Re-design Intermediate CasingTo Solve Corrosion Problem In Well In Higleeg – Case Study

Abstract

The well casing conceder one of the most important process during drilling and production so that must be designed carefully; there are many problems face the casing, one of this problems is leakage pressure such as that occur in many wells in higleeg oil field in Sudan; In this project a case study has been made in an example of well in higleeg oil field. Where the corrosion occurred in the intermediate casing at depth of (4m) below surface. The old design which set before completion was investigated to know if the problem caused by fail in design or not by using the graphical method; after design calculation revealed that the casing which must be run is J-55 with nominal weight 36 Ibm/ft from depth 0 – 1040m and H-40 with nominal weight 36 Ibm/ft from depth 1040 – 1660m and H-40 with nominal weight 32.3 Ibm/ft from depth 1660 – 2156m; however the casing string which set befor completion was N-80 with nominal weight 47 Ibm/ft this casing is good; so that the fail cannot occur by design; after that recommend to solve the problem by design casing patch to the intermediate casing with ¼ 8 in outside diameter and 4 meter length.