Abstract: The Ugandan oil field is characteristic of high content of clay minerals in the reservoir; the long time contact of the completion fluid and the reservoir at the bottom of the well can damage the reservoir. In order to handle these problems, a new type of completion fluid with organic amine (PF-NETROL) is elaborated in this research. The inhibition test of the completion fluid is first of all utilized to determine the dosage ratio of organic amine in the completion fluid, then the reservoir protection performance test is conducted to verify the long-term effect of the optimized completion fluid on the reservoir protection. The experimental results showed that the anti-swelling rate that was initially 85.42% increased to 94.21% after being placed for one day in the completion fluid with different content of organic amine (PF-NETROL) proving that the anti-swelling effect with the organic amine is good; the anti-swelling rate of the completion fluid system with a dosage of 2% is still more than 90% after 90 d of placement and it maintained a good inhibition on bentonite; in addition, the completion fluid of the system has the least damage to the reservoir within 0~30 d and the pollution rate increased quickly after 30 d. The completion fluid with a dosage of 2% organic amine (PF-NETROL) is preferred as the completion fluid system of the oilfield in Uganda; therefore it is recommended to replace and supplement the completion fluid every 30 d in the actual operation to ensure the performance of the completion fluid and provide guarantee for long-term operation. The new organic amine (PF-NETROL) completion fluid formula proposed in this paper can play referrable effect on long-term completion fluid reservoir protection.

Key words: completion fluid, organic amine, long-term effect, reservoir protection, Uganda