Rotary drilling or functions

 Rotary drilling

After the well site has been carefully

prepared to meet environmental health

and safety standards drilling can begin

this is an intricate operation requiring

a well-planned infrastructure a variety

of processes an expert well trained

specialists are used to bring natural

gas to the surface

Chesapeake works with these experts

during every aspect of the project while

strictly adhering to all individual

state regulations during the drilling

process the rig is in constant operation

24 hours a day seven days a week for

approximately 21 to 28 days as an added

precaution in some areas a protective

mat covers two-thirds of the pad site

utilizing heavy-duty industrial-strength

drill bits

a typical well is drilled in several

stages starting with a large diameter

drill bit and then successively smaller

drill bits as the drilling is advanced

after drilling each portion of the well

nested steel protective casing is

cemented into place this will protect

groundwater and maintain the integrity

of the well initially and prior to

moving in the drilling rig a large

diameter hole is drilled for the first

50 to 80 feet conductor casing is then

cemented into place

stabilizing the ground around the

drilling rig and wellhead and isolating

the well from most private water wells

in the Marcella area the freshwater

zone extends to approximately 800 feet

below ground the freshwater zone

consists of porous sandstone and rock

Stratus containing water within the pore

space of the rock Chesapeake utilizes

air drilling until the hole is advanced

to an average of 100 to 200 feet below

the base of the freshwater zone this

provides added protection to the

freshwater zone

a series of compressors and boosters

generate the air that is used to lift

the rock cuttings and fresh water into

steel bins the rock cuttings are then

disposed of within state guidelines and

permits the drilling equipment is

retracted to the surface and stored for

the second stage of drilling to protect

the integrity of the hole and to protect

the surrounding deep freshwater zone a

second layer of steel casing called

surface casing is installed and cemented

inside the newly drilled hole in

conductor casing cement is pumped down

through the surface casing and up along

the sides of the well to provide a

proper seal this completely isolates the

well from the deepest of private or

municipal water wells a blowout

prev enter is installed after the surface

casing has been cemented the blowout

prev enter is a series of high-pressure

safety valves and seals attached to the

top of the casing to control well

pressure and prevent surface releases

next a small drilling assembly is passed

down through the surface casing at the

bottom of the casing the bit drills

through the float equipment and cement

continuing its journey to the natural

gas target area as deep as 8,000 feet

below the surface the drilling method

employed below the surface casing uses

drilling mud which is a non hazardous

mixture based on bentonite clay or

synthetic thickeners in addition to

lifting the rock cuttings out of the

hole drilling mud also helps to

stabilize the hole cool the drill bit

and control down hole pressure a few

hundred feet above the target shale the

drilling assembly comes to a stop the

entire string is retracted to the

surface to adjust the drilling assembly

and install a special drilling tool this

tool allows Chesapeake to gradually turn

the drill bit until a horizontal plane

is reached the remainder of the well is

drilled in this horizontal plane while

in contact with the gas producing shale

drilling continues horizontally through

the shale at links greater than 4,000

feet from the point where it entered the

formation once drilling is completed

the equipment is retracted to the

surface then a smaller diameter casing

called production casing is installed

throughout the total length of the well

the production casing is cemented and

secured in place by pumping cement down

through the end of the casing depending

on regional geologic conditions the

cement is pumped around the outside

casing wall to approximately 2,500 feet

above the producing shale formation or

to the surface the cement creates a seal

to ensure that formation fluids can only

be produced via the production casing

after each layer of casing is installed

the Wellness pressure tested to ensure

its integrity for continued drilling a

cross-section of the well below surface

reveals several protective layers cement

conductor casing cement surface casing

drilling mud production casing and then

production tubing through which the

produced gas and water will flow seven

layers of protection horizontal drilling

offers many advantages when compared to

vertical drilling since horizontal wells

contact more of the gas producing shale

fewer wells are needed to optimally

develop a gas field multiple wells can

be drilled from the same pad sites for

example development of a 1280 acre tract

of land using conventional vertical

drilling techniques could require as

many as 32 vertical wells with each

having its own pad site however one

multi wall pad site with horizontal

wells can effectively recover the same

natural gas reserves from the 1280 acre

tract of land while reducing the overall

surface disturbance by 90%

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