Course Description
This is an introductory level drilling course which covers basic principles of planning, design as well as execution of casing and cementing operations. The topics pertinent to casing design includes, but not limited to; primary functions of different set of casing strings; casing material properties; things to consider when planning casing shoe depths; casing sizes and minimum recommended hole sizes; things to consider when designing casing grades, such as; wellbore loads, design considerations, safety factors; design procedures, and finally, casing landing operations. The topics pertinent to oil well cementing includes; classification of cementing operations such as; primary cementing, squeeze cementing, plug-back cementing; functions of set cement; cement slurry properties; set cement physical properties; cement hydraulics; Equivalent Circulation Density and circulation pressures; complete cement design including planning, execution, as well as cementing equipment. Throughout the course, there will be a number of class-work sessions which participants expected to be involved in to supplement and enhance the learning process. Hence, course participants are encouraged to bring their own field cases to the classroom in order to practice the introduced concepts and let the floor open for classroom discussions.
Course Objectives
- Familiarizing with two key operations in drilling oil and gas wells; casing and cementing
- Being able to plan and design primary cementing as well as plug-back cementing in oil wells
- Being able to decide where to set casing points in a given field
- Being able to plan and design casings strings for oil and gas wells
Who Should Attend?
- Drilling Supervisors, rig managers, drillers, toolpushers, assistant drillers
- Technical personnel who are in charge of designing casing strings
- Junior drilling engineers under development
- Job seekers in drilling and wellbore engineering
Course Details/Schedule
- Opening-Addressing location HSE issues; fire alarms, etc.
- Introduction to the course and the course conduct.
- Functions of Conductor, Surface, Intermediate and Production casing strings
- Introduction to Casing Point (Shoe) Design.
- Estimating Formation Pore Pressure gradients (Prior to Drilling.)
- Practical Session In this practical session, course participants will be supplied a table of Seismic Interval Transit Time vs. TVD data. Then, they will be asked to produce a chart of formation pore pressure vs. TVD. Finally, they will have to select the mud weights in order to meet a given trip margin.
- Estimating Formation Fracture Pressure gradients (Ben Eaton method and LOT method.)
- Casing Point selection based on simple a graphical method.
- Introducing the concept of ‘Kick Tolerance’ in casing shoe design.
- Casing Point selection based on Kick Tolerance method.
- Additional considerations in Casing Point Selection (Losses, Differential Sticking, etc.)
- Practical Session Course participants will be supplied a table of formation pore pressure (psi) vs. TVD (ft.) data. Given surface casing shoe depths, they will be asked and guided to select the next intermediate casing point by using the kick tolerance method.
- Guidelines and Recommendations for Casing size, bit size and annual clearances.
- Lecture on Casing Physical Properties; Alloy, Heat Treatment, Yield Strength and Grade.
- What are differences among different casing grades?
- Stretch, OD, ID and Wall Strains
- Change in the diameter of a Casing
- Micro-Annulus Problem
- Practical Session In this practical session, course participants will be supplied data to exercise wall strains, chance in the diameter of a stressed casing and predict the micro-annulus development for a given loading condition.
- Summary of Day 1 materials.
- Introducing what is meant by a ‘Casing Grade Design’
- Principles of casing grade design.
- Introducing ‘Design Criteria’ and ‘Design Factors’
- Managements Guidelines in Casing Grade Design
- Well bore and casing stresses.
- Casing Failures; Body, Joint, Collapse and Internal Yield (Burst) Failures.
- Designing for casing body (axially)
- Practical Session Course participants will be given a section view of a planned directional (slant) well as well as a table of casing grades. Then, they will be asked and supervised to design minimum cost casing grades considering axial stress and yield strength criteria.
- Design Considerations and API design (safety) factors for Internal Yield (Burst) Pressure
- What is meant by ‘Bi-axial’ Design and ‘Tri-axial’ Design
- Explaining why casing axial tension or compression must be taken into account when designing for burst.
- Practical Session In this practical session, course participants will be provided a set of data including available casing grades, a given casing point, as well as expected shoe strength (psi). Each participant will then be assigned a specific casing residing depth to work on. Finally, they all will be asked to contribute producing a table of minimum casing grades for their assigned depths considering the internal yield (burst) failure only.
- Summary of Day 1&2 materials.
- Design Considerations and API design (safety) factors for the case of Collapse Failure
- Estimating maximum anticipated collapse stresses
- Introducing Collapse Strength of Equations (Yield, Plastic, Transitional and Elastic Collapse)
- Selecting the correct collapse strength equation for a given OD and thickness
- Yield Strength and Adjusted Yield Strength of casings (with Tension and Compression)
- Bi-axial vs. Tri-axial stress considerations and casing collapse strengths.
- Practical Session In this practical session, course participants will be using the same data as introduced in the earlier exercise. However, this time they will be asked to contribute producing a table to minimum casing grades for their assigned depths by considering collapse failure only.
- Design Considerations and API design (safety) factors for the case of casing Joint Failure
- Estimating maximum anticipated joint stresses (vertical well case and well bore with a given dog-leg).
- Types of Casing Connections; Long T&C, Short T&C and Buttress.
- How to estimate Casing Coupling Strengths as per API 5C3 and 5B (vertical hole case)
- Practical Session In this practical session, course participants will be supplied data which includes a table with available casing grades, coupling type, a given casing point. Each participant will then be assigned a specific casing residing depth to select the casing type considering the joint stress and joint strength criteria. They will have to use the API Standards 5C3 and 5B in order to come up with the joint strength for their assigned casing joint type.
- Summary of Day 1-3 materials.
- Functions of Cement
- Primary Cementing, squeeze cementing and plug-back cementing
- Cement Slurry Properties
- Set Cement Properties
- Eight Cement Classes and Three cement types
- Cement additives; accelerators, retarders, filtration loss control, etc.
- Definition of ‘YIELD’ and ‘PERCENT MIX’
- Cement Design; sack, volume and pressure calculations.
- Conditioning mud and borehole prior to primary cement job.
- Cementing equipment; cement retainers and bridge plugs, etc.
- Primary cementing and pre-flush, cement volume calculations.
- Proper cement displacement.
- Cement circulation pressure and ECD
- Class-Work Session- In this practical session, all course participants will be given a caliper log data from a previously drilled and cemented hole. For a given set of data, they then will have to calculate the cement slurry volume, displacement rate to flow in turbulent regime in the annulus.
- Summary of Day 1-4 materials.
- Balance plug balancing techniques
- Class-Work Session- In this practical session, all course participants will be given set of data by means of which will practice how to determine the required volumes of cement and displacing fluid in order to perform a balanced plug cementing operation
- Cement quality analysis cement bond log and variable density log.
- Cement shield problems and zonal isolation, what are the contributors for behind casing gas migration or micro annulus. What can be done?
- Liner cementing procedures-Squeeze and Multistage cementing
