Flow behavior of N2 huff and puff process for enhanced oil recovery in tight oil reservoirs
In the present work, the potential of N2 huff and puff process to enhance the recovery of tight oil reservoir was evaluated. N2 huff and puff experiments were performed in micromodels and cores to investigate the flow behaviors of different cycles. The results showed that, in the first cycle, N2 was dispersed in the oil, forming the foamy oil flow. In the second cycle, the dispersed gas bubbles gradually coalesced into the continuous gas phase. In the third cycle, N2 was produced in the form of continuous gas phase. The results from the coreflood tests showed that, the primary recovery was only 5.32%, while the recoveries for the three N2 huff and puff cycles were 15.1%, 8.53% and 3.22%, respectively.The recovery and the pressure gradient in the first cycle were high. With the increase of huff and puff cycles, and the oil recovery and the pressure gradient rapidly decreased. The oil recovery of N2 huff and puff has been found to increase as the N2 injection pressure and the soaking time increased. These results showed that, the properly designed and controlled N2 huff and puff process can lead to enhanced recovery of tight oil reservoirs.
Experience of virtual commissioning of a process control system for the production of high-paraffin oil
This work describes the experience in developing and testing software for oil industry automation control systems based on the simulation of technological processes and control systems combined in virtual reality, this approach is called virtual commissioning and is widely used in the world both to create automated process control systems and to simulate interactions between different systems.
Development of a four-phase thermal-chemical reservoir simulator for heavy oil
... ................................................................................................................... vii List of Tables ................................................................................................................ xv List of Figures ............................................................................................................ xvii Chapter 1: Introduction ................................................................................................... 1 1.1 Problem Description ............................................................................ 1 1.2 Research Objective .............................................................................. 8 1.3 Review of Chapters .............................................................................. 9 Chapter 2: Background and Literature Review ............................................................ 11 2.1 Literature Review ............................................................................... 11 2.2 Cold Production ................................................................................. 12 2.3 Water Flooding .................................................................................. 13 2.4 Solvent Injection ................................................................................ 15 2.5 Thermal Oil Recovery ........................................................................ 16 2.5.1 Cyclic Steam Stimulation (CSS) ............................................ 18 2.5.2 Steam Flooding ....................................................................... 19 2.5.3 Steam Assisted Gravity Drainage (SAGD) ............................ 19 2.5.4 Electrical Resistance Low Frequency (Joule) Heating ........... 20 2.5.5 Thermal Effect on Geomechanics .......................................... 21 2.6 Chemical Flooding ............................................................................. 22 2.6.1 Alkaline-Surfactant Steam-Foam Flooding ............................ 24 2.6.2 Modeling of Emulsion Viscosity ............................................ 25 Chapter 3: Four-Phase Fluid Flow Model .................................................................... 27 3.1 Basic Assumption .............................................................................. 27 3.2 Mass Conservation Equation ............................................................. 28 3.3 Pressure Equation ............................................................................... 33 3.3.1 Accumulation Term ................................................................ 34 xii 3.3.2 Fluid Compressibility ............................................................. 38 3.3.3 Diffusion and Source/Sink terms ............................................ 40 Chapter 4: Numerical Formulation ............................................................................... 42 4.1 Discretization of Pressure Equation ................................................... 42 4.2 Discretization of Mass concentration Equation ................................. 51 4.2.1 Accumulation Term ................................................................ 51 4.2.2 Convection Term .................................................................... 52 4.2.3 Dispersion and Molecular Diffusion Term ............................. 52 4.3 Discretization of Well Model ............................................................. 57 4.3.1 Vertical Wells ......................................................................... 57 4.3.2 Horizontal Well with Cartesian Gridblocks ........................... 61 Chapter 5: Four-Phase Behavior Equilibrium Formulation .......................................... 64 5.1 Phase Density ..................................................................................... 64 5.2 Phase Viscosity .................................................................................. 70 5.3 Surfactant Phase Behavior ................................................................. 73 5.4 Effect of Temperature ........................................................................ 75 5.5 Effect of Pressure and Solution Gas .................................................. 76 5.6 Effective Salinity ............................................................................... 77 5.6.1 Binodal Curve Approach ........................................................ 78 5.6.2 Tie Lines for Two Phases ....................................................... 79 5.6.3 Tie Lines for Type III ............................................................. 80 5.7 Bubble Point Tracking in Oil/Gas Phase behavior ............................ 84 5.8 Phase Saturations ............................................................................... 87 5.9 Relative Permeability ......................................................................... 87 Chapter 6: Verification of Three-Phase Models and Developed Four-Phase Model ... 90 6.1 Water Injection with Two Phase Flow Case (Case 1) ....................... 90 6.2 Gas and Water Injection with Three Phase Flow Case (Case-2) ....... 96 6.3 Water Injection below Bubble Point with Three Phase Flow Case (Case-3) ............................................................................................ 102 6.4 Production from a Field case with Three Phases Flow Case (Case-4)115 xiii 6.5 Surfactant Injection with Three Phase Flow Case (Case-5) ............ 131 6.6 Surfactant and Gas Injection With Four Phase Flow Case (Case-6)144 Chapter 7: Thermal Model .......................................................................................... 164 7.1 Governing Energy and Steam Equations ......................................... 167 7.2 Numerical Formulation .................................................................... 176 7.2.1 Accumulation Term .............................................................. 178 7.2.2 Convection Term .................................................................. 178 7.2.3 Conduction Term .................................................................. 180 7.3 Heat Loss Term ................................................................................ 181 7.4 Well Terms ....................................................................................... 186 7.5 Case Studies of the Thermal Model ................................................. 187 7.5.1 One Dimensional Hot Water Injection Case ........................ 188 7.5.2 Three Dimensional Hot Water Injection Case ...................... 193 7.5.3 One Dimensional Steam Injection Case ............................... 201 7.5.4 Two Dimensional Vertical Steam Injection Case (SAGD) .. 205 Chapter 8: Electrical Heating ...................................................................................... 212 8.