Fishing Techniques PDF

Fishing  The definition of fishing Losing equipment in the hole is one of the most expensive and potentially dangerous things that can happen. Recovering any lost or stuck items from the hole is called fishing  What causes fish to occur Perhaps the most important aspect of...

Fishing  The definition of fishing Losing equipment in the hole is one of the most expensive and potentially dangerous things that can happen. Recovering any lost or stuck items from the hole is called fishing  What causes fish to occur Perhaps the most important aspect of fishing is to ascertain the events that caused the fish to occur. without knowing the causation correct tool selection and procedures will be impossible, Some main reasons are as follows: Tools failure Human error Bad hole condition Improper mud …  Two main types of sticking mechanisms: Differential pipe sticking Mechanical pipe sticking  Differential Sticking: Differential sticking happens when the drill string is pushed against permeable formations by differential pressure between hydrostatic & formation pressure.  Differential Sticking: Reducing the high differential pressure by optimizing the drilling fluid density Optimizing the mud cake thickness by reducing the fluid loss Reducing the time when the drill string is not rotated or reciprocated especially when making a connection or rig repair.  Mechanical Sticking: The Mechanical pipe sticking happens when we don’t have a proper hole cleaning, there is a borehole instability, there is a plastic formation and problematic borehole geometry & … Accumulation of drilled cuttings: Poor hole cleaning can lead to drilled cuttings accumulation into the annulus causing stuck pipe. This problem can be more difficult when drilling deviated wells.  Accumulation of drilled cuttings: high viscosity pill can be pumped when drilling vertical wells low viscosity and high density pill can be used to clean highly deviated wells. The use of pills has to be accompanied by rotating the drill string to create agitation to make cutting beds removal more effective.  Borehole Instability: According to the mud weight and mud composition, the shale can slough or plastically move inward and cause mechanical pipe sticking. Another type of formation that can plastically flow is the salt in the case when the mud weight is not high enough. Also, using a low drilling fluid density can lead to hole collapsing that can cause stuck pipe. Fishing Tools  Free point indicator (FPI) Locate precisely where your drill pipe, tubing, or casing is stuck or partially stuck with the Free Point Indicator (FPI) An electro-mechanical assembly, the FPI is designed to pinpoint stuck pipe locations by accurately measuring torque or stretch.  Back-Off Tool The backoff process involves applying a left-hand torque to the pipe string while firing a shot of prima cord explosive. The resulting explosion produces a concussion that partially unscrews the threads at the targeted joint.  Colliding/Severing Tool Colliding Tools are designed to help recovery operation by cutting off thick pipes using explosives in a variety of environments  Impression Block It may be run on wireline, coil tubing, or drill pipe. An impression is obtained by simply setting down weight onto the fish.  Mill A tool that grinds metal downhole. There are different types for different purposes such as: Taper mill, Junk mil, Skirted mill,…  Overshot The most versatile and widely used fishing tools in the industry. External catcher Four most common type: a) Series 10 b) Series 20 c) Series 70 d) Series 150  Overshot a) Series 10: Sucker Rod Overshots b) Series 20: Short Catch Sucker Rod Overshots c) Series 70: Short Catch Overshots d) Series 150: Releasing and circulating Overshots  Spear The Releasing Spear Fishing Tools are used to internally engage and to retrieve all sizes of tubing, drill pipe, and casing. It is designed to assure positive internal engagement with the fish and is ruggedly built to withstand severe jarring and pulling strains without distorting the fish.  Taper Tap Taper taps are internal catch fishing tools designed for retrieving fish by taping inside the fish. They are the economical choice for retrieving lost tools. They are easy to run, but difficult to release. Good for retrieving production packers, after milling the top section.  Die Collar Like taper tap, box tap or die collar tools are sometimes used to retrieve an irregularly sized fish or a fish with an unknown OD. However, the fish needs to be stationary for the box tap to be successful. Box taps are not typically recommended because they are not releasable. For that reason, a safety joint should always be run immediately above a die collar fishing tool. Threads  Threads There are 2 types of threads in drilling: Rotary shoulder threads Casing and tubing threads Rotary shoulder threads While drilling, Milling and any other rotary operation, we need threads which are high torque and robust enough to be made up and broken out repeatedly without being worn out. Some of Well known threads of this category are: Regular Internal Flush Hughes 90 Full Hole  Rotary shoulder threads Regular: Regular threads (REG) are usually used for bits, mills and drill collar connections. They are 5 thread per Inch The angel between 2 threads is 60 degrees  High Torque Threads Internal Flush: Internal Flush threads (IF) are usually used for different sizes of Drill Pipes and drill collars, some fishing tools and … connections. They are 4 thread per Inch The angel between 2 threads is 60 degrees. This thread was modified, and the name for modified thread is no longer IF, but still we use the IF name.  Rotary shoulder threads Hughes 90: Hughes 90 threads (H90) were used to be used for drill collars connection. Not used in Iran nowadays. They are 3.5 thread per Inch The angel between 2 threads is 90 degrees.  Rotary shoulder threads Full Hole: Full Hole threads (FH) are usually used for Drill Pipes connections. They are 4 thread per Inch The angel between 2 threads is 60 degrees.  Casing & tubing threads Buttress Thread: This thread is used for large casing sizes. There is a Triangle on the thread and it should be made up to the base of triangle. After making up several joints to the base of triangle the average make up torque should be used for other joints. The treads are made on both ends of non upset pipe and the pipes are connected using internally threaded couplings  Casing & tubing threads Hydril CS: The thread of Pin & Box are machined on external- internal upset ends of pipe. The thread is not tapered, but has stair steps with 2 different diameters which are made up simultaneously.  Casing & tubing threads Hydril PH4/PH6: These threads are designed for extra heavy-walled tubing necessary to complete deepest high-press formation. Integral joint externally and internally upset. Two step, non tapered thread profile, 4 thread per inch for PH-4 an 6 TPI for PH-6  Casing & tubing threads VAM TOP: Excellent gas-tight sealing under combined loads Excellent resistance to bending, compression, and torque Excellent resistance to external pressure and compression Easy to use and repair  Casing & tubing threads Torque Turn Graph:  Casing & tubing threads When inspecting the pin and box end connections check the following Dents, dings or mashes caused by impact Galling caused by a poor make-up Rust, corrosion or pitting caused by the environment Thank you!