Fishing

Accelerator, Intensifier, or Booster are different names for the same tool. An accelerator is used in conjunction with a jar in the string to intensify the force generated by the jar. It is positioned above the jar separated by drill collars. Accelerators are also available in double-acting mode to match the jar action.

A compressible fluid and an effective sealing assembly in the accelerator make the intensifying action possible. It stores energy when put under strain and acts like a hydraulic spring by releasing the energy as the strain is removed. It becomes a handy tool in shallow intervals where the drill string is not too long. Using an accelerator in combination with a jar increases the chances of releasing a stuck string.

Accelerator helps in keeping the energy generated by the jarring impact from being lost up the hole. Without an accelerator, the drill string absorbs some of the impact force of the jar, which reduces its effectiveness, and the string is also subject to undesirable jarring shock loads. The jar accelerator combination is used to intensify the effect of the jar at any depth.

Fishing Equipment & Services

Basket Grapple is an expandable cylindrical shape insert used inside and overshot bowl for catching and pulling a fish left in a well. It has wickers on inside to catch the fish and tapered helical spiral on the outside that matches with the internal profile on the bowl.

The overshot assembly installed with a basket grapple inside its bowl is lowered to the top of fish. The fish is engaged by swallowing and slacking off. Once engaged, the fish is pulled out of the hole.

Intensifier, Accelerator or Booster are different names of the tool that is used in conjunction with jar to intensify or accelerate the jarring action. A good compressible fluid and an effective sealing assembly makes the intensifying action possible. It acts like a hydraulic spring that stores energy when put under strain and releases it as the strain is removed. It becomes a very useful tool in shallow intervals where the drill string length is not much.

Bumper sub is a tool used in the fishing assembly for applying downward blows. It is made up of high strength alloy steel to be able to withstand severe stresses. Some of the typical applications of Bumper sub are in fishing operations for releasing a stuck pipe or fish. It is also used with spear for fish recovery operations.

Die Collar is an external catching fishing tool. It has a taper hardened teeth inside. Die Collar can have a plain end or lipped guide at bottom. It is run on the fishing string to the top of fish. After tagging the fish, the string is picked up couple of feet and is rotated slowly while lowering the string for Die Collar to swallow the fish and cut engaging threads on the body of the fish.

Fishing Jars are the jars that are used in fishing assemble. Fishing Jars are designed to provide upward blows only and converts energy stored in the stretched drill pipe into impact force. Impact force can be varied by varying the pipe stretch.

Grapple control is a ring with a control finger sticking upward. Once the grapple is installed in the bowl, grapple control is installed below it to keep the grapple securely in its place.

Guide is the lower part of Overshot assembly that directs the top of the fish from the wall to the centre of the tool. Guide is run below the overshot assembly. With string rotation, it scoops the fish to the centre of the hole and helps the grapple in overshot swallow the top to engage and retrieve it.

Impression Block is a tool designed to determine configuration of top of fish. It has lead insert at the bottom of a steel housing. Impression block is run on the lower end of the fishing string. Once reaching to top of fish, weight is set straight down to get an impression of the top of fish on soft lead insert. Studying the impression can provide vital clues about the condition of the fish and help in devising appropriate fishing strategy.

Intensifier, Accelerator or Booster are different names of the tool that is used in conjunction with jar to intensify or accelerate the jarring action. A good compressible fluid and an effective sealing assembly makes the intensifying action possible. It acts like a hydraulic spring that stores energy when put under strain and releases it as the strain is removed. It becomes a very useful tool in shallow intervals where the drill string length is not much.

Jar is used in the string for generating heavy blows and thus helping in releasing stuck pipes. Jars can be classified as Fishing Jar or Drilling Jar. They can also be classified based on operating mechanism as Mechanical or Hydraulic Jars. The mechanism inside jar allows to build up high energy level in the string by way of stretch or slack off weight and makes it release suddenly to create heavy blow.

Mill Guide is a guide with a milling end at the bottom. It is used for catching the fish with badly damaged fish top. It helps in trimming the burr off the top of fish so that it can enter the overshot.

Overshot is a fishing tool for catching the fish externally. Most overshots have primarily three parts. Top sub, bowl and guide. Top sub has connection for the running string. Bowl houses packer, spiral grapple and spiral grapple control. Guide directs the tool on top of fish. Packer is a rubber ring.

As the overshot moves down over the fish, the rubber provides a sealing around fish making it possible to pump drilling fluid down the fish and to circulate it under pressure outside of the stuck fish. Bowl has tapered helical spiral on the inside. Grapple has identical tapered helical spiral on the outside.

Grapple control keeps the grapple into its place. The tool is slowly rotated close to top of fish. As the guide washes over the top of the fish and brings it inside the overshot, the top of the fish is swallowed by the grapple. A slow upward pull tends to move the grapple down. The helical wedges on the inside of the bowl make the grapple to contract and grip the fish tightly.

If the size of the hole is much greater than the fish size, there is a possibility that a standard guide may pass the top of the fish without guiding it to the centre of the overshot. In that case running an oversize guide has greater chances of success in catching the fish.

The guide is run below the overshot assembly. With string rotation, it scoops the fish to the centre of the hole and helps the grapple in overshot swallow the top to engage and retrieve it.

Spear is used for internally catching the tubular fish. Spear has a mandrel, grapple, release ring and nut. The mandrel has a tapered helix. Grapple has a matching surface. Turing left moves the mandrel down and places the grapple in engaged position. Grapple expands due to helical wedge surface on the mandrel and grips the fish from inside. For releasing, the spear is bumped down and turned to the right. This tends to move the grapple down and place it in release position.

Spiral grapple has a helical spring type shape. It is installed into an Overshot Bowl. It has wickers on the inside to catch the fish and tapered helical spirals on the outside that match with the helical spiral on the inside of the Bowl. Spear grapple is used for swallowing and catching the fish from outside.

Taper tap is an internal catching fishing tool. It has a simple taper mandrel with hardened teeth on it. It is used in situations where there isn't enough annular clearance to catch the fish externally. The tap is run inside the fish top. Slow rotation while lowering the string cuts threads inside the fish body and helps in engaging it to the tap.

Wall Hook Guide is also used if the hole size is much larger than the size of the fish. It has a long opening on the side. The longer opening helps in bringing the fish to the centre of the tool even if guide passes alongside the top of the fish.