scholarly journals Water saturation effects on elastic wave attenuation in porous rocks with aligned fractures

2014 ◽  
Vol 197 (2) ◽  
pp. 943-947 ◽  
Author(s):  
Kelvin Amalokwu ◽  
Angus I. Best ◽  
Jeremy Sothcott ◽  
Mark Chapman ◽  
Tim Minshull ◽  
...  
Keyword(s):  
Elastic Wave ◽  
Reservoir Characterization ◽  
Wave Attenuation ◽  
Water Saturation ◽  
Theoretical Models ◽  
Ultrasonic Pulse ◽  
Fracture Density ◽  
Porous Rocks ◽  
Saturation State ◽  
Hydrocarbon Reservoir

Abstract Elastic wave attenuation anisotropy in porous rocks with aligned fractures is of interest to seismic remote sensing of the Earth's structure and to hydrocarbon reservoir characterization in particular. We investigated the effect of partial water saturation on attenuation in fractured rocks in the laboratory by conducting ultrasonic pulse-echo measurements on synthetic, silica-cemented, sandstones with aligned penny-shaped voids (fracture density of 0.0298 ± 0.0077), chosen to simulate the effect of natural fractures in the Earth according to theoretical models. Our results show, for the first time, contrasting variations in the attenuation (Q−1) of P and S waves with water saturation in samples with and without fractures. The observed Qs/Qp ratios are indicative of saturation state and the presence or absence of fractures, offering an important new possibility for remote fluid detection and characterization.

Incorporating mechanisms of fluid pressure relaxation into inclusion‐based models of elastic wave velocities

Geophysics ◽  
2003 ◽  
Vol 68 (4) ◽  
pp. 1173-1181 ◽  
Author(s):  
S. Richard Taylor ◽  
Rosemary J. Knight
Keyword(s):  
Elastic Wave ◽  
Water Saturation ◽  
Laboratory Data ◽  
Fluid Pressure ◽  
P Wave ◽  
Porous Rocks ◽  
Low Frequencies ◽  
Wave Velocities ◽  
Exact Agreement ◽  
Flow Through

Our new method incorporates fluid pressure communication into inclusion‐based models of elastic wave velocities in porous rocks by defining effective elastic moduli for fluid‐filled inclusions. We illustrate this approach with two models: (1) flow between nearest‐neighbor pairs of inclusions and (2) flow through a network of inclusions that communicates fluid pressure throughout a rock sample. In both models, we assume that pore pressure gradients induce laminar flow through narrow ducts, and we give expressions for the effective bulk moduli of inclusions. We compute P‐wave velocities and attenuation in a model sandstone and illustrate that the dependence on frequency and water‐saturation agrees qualitatively with laboratory data. We consider levels of water saturation from 0 to 100% and all wavelengths much larger than the scale of material heterogeneity, obtaining near‐exact agreement with Gassmann theory at low frequencies and exact agreement with inclusion‐based models at high frequencies.

scholarly journals Hydrocarbon reservoir characterization of “Otan-Ile” field, Niger Delta

2021 ◽  
Vol 11 (2) ◽  
pp. 601-615
Author(s):  
Tokunbo Sanmi Fagbemigun ◽  
Michael Ayu Ayuk ◽  
Olufemi Enitan Oyanameh ◽  
Opeyemi Joshua Akinrinade ◽  
Joel Olayide Amosun ◽  
...  
Keyword(s):  
Niger Delta ◽  
Reservoir Characterization ◽  
Water Saturation ◽  
Structural Deformation ◽  
Well Log ◽  
Reservoir Properties ◽  
Good Tool ◽  
Log Data ◽  
Hydrocarbon Reservoir ◽  
Hydrocarbon Saturation

AbstractOtan-Ile field, located in the transition zone Niger Delta, is characterized by complex structural deformation and faulting which lead to high uncertainties of reservoir properties. These high uncertainties greatly affect the exploration and development of the Otan-Ile field, and thus require proper characterization. Reservoir characterization requires integration of different data such as seismic and well log data, which are used to develop proper reservoir model. Therefore, the objective of this study is to characterize the reservoir sand bodies across the Otan-Ile field and to evaluate the petrophysical parameters using 3-dimension seismic and well log data from four wells. Reservoir sands were delineated using combination of resistivity and gamma ray logs. The estimation of reservoir properties, such as gross thickness, net thickness, volume of shale, porosity, water saturation and hydrocarbon saturation, were done using standard equations. Two horizons (T and U) as well as major and minor faults were mapped across the ‘Otan-Ile’ field. The results show that the average net thickness, volume of shale, porosity, hydrocarbon saturation and permeability across the field are 28.19 m, 15%, 37%, 71% and 26,740.24 md respectively. Two major faults (F1 and F5) dipping in northeastern and northwestern direction were identified. The horizons were characterized by structural closures which can accommodate hydrocarbon were identified. Amplitude maps superimposed on depth-structure map also validate the hydrocarbon potential of the closures on it. This study shows that the integration of 3D seismic and well log data with seismic attribute is a good tool for proper hydrocarbon reservoir characterization.

Experimental evidence for the Biot‐Gardner theory

Geophysics ◽  
1989 ◽  
Vol 54 (4) ◽  
pp. 524-527 ◽  
Author(s):  
R. Mörig ◽  
H. Burkhardt
Keyword(s):  
Experimental Evidence ◽  
Seismic Wave ◽  
Seismic Data ◽  
Seismic Waves ◽  
Wave Attenuation ◽  
Wide Spectrum ◽  
Seismic Energy ◽  
Porous Rocks ◽  
Saturation State ◽  
Seismic Wave Attenuation

Seismic wave attenuation has been a subject of interest during the last 40 years because it may be of use in interpreting seismic data. From this attenuation parameter, more detailed information about the lithology of the subsurface may be deduced if we understand the absorption mechanisms by which dissipation of seismic energy is governed. We are, therefore, studying in the laboratory the effects of different parameters such as porosity, permeability, pore fluid, and saturation state on the absorption of seismic waves in porous rocks over a wide spectrum ranging from seismic to ultrasonic frequencies (Burkhardt et al., 1986).

Outcrop Analogues to Fractured Reservoirs, UAE

2021 ◽  
Author(s):  
Abdelwahab Noufal
Keyword(s):  
Fluid Flow ◽  
Reservoir Characterization ◽  
Fractured Reservoirs ◽  
Abu Dhabi ◽  
Fracture Density ◽  
Tectonic Event ◽  
Rock Composition ◽  
Hydrocarbon Reservoir ◽  
Fracture Orientation ◽  
Bed Thickness

Abstract Fractures were not the focus of reservoir studies in Abu Dhabi for the last decades, although its importance in enhancing production, as the general understanding considering fractures are not contributing to production. The fractured carbonate outcrops provide useful analogue observations, data and concepts to support subsurface hydrocarbon reservoir characterization from well and seismic data. The fracture orientation, size, porosity, length, spacing, crosscutting relationships, fracture density versus lithology and bed thickness and connectivity are difficult to measure directly from subsurface well and core data. The understanding of fracture formation and distribution and their effects on fluid flow has been greatly improved by the use of outcrop analogue data through the current work. This paper address the fracture geometry, kinematics and mechanical properties based on outcrops matching Abu Dhabi subsurface reservoir analogues. Integrating outcrop data with fracture orientation and fracture density from core and borehole image data, and seismic capturing fractures characteristics. The outcrop analogues constrain the uncertainty and developing new concepts in characterizing the interplay of rock matrix and fracture networks relevant to fluid flow and hydrocarbon recovery. Analysing the fractures with fracture lengths, aperture, spacing per each interval and relate them to the tectonic event are extracted strictly in the reservoir section. The results showing developed highly dipping shear fractures with short length, small spacing and bimodal aperture distribution that related to fracture orientation. Fracture porosity is dependent on size and controlled by lithology, bed thickness, paleostress and rock composition. Understanding fractures and their behaviour will optimize production greatly and they create exploration targets in otherwise tight reservoir zones, including under-explored sections.

scholarly journals PETROPHYSICAL ANALYSIS AND SEISMIC STRATIGRAPHY INTERPRETATION TO DETERMINE HYDROCARBON RESERVOIR IN TARAKAN BASIN, BUNYU ISLAND WATERS

2021 ◽  
Vol 36 (1) ◽  
Author(s):  
Daffa Dzakwan Shiddiq ◽  
Eleonora Agustine ◽  
Tumpal Bernhard Nainggolan ◽  
Imam Setiadi ◽  
Shaska Zulivandama
Keyword(s):  
Reservoir Characterization ◽  
Water Saturation ◽  
Seismic Stratigraphy ◽  
Effective Porosity ◽  
Geological Structures ◽  
Seismic Line ◽  
Petrophysical Analysis ◽  
Hydrocarbon Reservoir ◽  
Shale Volume ◽  
Basin Area

Tarakan Basin area of Bunyu Island Waters is known to have hydrocarbon potential with complex geological structures. This study aims to determine reservoir characterization and to obtain prospect of hydrocarbon reservoir zones based on petrophysical and seismic stratigraphy analysis with reference to Well DDS-1 and 2D seismic Line S88. Petrophysical analysis results 3 zones that have potential as hydrocarbon reservoirs. Based on petrophysical quantitative analysis, Zone 1 has values of 52.25% for shale volume, 18.48% for effective porosity, 39.84% for water saturation and 13.03 mD for permeability. Zone 2 has values of 54.66% for shale volume, 10.27% for effective porosity, 40.9% for water saturation and 1.14 mD for permeability. Zone 3 has values of 49.22% for shale volume, 9.33% for effective porosity, 56.33% for water saturation and 0.22 mD for permeability. Out of these three reservoir zones in Well DDS- 1, Zone 1 has the prospect of hydrocarbons which is supported by the net pay value. Based on seismic stratigraphy interpretation, the reservoir zone is correlated to the Tabul Formation, which comprises calcareous clay and limestone.

scholarly journals Hydrocarbon Reservoir Characterization of ‘Khume’ Field, Offshore Niger Delta, Nigeria

2021 ◽  
pp. 47-60
Author(s):  
K. A. Obakhume ◽  
O. M. Ekeng ◽  
C. Atuanya
Keyword(s):  
Niger Delta ◽  
Reservoir Characterization ◽  
Gamma Ray ◽  
Water Saturation ◽  
Seismic Interpretation ◽  
Effective Porosity ◽  
Well Logs ◽  
Integrative Approach ◽  
Neutron Density ◽  
Hydrocarbon Reservoir

The integrative approach of well log correlation and seismic interpretation was adopted in this study to adequately characterize and evaluate the hydrocarbon potentials of Khume field, offshore Niger Delta, Nigeria. 3-D seismic data and well logs data from ten (10) wells were utilized to delineate the geometry of the reservoirs in Khume field, and as well as to estimate the hydrocarbon reserves. Three hydrocarbon-bearing reservoirs of interest (D-04, D-06, and E-09A) were delineated using an array of gamma-ray logs, resistivity log, and neutron/density log suites. Stratigraphic interpretation of the lithologies in Khume field showed considerable uniform gross thickness across all three sand bodies. Results of petrophysical evaluations conducted on the three reservoirs correlated across the field showed that; shale volume ranged from 7-14%, total and effective porosity ranged from 19-26% and 17-23% respectively, NTG from 42 to 100%, water saturation from 40%-100% and permeability from 1265-2102 mD. Seismic interpretation established the presence of both synthetic and antithetic faults. A total of six synthetic and four antithetic faults were interpreted from the study area. Horizons interpretation was done both in the strike and dip directions. Time and depth structure maps revealed reservoir closures to be anticlinal and fault supported in the field. Hydrocarbon volumes were calculated using the deterministic (map-based) approach. Stock tank oil initially in place (STOIIP) for the proven oil column estimated for the D-04 reservoir was 11.13 MMSTB, 0.54 MMSTB for D-06, and 2.16 MMSTB for E-09A reservoir. For the possible oil reserves, a STOIIP value of 7.28 MMSTB was estimated for D-06 and 6.30 MMSTB for E-09A reservoir, while a hydrocarbon initially in place (HIIP) of 4.13 MMSTB of oil equivalents was derived for the undefined fluid (oil/gas) in D-06 reservoir. A proven gas reserve of 1.07 MMSCF was derived for the D-06 reservoir. This study demonstrated the effectiveness of 3-D seismic and well logs data in delineating reservoir structural architecture and in estimating hydrocarbon volumes

Sign in / Sign up

Export Citation Format

Share Document