A Long-term Inhibitor Released Technology for Low Permeability Oilfield

摘要

During the low permeability oilfield development, it's a challenge for operation company to balance the OPEX and the large quantity of oil wells with low output of single well, especially for the daily inhibitor injection and related management. It is necessary to prolong the continuous production period and mitigate the corrosion and scaling of the tubular caused by complex production medium. A long-term inhibitor released technology has been designed which combines encapsulated corrosion/scale inhibitors and soluble alloy baffle chamber without extra energy or mechanical controlling system. Therefore, the long-effective prevention would be achieved by slow release of corrosion and scale inhibitors just as bamboo joint in sequence. As the key materials of this technology, a magnesium-aluminum alloy as the soluble baffle for the bamboo chambers and encapsulated inhibitor have been developed. Through chemical component design, the alloy reaches high strength under 10MPa pressure and below 80°C. Th e relationship between structure and strength relationship have been tested according to the requirements of produced brine and periodic soluble reaction. The released characterization of encapsulated inhibitor stored in the dissolvable baffle chambers has been researched to adapt the release requirement. The following problems of the segmental dissolution-release controlling process have been discussed; (1) density and release controlling of corrosion/scale inhibitors; (2) pressure resistance of structure; (3) blocking effect of evolved gas. Compared with the capillary line mechanical injection or wellhead manual injection methods, this technology possesses effective releasing, simple structure, and low investment at the same time. The cost of a single well using this technology is about $5,000/a, achieving a theoretically two-year lifespan. It is a novel production flow assurance technology suitable for low permeability oil wells.