Designing and evaluating a casing program for petroleum wellbores

Abstract

Due to high operational and financial risks associated with the investments in the petroleum industry, all precautions are taken by the operators to achieve a safe and cost effective well completion. Casing design of a drilling program is a critical element which contributes greatly to safety and cost of the operation. The objective of this research was to develop a casing design program which enables the user to evaluate casing design proposed or implemented in a drilling campaign. The developed casing design program consists of sequential criteria to select casing setting depth and establish optimum casing strength. Knowledge on local pore pressure gradient and facture gradient are essential to select the casing setting depths. Since both the factors are regional stratigraphy dependants, casing setting depth selection was designed in the way it allows user to assign variables for these parameters. Developed casing design program was validated with the casing design done by Rahman, S. S and Chilingar, G. V(1995). Validation results shows that the casing design of Rahman and Chilingar and the casing design done with the use of developed program are having similar casing setting depths except in the case of conductor casing.