Perpustakaan Digital ITB

Casing planning in drilling activities on onshore or offshore is an important aspect that must be planned. Selection of casing setting depths is based on the pore pressure and fracture pressure gradients for the well and is usually available from offset well data. The well X-06 is a development well with a depth of 987 ft of seawater and the distance from the rotary table to the seabed is 1056 ft, category of deepwater wells. The conductor casing used must be able to withstand heavy loads of heavy mud for the next section, withstand wellhead loads, blow out preventer (BOP) and additional casing loads. From offset well data analysis, conductor setting depth is designed at a depth of 124 ft below the seabed and 1180 ft from rotary tables, the determination is based on the intersection of the pressure between fracture gradient and the effective mud gradient. The point of intersection is the point of conductor setting depth. After the conductor depth setting is determined, process with the determination of the next casing. The determination is done by the top-down method and the bottom-up method. The top-down method for the surface casing is reduced to a depth of 9500 ft, followed by production casing production to a depth of 11542 ft. The bottom-up method for the surface casing is lowered to a depth of 3200 ft and continued with the production casing to a depth of 11542 ft. Design conductor settings depth in the field is set at a depth 1210 ft, the surface at depth 9845 ft, and production casing is set at a depth of 11542 ft. Calculation results and analysis of the casing setting depth in the well X-06 using the bottom-up method. The bottom-up method was chosen because X-06 wells are a development well and are cheaper for the casing program costs. The cost of the casing is determined based on the size of the diameter and the quality of the casing that is designed to be used, the larger the diameter and the longer the depth of the casing circuit used, the greater the cost for the casing.