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26 Oilfield Review Landing the Big One—The Art of Fishing Drillers often refer to tools and equipment left in the borehole as “lost.” In reality, these items have been misplaced thou sands of feet belo w the surface. R emoval of these objects from the wellbore has challenged drillers since the earliest days of the oil field. Enos Johnson Hobbs, New Mexico, USA Jimmy Land Mark Lee Houston, Texas, USA Robert Robertson Stavanger, Norway Oilfield Review Winter 2012/2013: 24, no. 4. Copyright © 2013 Schlumberger. For help in preparation of this article, thanks to Torodd Solheim , Stavanger; and Eric Wilshusen, Houston. FPIT is a mark of Schlumberger. In the oil field, a fish is any item left in a wellbore that impedes further operations. This broad defi- nition encompasses every variety of drilling, log- ging or production equipment, including drill bits, pipe, logging tools, hand tools or any other junk that may be lost, damaged, stuck or other- wise left in a borehole. When junk or hardware blocks the path to continued operations, these items must first be removed from the hole through a process known as fishing. The origins of this term are attributed to the early days of cable-tool drilling, in which a cable attached to a spring pole repeatedly lifted and dropped a heavy bit that chiseled away at the rock to create a wellbore. When the cable parted, drillers attempted to retrieve the cable and bit from the bottom of the hole using an improvised hook lowered on a length of new cable hung from the spring pole. Experts in the art of retrieving junk from the subsurface became known as fish- ermen. Over the years, their services have become highly sought after, and the art of fishing has grown to fill a specialized niche within the well services industry . All manner of equipment may fail, become stuck, need replacement or otherwise require retrieval from a wellbore. Fishing operations may be needed at any point during the life of a well— from drilling through abandonment. During the drilling phase, most fishing jobs are unexpected and are often caused by mechanical failure or by sticking of the drillstring. Sticking may also occur during wireline logging or testing operations. Later, during the completion phase, operations may be thwarted by a variety of problems, includ- ing stuck perforating guns, prematurely set pack- ers or failed gravel pack screens. After a well has been put on production, fishing operations may be scheduled as part of the overall process of maintaining, replacing or recovering downhole equipment and tubulars during workover or abandonment procedures. In many fields, the workover process entails cleanout or retrieval of tubing that has sanded up after years of produc- tion, thus prompting a fishing job at the outset of operations. During abandonment, operators often try to salvage downhole tubulars, pumps and completion equipment before plugging the well. Even the fishing equipment may become stuck, necessitating revision of the original fish- ing strategy . In the oil field, no operation, it would seem, is exempt from the possibility of fishing. Statistics from the mid-1990s indicate that fishing operations accounted for 25% of drilling costs worldwide. 1 These days, fishing can fre- quently be avoided or sidestepped using other, more cost-effective options. For instance, mod- ern drilling technology, such as rotary steering, is creating a shift in fishing strategies by influenc- ing the economics used to determine whether to fish, to buy the stuck equipment, known as the fish, and sidetrack, or to junk and abandon (J&A) the hole. Each fishing situation—planned or unplanned, openhole or cased, coiled tubing or wireline—is unique, and each presents its own set of conditions 1. Short JA: Prevention, Fishing, and Casing Repair . Tulsa: PennWell Publishing, 1995. 2. A dogleg is an abrupt turn, bend or change of direction in a wellbore and can be quantified in degrees or degrees per unit of distance. 3. Drilling fluid pressure can erode a wellbore to create a washout and it can erode drillpipe to create a hole, which is also termed a washout.
