Directional, Horizontal and Multilateral Well Drilling


This is a comprehensive, technical course which introduces participants with directional, horizontal and multilateral drilling and planning. It covers key directional drilling topics such as 2-D geometric planning, tubular and BHA design, surveying of directional wells, equipment used, directional drilling challenges, required circulation rates, etc.

Up on completing the course, the participants should be able to understand the directional well planning, design drill strings, select BHA, know TAML classification of multi laterals, be aware of horizontal well issues such as; hole cleaning, buckling, torque and drag and finally be familiar with survey tools and methods.

Participants will be supervised by the course instructor through a number of class-work sessions to master some of the complicated subjects such as fishing in directional holes.

Directional and Horizontal Wells


  • The need for Directional Drilling.
  • Introducing Directional Drilling Terminology; Section view, Plane view, Measured Depth, True Vertical Depth, Departure, Dog-Leg Severity, Kick Off Point, Build Gradient, Build up radius, Tangent Section, Slant Angle, Drop off gradient, Drop off radius, Hang Section, Hang down angle, Survey Points, coordinate systems (Polar, Cartesian and Cylindrical) in directional drilling.
  • Types of Directional Wells and their applications; Slant, S-Type and Double-build and J type horizontal wells.
  • Deviation techniques and deflection tools; Jetting, Whip stock, motors and bend sub.
  • Reviewing basic math and geometry to perform directional drilling calculations.
  • Transposing  Measured Depth (MD) to True Vertical Depth (TVD) and transposing TVD to MD
  • Understanding the meaning of Dog-Leg Severity (DLS) and relating it to radius of curvature.
  • Understanding the relationship among DLS, hole inclination and MD 
  • Understanding Horizontal Departure and relating it to hole inclination.

Practical Session : In this session, course participants will be given a set data to practice the required basic directional drilling mathematics.



  • Designing Directional wells: Slant, S-type and Double Build and Horizontal Wells.
  • How to generate a ‘section view’ of directional well.
  • Things to consider when planning a directional well. How to avoid potential problems and industrially accepted ‘Rule of Thumbs’ considered in directional well planning.
  • Important considerations in a 3-D well planning.
  • Collision and Target intersection.

Practical Session : In this practical session, each participant will be given a set of data to practice the process of directional well planning. Such data consists of wellhead location, target location, build up and drop off gradients as well as kick-off point. In this exercise, they are expected: firstly, design a double build horizontal well; then; they are expected to draw the section view of the planned horizontal well.



  • What we mean by ‘Monitoring a directionally drilled well’ and What do we survey?
  • Surveying tools (Single shot, Tatco, gyro, etc)
  • ‘Hot-Spots’, Magnetic and non-magnetic Drill Collars. How to decide the minimum required length for non-magnetic drill collars.
  • Three definitions of NORTH; True North, Magnetic North and Grid North.
  • Survey calculations: Tangential Method, ROC and Minimum Curvature Methods
  • How to generate a ‘Horizontal (plane) view’ of a directional well.
  • Circle of uncertainty in directional calculations.
  • Survey computations by using popular computer software packages.

Practical Session-Participants will be given a set of survey data, such as; inclinations, directions at different survey points (measured depths). They will be asked to determine North and East coordinates and True Vertical Depths by one of the popular survey techniques. They then, will be asked to draw two dimensional plane view of the drilled trajectory.



  • Drill String Design for Directional Wells (BHA and DPs)
  • Dog legs and Lubinski’s bending stresses.
  • Surface running loads and dog leg running loads.

Practical Session The participants will determine whether a given drill pipe in given borehole condition will be able to run through a severe dogleg without failing. They will have to determine the anticipated dogleg and surface running loads and compare with the yield strength of the tubular.

  • Directional Drilling Issues; Cuttings Bed Deposition, Severe Dog-Legs, Key Seats, Differential Sticking, Ledges, Stuck Pipe.
  • Importance of Solids Control and Optimum Solids Concentration.
  • Safe fishing loads in directional wells under combined loading; simultaneous torque, tension and pressure loading-How to compute von Misses’ stress and how to avoid failures while fishing.
  • Horizontal well issues; Critical Buckling Loads.



  • Multi-lateral wells and  their applications
  • TAML Classification
  • Multilateral Junctions and selection criteria
  • Horizontal and Extended reach wells
  • Torque and Drag Calculations and Maximum Available WOB
  • Cementing and Centralizer Spacing
  • Closing


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For registration, please e-mail or contact Andrew at (65) 6336 5458.