Perpustakaan Digital ITB

Carbon dioxide emission problems have been puzzling these days. Carbon capture and storage (CCS), or with utilization becomes CCUS, is believed to be a key pillar to accomplish the Paris Agreement’s target of limiting the global temperature rise to 1.5°C (Global CCS Institute, 2024). An actualization sample in Indonesia is the planned operation in Well X, an exploration gas well that was abandoned in 2008. Prior to well conversion, evaluations must be performed, cement sheath evaluation behind the existing casing and liner emerges as the major one. Marbun et al. (2019) amplify that injection wells are supposed to have good isolation quality. Therefore, a study is conducted here to assess the cement bond quality through post-drilling cement bond log (CBL) and variable density log (VDL), with the focus specifically limited to behind the 7” liner. CBL evaluation leads to amplitude reading and VDL presence provides the propagated waveforms visualization, albeit both logs come from the same transmitter in the same CBL-VDL tool. Based on the performed study, CBL amplitude is processed through the attenuation reading for better bonding quality interpretation, while VDL is used for the interpretation reconfirmation as well as locating the suspected existing cement problems. In the end, zones behind the liner section are concluded to have bad cement bond, especially the ones around the injection target. Preliminary conjectures also show serious micro-annulus problems in certain depths. Hence, though better evaluation is necessary such as through ultrasonic logging implementation, remedial cementing is inevitable to solve all the alarming zones prior to well conversion.