FISHING AND IT`S IMPORTANCE IN OIL FIELD INDUSTRY Episode 3
FISHING AND IT`S IMPORTANCE IN OIL FIELD INDUSTRY
Last time we stopped at junk basket and its usage during fishing for junk process.
Or even during milling operation.
The second type is;
§ Used in soft to medium formations to cut a core and retrieve junk
§ Top sub, barrel, carbide shoe & two finger catchers
§ Thrust ball-bearing assembly for free rotation of the barrel and shoe around the catchers to minimize finger catcher breakage
§ Mill O D: 1/4” less hole size
§ Carbide ID of shoe: slightly less than ID of catchers
§ The fingers in the upper catcher extend only halfway to the center, it’s function being to break the core when an upper strain is taken on the string.
§ The lower catcher has alternately long and short fingers which extend almost to the center, forming a close fitting basket which will retain the core or small pieces of junk
REVERSE CIRCULATION JUNK BASKET:
Reverse circulating junk baskets are the preferred tool for use in hard formations. It is not necessary to cut a core with a reverse circulating junk basket. This junk basket uses only a single junk catcher to insure that the lower circulating ports are as close to the bottom of the hole as possible .The design of the catcher is the same as that used in the Bowen Itco type junk basket.
To operate the tool, run it to within 10 or 15 feet of bottom, and begin circulating. Circulate long enough to clean the barrel and any cuttings that may be on bottom. A steel ball is dropped down the pipe and when it is seated it initiates the reverse circulation of the fluid. At full pump capacity, the fluid is jetted outwardly and downwardly against the full circumference of the hole where is is deflected in a manner that pushes all objects toward the center. Fluid flows to the center carrying any junk with it up through the tool and out the upper ports to the annulus. Any junk is caught by the retaining fingers.
IT CONSISTS OF:
§ Double-wall barrel assembly for producing reverse circulation
§ Bearing for free rotation of barrel and shoe around the finger cages Close-fitting finger catchers hold smaller pieces of junk
§ Circulate capacity of string
§ Check ID’s/ insure ball will pass
§ Drop ball: shear pins: reverse
§ Not necessary to cut core
§ Hyd. power deflects junk/barrel
Preferred tool for hard formation
A junk shot is a shaped charge used to break up large pieces of junk so they can be more easily recovered using conventional methods. A junk shot should be run only in open hole because the shot could damage the casing. The shot should be run on drill pipe so that the weight of the pipe will prevent the shot from being blown up the hole. The tool is lowered to the junk and all fill is circulated off the junk. A go devil is dropped inside the pipe to set off the charge and its downward directed blow breaks up the junk. Occasionally, the force of the explosion embeds the junk into the formation where it will not impede a roller cone bit. A short tooth bit along with a boot basket may do the job. The junk may be walled off and drilling resumes.
POOR BOY BASKET:
Used when fish is too large for conventional baskets and can be of several types including:
§ finger type
§ peen type
§ spring tine
§ wire welded inside type
FINGER TYPE SHOE:
§ A finger type shoe may be run when there is large but free junk lying on the bottom of the hole.
§ Made of mild steel for easy bending.
§ While rotating and circulating, slight weight is applied closing the fingers in to secure the fish.
SPRING TINE TYPE SHOE:
§ Diamond shapes are cut and then bent in to catch junk.
§ Again, should use a gauge the same O.D. as the fish prior to running.
§ Relies on friction to catch the junk.
§ Small O.D. sub, perforation gun, Shepherd’s hook.
WIRE CATCHER SHOE:
§ The wire catcher shoe has flexible wire welded inside to catch the junk.
§ Good for loose junk.
§ Use care, not to rotate too much or the wire might break off.
§ Might be good to catch a hammer, lead, rubber, or a pipe wrench.
NEXT ARTICLE WE ARE GOING TO EXPLAIN THE MILLS TYPES AND HOW TO USE AND IT`S PARAMETERS