SYNTHESIS, PERFORMANCE EVALUATION AND FIELD APPLICATION OF POLYMER-TYPE NATURAL GAS DRAG REDUCTION AGENT

摘要

Natural gas is gaining popularity in the world as a high quality, clean burning alternative to oil and coal. The Mechanism of Drag Reduction in the natural gas pipelines is to control the radial pulsation of gas adjacent to pipeline wall effectively. The way to lower the pulsation intension of the gas in the thin layer along the wall is to use gas drag reduction agents, whose polar end absorbs fixedly to the surface and whose non-polar long chain suspends in natural gas so as to have a function of restraining the gas' radial pulsation. The drag reduction agent molecule absorbed to the protruding is mainly to weaken the gas pulsation producing by virtue of roughness degree. The drag reduction agent molecule absorbed to and collected in the dents also has the function of lowering the equivalent roughness degree of the wall surface. A polymer-type natural gas drag reduction agent with polarity as well as nonpolarity long chain was studied. We synthesized polymers that contain long chain fatty acid (F) or long chain ester(E) as soft chain, and alkoxy residues or acylations as polar group ,then studied the effects of this polymer-type gas drag reduction agent on the pipe wall, natural gas quality, station processes and equipments as well as post-processing. A test loop with control software was developed for evaluating natural gas drag reduction agents. An on-line injected system for natural gas reduction agent was established. The product was applied on natural gas pipelines in China. In No.1 oil production plant of Changqing oilfield, the drag reducing efficiency is 19.5%, and the flow increase rate is 12.4%. In pipeline from Lanzhou to Yinchuan, the drag reducing efficiency is all above 10%, and the flow increase rate is all above 5%.