Assessment of Reservoir Rock Properties from Rock Physics Modeling and Petrophysical Analysis of Borehole Logging Data to Lessen Uncertainty in Formation Characterization in Ratana Gas Field, Northern Potwar, Pakistan

2018 ◽  
Vol 91 (6) ◽  
pp. 736-742 ◽  
Author(s):  
Nisar Ahmed ◽  
Tayyaba Kausar ◽  
Perveiz Khalid ◽  
Sohail Akram
Keyword(s):  
Rock Physics ◽  
Reservoir Rock ◽  
Rock Properties ◽  
Gas Field ◽  
Petrophysical Analysis ◽  
Borehole Logging ◽  
Rock Physics Modeling ◽  
Physics Modeling

Rock-physics diagnostics of an offshore gas field

Geophysics ◽  
2017 ◽  
Vol 82 (4) ◽  
pp. MR121-MR132 ◽  
Author(s):  
Uri Wollner ◽  
Yunfei Yang ◽  
Jack P. Dvorkin
Keyword(s):  
Rock Physics ◽  
Rock Properties ◽  
Gas Field ◽  
Amplitude Variation With Offset ◽  
Rock Physics Modeling ◽  
Physics Modeling ◽  
Using Data ◽  
Physics Model ◽  
Well Data ◽  
Rock Physics Model

Seismic reflections depend on the contrasts of the elastic properties of the subsurface and their 3D geometry. As a result, interpreting seismic data for petrophysical rock properties requires a theoretical rock-physics model that links the seismic response to a rock’s velocity and density. Such a model is based on controlled experiments in which the petrophysical and elastic rock properties are measured on the same samples, such as in the wellbore. Using data from three wells drilled through a clastic offshore gas reservoir, we establish a theoretical rock-physics model that quantitatively explains these data. The modeling is based on the assumption that only three minerals are present: quartz, clay, and feldspar. To have a single rock-physics transform to quantify the well data in the entire intervals under examination in all three wells, we introduced field-specific elastic moduli for the clay. We then used the model to correct the measured shear-wave velocity because it appeared to be unreasonably low. The resulting model-derived Poisson’s ratio is much smaller than the measured ratio, especially in the reservoir. The associated synthetic amplitude variation with offset response appears to be consistent with the recorded seismic angle stacks. We have shown how rock-physics modeling not only helps us to correct the well data, but also allows us to go beyond the settings represented in the wells and quantify the seismic signatures of rock properties and conditions varying in a wider range using forward seismic modeling.

scholarly journals Rock Physics Modeling and Seismic Interpretation to Estimate Shally Cemented Zone in Carbonate Reservoir Rock

2016 ◽  
Vol 1 (1) ◽  
pp. 45
Author(s):  
Handoyo Handoyo ◽  
M Rizki Sudarsana ◽  
Restu Almiati
Keyword(s):  
Elastic Properties ◽  
Wave Velocity ◽  
Carbonate Rock ◽  
Rock Physics ◽  
Carbonate Reservoir ◽  
Reservoir Rock ◽  
Rock Physics Modeling ◽  
Porosity And Permeability ◽  
Physics Modeling ◽  
The Relationship

Carbonate rock are important hydrocarbon reservoir rocks with complex texture and petrophysical properties (porosity and permeability). These complexities make the prediction reservoir characteristics (e.g. porosity and permeability) from their seismic properties more difficult. The goal of this paper are to understanding the relationship of physical properties and to see the signature carbonate initial rock and shally-carbonate rock from the reservoir. To understand the relationship between the seismic, petrophysical and geological properties, we used rock physics modeling from ultrasonic P- and S- wave velocity that measured from log data. The measurements obtained from carbonate reservoir field (gas production). X-ray diffraction and scanning electron microscope studies shown the reservoir rock are contain wackestone-packstone content. Effective medium theory to rock physics modeling are using Voigt, Reuss, and Hill.  It is shown the elastic moduly proposionally decrease with increasing porosity. Elastic properties and wave velocity are decreasing proporsionally with increasing porosity and shally cemented on the carbonate rock give higher elastic properties than initial carbonate non-cemented. Rock physics modeling can separated zones which rich of shale and less of shale.

Accuracy and effectiveness of three-dimensional controlled source electromagnetic data inversions

Geophysics ◽  
2015 ◽  
Vol 80 (2) ◽  
pp. E83-E95
Author(s):  
Richard T. Houck ◽  
Adrian Ciucivara ◽  
Scott Hornbostel
Keyword(s):  
Three Dimensional ◽  
Rock Physics ◽  
Hydrocarbon Reservoirs ◽  
Rock Properties ◽  
Data Sets ◽  
Controlled Source ◽  
Electromagnetic Data ◽  
Fluid Properties ◽  
Rock Physics Modeling ◽  
Physics Modeling

Unconstrained 3D inversion of marine controlled source electromagnetic data (CSEM) data sets produces resistivity volumes that have an uncertain relationship to the true subsurface resistivity at the scale of typical hydrocarbon reservoirs. Furthermore, CSEM-scale resistivity is an ambiguous indicator of hydrocarbon presence; not all resistivity anomalies are caused by hydrocarbon reservoirs, and not all hydrocarbon reservoirs produce a distinct resistivity anomaly. We have developed a method for quantifying the effectiveness of resistivities from CSEM inversion in detecting hydrocarbon reservoirs. Our approach uses probabilistic rock-physics modeling to update information from a preexisting prospect assessment, based on uncertain resistivities from CSEM. The result is an estimate the probability of hydrocarbon presence that accounts for uncertainty in the resistivity and in rock properties. Examples using synthetic and real CSEM data sets demonstrate that the effectiveness of CSEM inversion in identifying hydrocarbon reservoirs depends on the interaction between the uncertainty associated with the inversion-derived resistivity and the range of rock and fluid properties that were expected for the targeted prospect. Resistivity uncertainty that has a small effect on hydrocarbon probability for one set of rock property distributions may have a large effect for a different set of rock properties. Depending on the consequences of this interaction, resistivities from CSEM inversion might reduce the risk associated with predictions of hydrocarbon presence, but they cannot be expected to guarantee a specific well outcome.

scholarly journals Probabilistic approach to rock physics modeling

Geophysics ◽  
2014 ◽  
Vol 79 (2) ◽  
pp. D123-D143 ◽  
Author(s):  
Dario Grana
Keyword(s):  
Probability Distribution ◽  
Reservoir Characterization ◽  
Probability Distributions ◽  
Probabilistic Approach ◽  
Rock Physics ◽  
Random Variable ◽  
Rock Properties ◽  
Fluid Saturation ◽  
Rock Physics Modeling ◽  
Physics Modeling

Rock physics modeling aims to provide a link between rock properties, such as porosity, lithology, and fluid saturation, and elastic attributes, such as velocities or impedances. These models are then used in quantitative seismic interpretation and reservoir characterization. However, most of the geophysical measurements are uncertain; therefore, rock physics equations must be combined with mathematical tools to account for the uncertainty in the data. We combined probability theory with rock physics modeling to make predictions of elastic properties using probability distributions rather than definite values. The method provided analytical solutions of rock physics models in which the input is a random variable whose exact value is unknown but whose probability distribution is known. The probability distribution derived with this approach can be used to quantify the uncertainty in rock physics model predictions and in rock property estimation from seismic attributes. Examples of fluid substitution and rock physics modeling were studied to illustrate the application of the method.

Rock physics modeling to monitor movement of CO2in Sleipner gas field, North Sea: An ideal CCS field

2014 ◽  
Author(s):  
Ranjana Ghosh* ◽  
Nimisha Vedanti ◽  
Reetam Biswas ◽  
Mrinal K. Sen
Keyword(s):  
North Sea ◽  
Rock Physics ◽  
Gas Field ◽  
Rock Physics Modeling ◽  
Physics Modeling
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