Well No.

Underbalance interval

m

Underbalanced drilling fluid density

g/cm³

Adjoining well conventional drilling fluid density g/cm³

Coefficient of formation drillability

Calculate multiples

r

Adjoining well conventional actual drilling rate of penetration m/h

Under-balanced drilling the actual rate of penetration m/h

The actual ratio

Calculate multiples ratio and the actual error rate

SongShen101#

2974 - 3480

0.92

1.15

5.24

1.77

1.16

2.27

1.95

9.2%

WeiShen5#

3087 - 3610

0.94

1.15

5.16

1.78

1.25

2.46

1.97

9.6%

WeiShen501#

3098 - 3457

0.92

1.15

5.67

1.76

1.33

2.60

1.95

9.7%

ZhaoShen11#

3170 - 3410

0,93

1.10

5.48

1.80

1.02

1.92

1.91

5.8%

XuShen1#

3187 - 3960

0.94

1.12

5.84

1.78

1.56

2.88

1.84

3.3%

XuShen3#

3625 - 4763

0.92

1.10

6.23

1.81

1.14

1.95

1.71

5.9%

XuShen5#

3338 - 4057

0.92

1.15

5.89

1.77

1.04

1.88

1.82

2.7%