RESERVOIR CHARACTERIZATION AND MODELING OF THE GLORIETA AND THE CLEARFORK FORMATIONS, MONAHANS FIELD, PERMIAN BASIN, TEXAS A Thesis by RYAN DAVID YEATMAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2011 Major Subject: Geology RESERVOIR CHARACTERIZATION AND MODELING OF THE GLORIETA AND THE CLEARFORK FORMATIONS, MONAHANS FIELD, PERMIAN BASIN, TEXAS A Thesis by RYAN DAVID YEATMAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Michael C. Pope Committee Members, Wayne M. Ahr Walter B. Ayers Head of Department, Andreas Kronenberg August 2011 Major Subject: Geology iii ABSTRACT Reservoir Characterization and Modeling of the Glorieta and the Clearfork Formations, Monahans Field, Permian Basin, Texas. (August 2011) Ryan David Yeatman, B.S., Texas A&M University Chair of Advisory Committee: Dr. Michael C. Pope Monahans Field of the Permian Basin in West Texas is a complex carbonate reservoir due to the lateral heterogeneity caused by facies changes throughout the Lower Guadalupian Glorieta Formation and the Upper Leonardian Upper Clearfork Formation. A facies model, porosity model, and a siltstone model were generated in Petrel® to better characterize the Monahans Field reservoir. Interbedded impermeable siltstone beds in Monahans Field partition the reservoir making oil production and water injection difficult. The facies model indicates that during deposition, a tectonically uplifted area (island) influenced sedimentation and also shows that the Upper Clearfork Formation is mainly subtidal facies and the Glorieta Formation consists mainly of tidal flat facies. The porosity model shows the greatest porosity to be in the diagenetically altered supratidal deposits. The siltstone model identified siltstone barriers that prograded across the platform when sea level was low. 4th-order sequences occur within the larger 3rd-order sequence. The models identified multiple flow units in Monahans Field. Preferential injection of water within the reservoir compartments, horizontal drilling, and hydraulic fracture stimulation may all provide mechanisms to more efficiently sweep the remaining reserves from the reservoir. iv DEDICATION I would like to dedicate this thesis to my family and friends who helped me get through school. Without them I would not be where I am at today. v ACKNOWLEDGEMENTS I would like to thank my committee chair, Dr. Pope, and my committee members, Dr. Ahr, and Dr. Ayers, for their guidance and support throughout the course of this research. I would also like to give a special thanks to Occidental Petroleum for giving me the data set and to all at Occidental Petroleum who helped guide me through this thesis project. vi NOMENCLATURE API Weight of Oil Compared to Water Bbbl Billion Barrels Bbl Barrels BOPD Barrels of Oil per Day CBP Central Basin Platform K Permeability md Millidarcy MFS Maximum Flooding Surface MMBO Million Barrels of Oil MMBW Million Barrels of Water m.y. Million Years NPHI Neutron Porosity PHI_CORE Core Porosity QC Quality Check SGR Spectral Gamma Ray Log TD Total Depth TVDSS True Vertical Depth Sub-Sea UCF Upper Clearfork XPHITX Cross Plotted Neutron-Density Porosity Ф Porosity vii TABLE OF CONTENTS Page ABSTRACT.............................................................................................................. iii DEDICATION .......................................................................................................... iv ACKNOWLEDGEMENTS ...................................................................................... v NOMENCLATURE.................................................................................................. vi TABLE OF CONTENTS .......................................................................................... vii LIST OF FIGURES................................................................................................... ix LIST OF TABLES .................................................................................................... xi INTRODUCTION..................................................................................................... 1 Previous Studies in Monahans Field .......................................................... 1 Statement of Problems ............................................................................... 3 Objectives................................................................................................... 3 Methods...................................................................................................... 5 Data Set ...................................................................................................... 6 Field Location ............................................................................................ 7 Field History............................................................................................... 8 Reservoir Description................................................................................. 8 GEOLOGIC BACKGROUND ................................................................................. 10 Structural Evolution of the Permian Basin and CBP ................................. 10 Depositional Environment.......................................................................... 11 Third-Order Sequences .............................................................................. 11 Fourth-Order Sequences............................................................................. 12 PETROPHYSICAL ANALYSIS.............................................................................. 13 Quality Checking (QC) Log Data .............................................................. 13 Porosity Cutoffs.......................................................................................... 13 viii Page Log Normalization ..................................................................................... 13 PHI-CORE Logs ........................................................................................ 14 XPHITX Logs ............................................................................................ 14 NPHI Logs.................................................................................................. 15 Siltstone Logs............................................................................................. 17 PETREL MODELING.............................................................................................. 19 Petrel Methodology.................................................................................... 19 Grid Construction....................................................................................... 19 Log Correlations......................................................................................... 19 Layering ..................................................................................................... 22 Property Modeling...................................................................................... 22 Facies Logs................................................................................................. 22 Facies Modeling ......................................................................................... 23 Variogram Analysis.................................................................................... 24 RESULTS ................................................................................................................. 27 UCF Formation Facies Model.................................................................... 27 Glorieta Formation Facies Model .............................................................. 28 UCF Formation Siltstone Model ................................................................ 29 Glorieta Formation Siltstone Model........................................................... 30 Sequences ................................................................................................... 31 SUMMARY .............................................................................................................. 33 Eolian Siltstone Compartments.................................................................. 33 Preferential Injection .................................................................................. 34 Horizontal Drilling and Fracturing............................................................. 37 Further Infill Drilling ................................................................................. 38 Data Required............................................................................................. 39 Conclusions ................................................................................................ 40 REFERENCES CITED ............................................................................................. 41 VITA ......................................................................................................................... 44 ix LIST OF FIGURES Page Figure 1 Stratigraphic Column ................................................................................ 4 Figure 2 Workflow Outline ..................................................................................... 6 Figure 3 Location Map ............................................................................................ 7 Figure 4 Drilling Base Map ....................................................................................