Term
| What has caused an increase in efficiency and success rate for drilling for natural gas wells? |
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Definition
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Term
| For natural gas, what does the exact placement of the drill site depend on? |
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Definition
• Nature of the potential formation to be drilled
• Characteristics of the subsurface geology
• Depth and size of the target deposit |
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Term
| What are the necessary steps to ensure that they can legally drill for natural gas in that area? |
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Definition
• Securing permits for drilling operations
• Establishing a legal arrangement
• Design for gathering lines that will connect the well to the pipeline |
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Term
| When is the well determined a "dry well"? |
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Definition
if the exploration team was
incorrect in its estimation of the existence of marketable quantity of
natural gas and the production hence does not proceed |
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Term
| What is percussion drilling? |
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Definition
aka "cable tool drilling" raising and dropping
a heavy metal bit into the ground, effectively punching a hole down
through the earth
• It is used for shallow, low pressure formations |
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Term
| What are two main types of onshore drilling? |
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Definition
1. Percusiion or "cable tool drilling"
2. Rotary drilling |
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Term
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Definition
It consists of a sharp, rotating metal bit used to drill
through the earth’s crust
• It is used for deeper wells that may be under high downhole pressure |
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Term
| Is cable tool drilling still in use? |
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Definition
yes, in some of the shallow wells in the Appalachian Basin, although rotary drilling has taken over the bulk of modern drilling activities; Water is used to combine with all of the drill cuttings and is
periodically bailed out of the well when this ‘mud’ interferes with the
effectiveness of the drill bit |
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Term
| What was the "springpole" technique used in the early 1800s? |
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Definition
consisted of a flexible
pole anchored at one end, and laying across a fulcrum much like a
diving board |
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Term
| Who are the first drillers to use a casing in their well? |
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Definition
| David and Joseph Ruffner 1806 springpole techniques |
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Term
| Did Colonel Drake use steel casing to reinforce the natural gas well? |
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Definition
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Term
| What increased the efficiency and range of percussion drilling? |
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Definition
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Term
| What is the deepest known well dug with cable tool drilling? |
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Definition
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Term
| Why must an artificial drilling platform be constructed for offshore drilling? |
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Definition
the sea floor can sometimes be thousands of feet
below sea level |
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Term
| When did offshore drilling begin? |
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Definition
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Term
| When was the first offshore well built? |
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Definition
| After WWII in the gulf of mexico 1947 |
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Term
| The artificial platform that has to be created for offshore drilling depends on what? |
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Definition
• The characteristics of the well to be drilled
• And how far underwater the drilling target is |
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Term
| What is one of the most important pieces of equipment for offshore drilling? |
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Definition
| the subsea drilling template; remsembles a cookie cutter and consists of an open steel box with multiple holes in it; it is placed over the well site, usually lowered into the exact poistion required using satellite and GPS technology |
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Term
| What does the blowout preventer on the sea floor do?? |
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Definition
| prevents any oil or gas from seeping out into the water |
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Term
| What and where is the marine riser? |
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Definition
extends from the sea floor to the
drilling platform above the blowout preventer
• It is designed to house the drill bit and drillstring and be flexible
enough to deal with the movement of the drilling platform |
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Term
| What are the two types of offshore drilling rigs? |
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Definition
• Those that can be moved from place to place, allowing for drilling in
multiple locations. These are used for exploratory purposes and are
much cheaper to use
• Those that are permanently placed and are built once large deposits
of hydrocarbons have been found |
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Term
| What are drilling barges mainly used for? |
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Definition
They are used mostly for inland, shallow water drilling. It takes place
in lakes, swamps, rivers and canals |
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Term
| What are drilling barges? |
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Definition
They are large floating platforms and have to be towed tugboat from; They are not able to withstand the water movement experienced in
large open water situations
location to location |
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Term
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Definition
They are similar to drilling barges. The four ‘legs’ are lowered until
they rest on the sea bottom once a jack up rig is brought to the
drilling site |
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Term
| What are jack-up rigs suitable for? |
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Definition
• They are suitable for shallower waters as extending the legs deep
down would be impractical
• These are safer to operate than drilling barges |
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Term
| What are submersible rigs? |
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Definition
• These are also suitable for shallow waters
• They consist of platforms with two hulls positioned on top of one
another
• The upper hull contains the living quarters of the crew and the actual
drilling platform
• The lower hull works like the outer hull in a submarine and is filled
with air making the entire rig buoyant
• This has an advantage of mobility in water |
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Term
| What are semisubmersible rigs? |
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Definition
• These are the most common type of offshore drilling rigs combining
the advantages of submersible rigs with the ability to drill in deep
water
• They work on the same principle of ‘inflating’ and ‘deflating’ of the
lower hull
• The main difference is that when the air is left out of the lower hull,
the rig does not submerge to the sea floor
• They are held in place by huge anchors, each weighing upwards of
ten tons |
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Term
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Definition
• These are ships designed to carry out drilling operations
• They are specially designed to carry drilling platforms out to deep-sea
locations
• A drillship will have a drilling platform and derrick located on the
middle of its deck. They also contain a hole (‘moonpool’), extending
right through the ship down through the hull
• They are used to drill in very deep water which can be turbulent
• They use ‘dynamic positioning systems’ and are equipped with
electric motors which are capable of propelling the ship in any
direction |
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Term
| A fixed platform for offshore drilling is usually no more than what? |
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Definition
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Term
| Where are most permanent offshore rigs constructeD? |
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Definition
constructed near land and are
taken out to the drilling location once the components of the rig are
completed
• The construction can sometimes can take place as the rig is being
transported to its intended destination |
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Term
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Definition
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Term
| What are fixed platforms? |
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Definition
• It is possible to physically attach a platform on the sea floor in
shallower water
• Here, the legs are constructed with concrete or steel, extending
down from the platform and fixed to the seafloor with coils
• There are many designs to make fixed platforms |
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Term
| What are the advantages to fixed platforms? |
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Definition
• The advantages are their stability, and limited exposure to
movement due to wind and water forces
• They cannot be used in extremely deep water and it is not
economical to build legs that long |
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Term
| What are compliant towers? |
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Definition
They are much like fixed platforms and consist of a narrower tower,
attached to a foundation on the seafloor and extending up to the
platform |
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Term
| What are the benefits of compliant towers? |
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Definition
• It is flexible and this helps it to operate in much deeper water as it
can ‘absorb’ much of the pressure exerted on it by wind and sea
• It is strong enough to withstand hurricane conditions |
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Term
| What are seastar platforms? |
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Definition
• These are like miniature tension leg platforms and consist of a
floating rig, much like the semisubmersible
• They incorporate the tension leg system employed in larger
platforms
• Tension legs are long, hollow tendons that extend from the seafloor
to the floating platform
• They do not allow up or down movement of the platform
• They are typically used for smaller deep-water reservoirs (e.g. in the
Gulf of Mexico) when it is not economical to build a larger platform |
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Term
| What are floating production systems? |
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Definition
• They are essentially semisubmersible drilling rigs, except that they
contain petroleum production equipment as well as drilling
equipment
• They also use floating production systems
• They are kept in place through large, heavy anchors or through
dynamic positioning system used by drillships
• Risers are used for transportation from the wellhead to the
production facilities on the semisubmersible platform. They operate
in water depths of up to 6,000 feet |
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Term
| What are tension leg platforms? |
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Definition
• They are larger versions of the Seastar platform
• The long, flexible legs are attached to the seafloor and run up to the
platform itself
• The legs allow for significant side to side movement (up to 20 feet)
with little vertical movement
• They can operate as deep as 7,000 feet |
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Term
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Definition
• These are located on the sea floor as opposed to the surface
• The petroleum is extracted at the seafloor and then ‘tied-back’ to an
already existing production platform
• It can be drilled by a movable rig and instead of building a production
platform for that well, the transportation can be done by riser or
even undersea pipeline to a nearby production platform
• They are typically at depths of 7,000 feet or more and do not have
the ability to drill, only to extract and transport |
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Term
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Definition
• They are among the largest offshore platforms in use
• They consist of a large cylinder supporting a typical fixed rig platform
and does not extend all the way to the seafloor but is tethered to the
bottom by a series of cables and lines
• It serves to stabilize the platform in the water and allows for
movement to absorb the force of potential hurricanes
• “The first Spat platform in the Gulf of Mexico was installed in
September of 1996. Its cylinder measured 770 feet long and was 70
feet in diameter and the platform operated in 1,930 feet of water” |
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Term
| What are the types of drilling platforms in order of depth in ascending order? |
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Definition
1. Fixed platforms
2. compliant towers
3. seastar platforms
4. floating production systems
5. tension leg platforms
6. subsea system
7. spar platforms |
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