Fundamentals of Formation Evaluation

Introduction

This training provides the participant with an understanding of the concepts of formation evaluation and well logging; an understanding of the physical principles of the tools used in logging; and an ability to characterize formations based on interpretation of well logs. More specifically, by the end of the training, the participant will understand the properties of rocks and fluids that produce characteristic signals; be able to read and interpret a well log; be able to analyze the measurements and correction for environmental factors; and be able to interpret the log to discern porosity, water saturation, lithology, and hydrocarbon content. Core analysis studies required for determining saturation and rock properties such as porosity, permeability, relative permeability, wettability, capillary pressure and their application to reservoir studies will also be covered.

This training will feature:

• Logging methods and interpretation techniques
• Discussions on conditions around the wellbore, effects on measurements of mud filtrate invasion
• The terminology of well logging, formation and fluid properties
• The physical principles involved in geophysical well logging
• Differentiation between gas, oil and water zones and shale estimation
• The Archie Equations in clean formations and estimation of water saturation
• Types of cross-plots, gas and shale effects
• Effects of shaliness and modified equations
• Core analysis and laboratory measurements of saturation and rock properties and their application to reservoir studies

Objectives

By the end of this training, participants will be able to:

• Define the objectives of wireline logging and core analysis
• Outline the principles of conventional logging tools
• Explain the fundamental physics involved in various petrophysical measurements from cores to borehole logs
• Conduct log interpretation to determine petrophysical parameters and saturation for clean and shaly formations
• Describe core laboratory measurements of rock properties
• Apply rock properties to reservoir characterisation studies

Training Methodology

Our focus in this training will be on the engineering tools, measurements and analyses that are required for obtaining reservoir rock properties. You will learn how well logs and core data are obtained. You will be required to work with well logs to build your own spreadsheet for the analyses. The daily workshops will be highly interactive and participative. This involves regular discussion of applications as well as review questions on each topic. Delegates are strongly encouraged to bring and analyse data from their own work domain. This adds greater relevancy to the content.

Who Should Attend?

This training is suitable to a wide range of professionals but will greatly benefit:

• Petroleum and Reservoir Engineers who need to determine accurate values of the properties of reservoir rocks for use in engineering calculations and simulation studies
• Petroleum Engineers and Technologists who want to have an understanding of well log interpretation, core analyses and formation evaluation techniques commonly used in the Petroleum industry
• Petro-physicists, Geo-physicists, Geologists and Non – Engineers who work in teams with Petroleum and Reservoir Engineers to estimate hydrocarbon in place and reserves and to perform reservoir characterisation studies
• Managers who seek to derive greater decision making on field development

Seminar Outline

DAY 1

Introduction to Well Logging and Interpretation

• History, Wireline Logging (LWD) / (MWD), log data acquisition, data processing, data transmission, log runs, log presentations, rock classification system, porosity, saturation, permeability , capillary pressure, fluid properties, water salinity
• Summary of procedures used in log interpretation – correlate and depth match logs, interpret lithology, identification of permeable and non-permeable zones from logs, determine and divide the formations into water bearing and hydrocarbon bearing zones, determine the porosity of the zones of interest, determination of saturation
• Borehole environment and invasion profiles

DAY 2

Logging Tools Design – Direct and Indirect Measurements

• Log measurements and tools – caliper, spontaneous potential (SP) measurements and SP tool, SP log interpretation, calculation of formation water resistivity (rw) using SP log; radioactivity and gamma ray (GR) tools, GR log interpretation, limitations and various corrections applied, calculation of shale volume (vshale) using data from SP and GR tools
• Porosity type tools – detailed description of the main porosity type tools including sonic, density and neutron, their advantages, key limitations, and various corrections applied to the tools
• Porosity calculation from individual tools – determination of porosity from acoustic log, determination of porosity from density log, determination of porosity from neutron log
• Resistivity theory and resistivity tools – detailed description of the normal, laterolog and induction type resistivity tools, resistivity invasion profiles

DAY 3

Determination of Lithology Porosity and Water Resistivity from Crossplots

• Determination of lithology and mixture porosity in complex formations – neutron-density crossplots, sonic-density crossplots, sonic-neutron crossplots, density-photoelectric cross section crossplots, m-n plot, mid plot, matrix identification plot, effect of shaliness, secondary porosity and hydrocarbons on these crossplots
• Methods of determining Rw: resistivity vs porosity crossplot, resistivity ratio methods, Hingle and Pickett plot
• Nuclear magnetic resonance tool – its principle of operation and applications in hydrocarbon industry

DAY 4

Determination of Water Saturation and Moveable Oil Saturation

• Saturation determination – determination of saturation in clean formations, shaly sand analysis
• Determination of moveable oil saturation and Net pay
• Discussion on well log interpretation exercise

DAY 5

Core Laboratory Measurements and Analysis

• Coring and Core Analysis
• Core laboratory measurements of saturation and rock properties such as porosity, permeability, relative permeability, wettability, capillary pressure and their application to reservoir studies
• Imbibition, Drainage and Capillary Measurements
• Discussion on reservoir characterisation