lecture07 - coning in vertical & horizontal wells

8/10/2019 Lecture07 - Coning in Vertical & Horizontal Wells

1/41

Production TechnologyConing in Vertical & Horizontal Wells

Aug 2008

Master of Petroleum Engineering


2/41

2

Coning in Horizontal & Vertical Wells

R.F. for Various DrivesDimension of Water Production Problem

7 bbls water / bbl of oil - in US 3 bbls water / bbl of oil worldwide Water treatment cost: US$ 40b / year

0.4 $/bbl of water

Goodwater / Bad Water


3/41

3


Where in the Oil Column to Place a Well?

Objectives of perforations/well placement Communication of the well with reservoir fluid High productivity Delay gas/water brekthrough

Improve recoveryAll within the constraints of Reservoir Management

Plan (RMP)

Summary of the objectives: Improved well/fieldeconomics

Vertical Well: Where in the oil column do we perforate?


4/41

4


An Example of Horizontal Well Placement (small gascap, strong aquifer)


5/41

5


Coning Related Calculations

1. Critical Coning Rate

2. Breakthrough Time3. Post Breakthrough Production Performance

How to Delay Coning Breakthough?


6/41

6


Theory of Coning

Maximum drawdown of the well without waterentering the well

A rough estimate (not very accurate)

WELL

WATER CONE H

H

( ) hp ow = 433.0max


7/41

7


Water Coning

Assumption kv=kh

WELL

WATER CONE H

H


8/41

8


Theory of Coning

( ) hp ow = 433.0max

1. O

i

l

1. Original

OWC

1. Original

GOC

( )

( )[ ]PR

SrrB

pphkQ

weoo

weo

o+

=

/ln

00708.0

( ) ( )o

w ffhrfPR 90cos2/71+=

Assumption kv=kh

f = fractional penetration (or

perforation) = hp

/h


9/41

9


Water Coning

Assumption kv=kh


10/41

10


Muskat & Wyckoff (Laplace Eqn)

Chaney / Cheirici (Potentiometric Methods)

Wheatley (considers influence of cone shape on oil potential)

Critical Coning Rate Analytical Solutions (Vertical Wells)


11/41

11


Water Coning - Muskat & Wyckoffs Critical Coning Rate

oo

c

B

hkGq

2=

Originally derived for isotropic reservoir / water coning

Can also be used for anisotropic reservoir & gas coning problem

G = dimensionless factor =f(kv/k

h; geometry)

h = oil zone thickness

Assumptions

Single phase, SS flow Laplace Eqn applies

Uniform-flux boundary condition

Potential distribution in the oil phase not influenced by the coneshape


12/41

12


Meyer-Garder (isotropic)

Hoyland-Papatzacos-Skjaeveland (based on simulationruns)

Chaney et al. (isotropic; extend Meyer-Garder; math+potentiometric) Chaperon (anisotropic)

Schols (Lab & Numerical Simulation; isotropic) Chierici-Ciucci (potentiometric; anisotropic )

Critical Coning Rate Correlations (Vertical Wells)


13/41

13


Gas coning Water coning

Combined gas and water coning

Meyer-Garder Correlation (Isotropic; vertical well)


14/41

14



Water coning


15/41

15


Gas coningMeyer-Garder Correlation (Isotropic; vertical well)

[ ]224 )(ln

10246.0 too

o

w

e

go

oc DhhB

k

r

rQ

=

[ ]224

ln

10246.0 poo

o

w

e

ow

oc hhB

k

r

rQ

=

Water coning

(Eq. 7.4)

(Eq. 7.5)


16/41

16


Simultaneous Gas & Water ConingMeyer-Garder Correlation (Isotropic; vertical well)

Optimum Distance from Gas Cap, Dt

(Eq. 7.6)

+

=

2222

4 1)()()/ln(10246.0 gw

go

go

gw

go

ow

we

p

oo

oocrr

hh

B

kQ

(Eq. 7.6)

=

gw

go

pt hhD

1)(


17/41

17




18/41

18


Hoyland- Papatzacos-Skjiaeveland Method(anisotropic, vertical well) Water Coning

CD

oo

howt

oc qB

khQ

=

)(10246.0

24

where,

kh = horizontal permeability,mD

qCD = dimensionless critical flow rate

ht = total reservoir thickness, ft

qCD = f (rD and fp)

h

ve

D

k

k

h

rr =


19/41

19




20/41

20




21/41

21


Chaperons Method (anisotropic, vertical well)Water Coning

[ ]*

2

4)(

100783.0 coo

ph

oc qB

hhk

Q

=

)"/943.1(7311.0* +=cq

hve kkhr /)/("=


22/41

22


Chierici-Ciucci Method (anisotropic, vertical well)Water & Gas Coning

v

he

De

k

k

h

rr =


23/41

23



( )

( ) ( )wDewhrooo

ow

ow rkkB

h

Q

,,10492.0

24

=

( )( ) ( )gDeghro

oo

go

og rkkB

hQ

,,10492.0

2

4

=


24/41

24


1=

WO

OG


25/41

25


1=

WO

OG


26/41

26


1=

WO

OG


27/41

27


1=

WO

OG


28/41

28


1=

WO

OG


29/41

29


1=

WO

OG

C i i H i l & V i l W ll


30/41

30


1=

WO

OG

C i i H i t l & V ti l W ll


31/41

31



Given reservoir & fluid properties, hp (), =>

critical production rate

Given reservoir & fluid properties, , Q, =>

Optimum completion interval by trial & error method

Assume hp, ; know fluid properties => Q()



32/41

32


Cone Breakthrough Time

The Sobocinski-Cornelius Method

The Bournazel-Jeanson Method

Post Breakthrough Production Performance



33/41

33


Cone Breakthrough TimeThe Sobocinski-Cornelius Method (Experimental Data)

( )

ooo

phow

QB

hhhkZ

=

410492.0

Dimensionless cone height Z:

( )Z

ZZZtBTD

2775.075.14 32

+=

( )( ) ( ) Mkth

tvow

BTDoBT

+=

1

325,20



34/41

34


Cone Breakthrough TimeThe Sobocinski-Cornelius Method (Experimental Data)

( )( )

=

w

o

Swcro

Sorrw

kkM

= 0.5 forM 1 and = 0.6 for 1


35/41

35


Cresting in Horizontal Wells



36/41

36


Critical Coning (Cresting) Rate for Horizontal Wells

1. Chaperons Method

2. Efros Method3. Karchers Method4. Joshis Method



37/41

37


Breakthrough Time for Horizontal Wells

1. The Ozkan-Raghavan Method

2. Papatzacos Method



38/41

38


Figure (7.20) Dimensionless time for two-cone case.

(After Paptzacos, P. et. Al.)



39/41

39

g

Figure (7.21) Optimum well placement for two-cone case.(After Paptzacos, P. et. al.)



40/41

40

g

Practical Issues with Coning Calculations

Analytical solutions are based on simplified assumptions

Assume khomogenous

etc

Scarcity of data

Data quality & consistency

Quality of core data?

RFT data (density etc) matching with lab data Oil density graduation in reservoir

Permeability sequencing (fining/coarsening trend)

Kv?



41/41

41

Solution to Practical Issues

Analytical tools are still powerful in understanding the

physics of multiphase flow

Be practical & beaware of the assumptions and limitations

Perform sensitivity analysis define range of uncertainty

A range of outcome with various probability

Identify most likely / risked outcome

Be guided by analogy / experience / probability

lecture07 - coning in vertical & horizontal wells

Documents