Horizontal well technology has been used in the Pattani Basin to target oil and gas reservoirs since the late 1990’s. As of today, the Chevron Operated B8/32 block and Platong fields have been producing from 70 horizontal wells. While about 80 % of the horizontal wells in Platong have been completed barefoot, the use of ICD’s has been increasing since 2010. Recently, in the Platong field, two ICD equipped horizontal wells were used initially for primary production of a major reservoir, following which one of the two wells was converted into a water injector to enhance total recovery from the reservoir.

The ‘Z’ reservoir located in Platong field has significant barrels (in the millions) of oil in place with an initial gas cap and a water leg. The reservoir was initially appraised and tested with a single deviated wellbore. This well confirmed the reservoir potential and identified gas and water coning, together with sand production as the major risks to optimising oil recovery. To manage potential oil and gas coning, a reservoir development plan, based around a pair of horizontal well completions, was developed. Both well completions were designed with sand control screens incorporating ICD’s to optimize inflow along each horizontal wellbore. The wells were drilled and completed in early 2012. After collecting surveillance data and modeling the primary production performance of the reservoir, a waterflood opportunity to increase total recovery was planned. The asset team implemented the in-situ conversion of one of the horizontal wells into a waterflood injector in August 2013. Response to the water injection has been confirmed in the second well of the pair and incremental oil of >50 MBO has been recovered.

This case study presents an analysis of the target reservoir, the development strategy and then captures the lessons learned from the performance of horizontal producers with ICD completions during primary production and during the later waterflood phase. The main challenges for future horizontal wells applications in Platong are relatde to thin fluvial sands and depletion. The use of ICD’s will continue to be proposed for new horizontal targets based on the positive incremental production impact.

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