Petroleum Science >2020,??Issue 2:??1-16 DOI: https://doi.org/10.1007/s12182-019-00380-6
Compatibility evaluation of modified seawater for EOR in carbonate reservoirs through the introduction of polyphosphate compound Open?Access
文章信息
作者：Bisweswar Ghosh, Liying Sun, Nithin Chacko Thomas
作者單位：
Petroleum Engineering Department, Khalifa University, Abu Dhabi, United Arab Emirates; College of Petroleum Engineering, China University of Petroleum (Beijing), Beijing, China;
投稿時(shí)間：2019-03-17
引用方式：Ghosh, B., Sun, L. & Thomas, N.C. Pet. Sci. (2019). https://doi.org/10.1007/s12182-019-00380-6
文章摘要
Waterflood-assisted oil recovery with sulfate-spiked seawater would cause incompatibility scaling in carbonate reservoirs and reduce economic benefits. This research investigated the benefits of polyphosphate compounds in reducing scaling potential as well as its effect on oil recovery when mixed in high sulfate flood water. Severity of scaling potential of sulfate-spiked water in a carbonate reservoir environment was measured, followed by systematic screening of a polyphosphate compound, which successfully inhibited the sulfate scale precipitation at concentration as low as 100 ppm. The new formulation (seawater with four times sulfate and phosphate, SW4SP) was evaluated and compared with benchmark formulation (modified seawater with four times sulfate, SW4S). Contact angle, ζ-potential and drainage studies show that SW4SP changed the rock wettability from oil wet to water wet to a larger degree compared to SW4S. Improved recovery efficiency of SW4SP was confirmed through a set of core flooding studies in the tertiary and quaternary flood modes. Whereas SW4S recovered 7.7% of original oil in place (OOIP), SW4SP recovered about 8% of OOIP in the tertiary mode under approximately identical flow conditions. Flooding with SW4SP in the quaternary mode following a tertiary flood with SW4S on the same core resulted in 1.7% additional oil recovery, showing improved efficiency of the new flood water formulation.
關(guān)鍵詞
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Incompatibility scaling, Sodium trimetaphosphate (SHMP), Smart waterflood, Scale inhibitor, Water compatibility, Enhanced oil recovery