Petroleum Engineering 405 Drilling Engineering 1 Well Drilling Engineering Casing Design Dr DO QUANG KHANH 2 Casing Design Why Run Casing? Types of Casing Strings Classification of Casing Well[.]
Well Drilling Engineering Casing Design Dr DO QUANG KHANH Casing Design Why Run Casing? Types of Casing Strings Classification of Casing Wellheads Burst, Collapse and Tension Example Effect of Axial Tension on Collapse Strength Example Read Applied Drilling Engineering, Ch.7 HW # Casing Design What is casing? Casing Why run casing? Cement To prevent the hole from caving in Onshore - to prevent contamination of fresh water sands To prevent water migration to producing formation Casing Design - Why run casing, cont’d To confine production to the wellbore To control pressures during drilling To provide an acceptable environment for subsurface equipment in producing wells To enhance the probability of drilling to total depth (TD) e.g., you need 14 ppg to control a lower zone, but an upper zone will fracture at 12 lb/gal What you do? Types of Strings of Casing Drive pipe or structural pile Diameter Example 16”-60” 30” 16”-48” 20” 5/8”-20” 13 3/8” {Gulf Coast and offshore only} 150’-300’ below mudline Conductor string 100’ - 1,600’ (BML) Surface pipe 2,000’ - 4,000’ (BML) Types of Strings of Casing Diameter Intermediate String Production String (Csg.) 5/8”-13 3/8” 1/2”-9 5/8” Example 5/8” 7” Liner(s) Tubing String(s) Example Hole and String Sizes (in) Hole Size 36” 26” Pipe Size Structural casing Conductor string 17 1/2 Surface pipe 12 1/4 IntermediateString 3/4 Production Liner 30” 20” 13 3/8 5/8 Example Hole and String Sizes (in) Hole Size 36” 26” Pipe Size Structural casing Conductor string 17 1/2 Surface pipe 12 1/4 IntermediateString 3/4 Production Liner 30” 20” 13 3/8 5/8 Example Hole and String Sizes (in) Structural casing Mudline Conductor string 250’ 1,000’ 4,000’ Surface pipe IntermediateString Production Liner 10