bo 018 drilling operations

7/28/2019 BO 018 Drilling Operations

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Drilling Operations

Agip KCO Training Special Project SP 2 Basic Oil and Gas in Explorationand Production Activities BO-018-GIA-001-E

Drilling operations


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Drilling operations

a) Overview of drilling plants, equipment, components

b) Overview of drilling fluids: muds, cements & chemicals

c) Outline of drilling techniques. Innovative vs traditional

drilling. On-shore & off-shore drilling

d) Blowout prevention and control

e) Drilling site organisation

f) Cutting disposal: problems and solutions


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The main goal is to reach the target!

Original Well Path

Vertical wellDirectional well

Reservoir

Whats the purpose of well drilling?


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Sand

Shale

Limestone

30"

20"

13 3/8"

9 5/8"

7"

0 m

2000 m

4000 m

6000 m

Sand + shale

Reservoir

How should you drill a well?


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ReservoirReservoir

Whats the purpose of well drilling?


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Drilling Rigs


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Type of rigs


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Drilling Rigs


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Land rigs

Floating rigsSwamp rigs

Stationary platforms

Drilling Rigs


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Land Rig


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(Dynamic positioning)

Drilling ship

Tension legs(Anchored) drillingshipSemi sub rig

Jack up rigStationary Platform

Maximum operational depth

100 m

1000 m

3000 m

200 m

Off-shore Rigs


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Off-shore Rigs


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Inland Drilling Barge


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Inland Drilling Barge


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Posted Barge


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Non Posted Barge

S b ibl Ri


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Submersible Rig

Pl tf R i


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Platform Rgis

Pl tf Ri


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Platform Rigs

Pl tf Ri


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Platform Rigs

T d i


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Tender rig type

T d U it


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Tender Unit

T d U it T


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Tender Units Type

Tender Units Type


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Tender Units Type

Stationary Platform


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Stationary Platform

Off shore Rigs


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100 m

0 m

Surface Wellhead

Jack up rig

Off-shore Rigs

Jack up rig


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Jack-up rig

Jack up rig


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In legs-out position

Jack-up rig

Off-shore Rigs


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Subsea Wellhead

Semisub rig

Off-shore Rigs

Semi sub rig


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Semi-sub rig

Off-shore Rigs


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(Anchored)

Drilling shipSubsea Wellhead

Off-shore Rigs

Off shore Rigs


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(Dynamic positioning)

Drilling ship

Subsea Wellhead

Off-shore Rigs

Drilling Ship


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Ultra Deep Water Drillship SAIPEM 10000

Drilling Ship

Off-shore Rigs


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Max Water Depth

3000

+

SHELL

SHELL

SHELL

ELF

TEXACO

PETROBRASSHELL

SHELL

EXXON

EXXON

EXXON

HUMBLE OIL

PETROBRAS

SHELL

PETROBRAS

SHELL

2500

Expl. Prod.

Subsea Tree TLP

TotalFinaElf

SHELL

2000

1500

500

1000

0

1950 1960 1980 1990 2000 2001

Off shore Rigs


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Rig Equipment

Hoisting System


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Ground Floor

N

O

Cellar

A A

G

B

CF

D

E

HI

M

L

A)Asta motrice

B)TagliamobileC)Gancio

D)Piattaforma del pontistaE)Taglia fissa

F) Water table

G)Argano

H)Baracca del perforatore

I )Testina d'iniezioneL) Rotary hose

M)Aste di perforazione

N) Tool joint

O)Torre

A)Top Drive

B)Mobile pulley blockC)Hook

D)Derrickman Floor

E)Fixed pulley blockF)

G)

Winch

H)

Drillers cabin

I )

Injection head

J acket hose

M)

Drill pipes

O)

Mast

Blow Out Preventer (BOP)

Wellhead

L )

N)

g y

Rotary system


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Rotary system

Old Rotary System


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Kelly

Section

Bushing

Travelling block

Hook

Injection Head

RotaryHose

Drilling line

Kelly

Hoisting EquipmentRotary Equipment

The old rotary system comprises: kelly kelly bushing rotary table

injection head hook travelling block

y y


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Drilling Gear and Wellheads

Drilling String


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Drill Pipes

Heavy Weight (intermediate stiffness pipes)

X-over

Drill Collars (Heavy weight pipes)

J ar (Shock tool to be activated while drilling string stuck)

Drill Collars

Stabilizer (for hole reaming)

Drill Collar

Shock absorber (vibrations damper)

Stabilizer

Drill Collar

Near bitDrill bit

g g

Drilling String


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9,5 m (31 ft)

3-joint drill

pipe stand

Drill pipe

28,5 m - (94 ft)Drill pipe

Drill pipe

Drill Bits


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Drill Bits


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PDC BITS

Matrix BodySteel Body

Drill Bits


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NATURAL DIAMOND BITS

Nat. Diamond Impregnated


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Coil Tubing

Coil Tubing


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Coiled tubing can be used in

several wellbore operations:

perforating, fluid pumping, bridge

plug setting, etc.

It allows to carry out operations

in a well while other operationsare performed in a second well

It can also be used in the drilling

phase


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Drill Pipes

Steel for drill pipes


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Steels used for drill pipes are alloys of:

Iron-carbon

Manganese

Silicon

Molibden

Nickel, etcin different percentages.In these alloys impurities must not exceed the followingvalues:

0,060 % of sulphur

0,040 % of phosphorus (API Standard)


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Upset


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An upset is done at the two ends of the drill pipe body in order to

have higher thickness in the end part and therefore a gradual

change in section from drill pipe body to tool joint

There are three kinds of upsets:

Tool Joint


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Finished Tool Joint

Tool Joint


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The connection of a drill pipe body and a

tool joint should be provided by:

FLASH WELDING FRICTION WELDING

Non-destructive Tests


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Types of a drill pipe inspections :

Visual Inspection

Magnaflux

Penetrant Liquids Ultrasounds And Gamma Rays

Non-destructive Tests


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PENETRANT LIQUIDS:

They enable the identification of discontinuities having an outlet to the surface.

Unlike the MAGNAFLUX method, with penetrant liquids it is possible to survey

discontinuities (cracks) also at high depth only with an outlet on the surface.

ULTRASOUND AND GAMMA RAY:

These nondestructive test methods are very effective. They are able to survey

not only the presence of discontinuities inside the drill pipe, but also its position

and extent. They also enable to verify the thickness and transversal section of

the drill pipe.

Heavy Weight Drill Pipes


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The Heavy Weights are semi heavy drill pipes: something between DPand DC (drill collar)

They have similar configuration to normal drill pipes. However, the tooljoints are much longer and have an upset in the centre, working asstabilizer.

Both the tool joints and the centre upset are protected from wear by hardfacing bands.

Heavy Weight Drill Pipes


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Heavy Weights are normally installed between the drill pipes and

the drill collars to connect the flexibility of the drill pipes and the

stiffness of the drill collars, reducing the fatigue stress acting on thelast drill pipes, just above the DC.

HWDP are design to work also in compression: their positioning

above the DC enables the compensation of the shifting of the

neutral point during normal drilling.

Their function is providing weight to the bit, when the wellconditions require fewer drill collars.

In deviated wells characterized by high dip, they can be used

instead of DC.

They must work in tension when used in vertical wells with high

diameter. Field experiences have shown that excessive bend, inhigh diameter wells, damages the HWDP:

Drill Collar


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The drill collars (heavy drill pipes) are manufactured from a

solid bar, externally turned, internally bored and thread at its

ends.

Drill Collar


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External Configuration:

Drill Collar


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They are produced in a wide range of dimensions

Minimum external diameter: 2 7/8

Maximum external diameter: 14

Minimum internal diameter: 1

Maximum internal diameter: 3 1/4


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Drilling Muds

What are the main functions performed by drilling mud?


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Containing formation fluids by exercising a hydrostatic pressure

at bottom hole

Consolidating the borehole walls by creating a filter cake

Cooling and lubricating the drill bit

Conveying drilling debris from the bottom hole to the surface

Keeping cuttings in suspension when circulation is halted

Providing information on drilled formations

What Is A Drilling Fluid?


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Mud is a two-phase compound:

- LIQUID PHASE - SOLID PHASE

Fresh H2O

Salt H2O

Low Toxic OIL

Sintetic OIL

Foreign elements

Weigh-down materials

Solids incorporated in mud

How many mud types do we know?


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- (inhibiting or non-inhibiting) WATER-BASED MUDS

- (direct or reverse-emulsion) OIL BASED MUDS

- AIR-CUT MUDS (seldom employed)

Control Formation Pressure: Density


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One of the main functions of drilling fluid is to keep the formation

pressure under control

The pressure exerted by the mud column in static conditions

(without circulation) is called hydrostatic pressure.

Hydrostatic pressure is the product of the mud weight and theTrue Vertical Depth (TVD) of the well. If the hydrostatic pressure of

the column of drilling mud is equal to or higher than the formation

pressure, formation fluids cant flow into the wellbore

Control Formation Pressure: Density


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Formation pressure typically increases with depth

To compensate for this we increase the density of the mud with

barite

Mud weight must be limited to the minimum necessary to

control the well, maintain its stability, and still stay below the

fracture gradient

Cool and Lubricate the Drillstring and Bit


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Mechanical and hydraulic energy generated by pumping mud to the bit, and

abrasion between the drill stringand the hole, produces a great amount of

heat

Since the formation is a poor conductor the heat has no where to go

Circulating fluid helps to dissipate this heat at surface

Because of the composition of the mud, it has a lubricating effect which also

cuts down on the heat production. Indicators of poor lubrication are high

torque and drag

Circulation of the drilling fluids cools the bit and the drillstring

assembly, to temperatures lower than the bottom-hole

temperature

Transmit Hydraulic Power to Bit


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Maximize penetration rate (ROP)

Remove cuttings from under the bit and up to the surface

Run downhole motors and other special equipment

The hydraulic program is based on using the right diameter

nozzles in the bit, the pumps efficiency, and choosing the

proper circulation pressures and rates for the hole conditions

Hydraulic Power is used to:

Mud Circuit


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Mud chemicals store

Mixing hopper

Shale shaker


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Logistical problems


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Environmental concerns


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Multi-target wells


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To aim at a different target


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Original Well PathCorrectedWell Path

Original Well

Original Well

Sidetrack

Sidetrack

Reservoir


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Relief Wells


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Reservoir


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Horizontal Wells

To increase well productivity

Why use horizontal drilling?


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Horizontal well

p y

Vertical well

Horizontal wells have wider drainageareas than vertical ones

Different types of horizontal wells


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Long RadiusMedium Radius

Short Radius


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Directional Drilling Tools

Downhole Motors

PDM - (Positive Displacement Motors)


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BOS

Bent Sub & Motor

BOS

Kick Off Sub (KOS)

Motor

BOS

Double Kick Off (DKO)

Motor

1/2 - 3/100ft (30m)

Large BOS

No Surface Rotation

1/2 - 3/100ft (30m)

Smaller BOS

No Surface Rotation

6/100ft (30m)Large BOS

No Surface Rotation

Bent Sub

Kick-Off Sub

Double Kick-Off

Sub

BOS = Bit offset

Basic Steering Concept


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Rotating shaft

Non-rotating sleeve

Movable piston

AutoTrak Features

AUTOTRAK (for deviated wells)


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Rotary Closed-Loop Drilling System

It can change direction while rotating

Expandable ribs create a side force on the bit, producing a controlled

closed loop with the MWD tool

Standard Steerable Drilling System compared to Autotrak


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Autotrak

Standard steerable


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Casing

What is a Casing ?

C i i t lli i th t i l d i


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Casing is metallic pipe that is lowered in a

well in order to cover the open hole,

isolating it from the drilled formations.

Once positioned at the desired depth,

casing is cemented in place by pumping a

slurry inside it. The slurry goes out of the

casings bottom, which is called shoe,

and rises in the casing/open hole annulus.

What is the casing function?

T t th llh d d th BOP


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To support the wellhead and the BOPs

To allow mud circulation to the surface

To isolate formations having different pore

pressure or fracture gradients

To exclude formations that can cause

problems to drilling activities on account oftheir geological characteristics

To isolate productive formations

Different Types of Casing


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Conductor pipe

Surface casing

Intermediate casing

Production casing

Liner (a casing string that does

not extend to the top of the wellbore)


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Cementing Operations

What is casing cementing?

Casing is cemented in place by pumping slurry in the open hole/casing


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Why a cement should be use?

annulus. As the slurry solidifies, it acquires the necessary mechanical

resistances.

To cement casing in place (single-stage or multi-stage operations)

To run cement plugs (permanent abandonment, plugs to start a

sidetrack, isolation of depleted productive formations)

To squeeze cement into a formation to avoid lost circulation

Manufacturing Portland Cement

The following reactions take place during the product baking stage:


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The following reactions take place during the product baking stage:

100 C evaporation of free water

600 C dehydroxylation of clay minerals

900 C crystallization of dehydroxylated clay minerals

900 - 1200 C reactions between CaCO3 and CaCO with the

aluminiumsilicates

1250 - 1280 C start of the liquid phase

above 1280 C the material becomes Clinker

It will then be ground and mixed with gypsum to become CEMENT.

The characteristics of a cement slurry can be altered depending on its

Properties of cement slurry


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The characteristics of a cement slurry can be altered depending on its

use. These characteristics can be summed up as follows:

1. Easy mixing and pumping.

2. Ideal rheological characteristics for the removal of the mud.

3. Rapid development of compressive strength.

4. Capacity to prevent the passage of gas.5. Maintain a good level of compressive strength over time.

6. Capacity to fix to the surfaces.

7. Elasticity.

8. Capacity to maintain these characteristics at high temperatures.

Reasons for using cement


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Filling the annular space between the wall of an uncased hole and the casing is

the first operation after the bit has been run out of the hole and the casing has

been run in for the following reasons:

a) To support the casing and anchor it to the borehole wall.

b) To prevent the borehole from caving.

c) To protect the casing from corrosion.

d) To protect the casing from crushing or bursting.

e) To isolate adjacent zones of the borehole and prevent the different

formation fluids from mixing.

f) To extend and optimize the life of a well.

g) To increase well safety and control.

Types of cementing jobs


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Cement slurries can be used in three types of jobs:

a) Cementing of casing or strings (primary)

b) Remedial or complementary cementing

c) Cement plugs.

Casing Cementing


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Depending on the order, their position and purpose, casingcan be called:

a) Surface casing

b) Intermediate casingc) Production casing

d) Liner

Most common diameters


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The normal dimensions of the casing or liner and in which open hole they are run in are

shown below; the dimensions are given in inches:

casing/ liner dimension open hole dimension

(inches) (inches)

20 2618 5/8 24

13 3/8 17.5

9 5/8 12.25

7 8.5

5 6.5

Types of casings


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l Conductor pipel Surfacesl Intermediatel Productionl Liner

YIELD

Main characteristics of cement slurry


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This is an important value on which the calculation of the final volumes, in

bottomhole conditions, depends. There are additives such as Sferelite whose

microsfers tend to break under pressure and so undergo fluid invasion when

they are in the well, increasing the need for mixing water compared to the 0

pressure conditions on the surface.

It will therefore be the down hole yield, based on the volume of liquid cement

required for the job, which will therefore tell us the quantity of powdered cement

needed.

Yield is expressed in litres of slurry per 100 kg of cement, or in cubic feet per

sack.

For a class G cement without additives, these values are around 760 lt / 100

kg, or 1.15 cuft / sk.

THICKENING TIME



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This is perhaps the most significant and closely examined value in a

lab report.

For a very good reason, because the Thickening Time (T.T.) is the

value which allows us to carry out the job in safe conditions.

Underestimating the time can result in disastrous cementing whichcan even lead to the well having to be abandoned in the most serious

cases.


RHEOLOGY (Fann Reading)


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Cement slurry is classified as a nonNewtonian fluid; i.e. a fluid whose viscosity is

not constant but varies with the speed at which it flows through a pipe.

Rheology measurements on slurry allow the characteristics of its flow to be

predicted as well as its capacity to suspend solids.

The PV (Plastic Viscosity) and YP (Yield Point) values can be obtained on the

basis of the apparent viscosity values, determined for example using a Fann

Viscosimeter. These values tell us to what extent a slurry is fluid and if it is able to

transport solids and keep them in suspension.

Moreover, the Flow Index (n) and Consistency Index (K) are obtained and allow

us to estimate the pressure loss caused by friction during the motion of the slurry

and its flow type; that is, if it movement is plug, laminar or turbulent.

Cementer


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Operational sequence of casing cementing

alta

1)Displacement of cement by a drillingmud


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Ma

Fango

Fang

o Fango

mud

2)The plugs are in contact anddisplacement is completed.Cement starts to solidify

The time needed the cement to setat the end of displacement (WOC)will vary according to the type ofused slurry

What is the chemical composition of cement?

Cement is a complex mixture of silicates and calcium aluminates.


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p

Its grinding fineness determines its hydration capacity.A little difference in the chemical composition or in the physical

condition of cement can cause a strong performance variation.

It is essential to perform lab tests before each operation, using

water, cement and additives samples obtained from the site

where the operation will take place.


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Difficulties in drilling operations

PARTIAL LOSSES

Lost Circulation


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Absorption up to a maximum value of about 8 m3/h

TOTAL LOSSES

Mud doesnt return to the surface during drilling operations

Absorptions are caused by:

High-porosity and high-permeability formations Fractured formations

Underpressured formations

Karst

Lost Circulation


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Main stuck pipe causes are:

Stuck Pipe


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p p

Key seats Differential pressure (sticking) Wedging in (Packing off)

- While the drill string is being lowered- While the drill string is being pulled out

A collapse caused by:- Total circulation loss- Unstable formations- Debris accumulation in caved-in boreholes

Stuck Pipe: Key Seat Block


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Sticking Block


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Borehole

Drill pipes


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Fishing Operations

Overshot


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Magnetic Fisher


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Underground

Blow-out

Gas

Migration

Charged formation

Underground Blow-out


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Gas

MigrationShear Rams (open)

Underground Blow-out - 1


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Gas

MigrationShear Rams (closed)



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g

Fracturing below csg. shoe

Gas

MigrationShear Rams (closed)



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Initiation of

underground blow out


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Capping

1) Well Flowing


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2) positioning BOP

Capping


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= Valves Closed

Guide Line

3) Set Up Choke & Kill lines

Capping


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Chokeline

Kill line

BOP open

= Valves Closed

4) opening Choke & Kill lines

Capping


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= Valves Open

Choke line Kill line

BOP open

5) Closing BOP

Capping


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= Valves Open


BOP closed

6) Gradual Closing of Choke e Kill lines (the well is in pressure)

Capping


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BOPclosed

= Valves closed

7) Well Killing by pumping through kill line.

Capping


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= Choke closed

= Kill open


BOPclosed

Bag Preventer

Used on land, offshore, jack-up,

tender rigs and stationary platforms

Surface Bop Stack


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Double rams Preventer

Single ram Preventer

Drilling Spool

The BOP stack components are:

Bag BOP

Ram BOPs

Drilling spool (optional) Choke valves

Kill valves

They are usually built according to API

16 A standards.

Snapshots of real operations....


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Snapshots of real operations..


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Relief Well

Techniques

Relief well


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Reservoir

Relief well


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.

Surface Bop Control System


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Well Control

0

LOSSGAIN

Kick: Rise in Pit Levels


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Suction Pit

PitGain

Indicator placed onthe drillers console

Causes of a kick


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Drilling in an overpressurized formation

GasGas

Blowout Control Systems

Blowout control systems can be divided into:


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Primary (active): these are the systems that prevent the

occurrence of a blowout (i.e. hydrostatic load of a mud)

Secondary (passive): all safety equipment contributes to

close a wellbore when a serious possibility of blowout exists

or when a blowout is already under way

Logistical Services


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Road transports

Sea transports

Communications

Road Transports


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This service provides logistical

assistance and transport of

materials in onshore operations

The Supply Vessel Service provideslogistical assistance and transport ofmaterials in offshore operations

Sea Transports Supply Vessel Helicopter


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The Helicopter Service provides inout rig personnel transport

Communications


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The Communications Service allows datatransmission in the rig operational districtheadquarters loop


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Drilling Waste Management And Cycle

Drilling Waste

D illi C tti

Management And Cycle Of Drilling Waste


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Drilling fluids

Wash water

Exhaust mud

Drilling Cuttings

Municipal solid wastes

Drilling waste from WBM (mud and



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Drilling waste from WBM (mud andcuttings): non-hazardous

Drilling waste from OBM (mud andcuttings): hazardous

Operations priorities:

Reduction at source



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Recycle Re-use

Recovery

Treatment

Disposal

Waste

Reduction

Guiding criteria



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Waste volume reduction

Re-use of wash water

Solids control equipment

Storage by type

Use of dedicated corrals(excluding shallow wells)

Disposal methods:



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On-site treatment

Transport to treatment plant



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Semataf: aerial view of treatment and disposal site (2B type) in Lanciano

Cuttings

Cuttings can be treated chemically physically or



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Cuttings can be treated chemically, physically ormechanically in order to separate or fix contaminants to

reach legal standards

Consolidation/stabilization

Thermal treatment

Biodegradation

Consolidation and inertization

C t

Shale shakers



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CORRAL

excavator

CONSOLIDATION

CORRAL

Sodium

Silicate

Cement

Mixing conveyer

pomp

silos

Landfill

Re-use

Thermal treatment of cuttings

The process consists of heating the cuttings to reach a water-oil



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The process consists of heating the cuttings to reach a water oilgaseous stage and subsequent condensation

low Temp 250 - 370 (oil recovery)

high Temp >900 (incinerator)

Biodegradation

A natural process where adapted microorganisms degradecomplex hydrocarbons to a more elementary chain that can beeasily reduced to environmentally acceptable Carbon

compounds



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compounds

Operationally simple

Does not need special

equipment (farm equipment)

Does not generate a bi-

product:

recyclable cuttings/soil

Disposal methods:

On-site treatment Landfill

Re-use



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Cuttings

Exhaust mud

Washing water

Dehydration

process Water

Solid

Depurationprocess

Re-use on rig

Discharge

Waste water depuration plant

Dehydration



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Filterpress for dehydration of exhaust mud

Off-shore disposal methods:



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Discharge into the sea of

cuttings (OBM/WBM) and muds

(WBM)

Zero-discharge and consequent

transport to shore of solid and

liquid waste (WBM - OBM)

Up to 1987 :

From 1987:

Closed Loop System

Cuttings washer



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vibrovagl

Cuttings washer

Shale shakers

Cuttings slurrification and re-injection

Options :



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Options :

-- Existing well (production well)

-- Drilling and re-injection simultaneously well

-- Dedicated well

Cuttings re-injection

cuttings

Exhaus drilling fluids



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Injection fluid characteristics:

Particle size in suspension


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Waste Management

Drilling debris

Exhausted mud

What kinds of waste are produced in a rig site ?


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Washing H2O

Intervention fluids

Urban solid waste

Why to carry out a waste management ?

To reduce the environmental impact with respect to the

regulations in force


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regulations in force

To maximize waste recycling (cement, brick and expanded

clay plants, environmental restoration, RSU dump covers)

How we can manage waste disposal?

ONSHORE : OFFSHORE :

Zero discharge: solid and

liquid waste (WBMOBM) is transported

Rig site treatment

(consolidation anddehydration)


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OBM) is transported

onshore

dehydration)

Untreated waste disposal

H2O recycling ( a closed-loop

system allows reduction of

waste volumes to be disposed

of by recovering water from

exhausted mud)

bo 018 drilling operations

Documents