Abstract: The choice of pigging is especially important in the preparations in associated gas pipeline pigging because of its direct impact on pigging effect. Three kinds of common pigging are introduced, i.e., rubber pigging, steel pigging and polyurethane pigging, both qualitative and quantitative analysis of pigging choice are made. Several aspects are considered such as running direction, weight, abrasion resistance, using range and price in qualitative analysis and HYSYS is adopted to simulate in different conditions in quantitative analysis. At last, pigging and polyurethane foam pigging are both proposed for combination pigging since it has good effect and can reduce spoilage of polyurethane foam pigging and prolong lifetime, and the scheme economy is improved thereby.

Key words: oilfield, associated gas, pipeline, pigging, optimization, study