Perpustakaan Digital ITB

Sanding occurrence is a common case which can be usually discovered in sandstone reservoir. Produced unwanted sand may cause damage the downhole equipment material and the surface facilities. During a perforation design, an understanding to ascertain and distinguish the strong and weak formations is required to avoid excessive sand production. Well-developed design can increase the oil productivity, reduce operational and maintenance costs. This case was taken from one of onshore wells in field A, Sumatera Basin. It was found that the field was encountered large amount of sand production for several wells. To maintain oil production, re-perforation is carried out at a certain formation depth. This vertical well will be analyzed to predict its UCS formation at any depth using log porosity correlation and Palmer’s equation. Ten different formations with variations of reservoir pressure and rock stress has different critical UCS value, which can be integrated to UCS formation data to distinguish its formation resistance in certain pay zones. Six formations are predicted by the analysis to sand within 800 psia of a drawdown pressure. There are a total of 10 formations discovered within the wellbore in Well X. Pay zone with a lower UCS value than its critical UCS are more susceptible to sand. In this instance, a total of 126 ft of weak streaks inside the pay zone that were discovered in 5 different formations. Therefore, particular formation with great resistance profile will be selected to support perforation program. This will serve as a useful starting point for any subsequent countermeasure in the workover, such as sand screen or gravel pack installation.