Embodiment
Below in conjunction with drawings and Examples the present invention is described in detail.
As shown in Figure 1, described in the self-elevating drilling platform later situation such as background in place.By drilling platform is carried out force analysis as can be known, the spud leg after this moment, pitching pile was stood is equivalent to the semi-girder of a lower end build-in.For making things convenient for the research of problem, supposing does not have relative displacement between spud leg and the drilling platform, but along with drilling platform translation together.Hence one can see that, and when the drilling platform transverse vibration, the spud leg lower end is mounted in the seabed, and then must there be interior moment M the upper end on it with the drilling platform translation
0Exist.
1, obtains drilling platform lateral amplitude of vibration, cycle and frequency
As shown in Figure 2, drilling platform 1 deadweight w, rising the height degree is L
1It is following as position of fixity support drilling platform that spud leg 2 inserts the mud face, and the number of spud leg 2 is more than or equal to 3.Setting up coordinate system is the x axle along the spud leg axial direction, and horizontal direction is the y axle, and spud leg produces lateral amplitude of vibration y under the effect of transverse force P, the maximum transversal amplitude y of spud leg
MaxJust equal the lateral amplitude of vibration δ of drilling platform
StIf rise height degree L
1=l can ask drilling platform 1 along the axial transverse vibration period T of y.
1) Flexural Equation of spud leg
As shown in Figure 2, in the moment M of coordinate (x, 0) point
xComputing method be:
M
x=M
o-P(l-x) (1)
At this moment, the second derivative of the Flexural Equation of spud leg is:
And because
Then going into formula (3) for formula (1) can get:
Wherein c is an integration constant, and E is an elastic modulus, and I is a polar moment of inertia, to circular spud leg
OD is the spud leg external diameter, and ID is the spud leg internal diameter.Known boundaries condition: x=0, y '=0, substitution formula (4) can get c=0.The c=0 inverse iteration is gone into (4) Shi Kede:
The Flexural Equation that is got spud leg by formula (5) integration is:
Wherein d is an integration constant.With boundary condition x=0, y=0 substitution formula (6) can get d=0.The d=0 inverse iteration is gone into the Flexural Equation that formula (6) can get spud leg:
∵ has extremum conditions y '=0 when x=l again, and then substitution formula (5) can get interior moment of flexure:
Going into formula (6) for formula (8) can get:
Obviously, when x=l, the maximum value that y reaches absolute value is:
2) transverse vibration frequency, the cycle of drilling platform
When drilling platform is subjected to transverse force P
HDo the time spent, establishing the spud leg number is n, then the transverse force that is subjected on every spud leg
With P substitution formula (10), can get the drilling platform amplitude of spud leg x=l:
Wherein,
R is an atmospheric density, and v is a wind speed; c
DBe resistance coefficient, A
PBe the projection of wind-engaging hull area on the wind direction vertical plane.The bendind rigidity coefficient of spud leg can equivalence be:
Then as can be known, the cycle of drilling platform is:
Going into formula (13) for formula (12) can get:
Wherein, w is the drilling platform deadweight, and g is an acceleration of gravity.Then the transverse vibration natural frequency of drilling platform is:
3) three spud leg drilling platform transverse vibration amplitudes, cycle and frequency
The present invention considers that many drilling platform are arranged is three spud leg forms, n=3 so at this moment, and the power that then is subjected to horizontal direction on every spud leg is
With its substitution formula (11), the maximum horizontal displacement that in like manner can get drilling platform is:
Then the bendind rigidity equivalence of system is:
In like manner, can get its cycle is:
Its natural frequency is:
By above analysis, the present invention has obtained the Flexural Equation (9) of drilling platform leg and the transverse vibration amplitude equation (11) of drilling platform, and this lays a good foundation and convenience is provided for the present invention analyzes drilling platform transverse vibration characteristic.
I) through type (11) as can be known, the lateral amplitude of vibration δ of drilling platform
StTransverse force P suffered with it
HBe directly proportional.This has also shown under the strong wind condition, the transverse force P that drilling platform is subjected to
HBig more, its lateral amplitude of vibration δ then
StAlso just big more.
Ii) through type (14) as can be known, the period T of drilling platform and deadweight w and 3/2 power that rises height degree l are directly proportional, this proves absolutely that rising height degree l has the greatest impact to period T.Promptly in the marine site, deep-sea or at drilling platform when the spud leg operation at top, height degree l is very big to cause period T long owing to rising, this conclusion meets the result that empirical observations draws.
The iii) lateral amplitude of vibration δ of drilling platform simultaneously
StAlso the bendind rigidity coefficient EI with spud leg is inversely proportional to, and this shows the big more then δ of EI
StMore little.
2, accurately calculate well location
As shown in Figure 3, be the x coordinate with the longitude, set up earth coordinates with the latitude for the y coordinate.O (x wherein
0, y
0) point is for predefined well location coordinate, (x, y) for rising the terrestrial coordinate that records well location behind the ship by prior art, b ' (x ', y ') is well location coordinate accurately to b.α is that (x y) departs from o (x to b
0, y
0) deflection, α ' is that b ' (x ', y ') departs from o (x
0, y
0) deflection.
The step of measuring accurate well location is as follows:
A) by the assay method of prior art obtain well location terrestrial coordinate b (x, y);
B) try to achieve the lateral amplitude of vibration δ of drilling platform by formula (11) in the direction of the wind comes from
St, δ
StComponent on the x axle is
δ
st(x)=sin(α
w)δ
st (20)
Component on the y axle is
δ
st(y)=cos(α
w)δ
st (21)
α wherein
wDeflection for wind direction;
C) calculate accurately well location coordinate b ' (x ', y '), x '=x-δ
St(x), x '=y-δ
St(y); B ' (x ', y ') departs from o (x
0, y
0) deflection be
If (x y) is the average of the terrestrial coordinate that records in average period, lateral amplitude of vibration δ so to b
StJust should get the value substitution following formula of half.By above step, just can be in the hope of the accurate well location of drilling platform, thus effectively removed lateral amplitude of vibration δ
StInfluence, the difficulty that makes the tieback under water in later stage run into is solved.
3, specific embodiment
The spud leg of three spud leg drilling platform is a column type, and getting spud leg weight is 15160KN, its I=0.77 * 10
-3m
4, E=2.1 * 10
8KN/m
2The scope that rises height degree l of drilling platform changes in 10 ~ 40m scope.Platform is estimated one's own ability when rising the ship operation and is that 33650KN, travelling load are 7500KN.Under the drilling operation condition, changing load is 12700KN.Suppose rising under the ship condition that changing load is 4000KN only, and under the drilling operation condition, changing load is fully loaded with 19500KN; Fixed load is fully loaded, adds 2000m* φ 127mm drill string (29kg/m) and 200m* φ 203mm drill collar (220kg/m) simultaneously, and its drilling tool general assembly (TW) is about 1000KN.
Different wind directions changes as shown in Figure 4, and when wind direction was N/S, the drilling platform wind area was: A
P=609m
2When wind direction was E/W, wind area was: A
P=516m
2When wind direction was N/E, wind area was: A
P=474m
2Ask when wind load during by 5 to 10 grades, the first step is asked the lateral amplitude of vibration δ of the horizontal direction that drilling platform produces
St, period T and natural frequency f
nSecond step was calculated well location coordinate accurately.
The first step is asked the lateral amplitude of vibration δ of the horizontal direction of drilling platform generation
St, period T and natural frequency f
n:
By known, rising under the ship operating condition, platform weight is:
W=platform deadweight+spud leg weight+rise ship changing load+travelling load
=33650+15160+4000+7500-6031000KN
Under the drilling operation condition, platform weight is:
W=platform deadweight+spud leg weight+drilling well changing load+travelling load
=33650+15160+12700+7500=6907000Kg
Supposition now rises height degree l=12m, 6 grades of wind-force (wind speed v=10.8-13.8m/sec), and wind direction is N/S.Rising under the ship state, is example with wind speed v=13.8m/sec.Result of calculation is shown in boldface letter in the table 1, and concrete solution procedure is as follows:
Lateral amplitude of vibration is by formula (16) as can be known:
Cycle is by formula (18) as can be known:
Natural frequency by formula (19) as can be known
The different lateral amplitude of vibration δ that rise height degree and N/S, E/W, three wind directions of N/E under all the other conditions
St, period T, natural frequency f
nSee table 1~table 6 for details:
Table 1: rise ship state bow to N, wind direction N/S
Rise height degree lm |
Storm δ
st?cm
|
Strong gale δ
st?cm
|
Fresh gale δ
st?cm
|
Moderate gale δ
st?cm
|
Strong breeze δ
st?cm
|
Period T sec |
Natural frequency f
n 1/sec
|
10 |
0.2 |
0.095 |
0.06 |
0.04 |
0.02 |
6.46 |
0.15 |
10 |
0.3 |
0.137 |
0.09 |
0.06 |
0.04 |
6.46 |
0.15 |
12 |
0.3 |
0.160 |
0.11 |
0.06 |
0.04 |
**8.49 |
0.12 |
12 |
0.4 |
0.237 |
0.16 |
0.11 |
0.06 |
**8.49 |
0.12 |
14 |
0.5 |
0.254 |
0.17 |
0.10 |
0.06 |
10.70 |
0.09 |
14 |
0.7 |
0.376 |
0.25 |
0.17 |
0.10 |
10.70 |
0.09 |
15 |
0.7 |
0.31 |
0.21 |
0.13 |
0.07 |
**11.86 |
0.08 |
15 |
0.9 |
0.46 |
0.31 |
0.21 |
0.12 |
**11.86 |
0.08 |
20 |
1.6 |
0.74 |
0.50 |
0.30 |
0.16 |
18.26 |
0.05 |
20 |
2.1 |
1.10 |
0.74 |
0.49 |
0.29 |
18.26 |
0.05 |
30 |
5.3 |
2.50 |
1.69 |
1.01 |
0.55 |
33.55 |
0.03 |
30 |
7.0 |
3.70 |
2.5 |
1.65 |
0.99 |
33.55 |
0.03 |
40 |
12.6 |
5.92 |
4.0 |
2.39 |
1.31 |
51.66 |
0.02 |
40 |
16.5 |
8.78 |
5.9 |
3.90 |
2.35 |
51.66 |
0.02 |
50 |
24.6 |
11.56 |
7.8 |
4.67 |
2.56 |
72.19 |
0.01 |
50 |
32.3 |
17.15 |
11.6 |
7.62 |
4.58 |
72.19 |
0.01 |
*----is the common mean wave period in the South Sea and marine site, the Bohai Sea, and it is 12sec that normal conditions are got the South Sea, and the Bohai Sea is 8sec
Table 2: drilling state, bow be to N, wind direction N/S
Rise height degree lm |
Storm δ
st?cm
|
Strong gale δ
st?cm
|
Fresh gale δ
st?cm
|
Moderate gale δ
st?cm
|
Strong breeze δ
st?cm
|
Period T sec |
Natural frequency f
n 1/sec
|
10 |
0.2 |
0.07 |
0.05 |
0.04 |
0.02 |
6.91 |
0.14 |
10 |
0.3 |
0.10 |
0.07 |
0.06 |
0.03 |
6.91 |
0.14 |
12 |
0.3 |
0.12 |
0.08 |
0.06 |
0.03 |
**9.08 |
0.11 |
12 |
0.4 |
0.18 |
0.12 |
0.11 |
0.05 |
**9.08 |
0.11 |
14 |
0.5 |
0.19 |
0.13 |
0.10 |
0.04 |
**11.45 |
0.09 |
14 |
0.7 |
0.28 |
0.19 |
0.17 |
0.08 |
**11.45 |
0.09 |
15 |
0.7 |
0.24 |
0.16 |
0.13 |
0.05 |
**12.69 |
0.08 |
15 |
0.9 |
0.35 |
0.24 |
0.21 |
0.09 |
**12.69 |
0.08 |
20 |
1.6 |
0.56 |
0.38 |
0.30 |
0.12 |
19.54 |
0.05 |
20 |
2.1 |
0.83 |
0.56 |
0.49 |
0.22 |
19.54 |
0.05 |
30 |
5.3 |
1.89 |
1.28 |
1.01 |
0.42 |
35.91 |
0.03 |
30 |
7.0 |
2.80 |
1.89 |
1.65 |
0.75 |
35.91 |
0.03 |
40 |
12.6 |
4.47 |
3.03 |
2.39 |
0.99 |
55.28 |
0.02 |
40 |
16.5 |
6.63 |
4.47 |
3.90 |
1.77 |
55.28 |
0.02 |
50 |
24.6 |
8.74 |
5.92 |
4.67 |
1.93 |
77.26 |
0.01 |
50 |
32.3 |
12.95 |
8.74 |
7.62 |
3.46 |
77.26 |
0.01 |
*----is the common mean wave period in the South Sea and marine site, the Bohai Sea, and it is 12sec that normal conditions are got the South Sea, and the Bohai Sea is 8sec
Table 3: rise the ship state, bow is to N, wind direction E/W
Rise height degree lm |
Storm δ
st?cm
|
Strong gale δ
st?cm
|
Fresh gale δ
st?cm
|
Moderate gale δ
st?cm
|
Strong breeze δ
st?cm
|
Period T sec |
Natural frequency f
n 1/sec
|
10 |
0.167 |
0.078 |
0.053 |
0.032 |
0.017 |
6.46 |
0.15 |
10 |
0.22 |
0.140 |
0.08 |
0.05 |
0.03 |
6.46 |
0.15 |
12 |
0.29 |
0.135 |
0.09 |
0.05 |
0.03 |
**8.49 |
0.12 |
12 |
0.38 |
0.242 |
0.14 |
0.09 |
0.05 |
**8.49 |
0.12 |
14 |
0.46 |
0.215 |
0.15 |
0.09 |
0.05 |
10.70 |
0.09 |
14 |
0.60 |
0.384 |
0.22 |
0.14 |
0.09 |
10.70 |
0.09 |
15 |
0.56 |
0.24 |
0.18 |
0.11 |
0.06 |
**11.86 |
0.08 |
15 |
0.74 |
0.35 |
0.26 |
0.17 |
0.10 |
**11.86 |
0.08 |
20 |
1.33 |
0.56 |
0.43 |
0.25 |
0.14 |
18.26 |
0.05 |
20 |
1.75 |
0.83 |
0.63 |
0.41 |
0.25 |
18.26 |
0.05 |
30 |
4.50 |
1.89 |
1.44 |
0.85 |
0.47 |
33.55 |
0.03 |
30 |
5.91 |
2.80 |
2.1 |
1.39 |
0.84 |
33.55 |
0.03 |
40 |
10.68 |
4.47 |
3.4 |
2.02 |
1.11 |
51.66 |
0.02 |
40 |
14.00 |
6.63 |
5.0 |
3.31 |
1.99 |
51.66 |
0.02 |
50 |
20.85 |
8.74 |
6.6 |
3.95 |
2.17 |
72.19 |
0.01 |
50 |
27.35 |
12.95 |
9.8 |
6.46 |
3.88 |
72.19 |
0.01 |
*----is the common mean wave period in the South Sea and marine site, the Bohai Sea, and it is 12sec that normal conditions are got the South Sea, and the Bohai Sea is 8sec
Table 4: drilling state, bow be to N, wind direction E/W
Rise height degree lm |
Storm δ
st?cm
|
Strong gale δ
st?cm
|
Fresh gale δ
st?cm
|
Moderate gale δ
st?cm
|
Strong breeze δ
st?cm
|
Period T sec |
Natural frequency f
n 1/sec
|
10 |
0.167 |
0.078 |
0.053 |
0.053 |
0.015 |
**6.91 |
0.14 |
10 |
0.22 |
0.116 |
0.08 |
0.08 |
0.03 |
**6.91 |
0.14 |
12 |
0.38 |
0.201 |
0.14 |
0.14 |
0.05 |
**9.08 |
0.11 |
12 |
0.38 |
0.201 |
0.14 |
0.14 |
0.05 |
**9.07 |
0.11 |
14 |
0.60 |
0.319 |
0.22 |
0.22 |
0.08 |
**11.43 |
0.09 |
14 |
0.60 |
0.319 |
0.22 |
0.22 |
0.08 |
**11.42 |
0.09 |
15 |
0.56 |
0.265 |
0.18 |
0.18 |
0.05 |
**12.69 |
0.08 |
15 |
0.74 |
0.392 |
0.26 |
0.26 |
0.09 |
**12.69 |
0.08 |
20 |
1.33 |
0.627 |
0.43 |
0.43 |
0.12 |
19.54 |
0.05 |
20 |
1.75 |
0.930 |
0.63 |
0.63 |
0.22 |
19.54 |
0.05 |
30 |
4.50 |
2.117 |
1.44 |
1.44 |
0.42 |
35.91 |
0.03 |
30 |
5.91 |
3.138 |
2.12 |
2.12 |
0.75 |
35.91 |
0.03 |
40 |
10.68 |
5.017 |
3.40 |
3.40 |
0.99 |
55.28 |
0.02 |
40 |
14.00 |
7.438 |
5.02 |
5.02 |
1.77 |
55.28 |
0.02 |
50 |
20.85 |
9.799 |
6.65 |
6.65 |
1.93 |
77.26 |
0.01 |
50 |
27.35 |
14.528 |
9.80 |
9.80 |
3.46 |
77.26 |
0.01 |
*----is the common mean wave period in the South Sea and marine site, the Bohai Sea, and it is 12sec that normal conditions are got the South Sea, and the Bohai Sea is 8sec
Table 5: rise the ship state, bow is to N, wind direction N/E
Rise height degree lm |
Storm δ
st?cm
|
Strong gale δ
st?cm
|
Fresh gale δ
st?cm
|
Moderate gale δ
st?cm
|
Strong breeze δ
st cm
|
Period T sec |
Natural frequency f
n 1/sec
|
10 |
0.2 |
0.072 |
0.05 |
0.03 |
0.02 |
6.46 |
0.15 |
10 |
0.2 |
0.107 |
0.07 |
0.05 |
0.03 |
6.46 |
0.15 |
12 |
0.3 |
0.124 |
0.08 |
0.05 |
0.03 |
**8.49 |
0.12 |
12 |
0.3 |
0.184 |
0.12 |
0.08 |
0.05 |
**8.49 |
0.12 |
14 |
0.4 |
0.198 |
0.13 |
0.08 |
0.04 |
10.70 |
0.09 |
14 |
0.6 |
0.293 |
0.20 |
0.13 |
0.08 |
10.70 |
0.09 |
15 |
0.5 |
0.24 |
0.16 |
0.10 |
0.05 |
**11.86 |
0.08 |
15 |
0.7 |
0.36 |
0.24 |
0.16 |
0.10 |
**11.86 |
0.08 |
20 |
1.2 |
0.58 |
0.39 |
0.23 |
0.13 |
18.26 |
0.05 |
20 |
1.6 |
0.85 |
0.58 |
0.38 |
0.23 |
18.26 |
0.05 |
30 |
4.1 |
1.94 |
1.32 |
0.78 |
0.43 |
33.55 |
0.03 |
30 |
5.4 |
2.88 |
1.9 |
1.28 |
0.77 |
33.55 |
0.03 |
40 |
9.8 |
4.61 |
3.1 |
1.86 |
1.02 |
51.66 |
0.02 |
40 |
12.9 |
6.83 |
4.6 |
3.04 |
1.83 |
51.66 |
0.02 |
50 |
19.2 |
9.00 |
6.1 |
3.63 |
1.99 |
72.19 |
0.01 |
50 |
25.1 |
13.35 |
9.0 |
5.93 |
3.57 |
72.19 |
0.01 |
*-----be the common mean wave period in the South Sea and marine site, the Bohai Sea, it is 12sec that normal conditions are got the South Sea, the Bohai Sea is 8sec
Table 6: drilling state, bow be to N, wind direction N/E
Rise height degree lm |
Storm δ
st?cm
|
Strong gale δ
st?cm
|
Fresh gale δ
st?cm
|
Moderate gale δ
st?cm
|
Strong breeze δ
st cm
|
Period T sec |
Natural frequency f
n 1/sec
|
10 |
0.2 |
0.072 |
0.05 |
0.03 |
0.02 |
**6.91 |
0.14 |
10 |
0.2 |
0.107 |
0.07 |
0.05 |
0.03 |
**6.91 |
0.14 |
12 |
0.3 |
0.184 |
0.12 |
0.08 |
0.05 |
**9.08 |
0.14 |
12 |
0.3 |
0.184 |
0.12 |
0.08 |
0.05 |
**9.07 |
0.11 |
14 |
0.6 |
0.293 |
0.20 |
0.13 |
0.08 |
**11.43 |
0.11 |
14 |
0.6 |
0.293 |
0.20 |
0.13 |
0.08 |
**11.42 |
0.09 |
15 |
0.5 |
0.243 |
0.16 |
0.10 |
0.05 |
12.69 |
0.09 |
15 |
0.7 |
0.360 |
0.24 |
0.16 |
0.10 |
12.69 |
0.08 |
20 |
1.2 |
0.576 |
0.39 |
0.23 |
0.13 |
19.54 |
0.08 |
20 |
1.6 |
0.854 |
0.58 |
0.38 |
0.23 |
19.54 |
0.05 |
30 |
4.1 |
1.944 |
1.32 |
0.78 |
0.43 |
35.91 |
0.05 |
30 |
5.4 |
2.883 |
1.94 |
1.28 |
0.77 |
35.91 |
0.03 |
40 |
9.8 |
4.609 |
3.13 |
1.86 |
1.02 |
55.28 |
0.03 |
40 |
12.9 |
6.833 |
4.61 |
3.04 |
1.83 |
55.28 |
0.02 |
50 |
19.2 |
9.001 |
6.10 |
3.63 |
1.99 |
77.26 |
0.02 |
50 |
25.1 |
13.346 |
9.00 |
5.93 |
3.57 |
77.26 |
0.01 |
*----is the common mean wave period in the South Sea and marine site, the Bohai Sea, and it is 12sec that normal conditions are got the South Sea, and the Bohai Sea is 8sec
Observation table 1~table 6 can be found:
1) for three spud leg drilling platform, the transverse vibration amplitude δ of platform
StBe directly proportional with rising height degree l, promptly to rise the height degree high more for spud leg, then the amplitude δ of drilling platform
StJust big more.In at table 1, when rising height degree l10m, under strong breeze speed condition, amplitude δ
StBe 0.02cm; But when spud leg rises the height degree and increases to 20m, amplitude δ
StReached 0.16m, be spud leg and rise 1 times of height degree increase, amplitude δ
StThen increase about 8 times; As when rising the height degree and reach 40m, amplitude δ
StBe 1.31cm, also be about 8.2 times.
2) for three drilling platform, amplitude δ
StBe varied to direct ratio with the increase of wind-force, promptly wind-force is big more, amplitude δ
StAlso big more.In at table 1, same rising under the height degree condition, when rising height degree l and being 10m, during strong breeze speed, amplitude δ
StBe 0.02cm, during storm speed, amplitude δ
StIncrease by 10 times, reach 0.2cm; In like manner, when rising the height degree and be 40m, during strong breeze speed, amplitude δ
StBe 0.16cm, and storm when speed amplitude δ
StReach 1.6cm.
3) according to the setting of this subject design conditions, bow is to being N, is located at wind direction when being respectively N/S, E/W, N/W (N/E) direction, the front face area A of drilling platform
PDifference, then its amplitude δ
StChange thereupon.According to amplitude δ
StThe wind direction ordering from big to little correspondence be followed successively by: N/S, E/W and N/E (N/W).And have the amplitude of amplitude ratio E/W direction of N/S direction high by about 15%, the amplitude of the amplitude ratio N/E direction of E/W direction is high by about 8%.
4) the present invention has determined to rise the selection foundation of measuring and calculating well location under the ship state.In at table 1: rising under the ship state, bow is to N, wind direction N/S, and three drilling platform:
When rising height degree l and be 12m, its period T is 8.49sec, because about Bohai Sea Area wave 8sec average period.When rising height degree l and be 15m, its period T is 11.86sec.Because Nanhai area wave average period is about 12sec.Therefore rise in marine site, the South Sea and should note avoiding 12m and this resonance height of 15m when calculating well location under the ship state.
5) the present invention has determined the drilling state selection foundation of measuring and calculating well location down.In at table 6: under drilling state, bow is to N, wind direction N/E: three drilling platform:
When rising height degree l and be 11-12m, its period T is 7.97-9.08sec.Because Bohai Sea Area wave average period is about 8sec, therefore should note avoiding this resonance altitude range of 11-12m rising ship time, when calculating, well location to take into full account effect on amplitude simultaneously.When rising height degree l and be 11-14m, its period T is 9.08-11.43sec.Because Nanhai area wave average period is about 12sec, therefore should note avoiding this resonance altitude range rising ship time, when calculating, well location to take into full account effect on amplitude simultaneously.
Second step was calculated well location coordinate accurately:
According to the result in the table 1: the well location coordinate of setting when in place at sea as three spud leg drilling platform is o (x
0, y
0), x
0=4429932.41, y
0=592734.32, rise height degree l=40m.When wind-force reaches 8 grades, record well location terrestrial coordinate b (x, y), x=4429935.13, y=592743.00 departs from and sets well location o (x
0, y
0) direction angle alpha=287.4 °, well location offset distance d=9.1m (as shown in Figure 4).Ask consider platform vibration after, pithead position coordinate accurately.
Separate: table look-up 1 as can be known, under these conditions, drilling platform lateral amplitude of vibration δ
StBe 8.78~5.92cm, now make δ
St=8.78cm.
With reference to this moment wind direction and bow to, the deflection of wind direction is α
w, by formula (20) and (21) as can be known, lateral amplitude of vibration δ
StX axle component δ
St(x)=sin (α
w) δ
St=8.78cm, y axle component δ
St(y)=cos (α
w) δ
St=0.Then:
x′=x-δ
st(x)=4429935.04
y′=y=592743.0
By formula (22) as can be known, b ' (x ', y ') departs from o (x
0, y
0) deflection
Then terrestrial coordinate deflection error is: α-α '=0.7 °.
The present invention is according to different drilling operation states: rise ship state, drilling state, different wind directions and different wind scales thereof, the different height degree l that rise; Calculate three drilling platform lateral amplitude of vibration δ
StAnd period T.And need be with the well location deduction amplitude δ that calculates in average period
StInfluence after, just can obtain pithead position coordinate accurately.The present invention has given prominence in the on-the-spot use and has been illustrated and uses in the marine site at the Bohai Sea and South Sea concrete condition, the present invention makes self-elevating drilling platform horizontal vibration amplitude and accurate measuring and calculating well location that guide of theory arranged, and at sea drilling engineering is of great immediate significance in using.