Doctoral Dissertation Characterizing the Full In-Situ Stress Tensor and Its Applications for Petroleum Activities Department of Energy and Resources Engineering Graduate School, Chonnam National University Do Quang Khanh August 2013 Characterizing the Full In-Situ Stress Tensor and Its Applications for Petroleum Activities Department of Energy and Resources Engineering Graduate School, Chonnam National University Do Quang Khanh Supervised by Professor YANG, Hyung-Sik A dissertation submitted in partial fulfillment of the requirements for the Doctor of Philosophy in Energy and Resources Engineering. Committee in Charge : Dr. So-Keul Chung (KIGAM) “hf \ Prof. Tam Tran (CNU) ( aa Prof.
Jeong-Hwan Lee (CNU) Tes Prof. Piyush Rai (BHU, India) pot a Prof. Hyung-Sik Yang (CNU) 5 % August 2013 CONTENTS Characterizing the Full In-Situ Stress Tensor and Its Applications for Petroleum Activities Contents List of figures and tables IV Nomenclature of symbols Vill Abstract CHAPTER 1: INTRODUCTION —NW“SOI|D 1. Project philosophy and purposes 1.
Outline of thesis CHAPTER 2: IN-SITU STRESS TENSOR AND ITS RELATING CONCEPTS 2. In-situ stress tensor 2. State of in-situ stress 13 2. Pore pressure and effective stress 14 2.
Frictional limits to stress 15 2. Stresses and rock failure 17 CHAPTER 3: STRESS AND FAILURE ANALYSIS FOR WELLBORES 22 3. Stress and failure analysis for a vertical cylindrical wellbore 22 3. Stresses around a vertical cylindrical wellbore 22 3.
Failure analysis for a vertical wellbore 26 3. Stress and failure analysis for an arbitrarily deviated wellbore 28 3. Stresses around an arbitrarily deviated wellbore 28 3. Failure analysis for an arbitrary deviated wellbore 33 CHAPTER 4: METHODS FOR DETERMINING IN-SITU STRESS 35 4.
In-situ stress measurements in drilling boreholes 35 4. Hydraulic fracturing methods 35 4. Drilling induced tensile fractures methods 43 4. Earth focal mechanism (FMS) 45 4.
New integrated method for determining ISS using petroleum exploration data 47 4. Determining the orientations of horizontal stresses 49 4. Determining the vertical stress 51 4. Determining the minimum horizontal stress magnitude 54 4.
Constraining the maximum horizontal stress magnitude 57 4. Determining pore pressure 62 CHAPTER 5: MODEL DEVELOPMENT FOR FAILURE ANALYSIS OF WELLBORE (FAOWB) 65 5. Structures of the FAoWB software packages 65 5. Validation of the results of the packages FAOWB 71 5.
Case 1: Cross-checking Barton’s study (1998) on compressive failure and breakout width analysis at the KTB wellbore, Germany. Case 2: Cross-checking Meyer’s study (2002) on the well stability at the Swan Lake field, South Australia. 78 CHAPTER 6: CASE STUDIES AND IMPLICATIONS 89 6. Geological framework of the main studied area 89 6.
The White Tiger (Bach Ho) field, Centre of the Cuu Long basin, Vietnam 93 6. Statement of problem 93 6. In-situ stress determination techniques 96 6. In-situ stress tensor at the White Tiger field 105 6.
Summary of results 120 6. The X field, Northern of the Cuu Long basin, Vietnam 121 6. Statement of problem 121 6. In-situ stress determination techniques 123 6.
In-situ stress tensor at the X field 129 6. Summary of results 135 CHAPTER 7: CONCLUSIONS AND RECOMMENDATIONS 137 Reference 140 Abstract in Korean 148 Acknowledgements 150 LIST OF FIGURES AND TABLES Figure 2.1: Components of stresses acting on a plane.2: Components of stresses acting on the faces of a cube.3: The three states of stress and associated types of faulting.4: Frictional limits to stress based on the frictional strength of favourably oriented fault planes for u = 0.5: Two-dimensional Mohr circle.6: Three-dimensional Mohr circle.7: Mohr diagram with a failure envelope that fits closely to laboratory rock testing data.8: Three-dimensional Mohr diagram and Coulomb failure criterions for pre-existing planes of weakness and for intact rock.1: Vertical cylindrical wellbore with the orientations of the circumferential stress Ooo, axial stress o,, and radial stress o,, 23 Figure 3.2: Stress concentration around a vertical in a bi-axial stress field based on the Kirsch equations.3: The stress concentration around a circular borehole subject to only uniaxial compression.4: An arbitrarily deviated wellbore with the orientations of the cirumferential (Goo), axial (ø;;), radial (6,,), minimum (Timin) and MaximuM (Timax) Stresses.5: Three coordinate systems used to transform for an arbitrarily deviated wellbore.6: Lower hemisphere projection used to display relatively stability of wellbores with different azimuths and deviations.1: A schematic diagram with the equipment set-up and the propagation direction of the induced fracture during a hydraulic fracturing test.2: Typical procedure used in the overcoring technique 38 Figure 4.3: Circumferential stress around a vertical wellbore with respect to the orientation of the maximum horizontal stress for formation of BOs and DITFs.4: Section of four-arm dipmeter log data showing consistent breakouts in a north-south direction.5: An imaging log data with borehole breakouts.6: Hollow cylinder laboratory test.7: An imaging log data with drilling induced tensile fractures 44 Figure 4.8: The three main fault regimes and their corresponding fault plane solutions.9: Integration of density logs to estimate overburden stress at depths 52 Figure 4.10: Resistivity image, density log (RHOB), density correction log (DRHO) and caliper log (CALI). time record showing LOP, breakdown, P, and P,.12: Pressure versus root time plot showing P.1: Start screen of the software packages FAOWB.2: Main screen of the software packages FAOWB.3: Menu File of the software packages FAOWB.4: Menu Input Data of the software packages FAoWB.5: Tab Description of the software packages FAOWB.6: Tab Stress of the software packages FAoWB.7: Tab Rock properties of the software packages FAOWB.8: Tab Well of the software packages FAoWB.9: Menu Failure Criteria of the software packages FAOWB.10: Menu Process of the software packages FAOWB.11: Menu Output of the software packages FAoWB.12: Stress distribution of case 1 (from packages FAoWB).13: Risk diagrams of case Ï (from packages FAOWB).14: The breakout risk diagrams of the KTB wells for Mohr-Coulomb, Drucker-Prager and Mogi-Coulomb criteria.15: The mud weight required of the KTB wells.16: Risk diagrams of case 2 (from packages FAOWB).17: The breakout risk diagrams of wells at Swan Lake field for Mohr-Coulomb, Drucker-Prager and Mogi-Coulomb criteria.18: The mud weight required at the Swan Lake field.19: Stress distribution of case 2 (from packages FAoWB).20: Stress polygon and constraints for case 1 and 2.1: Location map of the Cuu Long Basin.2: Schematic cross-section of the Cuu Long Basin.3:Generalized stratigraphy column of the Cuu Long Basin. Location map of the White Tiger field at the Cuu long basin.5: Basement distribution at White Tiger field, Cuu Long basin.6: Main fault and fracture system at the White Tiger field.7: Generalized stratigraphy column at the White Tiger.8: Examples of the occurrence of BOs and DIFTs at the basement intervals of the wellbores at the White Tiger field.9: Histogram and rose diagrams of the orientation of Sumax from BOs at the basement intervals of the Whiter Tiger field.10: Histogram and rose diagrams of of the orientation of Snmax from DITFs at the basement intervals of the Whiter Tiger field.11: Histogram and rose diagrams of the orientation of Symax from both BOs and DITFs at the basement intervals of the Whiter Tiger field.12: Vertical stress or overburden stress at the White Tiger field.13: Plots of treatment pressure in the hydraulic fracturing tests.14: Minimum horizontal stress at the White Tiger field.15: Pore pressure at the White Tiger field.16: Stress Polygon and constraints at depths of the White Tiger field.17: Stress distribution at the depth 3900 m of the White Tiger field.18: Stress distribution at the depth 4100 m of the White Tiger field.19: Stress distribution at the depth 4300 m of the White Tiger field.20: Stress distribution at the depth 4500 m of the White Tiger field.21: Risk diagrams at the depth 3900 m of the White Tiger field.22: Risk diagrams at the depth 4100 m of the White Tiger field.23: Risk diagrams at the depth 4300 m of the White Tiger field.24: Risk diagrams at the depth 4500 m of the White Tiger field.25: Location map of the X field.26: The depth structural map at the X field.27: The stratigraphy column of the X field.28: Example of DITFs of the wellbore X1 at the X field.29: Histogram and rose diagrams of DITFs at the wellbore X1.30: Vertical stress or overburden stress at the X field.31: Plots of surface pressure in the LOTs/FITs at the X field.32: Minimum horizontal stress at the X field.33: Pore pressure at the X field.34: Stress Polygon and constraints at depth 2300 m of the X field.35: Stress distribution at the basement depth 2300 m of the X field.36: Risk diagrams at the basement depth 2300 m of the X field.37: Risk diagrams on evaluation for the applicability of under-balanced drilling techniques (P,=22 MPa).38: Stress distribution at two deviated wellbores of the X field.1: The full in-situ stress tensor at the basement depths of the White Tiger field.2: The full in-situ stress tensor at the basement depth 2300 m of the X field.
129 Vil NOMENCLATURE OF SYMBOLS C: compressive strength Co: uniaxial compressive strength Cy: biaxial compressive strength g: acceleration due to gravity P: stress tensor due to pore pressure P,: fracture closure pressure P;: fracture initiation pressure P,: pore pressure P,: fracture reopening pressure Py: wellbore fluid pressure R,: coordinate transform matrix Rg: coordinate transform matrix S: applied stress tensor S’: effective stress tensor 5¡, S2, S3: three principal stresses Sp: Stress tensor in the borehole coordinate system Sp: stress tensor in the geographic coordinate system SHmax: Maximum horizontal stress magnitude Shmin Minimum horizontal stress magnitude Ss. stress tensor in principal stress coordinate system Sy: vertical stress magnitude T: tensile strength z: depth a, B, y: Euler rotation angles 6: wellbore azimuth vill 6: Kronecker delta AP: difference between wellbore and pore pressure u: coefficient of friction 0: Poisson’s ratio ọ: density Ơi: Stress component acting in the j direction in the plane normal to the i direction Ơn: Normal stress Oi. effective radial stress Otmax. Maximum effective stress tangential to the wellbore wall Otmin.
Minimum effective stress tangential to the wellbore wall Ơ;;: effective axial stress Ooo: effective circumferential stress Ooomin: Minimum of the effective circumferential stress @: wellbore deviation w: angle between Otmax and the wellbore axis T: shear stress Characterizing the Full In-Situ Stress Tensor and Its Applications for Petroleum Activities Do Quang Khanh Department of Energy and Resources Engineering Graduate School, Chonnam National University (Supervised by Professor YANG, Hyung-Sik) (Abstract) Knowledge of the full in-situ stress tensor has an importance for petroleum activities. A demand in the determination of in-situ stress using petroleum exploration data available has increased during the last decades over the world. The new integrated method for determining the full in-situ stress tensor using the available petroleum data has been accepted as more reliable and widely applicable in many petroleum basins. This thesis developed and applied the new integrated method for determining the full tensor of in-situ stress using the available petroleum data.
This method involves many aspects in which the constraining related to the magnitude of the maximum horizontal stress is the most challenge. It also requires the integration and modification many techniques for studying specific problems using available datasets. The software packages on failure analysis of wellbores (FAoWB) written in the programming language MATLAB were designed and developed from this new integrated method for determining the full stress tensor and the extended theories on stresses and failures around the wellbore. They facilitate the determination of the full in-situ stress tensor using the observations of wellbore failures (breakouts BOs and/or drilling-induced tensile fractures DIFTs) in petroleum wellbores.
The forward calculating of stresses around the wellbores will be constrained with the observations of borehole failures and rock strength, pore pressure or mud _ pressure depending on available data at a particular petroleum field. Moreover, under the full in-situ stress tensor determined they also help to derive easily the implications related to the state of in-situ stress. Their accuracy and reliability were confirmed through the cross-checking of two well-known investigations earlier. Three different strength criteria including the Mohr- Coulomb, Drucker-Prager and Mogi-Coulomb criteria also were applied to recommend the selection of an appropriate criterion for relatively strong rocks.