Relative Rock Physics Templates in the Elastic Impedance Domain

2015 ◽  
Author(s):  
M. Gidlow ◽  
A. Msolo
Keyword(s):  
Rock Physics ◽  
Elastic Impedance

Analysis of the Hidrocarbon Sandstone Distribution Using Rock Physics and Petrophysic Calculations, Simultaneous Inversion, Extended Elastic Impedance (EEI) and Curved Pseudo-Elastic Impedance (CPEI) in X Field Bonaparte Basin

2020 ◽  
Author(s):  
A., H. Kusuma
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Rock Physics ◽  
Fluid Distribution ◽  
Elastic Parameters ◽  
Angular Rotation ◽  
Simultaneous Inversion ◽  
A Value ◽  
Seismic Volumes ◽  
Elastic Impedance

To analyze the distribution of hydrocarbon reservoirs in an area, appropriate methods and parameters can be used to map sediments in the area. In this study, the research was conducted on the X Field located in the Bonaparte Basin. The EEI and CPEI methods are used. The Extended Elastic Impedance (EEI) method is a method that can be used to connect seismic data with elastic parameters by applying the principle of angular rotation. From this method, seismic volumes of various elastic parameters and reservoir parameters will be obtained. The Curved Pseudo-elastic Impedance (CPEI which is able to answer the problem in describing the distribution of fluid in the study area) is also carried out. Gamma Ray (GR) is used to detect lithology and fluid distribution, while from the results of CPEI inversion, the water saturation volume is obtained to see the hydrocarbon distribution in the study area. The results show that the two inversions are able to differentiate the distribution of tight sand lithology, shale, wet sand, gas sand and porous sand. The presence of gas sand distribution can be identified by the value of GR = 20-40 API, λρ = 0-50 GPA*gr/cc, μρ > 80 GPA*g/cc, σ = 0.05-0.24 unitless and the value of Sw = 0-40%, lithology tight sand has a value of GR = 40-70 API, λρ = 70-80 GPA*gr/cc, σ>0.4 unitless, shale lithology has a value of GR > 90 API , μρ <30 GPA*gr/cc, and wet sand is shown with the value GR = 20-40 API, λρ = 50-80 GPA*gr/cc, σ = 0.25-0.35 unitless and Sw> 70%. Based on the results of these interpretations, a sandstone distribution map in X Field was generated and it consists of 2 reservoir layers in the research target zone.

Prediction of deep-buried gas carbonate reservoir by combining prestack seismic-driven elastic properties with rock physics in Sichuan Basin, southwestern China

2014 ◽  
Vol 2 (4) ◽  
pp. T193-T204
Author(s):  
Jiqiang Ma ◽  
Jianhua Geng ◽  
Tonglou Guo
Keyword(s):  
Elastic Properties ◽  
Seismic Data ◽  
Sichuan Basin ◽  
Incident Angle ◽  
Rock Physics ◽  
Carbonate Reservoir ◽  
Southwestern China ◽  
Marine Carbonate ◽  
The Sichuan Basin ◽  
Elastic Impedance

The prediction of seismic reservoirs in marine carbonate areas in the Sichuan Basin, southwestern China, is very challenging because the target zone is deeply buried (more than 6 km), with multiphase tectonic movements, complex diagenesis, and low porosity, and the incident angle of the seismic data is finite. We developed reliable hydrocarbon indicators of a marine carbonate deposit based on prestack elastic impedance (EI) and well observations. Although the hydrocarbon indicators can be calculated from elastic parameters, the inversion for EI-driven elastic attributes is usually unstable. To constrain the inversion process, we discovered a new strategy to recover the elastic properties from EIs within a Bayesian framework (called Bayesian elastic parameter inversion from elastic impedance). We applied the strategy to a carbonate reef identified at the center of a study line based on the geologic context and the seismic reflection patterns. We then used rock-physics analyses to classify the lithologies and the reservoir at a well location. Rock-physics modeling quantified the hydrocarbon sensitivity of the elastic attributes. Fluid substitution was used to investigate the effects of pore fluids on the elastic properties. A comparison of two synthetic amplitude-versus-angle responses (for gas and brine saturation) with real seismic data showed that the reservoir was gas charged. Using well-based crossplot analyses, reliable direct hydrocarbon indicators can be constructed for a deeply buried gas reservoir and were effective for interpretation in an area of marine carbonates in the Sichuan Basin.

Seismic screening of rock stiffness and fluid softening using rock-physics attributes

2015 ◽  
Vol 3 (4) ◽  
pp. SAE85-SAE93 ◽  
Author(s):  
Per Avseth ◽  
Tor Veggeland
Keyword(s):  
Rock Physics ◽  
Seismic Inversion ◽  
Well Log ◽  
Reservoir Properties ◽  
Empirical Relationships ◽  
Norwegian Sea ◽  
Reservoir Rocks ◽  
Fluid Saturation ◽  
Reservoir Sandstones ◽  
Elastic Impedance

We have developed a methodology to create easy-to-implement rock-physics attributes that can be used to screen for reservoir sandstones and hydrocarbon pore fill from seismic inversion data. Most seismic attributes are based on the empirical relationships between reservoir properties and seismic observables. We have honored the physical properties of the rocks by defining attributes that complied with calibrated rock-physics models. These attributes included the fluid saturation sensitive curved pseudo-elastic impedance (CPEI) and the rock stiffness/lithology attribute pseudo-elastic impedance for lithology (PEIL). We found that the CPEI attribute correlated nicely with saturation and resistivity, whereas the PEIL attribute in practice was a scaled version of the shear modulus and correlated nicely with porosity. We determined the use of these attributes on well log and seismic inversion data from the Norwegian Sea, and we successfully screened out reservoir rocks filled with either water or hydrocarbons.

Distinguishing gas-bearing sandstone reservoirs within mixed siliciclastic-carbonate sequences using extended elastic impedance: Nile Delta — Egypt

2016 ◽  
Vol 4 (4) ◽  
pp. T427-T441 ◽  
Author(s):  
Ahmed Hafez ◽  
John P. Castagna
Keyword(s):  
Nile Delta ◽  
Rock Physics ◽  
Seismic Inversion ◽  
Anomalous Behavior ◽  
Well Logs ◽  
High Impedance ◽  
Bright Spots ◽  
Fluid Properties ◽  
Elastic Impedance ◽  
Gas Bearing

In the Abu Madi Formation of the Nile Delta Basin, false bright spots may be misinterpreted as being indicative of hydrocarbons due to mixed clastics and carbonates. However, rock-physics analysis of well logs in a particular prospect area where such ambiguity exists suggests that attributes derived using extended elastic impedance (EEI) inversion may help identify hydrocarbons because they better show anomalous behavior in particular directions that are readily related to pore fluids and lithology. The EEI attributes calculated from well logs correlate extremely well to lithology and fluid properties, thereby differentiating amplitude anomalies caused by gas-bearing sandstones encased in shale from similar amplitudes caused by juxtaposition of high-impedance carbonates over lower impedance water-filled sandstones. Comparing seismically derived EEI attributes to well logs from a productive well and a nonproductive well indicates that seismic inversion can successfully identify lithologies such as shales, sandstones, carbonates, and anhydrite and distinguish gas-bearing from water-bearing sandstones. The technique can thus potentially be used to better delineate and risk prospects in the area, as well as assisting exploration efforts in other locations where similar ambiguities in amplitude interpretation exist.

Elastic-impedance analysis constrained by rock-physics bounds

2007 ◽  
Vol 55 (3) ◽  
pp. 289-306 ◽  
Author(s):  
Futoshi Tsuneyama ◽  
Gary Mavko
Keyword(s):  
Rock Physics ◽  
Impedance Analysis ◽  
Elastic Impedance

Azimuthally anisotropic elastic impedance inversion for fluid indicator driven by rock physics

Geophysics ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. C211-C227 ◽  
Author(s):  
Xinpeng Pan ◽  
Guangzhi Zhang ◽  
Xingyao Yin
Keyword(s):  
Fractured Reservoirs ◽  
Low Frequency ◽  
Rock Physics ◽  
Real Data ◽  
Inversion Method ◽  
Anisotropic Rock ◽  
Weak Anisotropy ◽  
Fluid Identification ◽  
Anisotropic Elastic ◽  
Elastic Impedance

The normal-to-tangential fracture compliance ratio is usually used as a fracture fluid indicator (FFI) for fluid identification in fractured reservoirs. With a new parameterization for fracture weaknesses, we have defined a new FFI based on azimuthally anisotropic elastic impedance (EI) inversion and fractured anisotropic rock-physics models. First, we derived a new azimuthally anisotropic EI equation with a similar expression for the isotropic and anisotropic EI parts to remove the exponential correction of EI that is attributable to weak anisotropy. Then, we built a fractured anisotropic rock-physics model used for the estimation of well-log parameters for the normal and tangential fracture weaknesses, which built the initial background low-frequency trend of fracture weaknesses. Finally, based on the azimuthally anisotropic EI inversion method with the Cauchy-sparse and low-frequency information regularization, we estimated an FFI applied to fluid identification in fractured reservoirs. Tests on the synthetic and real data demonstrate that the anisotropic parameters related to fracture weaknesses can be estimated reasonably and stably and that our method appears to provide an alternative available for fluid identification in fractured reservoirs.

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