Acidizing Technology Review

Acidizing Technology Review (SLB, BJ, VSP)

Jul 2012

SLB Acidizing • Applicable for sandstone/carbonates reservoir and all types of completion. • Diversion techniques: –Mechanical: ball sealers, packer –Chemical: FOAMMAT, OilSEEKER. After 2010, there are 3 more clients employed Oil SEEKER technique in Malaysia Dulang Field, Petronas Carigali, Oil : 4 jobs Guntung Field, Exxon: 4 jobs Bokor Field, Petronas Carigali: 8 jobs South Furious Field, Shell: 1 job

• Other: OneSTEP technique A replacement for a conventional mud acid type stimulation.  It is a one step stimulation, as opposed to many different fluid types pumped in succession like a mud acid treatment.  It is designed to limit the bad reactions/precipitation that indefinitely occurs with a mud acid treatment.  As such it is less reactive and requires a higher BHST (200-375 degF).  The higher the temperature the more the stimulation.  It has shown promise in the limited amount of treatments that have been performed by itself, and has also been combined with fracturing in order to increase the effectiveness of the fracture stimulation by stabilizing clays.

SLB Acidizing with OilSEEKER

In Vietnam, this technique was used only by VSP back in 2010.

OneSTEP Track Record

BJ Acidizing • One study conducted for basement reservoir in 2011. Main objective is to remove Lost Circulation Materials (LCM) ie. Calcium Carbonate pumped during drilling to kill losses in moderate to high loss wells and Fill-in minerals /clays in the fracture as well as to clean up fracture faces in low to no loss wells. • Recommended acid: HCL or HCL/HF based system. • Some applications (since 1996 up to now for Petronas Carigali, JVPC, Hoang Long JOC, Hoan Vu JOC, Cuulong JOC, Lam Son JOC, Thang Long JOC) but no specific results can be given so far.

BJ Acidizing • More study should be done on cutting samples (mineralogy and acid solubility test) as well as acid/oil compatibility (if the oil sample is available) to fine tune and select the best acid formulation. Solubility test can be done in Vietnam. Mineralogy test can be done in Singapore however, based on recent studies, the mineralogy of cutting samples taken from different fileds in Cuulong Basin seem rather similar. • As for spotting method, bullheading via completion tubing or DST string is preferable for quicker operation and higher rate. CTU can be used if we want acid coverage at least the openhole section.

VSP Acidizing • Good successful rate with mud acid and acid/oil emulsion. • Track Records: VSP, Dai Hung, Con Son JOC.

Thank You