Journey of Hydraulic Fracturing Improvement to Increase Oil Recovery from Sandstone Formation in Rimau Block

摘要

A hydraulic fracturing stimulation campaign has been successfully conducted in Rimau block. The stimulation was applied in tight KTLS sandstone formation with permeability within the range of 5-10 mD and also conducted in medium permeability multilayer LTAF sandstone (>10 mD) to bypass nearby wellbore damage. The purpose of this paper is to share best practices and lessons learnt from the hydraulic fracturing campaign, which commenced in 2003. The campaign was divided into three stages, with the aim of continuous improvement. The first stage was conducted in 2003, when a trial with a generalized design was conducted. Later, the second stage was conducted during the period 2004-2009, when a hydraulic fracturing campaign with improved design was carried out. Finally, the third stage was conducted from 2010-onwards, when the campaign was improved by emphasizing operational excellence and technological diversification. Beginning with Stage 1, hydraulic fracturing was performed in 13 wells in KTLS using typical fracturing design. An increase in production from each characteristic of formation was observed. Following the success story of Stage 1, a campaign was conducted in Stage 2 by proposing a plan of development for 50 wells to generate an optimization of the fracturing design. Stage 3 consisted of performing further optimization through technology diversification to overcome pressure depletion and operational collaborations. Furthermore, fracturing was also applied to higher permeability sandstone formations to bypass nearby wellbore damage. The continuous improvement during all stages resulted in an increase in oil recovery of 10 to 25% in tight formation and 30% in higher permeability formation, with an oil gain ranging from 80-500 BOPD and a typical yearly decline of 40%. In the future, hydraulic fracturing will be applied to face further challenging conditions, such as tight gas, tight oil and shale gas.