Geologic characterization of the Morrow B reservoir in Farnsworth Unit, TX using 3D VSP seismic, seismic attributes, and well logs. by Paige Czoski Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science in Geophysics New Mexico Institute of Mining and Technology Socorro, New Mexico December, 2014 ABSTRACT Farnsworth Field is located in Ochiltree, Texas and has been selected for a Carbon Capture Utilization and Storage (CCUS) project that is being supported by the Department of Energy, the Southwest Regional Partnership on Carbon Sequestration, and Chaparral Energy Co. LLC. One million tonnes of 100% CO2 produced from the Arkalon Ethanol Plant in Liberal KS and the Agrium Fertilizer Plant in Borger TX will be injected into the Morrow B formation and monitored using seismic methods (Grigg and McPherson, 2012). Previous geologic char- acterization hypothesizes that the Morrow B Formation was an incised valley depositional environment. This study focuses on the 3D Vertical Seismic Profile (VSP) survey that overlaps two injection wells covering an area of approximately 1 by 2 miles. The purpose of this study is to geologically characterize the 3D VSP using seismic attributes and well logs. The Morrow B was auto picked in the 3D VSP data using gamma ray logs to locate the formation in depth. Low amplitude lens features that resemble channels were manually picked within the Morrow B. Seismic attributes aided in the geologic characterization by providing litho- logic and stratigraphic interpretations. The attributes discussed in this study are curvature, instantaneous frequency, signal envelope, sweetness, relative acoustic impedance, chaos, root mean square amplitude, and variance. An unsupervised neural network was utilized to compare the seismic attributes to find similarities that might relate to geology. The possible channel interpretation can influence CO2 flow through the reservoir and have an effect on production and storage. Keywords: Morrow B; Farnsworth Unit; 3D VSP; Seismic Attributes ACKNOWLEDGMENTS Funding for this project was provided by the U.S. Department of Energy’s (DOE) National Energy Technology Laboratory (NETL through the Southwest Partnership on Carbon Sequestration (SWP) under Award No. DE-FC26-05NT42591. Additional support has been provided by site operator Chaparral Energy, L.L.C., WesternGeco and Schlumberger Carbon Services. I would like to thank my committee members Robert Balch, Susan Bilek, and Peter Mozley who aided me both in my research and academics throughout the years. I would also like to thank Bob Will (Schlumberger) for helping me learn to use Petrel and aiding me in my interpretation. I also want to thank my fellow graduate students who are researching the Farnsworth Unit, especially Dylan Rose-Coss who aided in the well log interpretation, Ashley Hutton who helped me input the seismic data and interpret faults, Sara Gallagher, Evan Gragg, and William Ampomah. I want to thank all my friends and family who helped me through my education. I want to thank my parents Dana and Richard Czoski who supported me through my years of education and encouraged a love for geology by taking me to museums and other interesting geologic areas all over the world. Brooke Czoski for always being there for me as my best friend and sister. I would also like to thank my fellow graduate students and Logan Roberts for emotional support through my graduate school experience. 1 This thesis was typeset with LATEX by the author. 1 The LATEX document preparation system was developed by Leslie Lamport as a special ver- sion of Donald Knuth’s TEX program for computer typesetting. TEX is a trademark of the Ameri- can Mathematical Society. The LATEX macro package for the New Mexico Institute of Mining and Technology thesis format was written for the Tech Computer Center by John W. Shipman. ii CONTENTS LIST OF FIGURES v 1. INTRODUCTION 1 1.1 Research Motivation . 1 1.2 Farnsworth Unit History . 6 1.3 Carbon Capture Utilization and Storage (CCUS) or Enhanced Oil Recovery (EOR) . 7 2. GEOLOGIC SETTING 9 2.1 Regional Stratigraphic Framework . 9 2.2 Anadarko Basin Tectonic Evolution . 10 2.3 Depositional Environment . 12 2.4 Paleoflow Data . 16 2.5 Controls on Reservoir Quality and Heterogeneity . 17 3. METHODOLOGY 19 3.1 Seismic Survey Overview: Imaging goals . 19 3.2 3D VSP . 21 3.3 Crosswell Tomography . 23 3.4 Well Log Data . 23 3.5 Data Analysis Software . 23 3.6 Seismic Attributes . 23 3.6.1 Curvature Attributes . 24 3.6.2 Variance Attribute . 25 3.6.3 The Hilbert Transform . 25 3.6.4 Instantaneous Frequency . 27 3.6.5 Signal Envelope . 27 3.6.6 Sweetness . 28 3.6.7 Relative Acoustic Impedance (RAI) . 28 3.6.8 Root Mean Square (RMS) Amplitude . 28 3.7 Neural Network Comparison of Seismic Attributes . 28 iii 4. RESULTS 30 4.1 Morrow B Sandstone Delineation from 3D VSP Data . 30 4.1.1 Low Amplitude Lenses . 34 4.2 Stratigraphic and Structural Features Visible Within the Morrow B 41 4.3 Well Log Analysis . 44 4.4 Seismic Attributes . 48 4.4.1 Curvature Attributes . 48 4.4.2 Chaos . 49 4.4.3 Variance . 50 4.4.4 Instantaneous Frequency . 51 4.4.5 Signal Envelope . 52 4.4.6 Sweetness . 53 4.4.7 Relative Acoustic Impedance . 55 4.4.8 Root Mean Squared Amplitude . 56 4.5 Petrel’s Train Estimation Modeling . 57 4.5.1 Run #15 . 59 4.5.2 Run #6 . 60 4.5.3 Run#16 . 61 4.5.4 Run#4 . 62 5. DISCUSSION 63 6. CONCLUSIONS AND FUTURE WORK 67 6.1 Conclusions . 67 6.2 Suggestions for Future Work . 68 REFERENCES 69 A. TRAIN ESTIMATION MODEL RUNS 72 iv LIST OF FIGURES 1.1 Farnsworth Unit (pink square) located in northern Texas. Pur- ple lines represent state borders and green lines represent county boundaries. The field area is delineated by the blue outline in the blown up figure to the left. Well 13-10A is displayed by the green triangle. 2 1.2 Paleogeography of the Morrow. Light green represents shales and mudstones, dark green represents fluvial systems, and blue repre- sents seas. (Gallagher, 2014; Swanson, 1979). 3 1.3 (a) Structure map for the top of the Morrow B. The field dips to- wards the south east and is deeper within the middle of the field. (b) The Morrow B isopach generated from gamma ray well logs for the entire field (blue outline in Figure 1.1). The thicker sandstone runs through the middle of field. These observations support the hypothesis of the incised valley depositional environment. (Modi- fied from a figure courtesy of Dylan Rose-Coss). 5 1.4 Schematic diagram displaying the process of injecting CO2 and water into a reservoir. The super critical fluid pushing previously unproduced oil out of pore spaces, and pushing it towards a pro- duction well. (NETL and DOE, 2010). 8 2.1 Stratigraphic chart showing the stratigraphic framework of the Lower Atokan-aged and Upper Morrowan strata in the FWU. Wireline log is from well 32-2. (Gallagher, 2014; Modified from Munson(1988) and Puckette et al. (2008) by Dylan Rose-Coss and Sara Gallagher). 10 2.2 Tectonic map during the deposition of the Morrow. This figure displays possible structures that could be sediment source areas (Gallagher, 2014; Modified from Sonnenburg et al., 1990 in DeVries, 2005). 11 2.3 Incised valley systems flowing east and southeast during late Mor- rowan deposition. (Gallagher, 2014; Puckette et al, 2008). 13 2.4 Model of incised valley depositional system and how it changes with sea level. LST = low stand surface of erosion. TSE = Trans- gressive surface of erosion (Gallagher, 2014; Puckette et al., 2008). 14 2.5 Lithofacies descriptions for FWU core as characterized by Gallagher, 2014. 15 v 2.6 Depositional model for FWU constructed by Gallagher, 2014 (Mod- ified from Wheeler et al., 1990; Puckette et al., 2008). MFS = Max- imum flooding surface. LSE = Lowstand surface of erosion. TSE = Transgressive surface of erosion. TSE = Transgressive surface of erosion. 16 2.7 The top surface in depth of the Morrow B with wells 13-10A and 13-14 where the FMI images were taken. The rosette diagrams showing the azimuth of flow direction determined from the FMI images taken in the Morrow B formation. The paleoflow direction is mostly to the east, northeast, and southeast. (Courtesy of Dylan Rose Coss, 2014; Brown, 2014) . 17 3.1 (a) FWU map of seismic surveys. The injector wells are triangles and the producers are circles. This study focuses on the orange square on the north west corner of the field. (b) A zoomed in area square in (a). (b)shows the location of VSP (red oval) and crosswell tomography (yellow dashed lines) used for this study (Modified from Grigg and McPherson, 2012). 20 3.2 A model of the 3D VSP survey as designed by WesternGeco with the geophone arrays in wells 13-10A and 14-1. The top of the Mor- row B (grey surface) with the outline of the 3D VSP data footprint (rectangle in colored by incidence angle). The yellow dots on the surface represent the vibroseis shot points and the red lines repre- sent ray paths traveling down to where the geophones are placed at approximately 3500 ft . 21 3.3 Map displaying the 3D VSP shot points, the outline of the 3D VSP, and the crosswell tomography lines. The pink dot is producing well 13-16, the green dot is injection well 13-10A, the blue dot is producing well 13-14, and the yellow dot is injection well 14-1. Wells 13-10A and 14-1 had geophone arrays for the VSP data col- lection.