INTRODUCTION
1.1 BACKGROUND
Produced
water was defined by Veil et al. (2004) as saline water with hydro-carbons
extracted from the rocks to the surface. The oil and gas industry is a
combination of industries: oil, coal-bed methane and conventional
non-associated gas producers. The aqueous effluent from such process operations
is the largest volume stream in the oil and gas operation and exploration
processes. Different types of fluids such as saline-water, oil and gas are held
down by rocks in the sub-surfaces. The hydrocarbon compounds are saturated with
saline water and then captured in the rocks. Due to the density difference, the
hydrocarbons with lower density travelled to capture locations in rocks. This
led the displacement of saline water. At certain thermodynamic conditions,
saline water and hydrocarbons are absorbed by the rocks. Saline water comes
from lower side, above and the flow within hydrocarbon zone. There is another
type of water that comes with saline water referred to as “connate water” or
“formation water”. Formation water is the water which is produced during the
production activities by the injection of fluids and additives.
Table
1.1:Some
of the possible options available for the management of produced water are
|
Options
|
Description
|
|
Avoid
production of water onto the surface
|
Using polymer gels that block water contributing fissures or
fractures or Downhole Water Separators which separate water from oil or gas
streams downhole and reinject it into suitable formations.
|
|
Inject
produced water
|
Inject the produced water into the same formation or another
suitable formation; involves transportation of produced water from the
producing to the injection site.
|
|
Discharge
produced water
|
Treat the produced water to meet onshore or offshore discharge
regulations.
|
|
Reuse
in oil and gas operations
|
Treat
the produced water to meet the quality required to use it for drilling,
stimulation, and workover operations.
|
|
Consume
in beneficial use
|
In some cases, significant treatment of produced water is
required to meet the quality required for beneficial uses such as irrigation,
rangeland restoration, animal consumption, and drinking water for private use.
|
Increased
agricultural production to feed the increasing world population and the
everexpandingneed of industry, have made great demands on the limited water
supply. The total global water (surface and ground water) is estimated to be
1,52 million km cubic from which, salty water (sea and oceans) 95-97%, polar
water 4.2%. Hence, only 1% can be used and is available as surface and ground
water.A reliable and suitable irrigation water supply can result in vast improvement
in agricultural production and the economic vitality of the region.Irrigated
agriculture is dependent on an adequate water supply of suitable quality. Water
quality concerns have often been neglected because water supplies have been
plentiful and readily available in the past, this situation is now changing in
many countries.There is a steady increase of the amount of water used and wastewater
produced by urban communities and industry. This poses potential health and environmental
hazards. An effective way of treatment and reuse or disposal is necessary. At some
time increased attention is being focused on agricultural plantations to make
use of this water.
1.2 STATEMENT OF PROBLEM
Water produced during oil and gas extraction operations
constitutes the industry’s most important waste stream on the basis of volume.
The volume of water produced globally by oil and gas operations is staggering.
The last major global study of produced water, dating from the late 1990s,
estimated that the industry was bringing up 210m barrels of produced water each
day. The produced water contains both
dissolved and dispersed oil and these pose health hazards to human health and
contamination of the environment.
Oil
and gas production companies have always faced the problem of how to treat or
dispose produced water. Stricter environmental controls have added pressure to
the issue. High level of impurities make
this water an unusable by-product. This project will address the issue of
pollution caused by produced water discharge by treating the produced water to
meet irrigation purpose.
1.3 AIMS AND OBJECTIVES
The
aim of this project is to treat produced water to meet irrigation standard. The
objective is to treat, analyse and compare produced water physico chemical
parameters with Central Coast Regional Water Quality Control Board (CCRWQCB)
criteria for irrigation and DPR standard for disposable water.
1.4 SIGNIFICANCE
OF STUDY
Treated
produced water has the potential to be a valuable product rather than a
waste.Treating oil well produced water helps facilitate water management
options for operators, such as beneficial uses that provide certain community
and economic advantages. This project intends to tackle the problem of
pollution pose by produced water by treating the water to meet irrigation standard.
1.5 SCOPE AND LIMITATION
This
work will focus on using distillation and banana peel as a biosorbent to treat
produced water from Umutu flowstation, Oredo flowstation and Oredo field. Only
produced water from Umutu flowstation will be analyse. DPR standard and the
Central Coast Regional Water Quality Control Board (CCRWQCB) water quality
requirement for irrigation is the standard used, other standards were
neglected.