Evaluation of primary cementing in 7 inch production casing using CBL-VDL analysis in the TJ-19 well in the "Alfa" field

The TJ-19 well is a well located in the “Alfa” Field located in the Central Sumatra Basin. TJ-19 well reservoir is sandstone with shale insertion. The TJ-19 well is a development well which was drilled in 1978. The primary cementing process is carried out at intervals of 292 – 1345 ft on a 7 inch casing production route. Poor cementing can cause microannulus, channeling, and free pipe which can lead to poor casing insulation. If there is an indication of a problem with cementing, it is necessary to have a thorough look at whether it is necessary to do squeeze cementing, especially in the productive zone so that production activities can be carried out properly. In addition, an analysis of the results of primary cementing on the 7 inch casing production route at a depth of 292 – 1345 ft was also carried out using qualitative and quantitative analysis of the Cement Bond Log (CBL) and Variable Density Log (VDL) curves. From the qualitative analysis on the TJ-19 well, it shows 92.9% of good cementing results (good bond). The cementation between the formation and the casing is well bonded, which is where the cement bond conditions are expected to exist in the entire casing section in the annulus. Meanwhile, 9.1% showed poor cementing results which indicated bad bond, channeling/microannulus, bad to formation and free pipe at depths of 660, 1190-1220 ft. From the results of quantitative analysis at a depth of 292 – 1345 ft, the results of cementing the 7 inch TJ-19 Production Casing Well are 95.5% good Compressive Strength (CS>500 psi), 3.3% Medium Compressive Strength (300