Understanding Rock Quality Heterogeneity of Montney Shale
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UNDERSTANDING ROCK QUALITY HETEROGENEITY OF MONTNEY SHALE RESERVOIR, POUCE COUPE FIELD, ALBERTA, CANADA by Claudia Due~nas c Copyright by Claudia Due~nas2014 All Rights Reserved A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Master of Science (Geo- physics). Golden, Colorado Date Signed: Claudia Due~nas Signed: Dr. Thomas L. Davis Thesis Advisor Golden, Colorado Date Signed: Dr. Terence K. Young Professor and Head Department of Geophysics ii ABSTRACT Understanding the lateral heterogeneity of unconventional plays prior to hydraulic frac- turing is important for hydrocarbon production and recovery. Lateral and vertical variability can be affected by composition and textural variation of the rock, which define the rock qual- ity. To characterize the lateral and vertical heterogeneity of rock quality (composition) of the Montney Shale reservoir at Pouce Coupe, Alberta at different scales I conducted a multi- attribute analysis of wells logs integrated with post-stack and pre-stack inversion of a baseline multicomponent seismic survey. Cluster analysis was performed in four wells using the well logs that are most affected by composition. The cluster analysis provides more representative upscale input parameters for reservoir characterization that can be compared with seismic results. The result of this cluster analysis has indicated a lateral variation of composition of the unit C to the east side of the area, where six clusters were chosen and two of them have good petrophysical rock properties that were tied with core data. Post-stack and pre-stack inversions of the baseline of the multicomponent seismic data were performed using constrained sparse spike inversion (CSSI). Pre-stack results shows similar results for the P-impedance, however, there is an improvement in the accuracy of the estimated P-impedance from the pre-stack CSSI (compared to well log P-impedance). The results of P-impedance and S-impedance show the same strong change on the east side of the survey that was detected with the cluster analysis. Crossplots of elastic properties such as Lambda-rho and Mu-rho combined with the results of cluster analysis helped to identify the areas of better rock quality in the 3D seismic. The integration of this heterogeneity analysis with the production profile of the two horizontal wells in the area shows that the lithology has a major influence on the rock quality of the Montney interval. The combined interpretation of this work with an understanding iii of the natural fracture system and the stress state of the reservoir can provide a rock quality index (RQI). This RQI can aid in future exploration and operational development of the Montney play and other shale reservoirs worldwide. iv TABLE OF CONTENTS ABSTRACT . iii LIST OF FIGURES . viii LIST OF TABLES . xvi LIST OF SYMBOLS . xvii ACKNOWLEDGMENTS . xviii DEDICATION . xix CHAPTER 1 INTRODUCTION . 1 1.1 Objectives . 4 1.2 Geology . 4 1.2.1 Reservoir units . 4 1.2.2 Regional tectonics . 7 1.2.3 Petroleum system . 9 1.3 Time-lapse multicomponent seismic, microseismic data . 10 1.3.1 Surface seismic acquisition . 10 1.3.2 Seismic processing . 11 1.3.3 Microseismicity . 13 1.4 Available thesis data . 15 1.4.1 Production and completion data . 17 1.5 Previous work . 19 1.5.1 Geomechanical characterization . 26 v 1.6 Methodology of this work . 29 CHAPTER 2 CLUSTER ANALYSIS . 31 2.1 Theory and workflow . 31 2.1.1 Example in literature . 35 2.2 Cluster Analysis of composition in four wells of Pouce Coupe . 36 2.2.1 Correction and edition of well logs . 37 2.2.2 Definition of clusters in the master well log . 38 2.2.3 Integration of cluster analysis and core data . 40 2.2.4 Cluster tagging . 42 2.2.5 Interpretation . 46 2.3 Summary . 47 CHAPTER 3 INVERSION . 48 3.1 Method and theory . 48 3.1.1 Convolutional model . 49 3.1.2 Constrained Sparse Spike Inversion (CSSI) . 49 3.1.3 Post-stack and pre-stack inversion . 50 3.1.4 The wavelet . 55 3.2 Available seismic and well log data . 56 3.3 PP data interpretation . 56 3.4 Building the low-frequency impedance model . 61 3.5 Post-stack inversion . 62 3.5.1 Well tie . 63 3.5.2 Wavelet estimation . 68 vi 3.5.3 Filtering the model . 68 3.5.4 Inversion parameters . 69 3.6 Pre-stack inversion . 73 3.6.1 Angle domain . 73 3.6.2 Well tie . 73 3.6.3 Angle - dependent wavelet estimation . 81 3.6.4 Inversion parameters . 81 3.7 Results and comparison . 82 3.7.1 Comparison of post-stack and pre-stack inversion . 94 3.8 Summary . 100 CHAPTER 4 PREDICTING ROCK QUALITY FROM PRE-STACK ATTRIBUTES . 101 4.1 Lambda-rho and Mu-rho crossplots . 102 4.1.1 Well response and clusters . 103 4.1.2 Seismic LMR response . 104 4.2 Integration with microseismicity and production data . 109 4.3 Summary . 116 CHAPTER 5 CONCLUSIONS AND RECOMMENDATIONS . 117 5.1 Recommendations . 118 REFERENCES CITED . 119 APPENDIX - CLUSTER ANALYSIS . 123 vii LIST OF FIGURES Figure 1.1 Map of Triassic strata in the Western Canada Sedimentary Basin showing the locations of Montney oil fields, conventional gas fields and tight gas plays. Pouce Coupe area is shown as a black start. Modified from Zonneveld (2011). 2 Figure 1.2 Reservoir characterization of rock quality of Montney Shale and methodology. Integrated study and analysis at different scales. 3 Figure 1.3 Triassic Montney Formation in the Peace River Arch region. Pouce Coupe Field is on the border of British Columbia (BC) and Alberta and is represented by the colored formations in the Talisman BC chart section (courtesy of Talisman Energy). 5 Figure 1.4 Schematic simple WestEast section of Lower Triassic Montney Formation facies . 6 Figure 1.5 Type log of the Triassic Montney of the southern Pouce Coupe Field. The red curve is the gamma ray log. Modified from Steinhoff (2013). 7 Figure 1.6 Comparison of predominant mineralogy of shales reservoir worldwide in a ternary plot. VacaMuerta Consortium. Sonnenberg, 2013 . 8 Figure 1.7 The stratigraphic framework at Farrell Creek and Pouce Coupe. Maximum regressive surfaces are defined by red lines while maximum flooding surfaces are defined by green lines (courtesy of Lindsay Dunn, Talisman Energy Inc.). Modified from Davey (2012) . 9 Figure 1.8 Pouce Coupe time-lapse, multicomponent surface seismic and field operations timeline. The map shows the horizontal wells hydraulically stimulated (blue and green color). Red circles are the vertical wells. Orange shows wells with microseismicity receivers. Modified from Atkinson (2010) . 11 Figure 1.9 Multicomponent seismic survey acquisition layout of Pouce Coupe time-lapse. 5km2 patch centered over horizontal wells 02/02-07 and 02/07-07. Modified from Atkinson (2010). 13 Figure 1.10 Workflow of seismic processing (2013) PP data of Pouce Coupe. Processed by Sensor Geophysical. 14 viii Figure 1.11 Pouce Coupe iline 4 baseline survey - PSTM of PP data. Comparison of version 2012 and 2013 PSTM in PP data. Red box show the zone of Montney Formation. 15 Figure 1.12 Results of the downhole microseismic events on both treatment wells, showing the total combined event location from the individual 5 stage of each treatment. 16 Figure 1.13 Map of the Pouce Coupe 3D seismic outline (orange), vertical wells used in the cluster analysis (black points) and the important horizontal wells (blue and red). 17 Figure 1.14 Pouce Coupe wells used in this project. Some wells are used in different stages of the project. 17 Figure 1.15 Production data decline of the horizontal wells. The wells drilled in Montney unit C have higher initial production. 20 Figure 1.16 Difference in sum of monitor 2 negative shifts and monitor 1 negative shifts from 2000-2200 ms, showing areas of increased azimuthal anisotropy. Indicated in red is the outline of the anisotropy present in the baseline. Calculated by Atkinson (2010). 21 Figure 1.17 Shear wave splitting map from the baseline survey (Steinhoff, 2013). 22 Figure 1.18 Shear wave splitting map from the monitor 1 survey after the 02/02-07 well had been stimulated. (Steinhoff, 2013). 24 Figure 1.19 Shear wave splitting map from the monitor 2 survey after the 02/07-07 well had been stimulated. (Steinhoff, 2013). 25 Figure 1.20 On the left is monitor 1 minus baseline of the SWS magnitudes. On the right is monitor 2 minus baseline of the SWS magnitudes. Also plotted is the production from each stage for each well indicated by percentage. (Steinhoff, 2013). 26 Figure 1.21 Correlation of microseismicity with RQI. First panel is RQI, second panel is Gamma Ray and third panel is mechanical stratigraphy. (Davey, 2012) . 28 Figure 1.22 Correlation of RQI log with the SWVA in the baseline. Hydraulic energy will preferentially propagate to more homogeneous areas of the reservoir. (Davey, 2012) . ..