MWD muleshoes and muleshoe components

Muleshoe is used in UBHO. Muleshoe assembly: composed of muleshoe body, main orifice, and key, etc. for support of the equipment and production of mud pressure pulse;

The muleshoe works by having a protruding key, which catches the helical edge on the helix end and orients the tool to a fixed location as it seats. The key is in line with the scribe on the mud motor and bolted through the wall of the UBHO sub with 2 set screws to orient and lock the muleshoe in place.

The muleshoe also contains the main orifice into which the pulser main signal poppet projects into to create the actual pressure pulse. There are many different sizes of orifices and they may be changed out by removing the muleshoe from the UBHO sub, removing the snap-ring, and sliding the orifice out of the bottom of the muleshoe. A new snap ring should be used whenever the orifice is re-seated and all o-rings should be replaced. The amount of the flow will dictate the size of the main orifice.

Installation of the muleshoe

(1) Mount the selected main orifice into the muleshoe, and fasten screws;

(2) Clean the inside wall of the UBHO with cotton yarn, and apply certain amount of lubricating oil (such as engine oil);

(3) Remove the overhead screw from the UBHO, and insert a screw driver or a metallic bar;

(4) Coat the four O-rings on the outside wall of the muleshoe with silicon grease or butter, and use muleshoe installation tool to press the muleshoe with keys into the UBHO;

(5) When the lower end of the muleshoe touches the screw driver, take out the driver, and apply flat screw to protect O-ring against breaking; then, press the muleshoe onto the connector;

(6) Use muleshoe installation tool to turn the muleshoe, to keep the key on the muleshoe and the flat screw on the same line;

(7) Remove the flat screw, fasten the overhead screw, and fix the muleshoe.

Operating steps of changing main orifice of φ95 and φ79 muleshoe

1. Loosen the screw, take the main orifice out of the three wings, and take out the O-rings as well;

2. Eliminate the mud on the sealing face, check the O-rings, change the damaged O-rings, place the O-rings onto the grooves, and coat them with silicon grease;

3. Mount the main orifice of necessary size into the muleshoe through the three wings; note: ① the slope side of the main orifice faces the inclined mouth of the muleshoe; ② do not use too much force, or the O-rings may be damaged.

4. Fasten the screw;

5. Clean and pack the removed main orifice for use next time.

Operating steps of changing main orifice of φ60 muleshoe

1. Take the block ring off with expansion ring clamp, and take out the main orifice and the O-rings one by one;

2. Eliminate the mud on the sealing face, check the O-rings, change the damaged O-rings, place the O-rings onto the grooves, and coat them with silicon grease;

3. Mount the main orifice of necessary size into the muleshoe through the three wings; note: ① the slope side of the main orifice faces the inclined mouth of the muleshoe; ② do not use too much force, or the O-rings may be damaged.

4. Mount the block ring into the groove with expansion ring clamp. Clean and pack the removed main orifice for use next time.