Environmental Implication of Exploration of Hydrocarbons

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Environmental Implication of Exploration of
Hydrocarbons Mitigation Measures
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NELP Blocks in India
Assam-Arakan(ON)
Rajasthan(RJ)
Gujarat-Kutch (GK)
I N D I A
Gujarat-Saurashtra (GS)
Tripura(ON)
CB-ON
MN-ON
West Bengal(WB)
Mumbai(MB)
Mahanadi(MN)
Krishna Godavari(KG)
CY-ON
Kerala-Konkan(KK)
Cavery Basin(CY)
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Offshore Blocks
East Coast
West Coast
Krishna-Godavari
Mahanadi
Mumbai
Gujarat-Saurashtra
Kerala - Kokan
Gulf of Kutch
Cauvery Basin
West Bengal
Andaman
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Onshore Blocks
Cambay Basin
Assam - Arakan
Mahanadi
Chennai
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Regulations
Disposal of Drill Cuttings Drilling Fluids

• Onshore
• Drill cuttings originating from on-shore or
  locations close to shore line and separated from
  Water Base Mud (WBM) should be properly washed
  and unusable drilling fluids such as WBM, Oil
  Base Mud (OBM), Synthetic Base Mud (SBM) should
  be disposed off-site or on-site. The disposal
  pit should be provided with leachate collection
  system.
• Details of design in respect of the impervious
  waste disposal pit and capping of disposal pit
  should be provided by the oil industry to
  concerned SPCB at the time of obtaining consent.

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Regulations
Disposal of Drill Cuttings Drilling Fluids

• Onshore (contd)
• Use of diesel base mud is prohibited. Only WBM
  should be used for on-shore oil drilling
  operations
• In case of any problem arising due to geological
  formation for drilling, low toxicity OBM having
  aromatic content gt 1 should be used. If the
  operators intend to use such OBM to mitigate
  specific hole problem, it should be intimated to
  MoEF and SPCB
• The chemical additives used for the preparation
  of drilling fluids should have low toxicity i.e.
  96 hr LC50 . 30,000 mg/l as per mysid toxicity or
  toxicity test conducted on locally available
  sensitive sea species. The chemicals used (mainly
  organic constituents) should be biodegradable

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Regulations
Disposal of Drill Cuttings Drilling Fluids

• Onshore (contd)
• Drill cuttings separated from OBM after washing
  should have oil content lt10 gm/kg for disposal
  into disposal pit.
• The waste pit, after it is filled up, shall be
  covered with impervious liner, over which, a
  thick layer of native soil with proper top slope
  be provided.
• Low toxicity OBM should be made available at
  installation during drilling operation.
• Drilling wastewater including drill cuttings wash
  water should be collected in a disposal pit,
  evaporated or treated and should comply with the
  notified standards for on-shore disposal.

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Regulations
Disposal of Drill Cuttings Drilling Fluids

• Onshore (contd)
• Barite used in preparation of drill fluid shall
  not contain Hg gt 1 mg/kg Cd gt 3 mg/kg
• Total area acquired for preparation of drill site
  must be restored after completion of drilling
  operation leaving no waste material at site.SPCB
  should be informed about the restoration work.
• In case, environmentally acceptable methods for
  disposal of drill waste such as (i) Injection to
  formation through casing annulus, if conditions
  allow, (b) land farming at suitable location (c)
  bio-remediation, (d) incineration or (e)
  solidification, are considered for adoption by
  oil industry, then proposal shall be submitted to
  SPCB and MoEF for approval.

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Regulations
Disposal of Drill Cuttings Drilling Fluids

• Offshore
• Use of diesel base mud (OBM) is prohibited. Only
  water base mud (WBM) is permitted for offshore
  drilling. If the operators intend to use low
  toxicity OBM or SBM to mitigate specific-hole
  problems in the formation, it should be intimated
  to MoEF and SPCB. The low toxicity OBM should
  have aromatic content lt 1.
• The toxicity of chemical additives used in the
  drilling fluids (WBM or OBM or SBM) should be
  biodegradable (mainly organic constituents) and
  should have toxicity of 96 hr LC50 value gt
  30,000 mg/l as per mysid toxicity of test
  conducted on locally available sensitive sea
  species.

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Regulations
Disposal of Drill Cuttings Drilling Fluids

• Offshore (contd)
• Hexavalent chromium compound should not be used
  in drilling fluids. Alternate chemicals in place
  of chrome lignosulfonate should be used in
  drilling fluids. In case, chrome compound is
  used, the drilling fluids and drill cuttings
  should not be disposed offshore.
• Bulk discharge of drilling fluids in offshore is
  prohibited except in emergency situations.
• WBM / OBM /SBM should be recycled to a maximum
  extent.Unusable portion of OBM should not be
  discharged into Sea and shall be brought to
  on-shore for treatment disposal in an
  impervious waste disposal pit.

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Regulations
Disposal of Drill Cuttings Drilling Fluids

• Offshore (contd)
• Thoroughly washed drill cuttings separated from
  WBM / SBM unusable portion of WBM /SBM having
  toxicity of 96 hr LC50gt 30,000 mg/l, shall be
  discharged off-shore into Sea intermittently at
  an average rate of 50 bbl/hr/well from a platform
  so as to have proper dilution and dispersion
  without any adverse impact on marine environment.
• Drill cuttings of any composition should not be
  discharged in sensitive areas notified by MoEF.
• In case of specific hole problem, use of OBM will
  be restricted with zero discharge of drill
  cuttings. Zero discharge would include
  re-injection of the drill cuttings into a
  suitable formation or to bring to shore for
  proper disposal. In such case, use of OBM for
  reinjection should be recorded and such records
  made available to the regulatory agency. Low
  toxic OBM having aromatic content lt 1 should be
  made available at the installation.

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Regulations
Disposal of Drill Cuttings Drilling Fluids

• Offshore (contd)
• In case, drill cuttings are associated with high
  oil content from hydrocarbon bearing formation,
  then disposal of drill cuttings should not have
  oil content .gt10 gm/kg.
• The drill cuttings wash water should be treated
  to conform with the limits notified under EPA,
  before disposal into sea. The treated effluent
  should be monitored regularly.
• Discharge of drill cuttings from the
  installatilon located within 5 km away from shore
  should ensure that there is no adverse impact on
  marine eco-system and on the shore. If, adverse
  impact is observed, then the industry has to
  bring the drill cuttings on-shore for disposal in
  an impervious waste disposal pit.

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Regulations
Disposal of Drill Cuttings Drilling Fluids

• Offshore (contd)
• If any, environmental friendly technology emerges
  for substitution of drilling fluids and disposal
  technology it may be brought to the notice of
  MoEF and regulatory agencies. If the operator
  desires to adopt such environment friendly
  technology, a prior approval from MoEF is
  required .
• Barite used in preparation of drilling fluids
  shall not contain Hg gt 1 mg/kg Cd gt 3 mg/kg.
• Oil drilling operators are required to record
  daily discharge of drill cuttings drilling
  fluids to offshore and also to monitor daily the
  effluent quality, and submit the compliance
  report once in every six months to MoEF.
• Enforcing Authority and the frequency for
  monitoring of ambient air marine water quality
  in respect of offshore installations, as
  discussed, may be decided by the MoEF before
  notification of these guidelines.

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Regulations

• Wastewater Discharge
• BOD5 40-50 mg/l or less
• COD 90-120 mg/l or less
• Suspended solid 30-40 mg/l or less
• Coliform count 200/100 ml

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Scope of Work for EIRA Studies for Offshore
Projects

• Collection of baseline environmental quality data
  for assessment of quality of marine environment
  including water, sediment and biological
  components
• Assessment of hydrography data in the study
  region
• Identification, predication and evaluation of
  significant impacts due to proposed exploratory
  drilling

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Scope of Work for Offshore Project(Contd)

• Evaluation of proposed pollution control
  facilities at the rig and recommendation of
  appropriate measures for pollution control
• Preparation of environmental impact statement
• Delineation of Environmental Management Plan
  (EMP) for mitigation of adverse impacts due to
  the proposed exploratory drilling
• Delineation of post project environmental quality
  programme

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Details of Work Plan for Offshore Project
Baseline Status

• Assessment of abiotic environment for water and
  sediment
• Assessment of biotic environment for water and
  sediment
• Assessment of primary and secondary productivity
  in the region
• Collation of hydrography data viz. current speed,
  direction, temperature gradient for assessing
  dilution and dispersion of wastes discharged from
  the rig in offshore areas
• Assessment of quality and quantity of wastes to
  be discharged in sea from drilling rigs
• Collection of data on coastal morphology and
  topography adjacent to the block

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Environmental Impact Studies for Offshore
Project

• Identification, quantification and evaluation of
  impacts on marine environment due to proposed
  exploratory drilling through
• Mathematical models describing transport/dispersio
  n, fate and effect of routine wastewater
  discharges and routine oil/chemical loadings from
  floater/rig
• Assessment of impact on marine productivity and
  diversity
• Assessment of positive and negative impacts on
  human interests with respect to fishing activity
  due to proposed exploratory drilling
• Assessment of impacts on coastal environment
  including ecologically sensitive areas, water
  bodies, intertidal and CRZ areas due to proposed
  drilling

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Details of Work Plan for Onshore Project
Baseline Environmental Quality Status

• Assessment of abiotic environment for water and
  soil components in terms of pH, buffering
  capacity, nutrient load, heavy metals,
  hydrocarbons and oil / grease etc.
• Assessment of biotic environment for water and
  soil components in terms of phytoplankton /
  zooplankton (enumeration, indices and
  distribution)
• Assessment of primary and secondary productivity
  in the region
• Assessment of quality and characteristics of
  wastes to be generated from drilling operations
• Identification of eco-sensitive and protected
  areas such as forests etc.

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Objectives of Study for Onshore Project
The study report is aimed at obtaining approvals
from the regulatory agencies viz. Assam State
Pollution Control Board, Assam State Environment
and Forest Department. If the project cost
exceed Rs. 100 crores, approval from the Ministry
of Environment and Forests (MoEF), New Delhi will
also be required. The studies shall cover the
following

• Collation and collection of environmental quality
  data / information for assessment of existing
  status / quality of air, noise, water, land,
  biological and socio-economic components of
  environment in and around the region proposed for
  drilling operations
• Identification, prediction and evaluation of
  significant environmental impacts due to proposed
  drilling operations
• Preparation of environmental impact assessment
  statement
• Delineation of environmental management plan for
  mitigation of adverse impacts

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Work Plan for Onshore Project
Baseline Environmental Quality Status The data
will be collated for the block area. Primary
data around the proposed drilling location will
be collected for all the components.

• Assessment of air quality around proposed
  drilling location
• Assessment of noise levels in the vicinity of
  drilling location
• Assessment of water quality in terms of its
  physico-chemical and biological characteristics
  in the vicinity of proposed drilling locations
• Assessment of soil quality in terms of texture
  porosity heavy metal and biological diversity at
  the drilling location and in its vicinity
• Assessment of terrestrial ecology and diversity
  of flora in the block and near the drilling
  location
• Assessment of quantity and characteristics of
  wastes to be disposed during drilling operations
• Identification of eco-sensitive and protected
  areas such as Reserved forests, Bird sanctuaries
  etc.

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Environmental Impact Assessment for Onshore
Project

• Identification, quantification and evaluation of
  impacts on air, water and land environment
  including terrestrial ecology and parameters of
  human interest due to proposed drilling operations

Environmental Management Plan for Onshore
Project

• Suggestion of appropriate measures to prevent/
  minimise potential impacts due to the drilling
  activity on various components of environment
• Preparation of environmental quality monitoring
  programme during drilling operations

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Risk Assessment
Objectives

• Identification of vulnerable operations
• Estimation of hazard distances with recourse to
  maximum credible accident scenarios
• Proposed risk mitigation measures
• Delineation of Disaster Management Plan

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Scenarios Assumed for Consequence Analysis

• Jet fire due to accidental release of natural gas
  
• Jet fire due to accidental release of oil and gas
  mixture
• Pool fire of crude oil spilled on sea surface

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Wastes Envisaged in Exploratory Drilling

• Drill Cuttings m3/well 91 500
• Wastewater during drilling operation m3/d 25
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• Sewage m3/d 30 35

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Physico-chemical Characteristics of Combined
Wastewater from Drilling Operations
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Three Dimensional Plume of Suspended Solids
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Concentration Vs Central Line Distance
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Prediction of Impact Due to Discharge of
Drilling Fluids and Drill Cuttings

• In this study CORMIX 1 was used to predict the
  impact due to discharges of drill wastes
  discharge from drilling operation discharge
  depth 20 m
• It is inferred from the model that the effect of
  the wastewater being discharged is localized,
  persists up to distance of 100 meter from the
  discharge port, and the background concentration
  is nearly attained
• Considering the wastewater quantity as 60 m3/d
  (30 m3/d shale shaker, desander, desilter 30
  m3/d domestic wastewater) with 40 mg/l BOD, the
  total load per day would be 2.4 kg. With the
  dilution of 105 times, the ultimate BOD load in
  the discharge point at a depth of 10 m would be
  less than 1 mg/l. Hence, impacts on
  characteristics of water column and benthos due
  to drilling activity in the study region will be
  negligible.
• The water based drilling mud is non toxic to the
  marine organisms
• Drilling mud toxicity, LC50 is gt30,000 mg/l hence
  impact on biological component in water column is
  not envisaged
• Drill cutting (average 150 m3/well or 3-5 m3/d)
  would be discharged below the water surface
  through a pipe and would distribute evenly on sea
  bed (depth 27 170 m). Benthic fauna at the
  drilling location may temporarily be affected but
  would recover to normal after drilling is
  completed.

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Prediction of Impacts due to DG Sets

• NOx emission from all the DG sets together has
  been computed to be around 1.0 g/sec.
• Considering the height of release (about 15 m
  above sea surface including the height of stack
  of DG set i.e. 5-6 m and the platform), wind
  directions both in SW and NE, and wind speeds
  varying from 11-25 km/hr., the maximum
  concentration of NOx at sea surface will be
  around 5 ?g/m3 at a distance of about 2 to 3 km
  in downwind direction.
• The location of drilling is 10 km away from coast
  hence the impact on land and coastal areas is not
  envisaged.
• The air quality monitored in offshore area in
  earlier studies also shows ambient levels of NOx
  to be around 5-6 ?g/m3

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Environmental Impact Statement

• The modeling studies indicate that the rise in
  turbidity levels is restricted to 100 m zone from
  rig and recover immediately due to dilution
  available at 20 m depth.
• The discharge of drill cuttings at this depth
  will temporarily affect benthic community for
  shorter duration and recover to normal after the
  activity is completed.
• The sediment near the rig will be disturbed due
  to drill cuttings discharge during drilling
  operation. Though the duration of drilling is
  22-47 days, actual drilling time is only 40 of
  the duration and wastes are generated only during
  drilling.

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Marine Environment

• Low toxicity WBM, having 96 h LC50gt30000 mg/l
  will be used
• The water based drilling muds will be recycled
  and reused to a maximum extent
• Drill cuttings, thoroughly washed and separated
  from WBM, will be discharged to the sea
  intermittently below the water surface.
• If the drilling is through complicated well
  formation, to mitigate the specific hole problem.
  Synthetic based mud with low toxicity of 96
  h LC50 gt30,000 mg/I as per mysid toxicity test or
  toxicity test conducted on locally available
  sensitive species will be used.
• Wastewater generated on drilling rigs will be
  treated as required under MARPOL and CPCB
  guidelines, before disposal to the sea. Modular
  treatment plants will be available for this
  purpose on board the drilling rig to treat
  domestic and drilling wastewater.

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Marine Environment (Contd)

• Disposal of waste oil into the sea is prohibited
  hence all oily wastes will be collected and
  incinerated at the rig.
• Emissions from diesel generator sets should be
  controlled through efficient maintenance of the
  rotary equipments and their accessories
• Barite in drilling fluids will contain Mercury lt
  1 mg/ kg and Cadmium lt 3 mg/kg. A certificate to
  this effect will be obtained from supplier
• Disposal of wastewater will be subsurface and
  free of oil
• Drill cuttings will be separated from the
  drilling fluid in a shale shaker or other similar
  device, thoroughly washed before discharged and
  the separated additives will be returned to the
  drilling mud system
•  

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Marine Environment (Contd)

• The biodegradable garbage will be separated from
  other disposable domestic wastes. This
  biodegradable garbage will be ground in a
  crushing machine, filled into Jute bags and
  discharged in sea. The non biodegradable solid
  wastes will be collected, compacted and stored in
  containers, or placed in special metal baskets or
  plastic bags for transport to onshore facilities
  
• Sewage will be treated at the facilities
  available at the rig and chlorination of treated
  sewage will be done to achieve 1 mg/l residual
  chlorine before discharging into sea.
• Liquid hydrocarbons from well will be brought to
  the shore for testing whereas gaseous
  hydrocarbons will be flared after testing at the
  rig itself
• All the balance drilling fluids after the
  drilling will be reused. Entire SBM mud will be
  always recycled and will not be discharge in sea
  whereas only nonusable WBM occasionally will be
  discharged into sea with proper dilution
• Based on risk assessment studies it is suggested
  that during drilling activity fishing should be
  restricted beyond 200 m zone from the drilling
  locations

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Air Environment

• All equipments would be operated within specified
  design parameters during drilling operations
• The DG emissions from DG sets must confine to
  standards stipulated by CPCB in 2002
• Any dry, dusty materials (chemicals), mud etc.
  would be stored in bags or sealed containers
• Flaring of gas during well testing will be
  minimized and restricted to the short duration

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Noise Environment

• While procuring major noise generating equipments
  such as diesel generators etc. it would be
  ensured that the manufacturers have taken
  measures for minimizing the noise levels
• Noise barriers/shields would be provided around
  the high noise units wherever possible
• Use of ear muffs/plugs and other protective
  devices would be provided to the workforce
• Enclosures around high noise sources would be
  provided depending on the size of the unit

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Summary of Consequence Analysis for Jet Fire of
Natural Gas
Operating Temperature 300F (148.9C) Diameter
of opening 8.5
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Summary of Consequence Analysis for Jet Fire of
Oil and Gas Mixture (70 Crude Oil 30 Natural
Gas)
Operating Temperature 300F (148.9C) Diameter
of opening 8.5
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Damage Contour for Jet Fire of Mixture of Crude
Oil and Natural Gas
Damage Contour for 4 kW/m2 (188m for 2F
condition)
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Risk Mitigation Measures

• Maintenance of mud weight
• Monitoring of active mud tank level
• Monitoring of hole fill-up/return mud volume
  during tripping
• Monitoring of inflow
• Monitoring of background/trip gas
• Safe handling of chemicals at drilling well
• Presence of well trained drillers and mud
  engineers
• Strict adherence to safety management procedures
  and well control procedures

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Disaster Management Plan

• A detailed response plan is formulated to handle
  level 1,2,3 emergencies
• MD, GSPC to ensure that the response plan is in
  place and operable and that selected personnel
  are trained to act as a team under the Chief
  Emergency Co-ordinator
• DMP incorporates all the possible risk scenarios
  and the actions to be taken through proper
  execution of the plan
• DMP will be integrated with the regional
  contingency plan for east coast which is already
  in place

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Thank You