(a) The oil and gas exploration methods has several steps in order to scope down from large concession area to the very promising locations to found oil and gas accumulation. The exploration activities are conducted to the geological study purposes to find the best location to drill the exploration well to prove the existing of hydrocarbon. The exploration activities are listed below from the very beginning to the end.1. Geological study study the type/ structure of formation by using the existing geological data such as outcrop and past exploration wells in nearby area. This is to pick up the interesting area where the components of hydrocarbon accumulation are existing such as source rock, migration, trap and reservoir rock.2. Gravitational survey to gather more information about the formation structure by measuring the gravitational anomaly over the large area. The information will roughly describe what the formation look like underground.3. Magnetic survey to measure the magnetic field anomaly over smaller area4. Seismic survey to measure the physical properties of rock layers by generating the acoustic sound generated on surface and measure the travel time of the sound wave when they returned to surface. This reveals the accurate details for the structure of formation. And, it is the most accurate way to see the structure of formation by mean of indirect measurement.5. Drill the exploration well to prove the existing of oil and gas reservoir(b) Round trip is the jargon which refers to the tripping in and tripping out the drill pipe.

(a) There are several functions of the drilling mud system such as Control the pressure prevent influx Well stability prevent swelling of reactive shale Remove and transport cutting Lubricating and cooling the drill string Transmit torque to down hole equipment MWD/ mud motor(b)

(c)

(a)

(b)

(a)In the Horizontal strata, the soft formation is much easier to drill and wash out by drilling mud than the hard formation. Therefore, the hard formation will align the bottom hole assembly to different direction from the previous drilled formation

(b)When the dip angle is less than 45 degree, the bit tend to drill the different size of cutting from the upside and downside of the well. The downside of the well will perform like the small wedge which deviate the BHA direction to the up dip direction. Also, if dip angle is less than 45 degree, the drilled plane will be in the perpendicular direction to the bedding plan because formation is the perpendicular direction is easier to drill. Therefore, the bit will drill perpendicular to the bedding plane.(c) On another hand, when the dip angle is more than 45 degree, the direction tend to be follow the formation plane (bedding plane).

(b)The slick BHA is rarely used in the directional drilling; however one of its applications is when want to make the kick-off point from the main hole.The pendulum BHA uses to drill directional well in the rotary drilling system. It consists of drilling collar to provide sufficient weight and the stabilizers to provide the tangential point. The direction of the drilling depends on the combination of weight of drill collar and the position of stabilizer on the BHA.

(c)The directional drilling is used because there are some limitation about the location, formation and operations. The main reasons why it may be used areAvoid the problematic formations such as salt dome.1. Drilling multiple wells from offshore platform2. Drill sidetrack well from the mother well3. Drill deviated or horizontal well4. Drill the relief well for well control purpose

(a) Rock bit or tri-cone bit is the bit made of steel. They are available in many sizes, teeth length and matrix body design to be suitable for different formation types. The tri-cone bit is usually picked up to drilling the soft-medium formation because it provides good penetration rate and lower cost per foot. (b) TCI bit (tungsten Carbine Insert) is the bit whose the teeth made of tungsten carbide which is very hard strong. Therefore, this type of bit will be use to drill in hard formation such as dolomite and chert.(c) PDC bit (polycrystalline diamond compact) is the bit whose teeth made of the artificial diamond made in laboratory. The PDC bit cutting action is mainly from the shearing action. It is very effective to drill in soft formation such as shale and even more benefit when used in the combination with oil based mud system.(d) Natural diamond bit the teeth of bit made of natural diamond which is the hardness among all material. It is the special bit used in very hard and abrasive formation where the long run is required.

(b) use the TCI bit or diamond bit

(c ) the blowout preventer is the safety/emergency equipment which is installed at the top of wellhead during drilling operations. It provided the emergency action to shut and isolate the well when the influx was expected and also, it provided the circulating path to circulate in the heavier mud and routed out the influx to flaring. There are three main components in the BOP which are,1. Pipe Ram close for specific size of drill pipe2. Shear Ram- cut the drill pipe by shearing force in case to leave all drilling pipe underground3. Blind Ram close and isolate the well4. Annular preventer provide isolation for various size of pipe