14-polymer flooding and asp flooding in daqing oilfield

8/21/2019 14-Polymer Flooding and ASP Flooding in Daqing Oilfield

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Polymer flooding

and ASP flooding

Flowchart of produced fluid treatment

Flowchart of polymer preparation process

A complete treatment process consisting of two stages for oil

removal and two other stages for filtering has been developed

and put into application. The system outputs water that meets

Chinas discharge standard for industrial wastewater (oil content

20mg/L and suspended solid content 20mg/L).Composite Production Curves in Nan-5 block

100

95

90

85

80

75

800

600

400

200

0

0 0 .0 5 0 .1 0 .1 5 0 .2 0 .2 5 0 .3 0 .3 5 0 .4 0 .4 5

Total water cut

Daily oil output

2006.6

(Pre-ASP)

2006.11

(ASP)

727.5

469.2

83.6

79.261.4

95.9 95.6

Totalwatercut(%) Da

ilyoiloutput(t/d)

Injection Volume (PV)

100

80

60

40

20

0

50

40

30

20

10

00 0.2 0.4 0.6 0.8 1.0 1.2

Recovery effect curves in Duandong of Bei-1 block

Totalwatercut(%)

Recoverypercent(%)

Pore volume injected (PV)

Predicted water cut by water flooding

Actual water cut by ASP flooding

Predicted water cut by ASP flooding

Produced fluidOutput oil index: water content0.3%

Oil content in water3000mg/L

Oil content3000mg/LWater content in oil30%

Water content in oil300mg/L

Oil content100mg/L

Suspended solid content50mg/LOil content20mg/L

Suspended solid content20mg/L

Oil content50mg/L

Suspended solid content30mg/L

Wastewatersettling tank

Secondarysettling tank

First filterSecondary filter

Watering

Mixer

Electric dewaterer

Free water removerWateringfurnace

Labeidong block

Initial time: 2008.05

Wells: 44 injectors/62 producers

Duandong of Bei-1 block



Nan-5 block



Central part of Xing-2 block



Duanxi of Bei-1 block

Time: 1997.03-2002.05


Recovery increment: 21.90

Western part of central block

Time: 1994.09-1996.05



Western part of Xing-2 block

Time: 1996.09-1999.10Wells: 4 injectors/9 producers


Central part of Xing-5 block

Time: 1995.01-1997.04

Wells: 1 injector/4 producers


North well group-small well spacing

Time: 1997.12-1998.12



Pilot field test Industrial field test

in Daqing Oilfield

Clean waterClean water filter

Stirring & Curing

Water/Polymer

powder mixer

PAMdry

powder

Water pump

Disperser

First filter

Curing tank

Output screw pumpFine filter

To injecting station

Mother liquor

storage tank

Cleanwatertank

Mother liquor filtering

800

600

400

200

0

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Polymer Flooding

Four stages of Daqings polymer flooding practice

In 1989, polymer flooding saw its first pilot test in the western

part the of central block, demonstrating an 11% increase of

recovery factor as compared to water flooding. In 1991, industrial

field tests were deployed in multiple well g roups of large spacing

in Duanxi of Bei-1 block and Lanan-1 block. In 1995, polymer

flooding was first put into industrial application in the western

part of block North-2.

After years of research and practice, Daqing has become the

world leader in polymer flooding in terms of application scale,

technical solution, and economic benefit. In fact, this tertiary

recovery method has become one of the important driving forces

to the sustainable development of the oilfield.

Polymer flooding can increase oil recovery to more than

50%, 10%+ higher than that by water flooding.

Alkaline/Surfactant/Polymer Flooding

Daqing Oilfield embarked on studies of ASP flooding in the

1980s.

All the five pilot field tests successively carried out in different

blocks since 1994 showed about 20% higher recovery factor

than water flooding.

Excellent results were obtained from four industrial field tests at

a larger scale since 2000. Industrial surfactants independently

developed by Daqing Oilfield were used in the tests.

From an enlarged industrial test carried out in 2007, ASP

flooding was expected to add more than 300 million tons to the

fields recoverable reserves. Such an increment is equivalent to

the discovery of a new oilfield with 800 million to 1 billion tons of

oil in place.

ASP flooding is a tertiary recovery method that much improves

ultimate oil recovery by injecting a compound system of alkaline,

surfactant and polymer, thus extends reservoir life. Besides

increasing the viscosity of injected fluid, decreasing the oil/water

mobility ratio, and enlarging sweeping volume in reservoirs, ASP

flooding may result in more efficient oil displacement than

polymer flooding.

Polymer flooding is a tertiary recovery method by adding

high-molecular-weight polyacrylamide into injected water, so as

to increase the viscosity of f luid, improve volumetric sweep

efficiency, and further increases oil recovery factor.

When oil is displaced by water, the oil/water mobility ratio is so

high that the injected water fingers through the reservoirs. By

injecting polymer solution into reservoirs, the oil/water mobility

ratio can be much reduced, and the displacement front advances

evenly to sweep a larger volume. The viscoelasticity of polymer

solution can help displace oil remaining in micro pores that

cannot be otherwise displaced by water flooding.

By September 2011, oil recovery at the test blocks had

been increased by 17.8-25.7%.

1970

LabResearch

1972

PilotTest

1991

IndustrialTest

1995

Application

Residual oil under SEM

After water flooding After polymer flooding After ASP flooding

Residual oil under SEM

Water floodingWater flooding

Displacement frontDisplacement of residual oil in dead-end

Displacment of residual oil film

Polymer floodingPolymer flooding

After water flooding After polymer floodingWater flooding Polymer flooding

40

50

60

70

80

90

100

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 .9

20

30

40

50

60

70

80

Pilot field test result in the central block



Predicted water cutby water flooding

Predicted recovery percentby water flooding

Recovery percentby polymer flooding

Oil increment by polymer flooding

Industrial test result in Duanxi of Bei-1 block

100

90

80

70

60

50

40

80

70

60

50

40

30

20

0.0 0.2 0.4 0.6 0.8 1.0

Actual water cutby polymer flooding

Predicted water cutby polymer flooding

Totalwater

cut(%)

Recoveryp

ercent(%)

Totalwatercut(%

)

Re

coverypercent(%)

Predicted water cutby water flooding

Water cut bypolymer flooding

14-polymer flooding and asp flooding in daqing oilfield

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