casing

     

I.            Function of Casing

Following are the important function of casing.

•   To prevent the caving of hole
•   To prevent  contamination of fresh  water in upper sand
•   To exclude watter from the producting formation
•   To confine production to well bore
•   To provide means of controlling pressures
•   To facilitate installation of subsurface equipment

II.            Classification of casing

       the classification of casing is bassed on primary function of the casing string. there are four types of casing :

            a. conductor casing 

            b. surface casing
     c. intermediate casing
     d. production casing

        

                                                                                             

Production casing

      A.   Conductor Casing

•   Diameter 16-48 inci
•   Digunakan di offshore / di kondisi extra
•   Kedalaman sampai 100-400 feet
•   Ukuran lingkaran general dari 8 5/8 hingga 20 inci OD (out side Diameter)
•   Mencegah underground blow out

B.      Intermediate Casing

•   Ukuran lingkaran general dari 7 5/8 -13 3/8 inci OD (out side diameter)
•   Untuk kedalaman 3000 s/d 8000 feet
•   Fungsi = mengisolasi formasi yang lunak, supaya pemboran bisa di perdalam

C.      Production Casing

•   Ukuran 4 ½ - 9 5/8 inci OD (out side diameter)
•   Casing paling bawah
•   Di pasang sampai zona produksi

D.      Production Tubing

•   Berada di dalam pipa
•   Ukuran 1 – 2 inci OD (out side diameter)