Journal of Soil Science and Environmental Management Vol. 1(5), pp. 86-91, July 2010
Available online at http://www.academicjournals.org/JSSEM
ISSN 2141-2391 ©2010 Academic Journals
Ful Length Research Paper
Environmental impact assessment of oil and gas
sector: A case study of Magurchara gas field
J. B. Alam1, A. A. M. Ahmed2, G. M. Munna1 and A. A. M. Ahmed3
1Department of Civil and Environmental Engineering, Shahjalal University of Science and Technology, Sylhet-3114,
2Department of Civil Engineering, Leading University, Sylhet-3100, Bangladesh.
3Department of Business Administration, Leading University, Sylhet-3100, Bangladesh.
Accepted 21 June, 2010
This study focuses on the environmental impact assessment of Magurcherra gas field through
environmental, socio-economical and meteorological study. The major activities involved are seismic
activities, drilling activities, exploration and production. In the case of Magurcherra gas field, improper
planning and drilling activities have created explosion and caused huge environmental damage. In
order to evaluate the environmental damage due to exploration and drilling activities, checklist of
possible environmental impact on the nature, society and socioeconomic activities of the proposed
area has been identified by focus group discussion, survey and sample testing. During the observation
pollution related with noise found as temporary and minor but the air is observed to be polluted by
dust, SPM, SOx, NOx, and CO2 etc. The effects of explosion on the natural forests, land, wildlife, tea
garden, infrastructure, local people and tea garden workers, livestock feeding, communication and
transport etc are measured. During observation, water quality deterioration by spills and leaks of oil
and grease, paints, solvents and chemicals was identified. It was found from the cumulative analysis of
the study that the project is environmentally feasible.
Key words: Magurcherra gas, meteorological study, environmental damage, feasible, socio-economical.
Bangladesh is poor in natural resources by global stand-
in various ways. During dril ing operations, dril ing fluid or
ards. Natural gas is the most important natural resource
mud is continuously circulated through dril pipe and back
that has been discovered and being utilized. Other impor-
to the surface equi-pments to balance underground
tant discoveries include coal, peat, hard rock and modest
hydrostatic pressure, to cool the bit and flush out rock
reserves of limestone, gravel, glass sand and various
cuttings. The location of a dril site depends on the
types of clay. Environmental issues and problems in Ban-
characteristics of the underlying geological formation;
gladesh are now recognized as the key concerns for the
however, environmental impacts can be minimized by
sustainable development of the country. Magurcherra gas
selecting appropriate site for dril ing.
field, 8 km from Srimangal on the road to kamalganj. The
One of the earliest contaminant of the dril ing site is the
gas field caught fire in 1997 and was ablaze for three
mud used while dril ing. Huge quantities of dril ing mud
months, laying waste to betel-nut plantations and tea
are required continuously. The returned mud is recycled,
estates in the vicinity (McAdam, 2008). General y, in the
but final y to be disposed of the effluent mud is usual y
petroleum sector major activities involved are seismic
stored in large pits. Around four to five thousand cubic
activities, dril ing activities, exploration and production.
meters of mud is stored at a time. Eventual y water
During those activities the Surrounding areas are affected
evaporates, leaving behind the clay in the pit and cont-
aminates top soil. Dril ing-mud requires large quantities of
water from the nearby sources. It is necessary to check
whether the water is contaminated by pathogens. If the
*Corresponding author. E-mail: email@example.com.
water is contaminated, it must be treated. Large quantities
Alam et al. 87
Planned project activities
Detection of changes
Actual changes in
in the environment
Evaluation of actual
Figure 1. Flow diagram for EIA of the project.
of fluid are let of on the ground or into a nearby stream.
consumption rate and emission factor (Kato and Akimoto, 1992) for
The amount of effluent disposed wil be very damaging
the unit consumption. The Gaussian Plume Model (Peterson, 1978)
for the neighboring areas. It is particularly damaging in
was used to estimate the pol utant concentration. Environmental
the case of off-shore exploration as there is no alternative
Impact Assessment (EIA) was assessed by the graded matrix
system developed by Leopold et al. (1971) in which ‘magnitude’
but to dispose it off into the sea (BUET, 2003). Envi-
and ‘importance’ of the impact in each cel of a matrix can be
ronmental Impact Assessment (EIA) for al petroleum
denoted by assigning numerical values. The flow diagram of the
projects wil al ow the planners and implem-enters to
EIA project shown in Figure 1.
understand the environmental impacts and con-seq-
uences of their projects (NEAB, 1998; DoE, 2001).
The EIA process is thought to consist of six main comp-
Baseline environmental condition of Magurchara gas field
onents: basics; impact identification; description of the
affected environment; prediction and assessment of
Magurchara gas field explosion
impacts; selection of proposed action and documentation
The gas field caught fire in 1997 and caused huge damage of life
in accordance with extant guidelines (Center, 1997). EIA
and property over the whole area. The Magurchara gas field exp-
has been fol owed to define a project and development
losion damaged about 60 hectors of natural forest and 300 hectors
alternatives, the environment on which it may be
of land were burnt. A large part of wild life (Deer, birds, foxes,
affecting, the potential impacts, mitigation alternatives,
monkeys etc) was destroyed or displaced to other places. Around
impact monitoring and public interests. In order to find out
3000 people were affected because 31 hectors of tea garden was
completely damaged during explosion (EPCT, 1997). So, the
possible beneficial and adverse impacts, environmental
overal socio-economic and environmental scenario was highly
impact analysis, construction related impacts, air
affected by the gas field explosion. Preliminary assessment of
pol ution, thermal pol ution of waste resources, noise
environmental damages and deterioration of Magurchara Gas Field
pol ution, soil cont-amination, sediment and dust
Explosion are given in Table 1 and its effects on plants, soil and at-
pol ution, waste disc-harges, occupational health and
mosphere are shown in Figure 2 which shows the deterioration soil
safety, changes in aesthetic environment etc were carried
properties, effects on plants on the Magurchara gas field site.
out in this study. The major objectives of the present
study were (i) to assess the socio-economic impacts of
these projects, (i ) to assess the impacts on land use
pattern and (i i) to identify and quantity the environmental
Noise, which is seldom recognized as a source of pol ution,
effects of these projects.
constitutes a danger to people’s health through physical, phy-
siological and even psychological stresses. Dril ing operations in
particular are very noisy and pose a threat to the relevant workers
at the site.
Checklist method was used in this study. A questionnaire was
Production of formation water
developed and the fol owing assessment was made based on
expert’s opinion. 100 experts from different fields related to gas and
Oils produced from wel s are invariably accompanied with water as
oil sector were asked and the evaluation was prepared. Pol utants
they are in close association in oil pool. Hence, whenever oil is
emission rates from the power plant are calculated by using the fuel
produced, some quantity of water is also produced. On an average
88 J. Soil Sci. Environ. Manage.
Table 1. Preliminary environmental assessment of Magurchara gas field explosion.
60 ha. completely damaged
100 ha completely burnt
Land (300 ha.)
Partly burned observed
Covered with ash and condensate observed
Landslide / Land subsidence observed
Deer, birds, foxes, monkeys etc. destroyed or displaced
Water logging/ pol ution
31 ha. completely damaged
1 km Train line damaged
1 km Medal ed road, 2 culverts damaged
1 km Gas line
Local people and Tea garden workers
Around 3000 people affected
Communication and transport
Air pol ution
Population / market displacement
Figure 2. Effects of Magurchara gas field explosion on the environment.
Alam et al. 89
Table 2. Possible environmental impacts of pipeline construction.
Positive and negative impact
Providing temporary housing, eating and
sanitary facilities for the construction force to
prevent overtaxing the local infrastructure
Compensation to owners have to be made for
crop loss, land should general y be acquired by
individual agreement with the owners
Soil fertility is to be preserved by segregating
the 30 cm. topsoil layer from common fil
material during trenching.
Impact is negligible (No)
No mitigation measures are necessary
Potable water used by the construction force
have to be tested to ensure that it meets the
quality standards of Bangladesh for drinking
water. Implementation of Waste Disposal Plan
Surface and groundwater quality
including proper sanitary facilities for the
construction force and proper disposal of solid
waste generated by the construction activities.
Select alternate routes of pipeline to avoid
forest. Construction force has to be prohibited
from hunting to prevent further degradation of
Fish and wildlife
this limited resource. Natural fish production
has to be protected by control ing water
Historical and archaeology resources
Impact is considered minor (Negative)
up to 20% water is associated with oil. This water needs to be
stated as negative where the air quality is negligible. A
separated and disposed off in a suitable manner. This water is
minor impact is stated on historical and archaeological
usual y charged with droplets of oil and some salts. Droplets of oil
are col ected as far as practicable by using demulsifies. Sometime
this water is used for injecting into the water-horizon in the oil field.
Environmental evolution has been shown in Table 3
The quantity of water to be disposed of is colossal and requires
where the identified environmental parameters are
careful thoughts as to how it can be done so that the environment is
analyses for finding out the feasibility of the project by
Leopold matrix. Leopold et al. (1971) have developed
graded matrix system in which ‘magnitude’ and
‘importance’ of the impact in each cel of a matrix can be
RESULTS AND DISCUSSION
denoted by assigning numerical values. This approach is
used of gross screening technique for impact identi-
Environmental impact assessment of dril ing and pipe line
fication purposes. This study used checklist method and
activities was predicted for the Magurchara Gas Field
identified the impact through three different dimensions of
exploration in oil and gas sector. A questionnaire was
environment physical, ecological and socio-economic.
developed and the fol owing assessment was made
The effects are stronger on the eco-logical and socio-
based on expert’s opinion. 100 experts from different
economic environment rather than physical environment.
fields related to gas and oil sector were asked and the
The effect on plane land is evaluated on low and hil y
evaluation was prepared. In Table 2, Negative and
terrain land medium. Most of the components of physical
Positive were used to classify the magnitude of the
environment are evaluated as insignificantly affected.
environmental parameters with the relevant mitigation
Ecological environment of the study area is seriously
measures. The impact on the socio-economic, land use,
affected by the gas field explosion. In the study area a
surface and groundwater quality, fish and wild life is
huge amount of forests are distracted and got high grade
90 J. Soil Sci. Environ. Manage.
Table 3. Environmental impact evaluation of Magurchara gas field explosion.
Types of impact
S/No. Environmental component
Hil y terrain
Air pol ution
Sox, Nox, CO2
Destruction of plantation
Disturbance to wildlife
Disturbance to migrated birds
Destruction of wetland
Loss of land
Alam et al. 91
Table 3. Contd.
Health and Safety
Noise to neighbors
in evaluation. The effects on wildlife and migrated birds
erosion has to be minimized with the measures for
are evaluated as low and medium, respectively.
conserving soil during stream crossings and during
Distribution of wetland is also considered by the gas field.
In socio-economic environment agriculture sector, crops
and plantation, and farming are affected and the effects
are evaluated as medium. The workers of the gas field
and the irrigation are affected highly by the gas field ex-
plosion. Other important components of socio-economic
BUET (2003). Workshop in Oil and Gas Sector”, organized by
Bangladesh University of Engineering and Technology, Dhaka.
environment like industrial, residential, commerce and
Canter LW (1997). “Environmental impact assessment”, 2nd edition,
industry, household, land communication, social structure
Mcgraw-hil Inc., p. 640
are also affected and effects are evaluated as low.
DoE (2001). “EIA Guidelines”, Department of Environment, Ministry of
Environment and Forest, Govt. of Bangladesh.
EPCT (1997). “Draft Report - Environmental Impact Assessment in Oil
and Gas Sector”, survey work conducted by Engineering Planning
Consultancy Team, Sylhet.
Kato N, Akimoto H (1992). Anthropogenic Emissions of SO2 and NOx in
It is clear from the study that the cumulative impact of the
Asia: Emission Inventories. Atmospheric Environment, 26A: 2997-
project is +220 which indicates that the project is environ-
Leopold LB, Clarke FE, Manshaw BB, Balsley JR (1971). A Procedure
mental y feasible. During back fil ing of trench the fertility
for Evaluating Environmental Impacts, U.S. Geological Survey
of soil has been reduced and the water quality has been
Circular No. 645, Government Printing Office, Washington, D.C.
deteriorated by spil s and leaks of oil and grease, paints,
McAdam M (2008). Bangladesh Travel Guide, Lonely Planet, 6th
Edition ISBN: 9781741045475, p. 153.
solvents and chemicals. The fish production of this area
NEAB (1998). “EIA Manual”, National Environmental Association of
has been observed to be affected by water pol -ution from
oil and grease, chemicals and sanitary wastes. Pol ution
related with noise found as temporary and minor but the
air is observed to be pol uted by dust, SPM, SOx, NOx,
and CO2 etc. Water used by the cons-truction force have
to be tested to ensure that it meets the quality standards
of Bangladesh for drinking water, or it should be
chlorinated so that the tested chlorine residual is 0.2 mg/l
or greater, after 10 min of contact time. Implementation of
Waste Disposal Plan including, proper sanitary facilities
for the construction force and proper disposal of solid
waste generated by the construction activities. Soil