UAE University Faculty of Engineering Graduation project II Casing Design in a Vertical WellFinal Presentation Dr. MD Rahman Advisor: Team Members: Omar Ahmed Kamel 200100051 AbdulRahman Hasan 199900460 Ibrahim Hussain Taqi 199900628 Sultan Hussain Ahmed 200106307
Presentation Layout • Acknowledgement • Introduction • Light Casing Design For Grade Selection • Heavy Casing Design For Grade Selection • Conductor Casing Design • API Coupling Selections • Economic Considerations • Conclusions
Acknowledgment • We would like to express our deepest thanks and appreciation to: • Prof. Reyadh Almehaideb and GP Advisor MD Rahman • Examiners Committee: Prof.Abdulrazq Zekri, Dr. Shedid Ali and Dr. Bilal El-Ariss • ADCO: represented mainly by Mr. Reymond Khairallah, S.A Turki and Adib Edris • Training and Graduation Projects Unit
Introduction • Casing is defined as a heavy large steel pipe which can be lowered into the well for the following functions: • Keeping the hole open by preventing the weak formations from collapsing. 2) Serving as a high strength flow conduit to surface for both drilling and production fluids. 3) Protecting the freshwater-bearing formations from contamination by drilling and production fluids.
Introduction 4) Providing a suitable support for wellhead equipment and blowout preventers for controlling subsurface pressure, and for the installation of tubing and subsurface equipment. 5) Providing safe passage for running wireline equipment. 6) Allowing isolated communication with selectively perforated formation(s) of interest.
The main types of casing are: Conductor Pipe Surface Casing Intermediate Casing Production Casing Liners As shown in the Figure Introduction
Project Objectives • To perform casing design for two vertical wells by: 1) Data collection from ADCO Company. 2) Selection of casing setting depths. 3) Selection of casing sizes. 4) Determination of number of casings. 5) Selection of casings grades and couplings. 6) Economic Analysis.
Casing Design For Grade Selection • Casing Design for grade selection is done based on maximum load and minimum cost. • Collapse pressure, burst pressure and tension loads are calculated for all casings to select there suitable grades. • Pressure testing and biaxial effects are then checked for all casings.
Light Surface Casing Tension Calculations Where BF is Buoyancy factor, Wn is casing weight in lb/ft and Yp is the grade yield strength in lbf and SF is the safety factor.
Light Surface Casing Pressure Testing • Pressure testing calculation : • Safety factor > 1.8, so H-40 can be used. • So, all four grades are safe to be used in the light surface casing.
Light Intermediate Casing Tension Calculations • The grades are safe to be used. • The grades are also found suitable if the total tension load increases due to pressure testing as the safety factor is much higher than 1.8.
Light Casing Production Liner Tension Calculations • Both grades are safe for use. • Here, also by calculating the additional tension due to pressure testing it is found that the safety factor > 1.8.
Heavy Surface Casing Grade Selection • All the Grades are suitable for the Burst Pressure.
Heavy Surface Casing Pressure Testing Calculations • Pressure Testing for the weakest grade which is H 40 is done based on the following equation:
Heavy Surface Casing Design Biaxial Calculations Biaxial effect: Where: σa is the axial stress due to tension (psi σy is minimum yield strength of the grade (psi) Ypa is the effect yield strength (psi) do is the outer casing diameter (in) di in the inner casing diameter (in)
Heavy Surface Casing Design Biaxial Calculations • Biaxial effect is calculated using the following set of equations: Where: A,B, C, F and G are empirical constants
Heavy Surface Casing Design Biaxial Calculations • The biaxial results for heavy surface casing: Stress Calculations Coefficients Calculations
Heavy Surface Casing Design Biaxial Calculations • From the results: • The collapse pressure remain unchanged (Elastic Model) Where do is the outer casing diameter, in t is the thickness of casing, in
1st Heavy Intermediate Casing Tension Calculations • Selected grades based on collapse and burst pressures and Tension Calculation: • The selected grades are safe and meet all the loads
2nd Heavy Intermediate Casing Tension Calculations • Grade C 75 of weight 32 lb/ft doesn’t satisfy tension load requirements so it is replaced with grade L 80 of weight 33.9 lb/ft. • Pressure testing and biaxial loads will not cause any change in the selected grades.