Issues of Using Fractal Modelto Analyze Mlutilevel Slug Test Data in Fractured

Formations

報告者 : 翁聖恩 指導教授 : 陳家洵 老師 報告日期 :2011/05/26

What is MLST

• Using double-sealed plug to well screen segments separated to flow only from the test section and out, let air into the connecting pipe, causing the water level surface of the tube down a steady rate.

• When release the gas, tube between inside and outside the pressure difference cause the groundwater level surface pressure changes .

Flow Field Geometry of n

planar, n=1 radial, n=2 spherical, n=3

n=1 1<n<3 n=2

Mass balance in the well

ww

nnw

nwn

wwnc

brrAnfor

nrbrAwhere

rrr

trhrKA

dt

tdHr

2,2

2//2

),()(

2

2/13

2

Flow Areas

ww

nnw

nwn

wwnc

brrAnfor

nrbrAwhere

rrr

trhrKA

dt

tdHr

2,2

2//2

),()(

2

2/13

2

10-3

10-2

10-1

10-3

10-2

10-1

100

101

102

103

rw/b

An(r w)/A2(r w)

n=1

n=1.5

n=2

n=2.5

n=3

Partial Penetration and Flow Dimension , High K

Partial Penetration and Flow Dimension , Low K

Skin Effect

• In the drilling process, Caused by human factors as changes in the wellbore permeabilitiy.

• If the permeability in the skin zone

(1)less than that in the rest of the formation , Sk will be positive.

(2) equal ,Sk=0.

(3)greater than that in the rest of the formation ,Sk will be negative.

Skin Effects on Flow Areas

10-3

10-2

10-1

10-4

10-3

10-2

10-1

100

101

102

103

104

rW/b

An(r e)/A2(r e)

Sk=3n=1

Sk=0n=1

Sk=-3n=1

n=2

n=3Sk=-3

n=3 Sk=0

n=3 Sk=3

Skn=S

k2=S

k 11

nSnw

kerre

Skin Effects and Flow Dimension

Conclusion

Effect hydraulic conductivity of the factors

(1)Flow dimension.

(2)Fully penetrating slug test or partially penetration slug test.

(3)Skin effect.

Cause several combinations, the formation of a non-unique.

Future Work

• Improve the understanding the Parameters of

Flow area 、 Skin effect and etc .• Adding observation well field data.

Thanks for Your Attention