CASE STUDY OF NITRIFIED ACID THAT ENABLE DEEPER PENETRATION OF ACID FOR MAXIMIZING PRODUCTION ENHANCEMENT IN SOUTHERN SARAWAK FIELD

With the increasing need for highly cost-effective well production enhancement applications,
acid stimulation is becoming increasingly popular. To be successful, acidizing procedures require
distribution of stimulation fluid across and within the desired treatment interval. Historically, this has
been approached with mechanical placement or chemical or chemical diversion of treatment fluids.
Method selection can be crucial to treatment success vary for matrix and fracture acidizing- in deviated
wellbores, in sandstones and carbonates and in cased and perforated, gravel packed and open hole
completions. Nitrified acid is the technique designed to remove well-bore formation damage which has
occurred during the productive life of the well without causing additional damage with kill fluids. West
Lutong and Tukau field are selected as the field of studies as this acid has shown several successful cases
in Southern of Sarawak field. Tukau field has reduced watercut after using nitrified acid method for
acidizing and currently this method is applied to West Lutong field with the combination of SAF MK II
acid for high watercut wells. SAF MK II not reducing water cut but the chemical diverts the acid to oil
zones and mostly stimulate oil zones only. Thus, more oil produce and water production maintained
prior acid job. The project is also to determine the skin reduction for each field by using method used in
PETRONAS Carigali Sdn. Bhd for acidizing treatment project. This project will be reviewed the production
trend of both field as the determination of skin that reduced the production. The history of acid job and
stimulation done for the fields will be analyzed to estimate the total reduction of skin and estimated the
oil gained by using several simple mathematical equations before a simulation by using PROSPER will be
done in order to confirm the calculations.