Techshore Inspection Services-Kochi-official blog of Techshore Kerala: TECHSHORE INSPECTION SERVICES : BOTTOM HOLE ASSEMBLY (BHA)

BHA consist of Drill Bit which is used to drill up the formation, Drill collar of different diameter which is used to give weight to the drill bit, Heavy Weight Drill Pipe which is used to give transition between drill collar and drill pipe, Stabilizers which is used to give stability to the drilled section and drill pipe which is for increasing drilling depth downwards .The BHA also consist of other equipments like down hole motor,Meassuring While Drilling(MWD) tool, Logging While Drilling(LWD) tool and Rotary Steerable System.

DRILL PIPE (DP)

DRILL PIPE is connected below Kelly sever sub. They are thick walled hollow metal pipe that is used in drilling rigs. The drilling hole depth is increased by adding drilling pipe. They are designed hollow to pump mud through the drill pipe for efficient drilling purpose. The drill pipe used in drilling rigs are of S, G, E grades. The drill pipe is of size 5” and 3 ½ “sizes of weight 19.5 ppf and13.3 ppf respectively. A single drill pipe is of 9.5 meter (approx).

HEAVY WEIGHT DRILL PIPE (HWDP)

HWDP is connected below drill pipe to provide a transaction between drill pipe and drill collar. The main purpose of HWDP is to reduce number of fatigue failures seen directly above the BHA.The secondary purpose of HWDP is to give additional weight to the drilling bit.HWDP is used generally in deviated well where too many drill collars hamper drilling operation.HWDP is of 5” and 3 ½” sizes having weight of50 ppf and 27 ppf respectively.

DRILL COLLAR (DC)

DC is metal steel tubular cross section used to apply more weight to the drill bit. The drill collar is also hollow thick walled pipe. The outer body of DC has circular grooves for the easy movement of return mud and formation cuttings to upwards. All the compressive loading is taken by the DC and make drill pipe free from all tensions.DC is of 9”, 8 ½”, 6 ½”, 4 ¾” sizes having weight of 217 ppf, 161 ppf, 92 ppf, 47 ppf respectively.

STABILIZERS

Stabilizers are device used for stabilizing the drilled bare hole. The other purpose of stabilizer is used to centralize the drill string inside the bore hole. Stabilizers are of two types Near BIT Stabilizer (NBS) and String Stabilizer (SS).As the name indicates NBS is connected nearer to the drill bit. It consist of box at it two ends for tight connection.SS is placed positioned between DC, IT consist of box at one end and pin at other end.

X-OVER

It is also hollow thick walled metallic tubular section of 1.5 meter (approx).The main purpose of X-over is to serve as a connector between box and pin of different size.

BIT SUB

BIT SUB is small lengthen hollow metallic pipe connect between drill bit and NBS.If there any sudden shock or torque arise bit sub absorb it and Prevent other BHA‘s from damage.

DRILL BIT

Drill BIT is used to break up the rock formation and make drilling more effective. Depending upon the formation drill bit is used.Drill bit is mainly of two types Rolling Cutter Bit and Fixed cutter Bit.

The rolling cutter bit provides a crushing motion as the drill bill can rotate itself.The bit cones roll along the bottom of hole in a circular manner, as the drill string rotates. This bit is used for drilling where the formation is very thick.

Fixed cutter bit is used for giving a scrapping motion to the formation. This bit does not consist of rolling parts as they are used for shearing purpose only. Fixed cutter bit is used where formation to be drilled is less thick.

Monday, March 27, 2017

TECHSHORE INSPECTION SERVICES : BOTTOM HOLE ASSEMBLY (BHA)