Reservoir Characterization Review in Sedimentary Basins (original) (raw)
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Complete overview of reservoir characterisation in sedimentary basins
Evaluating the subsurface characteristics of reservoirs is an important part of hydrocarbon exploration and production in sedimentary basins. This process combines geological, geophysical, and engineering data to comprehend the subsurface geology and fluid distribution, determine reserves, and predict the fluid movement in the reservoir. The primary goal of reservoir characterization is to create a precise and dependable model of the reservoir to maximize the production procedure and reduce the associated risks of hydrocarbon exploration and production. This review examines different approach utilized for reservoir characterization in sedimentary basins, including geological, geophysical, and engineering methods. Each method’s advantages and disadvantages are discussed, alongside their uses in different reservoir contexts. The importance of combining multiple lines of evidence to enhance the accuracy of the reservoir models is also examined.
SPE-180375-MS An Improved Approach for Sandstone Reservoir Characterization
This paper presents a field scale reservoir characterization for a late Pennsylvanian clastic reservoir at the Farnsworth Unit (FWU), located in the northeast Texas Panhandle on the northwest shelf of the Anadarko basin. The characterization is undertaken as part of a Phase III project conducted by the Southwest Regional Partnership on Carbon Sequestration (SWP). The target unit is the upper most Morrow sandstone bed (Morrow B Sand). Extensive data acquired from FWU was used to improve previously constructed static and dynamic models. The Morrow B reservoir was deposited as fluvial low-stand to transgressive clastic fill within an incised valley. It is predominantly, subarkosic, brown to grey, upper medium to very coarse sands and fine gravels with sub-angular, to sub-rounded poorly sorted grains either planar to massively bedded. It was shown that primary depositional fabrics have less effect than post depositional diagenetic features do on reservoir performance, although subtle variations in deposition may have had some effect on later diagenetic pathways. Three new wells were drilled for the purpose of field infilling and characterization. Cores and advanced wire-line logs from these wells were analyzed for stratigraphic context, sedimentological character and depositional setting in order to better predict porosity and permeability trends within the reservoir. Structural modeling was conducted through the integration of depth-converted 3D seismic data with well log data to create the framework stratigraphic intervals. This information, together with additional core, UBI image logs and an improved hydraulic flow unit methodology (HFU) was used to characterize and subsequently create a fine scale lithofacies based geological model of the field. Core and log analysis allowed subdivision of the target interval into Hydraulic Flow Units (HFUs). The HFU approach enhanced core analysis and was used to elucidate porosity-permeability correlations. This methodology proved to be an exceptional approach to assigning permeability as a function of porosity during petrophysical modeling. The integrated approach of combining seismic attributes with core calibrated facies and the HFU methodology was able to better constrain uncertainty within inter-well spacing and accurately quantify reservoir heterogeneity within FWU. The approach illustrated in this study presents an improved methodology in characterizing heterogeneous and complex reservoirs that can be applied to reservoirs with similar geological features.
University of Tulsa Centennial Petroleum Engineering Symposium, 1994
The reservoir character of the Cretaceous sand is evaluated in Lower Indus Basin, Pakistan where water flooding is very common. Thus, prediction of subsurface structure, lithology and reservoir characterization is fundamental for a successful oil or gas discovery. Seismic reflective response is an important tool to detect sub-surface structure. Seismic reflection response is not enough to highlight geological boundaries and fluids in the pore space therefore, the use of integrated approach is vital to map sub-surface heterogeneities with high level of confidence. Based on seismic character and continuity of prominent reflectors four seismic horizons are marked on the seismic sections. All the strata is highly disturbed and distorted with presence of a network of fault bounded horst and graben structures, which indicate that the area was under compressional tectonic regime. These fault bounded geological structure formed structural traps favorable for the accumulation of hydrocarbon. The petrophysical analysis reveals that the Cretaceous sand formation has four types of sand: Sand A, B, C and D with good porosity (15 % average) and low volume of shale. Although complete petroleum system is present with structural traps and reservoir character of sand interval is very good but these sands are highly saturated with water thus are water flooded, which is the main reason of the abundant wells in the study area.
Characterization of Reservoir by Using Geological, Reservoir and Core Data
Journal of Applied Sciences 23(1):34-46, 2023
Characterizing fracture properties in naturally fractured reservoirs poses a significant challenge. While well-testing remains valuable, it often fails to provide precise descriptions of these properties. Bridging this gap requires the integration of geological expertise to enhance fracture assessment. This study addresses the limitations of well-test analysis and explores the application of Conventional Image Logs in structural, fracture, and geomechanical analysis. However, effectively combining these applications with well-test analysis on a field scale reveals a substantial knowledge gap. A critical challenge in this context is the absence of a defined procedure for calculating the variable "σ," a crucial parameter for simulating fractured carbonate reservoirs using image log fracture density. Integrating geological knowledge is essential to reduce uncertainties associated with well-test analysis and provide more accurate characterizations of fracture properties. Image log data processing emerges as a valuable avenue for gaining insights into the static attributes of naturally fractured reservoirs. This study focuses on Characterizing fractures using data from ten image logs and Developing a more accurate simulation model through the interpretation of images, with a particular emphasis on OBM imaging. The main goals of this fracture study revolve around establishing correlations between fracture densities well by well within the simulation and enhancing the accuracy of the simulation model by incorporating fracture data from image logs. Borehole imaging tools such as FMI/FMS and OBMI-UBI play a pivotal role in identifying significant structural features, including faults, fractures, and bedding. Fine-tuning fracture parameters during the history matching process, while potentially time-consuming, significantly impacts other historical match parameters. Consequently, the reliability of reservoir simulation results, predictions, and recovery enhancement strategies hinges on the precision of fracture properties and their distribution within the model. Recent advances in interpretation techniques have expanded the horizons of image interpretation, enabling the creation of more accurate simulation models for fractured reservoirs using fracture data obtained from image logs. The overarching goal of this project is to comprehensively evaluate a fractured reservoir field by integrating data from ten individual wells. Keywords: Well-testing, fracture evaluation, Image log data, fracture density, simulation sensitivity analysis.
IOSR Journals , 2019
Well log data helps compute rock attributes, show correlations with reservoir properties and act as control datafor seismic data interpretation.The aim of this studyis to analyse and identify rock attributes robust in fluid and lithology discrimination of hydrocarbon reservoirs for seismic data interpretation and reservoir characterization. Rock physics analysis was used to determine the significance of rock attributes, establish relationship between the rock attributes and reservoir properties and identify robust attributes applicable in characterizing reservoir.The cross-plotresults show that acoustic impedance (Ip), poisson ratio (σ), compressional to shear velocity ratio (Vp/Vs), rigidity (μρ) and incompressibility (λρ) rock attributes are robust as fluid and lithology discriminators. The λρ and Vp/Vs ratio are more sensitive to fluid content, while σ and µρ to rock matrix.The µρ vs λρ cross plot was more robust in fluid and lithology discrimination.Hydrocarbon saturated sands were characterized by low λρ and Vp/Vs ratio, and low to moderate Ip, µρ and σ ratio. Low Ipcorresponded to low water saturation (Sw) and high porosity (ϕ).The petrophysical analysisdepictthe delineated reservoirs with good reservoir qualities: thickness in feet (177-324), porosity (0.28-0.29), water saturation (0.29-0.34) and net to gross (0.79-0.83) values.These rock attributes and its relation to reservoir properties are important for calibrating and interpretation of seismic data field wide and are applicable in seismic exploration for gas and oil, and monitoring changes within the reservoir during exploitation.
EPISODES, 2018
Formation evaluation and rock physics are powerful techniques to link the physical properties of rocks and pore fluids measured at boreholes with petrophysical, elastic, and seismic properties at boreholes or faraway from boreholes. However, several sources of uncertainty in the measurements of these properties can affect the strength of this link. A complete statistical workflow is proposed for obtaining petrophysical properties such as porosity, permeability, volume of shale, and water saturation at the well location. This workflow is based on the wireline logs and core plugs and is applied on the lower Jurassic siliciclastic reservoirs of Kohat-Potwar Geologic Province, Pakistan to determine its applicability, the advantages of the new integrated approach, and the value of uncertainty analysis. The linear regression relations are developed between several petrophysically derived parameters measured from core samples and calculated from well logs data. All these parameters are then used as input constraints in rock physics modeling to calculate seismic properties such as bulk and shear moduli, compressional and shear wave velocities etc. A linear relationship is established between porosity and seismic velocities obtained from rock physics model. The well logs predicted rock physics properties such as seismic (P and S-wave) velocities, effective densities and elastic moduli are in close agreement to those measured by using rock physics analysis. Statistical regression analysis revealed significant similarity in the porosity values obtained from geophysical well logs and core samples. The permeability of reservoir intervals show fairly strong linear relationship with the porosity, indicating that the reservoir interval of Datta sandstone is highly permeable and porous thus having large potential of hydrocarbon accumulation and production.
Next Generation Geological Modeling for Hydrocarbon Reservoir Characterization
Advances in Data, Methods, Models and Their Applications in Geoscience, 2011
Higher Lower Uncertainty impact Facies model controls depositional continuity Stratigraphic model layering controls lateral connectivity variogram range controls vertical connectivity Structural model defines gross volumes Petrophysical model defines property distribution Facies model controls depositional continuity Stratigraphic model layering controls lateral connectivity variogram range controls vertical connectivity Structural model defines gross volumes Petrophysical model defines property distribution
Structural and Stratigraphic Modeling Techniques in Shale and Tight Oil Basin Reservoir Studies
2022
The validity of regional and basin-wide geomodels of unconventional and tight-oil plays depends on the accuracy and precision of the available structural and stratigraphic frameworks. Integrated reservoir models, combining seismic, log, core, and production data, are critical tools necessary for capturing the basin fill history and for predicting the 3D facies architecture.For researchers, the lack of publicly available 3D seismic surveys is an impediment to creating accurate models of faults and stratigraphic zones. Three approaches were used to overcome this deficit: 1) well log correlation of detailed stratigraphic zones using densely spaced vertical wells; 2) calculation of trend surfaces from thousands of geosteered 3D horizontal well position logs; and 3) residual analysis of regional and local horizontal well trend surfaces to identify faults.Independent data and identification methods were used to confirm the validity of these new surfaces and faults, including 3D seismic in...