Optimum well trajectory design in a planned well in Blacktip field, Australia: a case study

2010 ◽  
Vol 50 (1) ◽  
pp. 535 ◽  
Author(s):  
Vamegh Rasouli ◽  
Zachariah Pallikathekathil ◽  
Elike Mawuli
Keyword(s):  
Strength Properties ◽  
Earth Model ◽  
Trajectory Design ◽  
Lower Section ◽  
Principal Stresses ◽  
Stress Anisotropy ◽  
Major Fault ◽  
Well Trajectory ◽  
Mechanical Earth Model ◽  
Well Data

A geomechanics study carried out in the Blacktip field, offshore Australia led to optimum wellbore deviation and azimuth to minimise drilling-associated instability problems near a major fault in the field. Elastic and strength properties of the formations and magnitude of principal stresses in the field were estimated from a mechanical earth model (MEM) based on offset well data. The direction of the minimum horizontal stresses was predicted from formation microresistivity image (FMI) logs available in offset wells. The MEM results were calibrated using results from laboratory experiments, well tests and drilling incidents from drilling reports. The MEM showed that formations at the lower section of the well are very competent and have high uniaxial strength; however, most of the failures in the form of breakouts observed from calliper and image logs were in this interval. Therefore, obtaining a good match between the model and observed failures required a large stress anisotropy to be considered for the lower section of the wellbore. Further investigations demonstrated that this is because the wellbore trajectory at deeper depth gets closer to the major fault plane, and this large stress anisotropy is due to the stress redistribution near the fault. The data from offset well was mapped into the planned trajectory, and the selection of the optimum trajectory and a stable mud weight window for the appropriate section led to successful drilling of the deviated well.

Integrated study of a fractured granitic basement reservoir with connectivity analysis and identification of sweet spots: Cauvery Basin, India

2019 ◽  
Vol 38 (4) ◽  
pp. 254-261
Author(s):  
Deepa ◽  
J. Nagaraju ◽  
Binod Chetia ◽  
Rajeev Tandon ◽  
P. K. Chaudhuary ◽  
...  
Keyword(s):  
Fracture Network ◽  
Earth Model ◽  
Connectivity Analysis ◽  
Fracture Permeability ◽  
Cauvery Basin ◽  
Well Production ◽  
Fracture Intensity ◽  
Mechanical Earth Model ◽  
Well Data ◽  
Sweet Spots

Basement exploration in India has seen increased interest after the recent discovery of a field in the Cauvery Basin in southeastern India, with an average individual well production of 700 b/d from a fractured basement reservoir. The field is presently under development, with several development well locations identified for drilling. Optimized development of a fractured basement reservoir requires identification of areas with a permeable fracture network. To meet this objective, we adopted a comprehensive integrated workflow involving the use of common reflection angle migrated seismic data, fracture modeling, a 1D mechanical earth model (MEM), identification of critically stressed fractures in 3D space, fracture permeability/connectivity analysis, and sweet spot identification. The workflow yielded a robust discrete fracture network model based on 3D directional fracture intensity, a 1D MEM that gave regional stress gradients (pore pressure, overburden, Shmin, and SHmax), and rock strength and elastic properties. In addition, we generated a critically stressed 3D fracture model and performed sequential stratal surface restoration for predictive strain modeling that was calibrated at wells. Our fracture permeability and connectivity analysis showed that existing hydrocarbon-producing wells are located within areas that have a fracture cluster/swarm with associated good fracture connectivity. A 3D basement facies model constructed by integrating well data and a poststack inversion impedance volume showed that major flow zones occur in weathered basement associated with low impedance. This model, in combination with fracture intensity data, provides good indication of the location of basement sweet spots in the Cauvery Basin. The understanding gained on the controls of occurrence of basement fractures explains why some wells in the field are producers and others are dry. This led to greater confidence in optimizing the locations of previously proposed new development wells.

Application of extended elastic impedance in seismic geomechanics

Geophysics ◽  
2019 ◽  
Vol 84 (3) ◽  
pp. R429-R446 ◽  
Author(s):  
Javad Sharifi ◽  
Naser Hafezi Moghaddas ◽  
Gholam Reza Lashkaripour ◽  
Abdolrahim Javaherian ◽  
Marzieh Mirzakhanian
Keyword(s):  
Carbonate Reservoir ◽  
Reservoir Rock ◽  
Earth Model ◽  
Physical Parameters ◽  
Simultaneous Inversion ◽  
Geomechanical Parameters ◽  
Mechanical Earth Model ◽  
Well Data ◽  
Southwest Of Iran ◽  
Elastic Impedance

We have evaluated an innovative application of extended elastic impedance (EEI) to integrate seismic and geomechanics for geomechanical interpretation of hydrocarbon reservoirs. EEI analysis is used to extract geomechanical parameters. To verify and assess the capabilities of EEI analysis for extracting geomechanical parameters, we selected a jointed, oil-bearing, shale carbonate reservoir in the southwest of Iran, and we used petrophysical data and core analysis to estimate static and dynamic moduli of the reservoir rock. We calculated the corresponding EEI curve to different intercept-gradient coordinate rotation angles (the chi angle, [Formula: see text]), and we selected the angles of the maximum correlation for the corresponding geomechanical parameters. Then, combining the intercept and gradient, we generated 3D reflectivity patterns of EEI at different angles. To obtain a cube of geomechanical parameters, we performed model-based inversion on the EEI reflectivity pattern. A comparison between the modeling results and well data indicated that the geomechanical parameters estimated by our method were well-correlated to the observed data. Accordingly, we extracted the geomechanical and rock-physical parameters from the EEI cube. We further found that EEI analysis was capable of giving a 3D mechanical earth model of the reservoir with the appropriate accuracy. Finally, we verified the proposed methodology on a blind well and compared the results with those of the simultaneous inversion, indicating comparable levels of accuracy. Therefore, application of this method in seismic geomechanics can bring about significant progress in the future.

The Mechanical Behavior of Short-Fiber-Elastomer Composites

1976 ◽  
Vol 49 (5) ◽  
pp. 1167-1181 ◽  
Author(s):  
A. Y. Coran ◽  
P. Hamed ◽  
L. A. Goettler
Keyword(s):  
Test Piece ◽  
Composite Plates ◽  
Short Fiber ◽  
Strength Properties ◽  
Unidirectional Composite ◽  
Short Fibers ◽  
Principal Stresses ◽  
Elastomer Composites ◽  
Ultimate Limit ◽  
Time Of Failure

Abstract The measured elastic and strength properties of angle-ply composites of short fibers and rubber depend on test-piece geometry. In general, higher tensile moduli and strengths are obtained when plies are both thin and wide. Once the effects of test-piece geometry are taken into account, elastic properties can be calculated as functions of the properties of a single ply. Classical compliance transformation equations can be used. However, because of the invariance of shear modulus in aligned composites, the tensor transformation equations are somewhat simplified. Tensile strengths of off-axis unidirectional composite plates and balanced-angle plies can be fitted by Hill's criterion. Unidirectional composites tend to fail in the weakest mode, depending on the angle of stress, but laminating causes all principal stresses in a ply to be near their ultimate limit at the time of failure.

Seismic pore pressure prediction with uncertainty using a probabilistic mechanical earth model

2003 ◽  
Author(s):  
P. M. Doyen ◽  
A. Malinverno ◽  
R. Prioul ◽  
P. Hooyman ◽  
S. Noeth ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Earth Model ◽  
Pore Pressure Prediction ◽  
Mechanical Earth Model

Joint Application of Diagenetic, Petrophysical and Geomechanical Data for Selecting Hydraulic Fracturing Candidate Zone

2021 ◽  
Vol 8 ◽  
pp. 55-79
Author(s):  
E. Bakhshi ◽  
A. Shahrabadi ◽  
N. Golsanami ◽  
Sh. Seyedsajadi ◽  
X. Liu ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Pore Pressure ◽  
Earth Model ◽  
Reservoir Properties ◽  
Stress Regime ◽  
Geomechanical Properties ◽  
Hydrocarbon Reservoir ◽  
Diagenetic Processes ◽  
Mechanical Earth Model ◽  
New Equation

The more comprehensive information on the reservoir properties will help to better plan drilling and design production. Herein, diagenetic processes and geomechanical properties are notable parameters that determine reservoir quality. Recognizing the geomechanical properties of the reservoir as well as building a mechanical earth model play a strong role in the hydrocarbon reservoir life cycle and are key factors in analyzing wellbore instability, drilling operation optimization, and hydraulic fracturing designing operation. Therefore, the present study focuses on selecting the candidate zone for hydraulic fracturing through a novel approach that simultaneously considers the diagenetic, petrophysical, and geomechanical properties. The diagenetic processes were analyzed to determine the porosity types in the reservoir. After that, based on the laboratory test results for estimating reservoir petrophysical parameters, the zones with suitable reservoir properties were selected. Moreover, based on the reservoir geomechanical parameters and the constructed mechanical earth model, the best zones were selected for hydraulic fracturing operation in one of the Iranian fractured carbonate reservoirs. Finally, a new empirical equation for estimating pore pressure in nine zones of the studied well was developed. This equation provides a more precise estimation of stress profiles and thus leads to more accurate decision-making for candidate zone selection. Based on the results, vuggy porosity was the best porosity type, and zones C2, E2 and G2, having suitable values of porosity, permeability, and water saturation, showed good reservoir properties. Therefore, zone E2 and G2 were chosen as the candidate for hydraulic fracturing simulation based on their E (Young’s modulus) and ν (Poisson’s ratio) values. Based on the mechanical earth model and changes in the acoustic data versus depth, a new equation is introduced for calculating the pore pressure in the studied reservoir. According to the new equation, the dominant stress regime in the whole well, especially in the candidate zones, is SigHmax>SigV>Sighmin, while according to the pore pressure equation presented in the literature, the dominant stress regime in the studied well turns out to be SigHmax>Sighmin>SigV.  

scholarly journals Integrating Multi-Disciplinary Data for Building Fit-For-Purpose 3D Mechanical Earth Model

2019 ◽  
Vol 2019 (1) ◽  
pp. 1-2
Author(s):  
Peter G Boothby ◽  
Ratih Puspitasari ◽  
Sanjay Thakur ◽  
John P Zachariah ◽  
Chris Walton
Keyword(s):  
Earth Model ◽  
Fit For Purpose ◽  
Mechanical Earth Model
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