OPTIMIZING SWEEP EFFICIENCY IN WATERFLOOD

COURSE OVERVIEW

This course will cover various aspects of waterflood theory, diagnostics, planning, evaluation and analysis. Both analytic and numerical techniques to evaluate waterflood will be presented. The method of teaching will be a combination of slides, discussions and hands-on practice problems. Students will benefit from the presentation of actual results of instituted waterfloods around the world. The course assumes students to have basic knowledge of waterflood, some experience in oil-field.

COURSE OBJECTIVES

• Learn factors affective successful institution of waterflood
• Understand how to design, predict and monitor waterflood
• Understand what are the different analytic and numerical techniques to predict waterflood recovery considering the important aspects of the drive mechanisms
• Learn various diagnostics and quantitative techniques to perform waterflood surveillance and rebalancing
• Learn special considerations of waterflood e.g. remediate excessive water production by water shutoffand/or profile modification, improving sweep efficiency, polymer augmented waterflood, LoSal (low salinity) waterflood, reservoir souring about the course

THIS COURSE IS INTENDED FOR

• Reservoir Engineer
• EOR Engineer
• Production Engineer
• Petroleum Engineer
• GeologistProject Engineers
• Project Managers
• Anyone else responsible for the support of the waterflood.

COURSE OUTLINES

General history and development of Waterflooding

some case studies and highlighting the importance of at least five important factors governing the functioning of waterflood namely : mobility, heterogeneity, capillary pressure, crossflow and gravity. Issues of multiple oil water contacts will also be discussed. Various theoretical treatments and hands on exercise problems will elaborate on the concepts of:

• Wettability, imbibitions, drainage concepts, capillary pressure, J-function, height above free water level
• air permeability, absolute permeability, effective permeability, relative permeability
• porosity-permeability cutoffs, net pay cutoff determination, rock continuity and floodable pay
• Vertical permeability variation, areal permeability variation, detection of stratification, selection of layers, Dykstra-Parsons coefficient, Lorentz coefficient, effect of cross flow, vertical sweep efficiency
• Need for waterflood patterns and selection criteria
• A lot of Case studies and exercises

Dedicated to examining the analytic techniques available to evaluate waterflood operations. Concepts of fractional flow, frontal advance theory and its application to Welge’s method will be discussed. The concepts will be extended to multi-layered system to compute pseudo relative permeability curves. Several hands on problems will help understand the application of the above in Stiles and Dyksta-Parson’s methods of computing vertical efficiency. Finally, a waterflood design problem will be solved using this analytic framework. Following topics will be included during the day :

• Frontal Advance theory, Water Tonguing, Viscous Fingering, Application of fractional flow, influence of rock wettability on oil production performance, influence of viscosities, influence of formation dip, influence of Initial gas saturation
• Influence of Mobility ratio, gravity forces, capillary forces
• Wasterflood displacement mechanism and sweep efficiency calculations

Dedicated to waterflood evaluation using a numerical approach. First, the theoritical background of numerical simulation will be elaborated. Students will be exposed to a waterflood simulator and oriented to the various input components. Students will spend the rest of the day setting up a reservoir model, institute waterflood and run various sensitivities to mobility, viscosity, grid orientation, permeability heterogeneity, etc to optimize the waterflood. Finally, various case studies will be presented to highlight the importance of reservoir simulation in waterflood design and evaluation. The following topics will be covered:

• Mathematical representation of two/three phase systems of transport equations associated with the various constitutive laws for closure
• Review of numerical methods to solve the system of equations
• How to set up a reservoir model to initiate waterflood evaluation
• How to run sensitivities, history match (pressure and saturation), forecast and analyze results

Monitoring both waterflood production and injection as needed to decide on remedialsolutions, surveillance and monitoring. Participants will learn about methods to plot and map diagnostics information to gauge the overall health of the ongoing waterflood. Production diagnostics metrics will reveal areas of the field needing more attention and redistribution of water. Similarly, various injection well monitoring techniques (Hall and
Modified Hall plots) and injectivity loss calculations will be discussed. Moreover, mechanical and chemical techniques to alleviate excessive water production will be elaborated. Various successful water shutoff /profile modification treatments will be elucidated. Participants will learn about :

• Production plots, WOR-cumulative production, Wcut-cumulative production, Rate of Change of Watercut-cumulative production
• Injection plots, Hall/Modified Hall plots, injectivity loss calculation, step rate test
• Swept volume calculation to determine water shut off or profile modification treatment volumes
• Capacitance Resistance Modeling

Variations of waterflood for special reservoir/fluid systems.

In particular, low salinity (LoSal) waterflood will be presented Some reasons of its success based on the current state-of-the-art understanding will be presented. Furthermore, for viscous oil, polymer augmented waterflood will be taught. The instructions will include extension of fraction flow theory for this type of systems (exercise problem). Finally, various case studies of actual successful waterflood (in different geological setting and reservoir attributes) will be cited. The participants will learn about the following :

• LoSal waterflood – reasons of increased recovery and mechanisms to capture production upside.
• Polymer augmented waterflood – fraction flow theory, recovery calculation
• Reservoir Souring (causes and remedial actions)
• Case studies of various successful waterfloods

INSTRUCTOR

Dr.Ir. Drs. Herianto, MSc. & Team