Petroleum Development Oman is advancing a pattern flood pilot in a major sandstone field in Southern Oman that uses a chemical EOR flooding process to recover additional reserves. An EOR screening study showed that Alkali-Surfactant-Polymer is a viable technology for this viscous oil reservoir (90 cP). A successful ASP pilot test will pave the way to potentially implement the process in other sandstone fields in the Southern Oman Basin.
The ASP pilot test is a unique project in which two anionic surfactants have been specifically designed for the actual reservoir conditions. Laboratory tests indicated significant and comparable recovery from both outcrop and field cores. A high molecular weight polyacrylamide polymer designed to provide a favorable mobility ratio has also been tested at in-situ conditions. The primary objectives of the ASP pilot test are to validate laboratory results, demonstrate long term injectivity of the viscous ASP solution, reduce the range of technical and economic uncertainties associated with recovery efficiency and field operations and obtain data to calibrate dynamic models for accurate full-field predictions and economics.
The field pilot consists of a 1.4 acres inverted 5-spot pattern that includes 4 corner vertical oil producers, 1 central injector and 2 observation wells. The 53m producer-to-injector distance enables early ASP flood response (4 to 5 months) and ensures completion of the field trial within one year of injection. Injection/production facilities will be skid-mounted and located in the vicinity of the pilot wells. Pilot commissioning and first ASP injection is anticipated to start in mid 2014. This paper presents both subsurface and facility aspects of the ASP pilot test design, including four successful single-well ASP/SWCT field tests, one ASP flood MicroPilot, and the experimental results of oil-water-ASP emulsion separation experiments.