The Guide to Oilwell Fishing Operations | ScienceDirect
Abstract. Washover pipe (or washpipe, as it is commonly called), is large pipe used to drill out, wash out, and circulate out cement, fill, formation, or other debris that is causing the fish to stick. Proper size selection in washover operations is critical. The washpipe’s inside diameter (ID) must be large enough to go over the fish, with clearance for circulation.