When hydrocarbon property and reservoir characteristics .Well test

        When the well is
ready for producing, the production staffs determine whether it is gas or oil
will come out from the reservoir, and also they examine the capacity of
producing oil. Therefore Initial well test or potential test are the suitable
tests for evaluate the capability of the well for producing hydrocarbon. It is
a set of planned data acquisition to understand the hydrocarbon property and
reservoir characteristics .Well test is an operation and set of planned data which used for
understanding the property of hydrocarbon in reservoir. It demonstrates the
existence of oil by establishing flow to the surface, the state of the well to
collect data, and the productivity of the reservoir. The most
essential data that can be obtained from this test is pressure and flow rate.
Also by well log data, Seismic data, and core sample the reservoir property
identified such as permeability of rock will be achieved. Well test is used to record pressure drop in
reservoir to detect its property and gathering data in order to define whether
it is a productive or non-productive reservoir. Also, it is useful for estimating
many parameters such as flow conductance,

, skin factor, s,
non-Darcy coefficient, D (multi rate
tests) , storability,

 (interference
tests),fractured reservoir parameters  ,fractured
well parameters xf and kfwf, drainage
area, distance to faults, and drainage shape. However it is difficult to
measure some other properties like k,
h, or ? individually. Also

it is hard to distinguish pseudo skins (e.g., partial penetration) from
mechanical skin, the location or properties of (small) heterogeneous regions
within the reservoir, the permeability of altered regions near the wellbore (a
few wellbore radii away), and radial variations in saturation and mobility. In
addition well test consist of changing rate , and pressure change obtained by
this rate therefore to obtain pressure test we have to be able to measure time,
pressure, and control rate. Well problems happen during production due to flow
of the fluid to the wellbore resulting
either in a decrease in production or in failure of equipment installed down
hole or at the surface which affects the formation and it leads
operation difficulties. Such problem can be avoided through early recognition
analysis of production rate, fluids,
and the well conditions. Such
practices can prevent a costly work over that may be required to restore
production from the well and may also prevent total loss of the wellbore.