II. ENVIRONMENTAL IMPACTS AND RISKS EVALUATION OF OFFSHORE DRILLING
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II.3.2 Calculation of well section damage and risk scores
The graph in Figure 20 shows the total scores in the damage classes for the different sections of
the well. Section 8’1/2 has the highest environmental burden on human health, climate change
and resource depletion with respectively 2.23E+05 [DALY], 3.97E+03 [Kg CO2 eq.] and
1.64E+04 [MJ Primary]. For ecosystem quality, section 36” has the highest impact score with
4.98E+06 [PDF.m2.yr] followed by sections 26” with 1.09E+06 PDF.m2/yr and 17 ½” with
4.38E+05 PDF.m2/yr (Tabl.7).
Figure 22: Damage and risks scores related to well sections
Table 7: Well section damage and risk scores, expressed by corresponding units
II.3.3 Contribution scores of well sections on the risk to human health
The ionizing radiation and human toxicity are the two categories of impact that cause damage to
human health, which are expressed in DALY. It can be observed that human toxicity has a
higher potential than ionizing radiation for all the sections (Fig. 22). This shows the majority
contribution of life cycle emissions from offshore drilling presenting a risk of human toxicity,
such as metals and hydrocarbons, much greater than the contribution of ionizing radiation such
as x-rays.
Catégorie de
dommages
Unité
Section 36"
Section 26"
Section 17
1/2"
Section 12
1/4"
Section 8
1/2"
Human health
DALY
7.22E+04
1.46E+05
1.45E+05
1.86E+05
2.23E+05
Ecosystem Quality
PDF*m2*yr
4.98E+06
1.09E+06
4.38E+05
3.30E+05
3.01E+05
Climate Change
Kg CO2 eq
1.10E+03
1.67E+03
1.94E+03
2.46E+03
3.97E+03
Resources
MJ Primary
2.93E+03
7.52E+03
9.01E+03
1.26E+04
1.64E+04
0
10
20
30
40
50
60
70
80
90
100
Human health
Ecosystem Quality
Climate Change
Resources
Total
damage
%
Section 36"
Section 26"
Section 17 1/2"
Section 12 1/4"
Section 8 1/2"