UNIVERSITY OF SULAIMANI COLLEGE OF SCIENCE GEOLOGY DEPARTMENT
WELL LOGGING COURSE BOOK FOR THE ACADEMIC YEAR 2010-2011 Contents 1-
Course coordinator and list of teachers on this course.
2-
Course overview
3-
Course objectives.
4-
Course Reading list.
5-
Course Contents.
6-
Syllabus.
7-
Exams: Rules and instructions.
8-
Samples of expected questions and their answers.
9-
External examiners.
10-
Student's feedback.
Well logging course Book College: Science
Department: Geology
th
Course: Well logging / 4 year students
Course coordinator: Mr.Omid M. Mustafa
Course link in the University: www.univsul.net
List of lecturers of this course: Name Mrs. Devan O. Hussein
Scientific title Assist.lecturer
Email
[email protected]
Course overview Well logging, also known as borehole logging is the practice of making a detailed record (a well log) of the geologic formations penetrated by a borehole. The log may be based either on visual inspection of samples brought to the surface (geological logs) or on physical measurements made by instruments lowered into the hole (geophysical logs). Well logging is done when drilling boreholes for oil and gas, groundwater, minerals, and for environmental and geotechnical studies.
The oil and gas industry records rock and fluid properties to find hydrocarbon zones in the geological formations intersected by a borehole. The logging procedure consists of lowering a 'logging tool' on the end of a wireline into an
oil well (or hole) to measure the rock and fluid properties of the formation. An interpretation of these measurements is then made to locate and quantify potential depth zones containing oil and gas (hydrocarbons). Logging tools developed over the year’s measure the electrical, acoustic, radioactive, electromagnetic, nuclear magnetic resonance, and other properties of the rocks and their contained fluids. Logging is usually performed as the logging tools are pulled out of the hole. This data is recorded to a printed record called a "well log" and is normally transmitted digitally to office locations. Well logging is performed at various intervals during the drilling of the well and when the total depth is drilled, which could range in depths from 300 m to 8000 m (1000 ft to 25,000 ft) or more.
Course objective Quantitative analysis of well logs provides the analyst with values for a variety of primary parameters, such as: porosity • • water saturation, fluid type (oil/gas/water) lithology • • permeability……etc At the end of this course, the students should be able to understand the basics of borehole geophysics, theory of measurements, interpretations and applications of the different types of wireline logs. Students should also know how to calculate the petrophysical parameters required for formation evaluation (source and reservoir rocks).
Course Reading list -Rider, M. 1996. The Geological Interpretation of well logs nd -Asquith, G., and Krygowski, D. 2004. Basic well log analysis, 2 edition -Schlumberger, 1972, log interpretation, Vol.I, principles: New York limited, 112 p. -Schlumberger, 1974, log interpretation……… -Schlumberger, 1975, A guide to well site interpretation -Schlumberger, 1979, log interpretation charts. -Schlumberger, 1998, log interpretation charts. -North, F.K., 1985. Petroleum geology. -www.worldofteaching.com
- www.brookes.ac.uk/geology/peg/short course
Syllabus No. 1
2 3 4 5 6 7 8 9 10 11 12 13
Title of the Subject Wireline well logging (General, Introduction)
Lecturer's/Tutor's Name Devan O. Hussein
Well logging (Borehole Environment- Invasion and Resistivity profiles) Basic Information needed in log interpretation Fluid saturation of Reservoir Gamma Ray Logs Porosity Logs The Neutron and combination Neutron-Density log The Spontaneous Self potential (Sp) log. The Resistivity logs. The estimation of Invasion diameter……
Devan O. Hussein
Caliper Log
Devan O. Hussein Devan O. Hussein Devan O. Hussein
Micro log (ML)
Mark -First Exam………………... 7 M -Second Exam ……………. 7 M -Third Exam……………….. 7 M -Quiz…………………………. 4 M -Reports…………………….. 5 M
Devan O. Hussein Devan O. Hussein Devan O. Hussein Devan O. Hussein Devan O. Hussein Devan O. Hussein Devan O. Hussein Devan O. Hussein
Examples of Questions University of Sulaimani College of Science Dept. of Geology
Well logging practical Exam. 4 th Year Geology Time: 90 Min.
Name:………………………………………………..
Group (
)
Q1: a- Determine the measurement and the values of these porosity logs Porosity
Measure
High values
Low values
logs Neutron Density Sonic
Q2: a-How you determine the lithology and porosity as the same time from logs? b-How you find the value of Rw (by equations and chart)?
Q3/ from the following schematic log curves, give your interpretation to A,B, C zones, from the view of permeability and bore hole wall condition
Q4/ Answer the following 1-Give the qualitative evaluation of the following porosity a-0.03 b-0.11 c-0.17 d-0.05 e-0.27 2- Define -tortuosity factor -Sxo -Absolute permeability -Total porosity
Answer of Questions Q1/ Porosity
Measure
High values
Low values
Hydrogen ion
Shale, Coals
Clean sand stones
logs Neutron
carbonates Density
Density of formations
Less dense
Dense sediment
sediment Sonic
Interval transit time
Porous sediment
Non-porous sediment
Q2/ a-From combination Neutron-Density log, by knowing type of drilling mud we plot on porosity and lithology determination from formation density log. b- From Sp-log SSP=SP*C.F SSP=-k*log Rmf /Rw By chart passing through three plots.
Q3/ Zone A: Permeable zone, MLN > MLI, from caliper log it clear that the hole diameter is smaller than the bit size due to the formation of Mud cake. Zone B: Impermeable zone, no separation of MLN and MLI, no change in hole diameter. Zone C: Impermeable zone inspite of MLN > MLI, because bore hole diameter is greater than the bit size these is due to presence of rock salt or gypsum in the bore hole. Q4/ 1a- Negligible b- Fair c- Good d- Negligible e- Very good
