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field perimeter, or the substitution of peripheral wells as
injection wells when they go wet.

TEXT №5.

1. Read the text.
2. Find the key sentence in each paragraph and translate it into
Ukrainian.

With the drilling of the appraisal wells, the nature of the
accumulation begins to emerge. With each well, the information
gained is used to refine the model of the accumulation until the
point is reached when it can be stated with some confidence that
the accumulation is sufficiently large and contains sufficient
recoverable oil or gas to make the development of the field
commercially sensible.
In a simple onshore structure, these appraisal wells may
be designed so that they can produce petroleum eventually; but
their real purpose is to obtain more information. Offshore, the
appraisal wells will not be capable of more than limited testing
of reservoirs because the economics of offshore production
requires production platforms that will be used first to drill a
number of deviated wells to develop part of the field, then to
produce them to a central facility for preliminary processing
(such as gas separation) and transport through pipelines to the
shore facilities. More than 20 wells are usually drilled and
produced to one platform, so the appraisal programme must be
sufficiently comprehensive offshore to permit planning of these
wells and the platforms.
It is in the nature of petroleum fields that the decision to
develop is made without full knowledge of the accumulation.
Full information is available only when it is no longer needed.
The appraisal phase ends with the decision either to abandon the
prospect as non-commercial, or to develop it as an oil or gas
field.
After the decision to develop is made, development wells
are drilled for the production of oil (or gas, as case may be); and
their siting is such that each reservoir will be developed as
economically as possible on the model that has evolved with the