Many reservoirs are comprised of
relatively young sediments, which are so poorly consolidated that sand
will be produced along with the reservoir fluids unless the production
rate is reduced significantly. Sand production leads to many numerous
production problems including erosion of down hole tubular, valves,
fitting and surface flow lines, collapsed casing because of lack of
formation support. Thus a means to eliminate sand production without
greatly limiting production rates is desirable.
Sand production can be controlled using
different methods but the method of utmost importance to this project is
the mechanical method which basically involves the use of gravel pack
This method is considered the oldest and
most effective sand control mechanism. It is simply a down hole
filter designed to prevent the production of unwanted sands which
involves the placement of gravel across a perforated interval in the
sand screen annulus and also in the perforation tunnel to prevent the
influx of sand.
Inaccurate determination of gravel pack
size, could lead to sand influx which could be detrimental to both the
technical and economic aspect of production which is the overall
objective of this project aimed at identifying means to selectively
select appropriate gravel pack sizes from formation sands produced
through sieve analysis to meet optimum sand control for maximum
production without any detrimental effect to production hard wares.
In a gravel pack completion, sand that
is larger than the average formation sand grain is placed between the
formation and a screen or slotted liner with the aim of retaining most
of the formation sand, but letting very fine particles through it and
The two most common types of gravel pack
completion are the inside casing gravel packing or internal gravel
packing (IGP) and underreamed gravel pack or external gravel pack (EGP).
The underreamed casing gravel pack provides better conductivity through
the gravel but is limited to single zone completion.
1.1 AIMS AND OBJECTIVES
This project is aimed at
- To study the various types of gravel packing methods used in the petroleum industry.
- To analyze sieve analysis data of formation sands gotten from
OBEN13L in other to determine the appropriate gravel pack size used.
- To make conclusions on the state of OBEN WELL 13L on the basis of sieve data analysis and give possible recommendations.
1.2 SCOPE AND LIMITATION
The scope of this project is limited to
the mechanical method of sand control with more emphasis on the sieve
analysis of formation sands gotten from OBEN13L.
The method to be adopted for this
project is the use of sieve analysis and sucier correlation to determine
the gravel pack size to be used for OBEN WELL 13 with formation sands
gotten from the case study as mentioned above and useful information
gotten from the internet, textbooks, petroleum journals. This method
simply involves collecting core samples and running them through
different sieves with different opening sizes, usually sieves with
larger openings at the top and sieves of smaller opening at the bottom
and plotting each weight retained on each sieve against the sieve
opening size to determine the average formation sand size which is used
to find accurate gravel size using sucier correlation.