploration drilling campaign in the last few years, Pertamina EP puts the recently discovered Wol Structure into the appraisal stage. The exploration wells Wol-001 and Wol-002 were spudded in 2017 and 2019 respectively, and both flowed a significant gas rate from an excellent reservoir of Miocene Reef of Minahaki Formation. A good understanding of the reservoir distribution was essential in such a stage. Therefore, a proper reservoir characterization was then carried out for further appraisal purposes. Using the improved quality data from the latest 5D interpolation-PSDM as input, integration of amplitude versus offset (AVO) techniques and rock physics analysis was conducted to investigate the hydrocarbon extent. The AVO class IIp was observed at the boundary between overlying Kintom Shale and gas saturated Minahaki limestone. It is indicated by a positive intercept (Ro), decreased amplitudes with offsets, and negative amplitudes in the far offsets. This polarity reversal characteristic is clearly seen from both AVO modeling and actual CDP in the well locations. Several CDPs inside and outside the closure were also examined to check the consistency. The slice of partial stack volumes has also exhibited a similar trend within the closure where class IIp is suggestive. Since the AVO attributes such as intercept and gradient solely were not able to visualize the reservoir extent properly, the pre-stack seismic inversion was performed to obtain a more accurate reservoir distribution through quantitative interpretation. A cross plot of P-impedance (Ip) over S-impedance (Is) differentiates the gas zone clearly from the wet linear trend. A depth slice at GWC (gas water contact) level describes that most of the Wol Structure is gas-saturated including the newly identified closure in the northwest. It is a three-way dip closure formed by limestone that was dragged upward by a thrust fault. Interestingly, it has a similar AVO response to the main Wol Structure which suggests a gas-bearing reservoir. This work brings an added value to the use of AVO analysis and pre-stack inversion for hydrocarbon mapping for appraisal purposes. Not only it has largely reduced the subsurface uncertainty, but also revealed an upside potential that is worth considering in future exploration.

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