3. Graduation Project 2020 1
Section 01
Oil and Gas well kicks
Kick is a well control problem in which the pressure found within the drilled rock is higher
than the mud hydrostatic pressure acting on the borehole or rock face. When this occurs,
the greater formation pressure has a tendency to force formation fluids into the wellbore.
This forced fluid flow is called a kick. If the flow is successfully controlled, the kick is
considered to have been killed. An uncontrolled kick that increases in severity may result
in what is known as a “blowout.”
Factors affecting kick severity
Several factors affect the severity of a kick. One factor, for example, is the “permeability” of
rock, which is its ability to allow fluid to move through the rock. Another factor affecting kick
severity is “porosity.” Porosity measures the amount of space in the rock containing fluids.
A rock with high permeability and high porosity has greater potential for a severe kick than
a rock with low permeability and low porosity. For example, sandstone is considered to
have greater kick potential than shale, because sandstone has greater permeability and
greater porosity than shale.
Yet another factor affecting kick severity is the “pressure differential” involved. Pressure
differential is the difference between the formation fluid pressure and the mud hydrostatic
pressure. If the formation pressure is much greater than the hydrostatic pressure, a large
negative differential pressure exists. If this negative differential pressure is coupled with
high permeability and high porosity, a severe kick may occur.
Causes of kicks
Kicks occur as a result of formation pressure being greater than mud hydrostatic pressure,
which causes fluids to flow from the formation into the wellbore. In almost all drilling
operations, the operator attempts to maintain a hydrostatic pressure greater than formation
pressure and, thus, prevent kicks; however, on occasion the formation will exceed the
mud pressure and a kick will occur. Reasons for this imbalance explain the key causes
of kicks:
• Insufficient mud weight.
• Improper hole fill-up during trips.
• Swabbing.
• Cut mud.
• Lost circulation.
4. 2 Graduation Project 2020
Well Control Simulator
Warning signs of kicks
Warning signs and possible kick indicators can be observed at the surface. Each crew
member has the responsibility to recognize and interpret these signs and take proper action.
All signs do not positively identify a kick; some merely warn of potential kick situations.
Key warning signs to watch for include the following:
• Flow rate increase
• Pit volume increase
• Flowing well with pumps off
• Pump pressure decrease and pump stroke increase
• Improper hole fill-up on trips
• String weight change
• Drilling break
• Cut mud weight
Kick indicators
What are the indicators that the well is flowing?
1. Increase in Flow Rate
2. Increase in Pit Level
3. Drop in pump pressure
What Action Should Be Taken?
1. Flow Check(Drilling/Tripping)
2. Shut the well
3. Circulate Bottoms Up
4. Raise Mud Weight
5. Graduation Project 2020 3
Section 01
Kill sheet calculations for vertical wells
Kill sheet calculations it’s very important Sheet when we decided to kill the well.
It used to read the well by determine well parameters/features.
Such as
– Volume, strokes & time Calculations ….why?
– Maximum Mud Weight of Drilling Fluid….why?
– MAASP….why?
– Kill Mud Weight K.M.W. …why?
– Initial/Final Circulating Pressure (ICP,FCP) …. Why?
– Draw Step Down Chart….why?
Sequence of kill sheet solution
1. Draw Your Own well profile case. includes The main features. (Vertical, Deviated,
Horizontal)
2. Location of each Tubular inside Hole.
3. Put the Data on the profile.
4. Start the calculations
Steps for vertical well
First of all we’ve to determine 3 things :-
A- Drill pipe Length = MD - (DC Length + HWDP Length)
B- Open hole Length= MD – Cased hole
C- Drill Collar length
If total length of Drill Collar and HWDP < Open hole section,
So all DC and HWDP in Open hole section.
And then the remaining O.H Section will have DP.
But if total length of Drill Collar and HWDP > Open hole section.
So there will be a part of HWDP or both (HWDP and DC) in
Open hole section.
6. 4 Graduation Project 2020
Well Control Simulator
1- Strokes from Surface to bit:-
Calculate Drill string Volume (DP/HWDP/DC)
For Drill pipe:-
=Drill pipe Capacity bbl./ft. x length of drill pipe
For Heavy walled Drill pipe:-
=HWDP Cap. Bbl./ft. x length of HWDP
For Drill Collar
=DC Cap. Bbl./ft. x length of DC
Then add all of them to obtain Total Volume inside String
No of Strokes =Total Volume (bbl.) / POP (bbl./stroke)
Time=No. of strokes / SPM (min)
2- Strokes from bit to shoe :- assuming the case when open hole > length
of HWDP+DC
Calculate open hole to (DP/HWDP/DC) Volume
For Open Hole / Drill Collar:-
=(O.H /Drill Collar) Capacity bbl./ft. x length of Drill Collar
For Open Hole / Heavy walled Drill pipe:-
=(O.H/ HWDP) Cap. Bbl./ft. x length of HWDP
For Open Hole / Drill Pipe:-
=(O.H/DP) Cap. Bbl./ft. x length of DP
Then add all of them to obtain Total Volume
No of Strokes =Total Volume (bbl.) / POP (bbl./stroke)
Time= No of strokes / SPM. (min)
3- Strokes from bit to surface:-
Calculate cased hole to DP Volume:-
=Drill pipe Capacity bbl./ft. x length cased hole ft.
No of Strokes =Total Volume (bbl.) / POP (bbl./stroke)
So Strokes from Bit to surface = strokes from bit to shoe +strokes from shoe to surface
Time = No. of strokes/ SPM (min)
7. Graduation Project 2020 5
Section 01
4- Time for Complete Circulation=time from surface to bit + time from bit to
surface + surface line time
5- Kill Mud Weight:-
Kill Mud Weight = SIDPP/(0.052xTVD) + Current M.wt.
6- Initial Circulating Pressure:-
ICP = DYNAMIC PRESSURE LOSS + SIDPP
7- Final Circulating Pressure:-
FCP= DYNAMIC PRESSURE LOSS x (K.M.W)/(Current M.Wt )
8- MAASP with current mud weight:-
Maximum Allowable M.WT (ppg) =( (LOT Pressure)/(0.052xShoe TVD )+Lot M.wt)
MAASP (psi) = (Maximum M.wt. - Current M.wt.)x0.052xShoe TVD
9- MAASP after circulation of kill mud:-
= Maximum M.wt. – K.M.W x 0.052 x Shoe TVD
10- Step Down Chart
Pressure Drop=(ICP-FCP)x100 / String Strokes
Example for step Down chart
8. 6 Graduation Project 2020
Well Control Simulator
Wait and Weight Method
The “Wait and Weight” is sometimes referred to as the ‘Engineers Method’ or the ‘One
Circulation Method’. It does, at least in theory, kill the well in one circulation.
Once the well is shut in and pressures stabilised, the shut in drill pipe pressure is used
to calculate the kill mud weight. Mud of the required weight is made up in the mud pits.
When ready, kill mud is pumped down the drill pipe. At commencement, enough drill
pipe pressure must be held to circulate the mud, plus a reserve equivalent to the original
shut in drill pipe pressure. This total steadily decreases as the mud goes down to the bit,
until with kill mud at the bit, the required pressure is simply that needed to pump kill mud
around the well.
The choke is adjusted to reduce drill pipe pressure while kill mud is pumped down the
string. With kill mud at the bit, the static head of mud in the drill pipe balances formation
pressure. For the remainder of the circulation, as the influx is pumped to the surface,
followed by drill pipe contents and the kill mud, the drill pipe pressure is held at the final
circulating pressure by choke adjustment.
Advantages of the Wait and Weight Method
• Lowest wellbore pressures, and lowest surface pressures - this means less
equipment stress.
• Minimum ‘on-choke’ circulating time - less chance of washing out the choke.
Disadvantages of the Wait and Weight Method
• Considerable waiting time (while weighting up) - gas migration.
• If large increases in mud weight required, this is difficult to do uniformly in one stage.
Steps of the weight and weight method for well control are as follow:
• Shut in the well.
• Allow pressure to stabilize and record stabilized shut in casing pressure, initial shut
in drill pipe pressure, and pit gain. If you have a float in the drill string, you must bump
the float in order to see the shut-in drill pipe pressure
• Perform well control calculations
• Raise mud weight in the system to required kill mud weight
• Establish circulation to required kill rate by holding casing pressure constant
• Follow drill pipe schedule until kill weight mud to the bit.
• Hold drill pipe pressure constant once kill weight mud out of the bit until complete
circulation.
• Check mud weight out and ensure that mud weight out is equal to kill mud weight.
• Shut down and flow check to confirm if a well is static
• Circulate and condition mud if required
9. Graduation Project 2020 7
Section 01
Well Control Simulator as a web application
We developed a simulator for kill sheet calculations and wait & weight method as a website
application using different web programming languages including mainly JavaScript, PHP,
and HTML.
Our simulator can:
• Make Kill sheet calculations
• Print the kill sheet
• Simulate wait & weight method from A to Z
Wait & weight simulation process description:
• You turn on the pump by increasing pump spm gradually 5 spm by 5 spm
• While you are increasing pump spm, you must keep SICP slightly above its recorded
value in the kill sheet
• This can be done by opening and closing choke buttons
• By this way you can circulate the kick safely and put well under control
Here are some screenshots of our simulator:
14. 12 Graduation Project 2020
Well Control Simulator
Kindly Try our wellcontrol simulator online through this link:
http://ahmedeltabakh.epizy.com/wellcontrolsimulator/index.php
16. 14 Graduation Project 2020
IPR Plotter
IPR Plotter (iOS App)
Description:
• Our App requires some inputs to draw IPR for two types of reservoir:
1. Oil Reservoir
2. Gas Reservoir
• Our App is calculated and draw IPR curve based on four methods (two method for
each reservoir type)
• We used Vogel Method and Standing Method for oil reservoir
• We used Backpressure method and Forchiemer method for gas reservoir
Our App include predication for Future IPR in Gas Reservoir
Screenshots of App:
Screenshots of Code:
1. Backpressure Method
2. Forchiemer method