Weather conditions, difficulties in programming tests and problems of storage security on the drilling barge often make it impossible to carry out offshore well tests if there are no means of disposing of the oil.
FLOPETROL has made a study of the destruction of the oil produced during initial tests by means of specially designed burners.
Particular characteristics of this oil are the unsteady rate of production and heavy pollution by water, mud and solid particles (sand and Capsule gun debris).
The burning device produced as a result of FLOPETROL's research enables the polluted oil to be burned and is designed in such a way that the platform is completely protected from the heat given out on combustion.
Well tests both on and offshore are carried out on more or less the same principle. Offshore, however, tests should be completed as quickly as possible for the obvious reasons of cost.
At the present time there is no particular difficulty in carrying out tests on wells producing dry gas, even on a drilling platform. In the North Sea it is common to obtain gas flow rates of 30 MMSCFD and, for security reasons, to burn off the gas without any ill effects on the equipment.
The case of oil wells or wells producing an effluent rich in condensate is not the same and disposing of the effluent creates a real problem.
For drill stem tests of short duration it is possible to stock the small quantities of effluent produced on the platform and afterwards to arrange for the transport of the full tanks to land by a supply boat.
If the tests are to last for some length of time and the flow rate is high, it is not possible to stock the oil on the platform due to lack of space, maximum loading restrictions and for reasons of safety.
Various solutions can be considered to solve this problem but none is particularly satisfactory.
One solution is to transport the oil to land by means of a tanker. The boat must be positioned near the well and loaded by gravity, the oil having first been passed through a low pressure separator. A flexible hose is required and the boat must have an excellent anchoring system.
This method is often employed for large quantities of oil, in the Middle East for example. But the system is not sufficiently adaptable - a boat of the required capacity must be chartered in time and there is always the possibility of the boat's arrival being delayed by bad weather. It is also necessary to be in an area where there are adequate unloading facilities on land and that there should be no customs or administrative problems. These difficulties often render this operation very costly.
Another solution is simply to dispose of the oil directly into the sea. All countries forbid this practise but, for very small quantities several companies resort to this method in cases of absolute necessity. This procedure can be dangerous.