Myanmar's Mann Field: Production Increase in Two Test Wells
- Lucas Evangelista
- Jul 1, 2011
- 3 min read
Updated: 5 hours ago
Oil production increased in two test wells in a mature oil reservoir in Mann Field, Myanmar by successfully applying an enzyme-enhanced oil recovery (EEOR) process, a subset of microbial-enhanced oil recovery. A concentrated, water-soluble enzyme preparation made from DNA-modified proteins released from selected microbes was specifically prepared and injected in oil zones of one well and then recycled and applied in a second well.
Mann Field is a brownfield located in the Salin sub-basin of the central basin of Myanmar in Southeast Asia. The field began producing in 1970, predominately from Oligocene reservoirs that consist of 26 stacked sandstone payzones. More than 667 wells have been drilled and completed, and 118 million stock tank barrels of oil have been produced. Average porosity of the field is 18% with an average permeability of 10-250 md. Oil gravity is typically 36.5°API, which is paraffinic in certain horizons, and the gas gravity is 0.65.
GreenZyme is a water-soluble enzyme technology first deployed in crude oil fields in 1999 — distinct from microbial EOR techniques and from chemical polymer floods. By the time this study was presented, E-EOR applications had also been documented in China, and Venezuela in 2000, making Mann Field one of several international proving grounds for the technology.
There are unlimited targets for EEOR applications, not only in Myanmar, but throughout the world. These successful initial EEOR applications in Mann Field will allow for treatment design improvements in future wells.
Test Well Selection
The Mann Field EEOR tests were conducted on Well 395, completed in September 1981, and Well 101, completed in March 1976. Both wells experienced periodic paraffin buildup and had produced 433,500 and 1,384,525 cumulative barrels of oil, respectively. Both wells met the criteria for a modified-enzyme application.
The modified-enzyme treatment in Well 395 was preceded by a wellbore clean-out procedure to prevent injecting wellbore contaminants into the perforations. One treatment of modified-enzyme concentrate, diluted to 2% in filtered 2% KCl water, was then used to treat Well 395. Injection pressure was maintained below the formation fracture pressure, and the entire 155 ft interval was open during treatment, with no diversion of fluid. The well was shut in for four days for soaking before being returned to production.
The modified enzyme works biologically, not chemically or bacterially, and acts in three stages: it first attaches to the oil coating the rock surface, then undergoes a biochemical reaction that forms an enzyme–oil complex, and finally disperses, releasing the oil and restoring the enzyme (catalytic) so it can continue working elsewhere in the formation.
Pretreatment production on the first test well was 14 bopd and 2 bwpd. Current production is 18 bopd, and some 530 incremental barrels have been produced in the 13 months following treatment.
Pretreatment production from the second well was 10 bopd and 109 bwpd. Current production is 16 to 17 bopd, and approximately 1,636 barrels of incremental oil have been produced during the nine months since treatment. Additional enzyme treatments are being designed for wells in Mann Field with higher current oil productivity.
Conclusions
Application of a modified enzyme in Mann Field improves oil production.
Treating higher-impact wells should result in greater profitability.
Diverting modified-enzyme treatments into more intervals should improve treatment results.
Arresting the decline rate after treatment is a significant result of this test.
Preliminary tests indicate the treatment is effective in high water-cut wells.
Sources & Credits
Ott, W. K., Nyo, T., Aung, W. N., & Khaing, A. T. (2011, July 19–21). EEOR Success in Mann Field, Myanmar. Presented at the SPE Enhanced Oil Recovery Conference, Kuala Lumpur, Malaysia. Society of Petroleum Engineers. doi:10.2118/144231-MS
The full SPE 144231 paper is archived in our Case Studies library.
