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DRLG 305 > Final Review > Flashcards

Final Review Flashcards

1
Q

name 4 of the 8 reasons for horizontal drilling

A

maximize reservoir exposure, maximize production, intersect natural fractures, SAGD, shale reservoirs (low permeability), gas storage schemes, EOR schemes (water flood), and thin pay zones

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2
Q

why do horizontal wells cost more?

A

more casing, drill pipe wears faster, rig time, directional program (tools, DD, MWD, LWD) top drive rig, more cementing costs, and higher completion costs

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3
Q

what bit is preferred for horizontal wells?

A

roller cones, although PDC’s are more practical (no bearing failure)

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4
Q

what are the 4 areas of benefit using horizontal drilling

A

productivity: increase direct contact w/ reservoir, reduced pressure gradient at well bore, and more linear drainage along well bore
Development: reduced number of wells for max drainage, penetrates natural fractures
heterogeneous reserovirs: penetrate reservoir barriers that impede flow to the well bore
enhanced oil recovery projects: provide more contact for producers and injectors, increase sweep efficiency, etc

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5
Q

why are horizontal wells beneficial in thin reservoirs?

A

the horizontal section does not have to be very long to exceed formation thickness

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6
Q

know some of what info the well operator needs prior to planning the well

A

literally about 50 things to pick from

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7
Q

know the roles of the drilling team and drilling engineer

A

Team: develop well trajectory & profile, well bore length, drilling fluids, casing requirements and program, and evaluation requirements.
Engineer: pick rig, design radius, pick bits,research offsets for borehole stability and prepare budgets

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8
Q

what are the 3 types of well profiles

A

long, medium and short

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9
Q

which profile requires the most space to reach 90degrees

A

long

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10
Q

know some of the factors affecting choice of well profile

A

casing program, location of target entry point, surface location & ability to move it, distance between target entry & surface, minimum BUR restrictions, KOP restrictions, hole size & relationship to casing program, pay zone thickness, geological control, formation characteristics, lease restrictions, and completion techniques

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11
Q

what profile does a SAGD well require?

A

Short

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12
Q

be able to calculate the # of stations required to reach 90 given a BUR/30m

A

pretty straightforward, remember first angle is 0, not BUR angle

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13
Q

what limits the length of the horizontal leg

A

torque, drag, WOB, hole size, and hole cleaning

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14
Q

what is a multi lateral well?

A

multiple horizontal wells run through one mother well bore

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15
Q

what are 3 reasons for multilateral wells?

A

stable or declining oil price, environmental concerns, and increasing costs

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16
Q

what are 4 uses for multi lateral wells?

A

shallow or depleted reservoirs, layered reservoirs, fractured reservoirs, and steam soak. (wouldn’t hurt to be able to know how to draw all these)

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17
Q

what are benefits of multi laterals

A

reduced well costs, higher production, less environmental impact, improved economics, increased recoverable reserves, additional fracture development, and heavy oil development

18
Q

know all 6 SPE classifications, & which 2 are the most common?

A

Level 3 & Level 6 are the most common

19
Q

what percentage of a companies Non Productive Time (NPT) does stuck pipe account for?

A

50%

20
Q

downhole problems can be classified 2 ways, what are they?

A

fluid related (poor hole cleaning, differential sticking, and lost circulation) or formation related (salt sections and sloughing shales)

21
Q

what are factors for preventing stuck pipe?

A

good planning, teamwork & communication, safe effective & standardized practises, understanding of downhole conditions, and recognition of early warning signs of stuck pipe

22
Q

what are the 4 key activities associated with stuck pipe?

A

selecting/changing the BHA, drilling, tripping, and running casing

23
Q

how do you prevent stkpp when selecting or changing the BHA

A

optimize JAR placement
accurately gauge worn bits & stabilizers
minimize total wall contact area (spiral collars)

24
Q

how do you prevent stkpp while drilling

A

use lessons learned from previous wells
record & monitor trends
ensure efficient hole cleaning (mud type & rheology, solids content, and flow rate)
regularly sweep with a Hi-Vis or Low-Vis pill
wipertrip
reream tight sections

25
Q

how do you prevent stkpp during tripping

A

prepare for the worst
monitor circulating time & effectiveness of hole cleaning
be prepared for issues (swab, excessive over pull)

26
Q

how do you prevent stkpp while running casing

A

only run casing when you know it’ll reach bottom
select proper run in speeds (minimize surge pressures)
selection & number of centralizers (reduce drag)
optimize mud rheology to suit running of casing & cement
prepare response when encountering excessive drag and solids build up

27
Q

what are the 12 causes of stuck pipe?

A

differential sticking, geo pressurized formation, unconsolidated zone, key seating, reactive formation, drill string vibration, fractured/faulted formation, mobile formation, hole cleaning, borehole geometry, poor cement job, under gauge hole

28
Q

what are 2 early indicators of stuck pipe

A

increased torque and drag

29
Q

what is required in horizontal wells for effective hole cleaning?

A

higher annular velocity and higher viscosity mud

30
Q

what is minimum annular velocity determined by?

A

the cuttings slip velocity (the velocity the cuttings fall through mud)

31
Q

what is cuttings typical slip velocity?

A

15-18 meters/minute

32
Q

what is the assumption using stokes law?

A

perfectly spherical cutting, nu turbulent eddies formed behind particle.

33
Q

what equation should you never use to determine “f” or else Brendon will yell at you

A

equation 4, use Cd, sphericity, and Reynolds number on the chart to find “f”

34
Q

what are 6 of the 12 factors affecting cutting transport?

A

particle shape & size, fluid density, particle density, gravity, viscosity, borehole shape/quality, tubular sizes, inclination, fluid velocity, string rotation, ROP, and mud type

35
Q

understand how cutting accumulation in the well bore act at different inclinations

A

0-10: same as vertical, no buildup
10-30: will settle on low side of hole, form dunes that are picked and moved
30-60: most difficult, between 40-50 is most difficult to clean, cuttings accumulate & slide, can take up 25-30% of borehole diameter
60-90: settling doesn’t get any worse closer to 90, particles don’t slide because there already on bottom

36
Q

what problem can happen when the pumps are shut off between 40-50 degrees

A

cuttings slide down and can slide down annulus and block off the borehole (stuck pipe)

37
Q

what is the purpose of backing off?

A

to remove the string from the stuck portion of the BHA (fish)

38
Q

how does backing off work?

A

select back off point with 80% free pipe in tension & a minimum 80% free in torque, wireline will use a shot charge to loosen the threads, then back the string out of the fish.

39
Q

what are the 3 categories of fishing tools?

A

tools that destroy the fish, grab the outside of the fish, and grab the inside of the fish

40
Q

what are 8 kinds of fishing tools?

A

mills, overshot, junk basket, magnet, taper tap, washover shoe, spears, jars/bumper subs, junk sub, washover pipe

41
Q

what are the 3 types of fishing operations?

A

milling, displacement, and retrieval

42
Q

know how they all work, get other peoples prezies

A

and say please

DRLG 305 (1 decks)

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