MODULE 1- COMPLETIONS PROGRAMS, WELLHEADS AND TUBULARS

Question 1

What are 4 uses of casing?

Answer 1

1. to prevent hole collapse
2. prevent fresh water contamination
3. prevent fluid migration between formations
4. to selectively produce certain zones

Question 2

What 5 factors need to be considered when selecting casing and why?

Answer 2

1. Burst
   must be able to withstand pressure of a potential fracing job.
2. Corrosion
   must be designed to encounter corrosive reaction including CO2, H2S, etc
3. Drift
   the max allowable size for tools or other strings to be run through the casing.
4. Temperature
   must be able to withstand the high temperature encountered during repeatedly loading especially in thermal operations (SAGD, steam injections, etc)
5. Abrasion/erosion
   must withstand the erosion limits of proppant

Question 3

How is casing described?

Answer 3

according to OD, weight and grade of steel.

Question 4

casing diameters range from what size to what size?

Answer 4

114.1mm(4.5in) to 508mm(20”)

Question 5

the weight and grades of casing steel selected is based on what?

Answer 5

expected pressure in the well and corrosion requirements

Question 6

what are the 3 loads experienced on casing and when do they occur?

Answer 6

1. Tension- encountered most commonly during the running of the casing
2. Burst- internal pressure caused during drilling, completions or productions
3. Collapse- external pressure caused by drawdown, mechanical loads and zone pressures.

Question 7

why are tubing connections so important?

Answer 7

they determine the strength and sealing ability on the casing

Question 8

The sealing ability is further supplemented by using what?

Answer 8

pipe dope

premium connections feature metal or elastomers seals for additional sealing power.

Question 9

what do the following abbreviations stand for?
STC
LTC

Answer 9

short threaded and coupling

long threaded and coupling

Question 10

what does a thread labelled eight round mean?

Answer 10

that there are 8 threads per inch

Question 11

When is an EUE connections used?

Answer 11

when the thicker (larger outside diameter) sections is left at the end of the pipe so that threads can be cut without making the wall thickness of the pipe thinner than the body.

Question 12

What is the result of using an EUE connection?

Answer 12

stronger connection with full drift.

Can cause problems due to larger OD, getting stuck in hole

Question 13

What is an NUE?

Answer 13

opposite of an EUE. Connection allows for both full drift on the inside of the pipe and a smooth outside for ease of running. weaker connection than EUE

Question 14

where does casing failure most commonly occur?

Answer 14

connections between joints. ensure proper torque!!

Question 15

What are the 2 types of tubing?

Answer 15

1. Conventional (jointed)

2. Coiled tubing

Question 16

MAWP?

Answer 16

maximum allowable working pressure

Question 17

What 2 main criteria must fluids used in completions or workover satisfy?

Answer 17

1. Maintain control of the well

2. Not be damaging to the formation

Question 18

What are 6 example of workover fluids?

Answer 18

1. Nitrogen gas
2. Methyl Alcohol
3. Light HC’s (diesel, kerosene, gas)
4. Brines (seawater, NaCl, Kcl)
5. Gasoline
6. Aqueous foams

Question 19

all water must be treated prior to reinjection into the well. T or F?

Answer 19

True

Question 20

Why do produced waters need to be treated prior to reinjected?

Answer 20

HC contamination
scale potential
suspended solids
corrosion products

fresh water may have suspended solids and bacterial problems and can cause welling in some shale in the rock.

Question 21

Soluble salts can be added to suitable water sources to produce brines up to?

Answer 21

1900 kg/m3

Question 22

Heavier weight brines are?

Answer 22

more expensive
pose an environmental concern
more likely to cause errosion

Question 23

Wellheads are designed to meet API standards that define pressure rating and sizes for all flanged connections. What do the following specs cover?
API Spec 6A
API Spec 11IW
API Spec 17D

Answer 23

6A- wellhead and Christmas tree equipement
11IW- independent wellhead equipment
17D- subsea wellhead and Christmas tree equipment

Question 24

4 main components of a wellhead?

Answer 24

1. Wellhead Flange (casing head)
2. Casing spool
3. Tubing Head
4. Christmas tree valve assembly

Question 25

describe the casing head

Answer 25

• outermost cemented casing string
• fitted with a slip type or threaded casing head
• flange used to support BOP
• communication with annulus is possible with a port on the side of the head

Question 26

describe the casing spool

Answer 26

• used for each casing string beyond what is attached to the wellhead flange
• flange at each end and the diameter, bolt pattern and seal assembly of these flanges are a function of size of flange and API pressure rating

Question 27

Describe tubing head

Answer 27

• If tubing used, it is also hung and isolated in a tubing spool
• Pup joints used to bring the tubing to proper heights to be hung

Question 28

Describe Christmas tree valve assembly

Answer 28

sits of top of the uppermost tubing or casing spool and hold valves used in well operation

• main surface control is the master valve (fully opens)
• immediately above the master with be another spool with the wing valves (usually 2) in a T configuration (allows for repairs to flowline or chokes)
• Above wing valves can be a swabbing valve(used to open the well to entry by a tool string)

Question 29

When specifying wellhead components, its generally recommended that?

Answer 29

they all have the same pressure rating

Question 30

most common wellheads you can order?

Answer 30

2000
3000
5000
10000
15000psi

Question 31

It is common in recompletion operations to find that a wellhead assembly can not withstand fracturing pressure. In this case you can opt to run a?

Answer 31

treesaver tool (string inside the wellhead to seal it off from pressured during fracturing)