Page 74 - Hydrocarbon

Drilling Engineering 61

air emission
effluent and waste disposal
pollution control
visual impact
traffic (rig transport and supply)
emergency response (e.g. fire, spills).

The EIA is an important document, often on the drilling project’s critical path.
In new areas, the required environmental data may not be available. Data collection
may stretch over several seasons to capture such parameters as currents, migration
paths, breeding habitats or weather patterns.

4.4.1. Onshore sites
A site survey will be carried out, from which a number of geotechnical parameters
can be established, for example carrying capacity of the soil at the planned location,
possible access routes, surface restrictions like built-up areas, lakes, nature reserves,
the general topography and possible water supplies. The survey will allow the
adequate preparation of the future location. For instance, onshore in a swamp area
the soil needs to be covered with support mats.
The size of the rig site will depend on operational requirements and possible
constraints imposed by the particular location. It will be determined by
the type of derrick or mast (which will depend on the required loads); it must be
possible to rig this up on site
the layout of the drilling equipment
the size of the waste pit
the amount of storage space required for consumables and equipment
the number of wells to be drilled
whether the site will be permanent (in case of development drilling).
A land rig can weigh over 200 tons and is transported in smaller loads to be
assembled on site.
Prior to moving the rig and all auxiliary equipment, the site will have to be
cleared of vegetation and levelled. To protect against possible spills of hydrocarbons
or chemicals, the surface area of a location should be coated with plastic lining and a
closed draining system installed. Site management should ensure that any pollutant
is trapped and properly disposed of.
If drilling and service personnel require accommodation at the well site, a camp
will need to be constructed. For safety reasons, the camp will be located at a distance
from the drilling rig and consist of various types of portacabins. For the camp, waste
pits, access roads, parking space and drinking water supplies will be required.

4.4.2. Offshore sites

The survey requirements will depend on rig type and the extent of the planned
development, for example single exploration well or drilling jacket installation.