A

TERM PAPER

by

BLANKSON EYITUOYO .R (060409015)

ANIMASHAUN OLANRENWAJU (050409011)

NDIGWE EMEKA (060409022)

ADEYINKA ADESHOLA (050409007)

SUBMITTED TO THE UNIVERSITY OF LAGOS

IN

PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE DEGREE OF BACHELOR OF SCIENCE

IN THE

DEPARTMENT OF PETROLEUM AND GAS ENGINEERING, FACULTY OF ENGINEERING

ABSTRACT

The disposal of associated gases through flaring has been a major problem for the

Nigerian oil and gas industries and most of these gases are flared due to the lack of

commercial out lets. The resultant effects of gas flaring are the damaging effect of the

environment due to acid rain formation, green house effect, global warming and ozone

depletion.

This write up is aimed at evaluating the situation of gas flaring in the Niger Delta, the

effects of gas flaring, measures and attempts being made to stop/reduce gas flaring in the

area and possible solutions to put an end to gas flaring in the country.

TABLE OF CONTENT

Title Page

Abstract i

0.0 INTRODUCTION 1

1.0 THEORETICAL PRINCIPLES 21.1 Gas Flaring Systems 2

1.1.1 Open Flare Systems 31.1.2 Enclosed Flare Systems 3

2.0 GAS FLARING IN THE NIGER DELTA 42.1 Effects of Gas Flaring in the Niger Delta 42.2 Attempts to stop/reduce gas flaring in the Niger Delta 6

2.2.1 Domestic Gas Market 72.2.2 Export-oriented Gas Market 72.2.3 Escravos Gas Project 72.2.4 Oso NGL Project 72.2.5 LNG Project 72.2.6 Ekpe Gas Compression Project 82.2.7 Oso 2Y2 Project 82.2.8 Belema Gas Injection Project 82.2.9 Odigbo Node Gas Project 82.2.10 Cawthorne channel Gas Pipeline Project 82.2.11 The West African Gas Pipeline project 8

3.0 CONCLUSION 104.0 APPENDIX

1.0 INTRODUCTION

A gas flare or flare stack is an elevated vertical stack or pipe found on oil & gas wells, oil & gas drilling rigs, natural gas well completion activities, in refineries, chemical plants, natural gas processing plants and landfills used for combusting waste gas released by pressure relief valves during unplanned over-pressuring of plant equipment and also for releasing the excess amount of natural gas that cannot be used so we burn this gas and carbon dioxide formed is released to atmosphere landfills. Its primary purpose is to combust waste methane gas which results from the decomposition of organic materials in the landfill.

On oil production rigs, in refineries and chemical plants, its primary purpose is to act as a safety device to protect vessels or pipes from over-pressuring due to unplanned upsets. This acts just like the spout on a tea kettle when it starts whistling as the water in it starts boiling. Whenever plant equipment items are over-pressured, the pressure relief valves on the equipment automatically release gases (and sometimes liquids as well) which are routed through large piping runs called flare headers to the flare stacks. The released gases and/or liquids are burned as they exit the flare stacks. The size and brightness of the resulting flame depends upon how much flammable material was released. Steam can be injected into the flame to reduce the formation of black smoke. The injected steam does however make the burning of gas sound louder, which can cause complaints from nearby residents. Compared to the emission of black smoke, it can be seen as a valid trade off. In more advanced flare tip designs, if the steam used is too wet it can freeze just below the tip, disrupting operations and causing the formation of large icicles. In order to keep the flare system functional, a small amount of gas is continuously burned, like a pilot light, so that the system is always ready for its primary purpose as an over-pressure safety system. The continuous gas source also helps diluted mixtures achieve complete combustion. Enclosed ground flares are engineered to eliminate smoke, and contain the flame within the stack.

Flaring and venting of natural gas from oil & gas wells is a significant source of greenhouse gas emissions. Its contribution to greenhouse gases has declined by three-quarters in absolute terms since a peak in the 1970s of approximately 110 million metric tons/year and now accounts for 0.5% of all anthropogenic carbon dioxide emissions. This flaring is highly concentrated: 10 countries account for 75% of emissions, and twenty for 90%. The largest flaring operations occur in the Niger Delta region of Nigeria. The leading contributors to gas flaring are (in declining order): Nigeria, Russia, Iran, Algeria, Mexico, Venezuela, Indonesia, and the United States. In spite of a ruling by the Federal High Court of Nigeria (that forbade flaring) in 2005, 43% of the gas retrieval was still being flared in 2006.

The number for Nigeria is 23 billion cubic meters.

2.0 THEORITICAL PRINCIPLES

Natural Gas could be either associated gas or non-associated gas. This depends on whether it is produced together with crude oil or produced from a defined gas reservoir. In cases where crude oil is the only resource of interest, natural gas becomes not only an unwanted figure but also an embarrassment. As a result it has become imperative to put together a means of collection for the accompanying hydrocarbon.

On the other hand, the lack of availability of gas resources in gas producing countries like Nigeria has made this hydrocarbon resource somewhat useless. Thus, natural gas becomes a waste and a profit reduction term. Waste gases are uneconomical to recover/retain. This leaves such a country with only one option: “Gas Flaring”.

2.1 Gas Flaring Systems

The flare system fills a key role in the overall safety and environmental compliance of a hydrocarbon processing plant or production facility. A Flare system consists of:

Staging/Control System Liquid Seal Elevated Stack

Due to the facts that flare applications ranges, there are different types of flares. Flares could be broad categorized into the following:

Open Flares Enclosed Flares

2.1.1 Open Flare SystemsOpen flares burn waste gases as open flames, though a windshield is normally fitted. If provided, combustion control is rudimentary. Open flares are also known as elevated flares.

FIG 2: Open Flare System

2.1.2 Enclosed Flare SystemsEnclosed flares burn waste gases in a vertical, cylindrical or rectilinear enclosure. Some means of combustion control is normally provided, and the enclosure is often insulated to reduce heat losses and allow operation at higher temperatures. Enclosed flares are also known as ground flares.

A Typical Enclosed Flare System

3.0 GAS FLARING IN THE NIGER DELTA

Nigeria holds 11,700 square kilometers of mangrove forest: the third largest in the world and the largest in Africa. Most of this mangrove is found in the Niger Delta.

She is also a major oil producer and most oil extraction takes place in the Niger Delta. Here, petroleum or crude oil abounds in rock formations. The complex mixture of hydrocarbons and other organic compounds that make up the flammable liquid fossil fuel is extracted from oil wells found in those oil fields.

When crude oil is pumped out it also drags associated gas with it. Such natural gas could be separated from the oil and be used but oil companies prefer to burn it off. Shell-BP was the first one to start with this practice in the 1960s.

Nigeria is Africa’s most populated country, with significant oil, and even more gas, reserves. Oil production began in the Niger Delta about 45 years ago and so did the practice of flaring associated gas. The waste involved in the practice, and the expected controversy, was recognized early on. Following the oil-fuelled 1967-1970 civil war, the industry developed via joint ventures with the government’s Nigerian National Petroleum Corporation in which companies such as Shell, ExxonMobil, ChevronTexaco and TotalFinaElf are the operators, but hold minority interests.

There is confusion over how much oil and associated gas is produced in Nigeria. The most recent and independent information source suggests that over 3.5 billion standard cubic feet (SCF) of associated gas was produced in 2000, of which more than 70 per cent was burnt off, ie flared. As oil production has increased, Nigeria has become the world’s biggest gas flarer, both proportionally and absolutely, with around 2 billion scf, perhaps 2.5billion SCF/day being flared. This is equal to about 25 per cent of the UK’s gas consumption. The single biggest flarer is the Shell Petroleum Development Company of Nigeria Ltd (SPDC).

A recent report estimates flaring to represent an annual economic loss to the country of about US $2.5 billion.

3.1 EFFECTS OF GAS FLARING IN THE NIGER DELTA

The impact of gas flared is of local and global concern. The main components of this flared gas

include carbon (iv) oxide (CO2), methane (CH4), nitrous oxide (NO2), water vapour and sulphur

dioxide (SO2). It is estimated that the Nigerian gas flared has released 35 million tons of carbon

dioxide and 12 million tons of methane in a year. The low combustion efficiency of Nigerian

flare stack (60 – 80%) results in a large portion of the gas emitted being methane and since

methane has a higher global warming potential (64 against 1 for CO2). The Nigerian oil industry

probably contributes more than any other company of these serious global commons

environmental problems. As carbon dioxide and methane are the main green house effect and

consequently, this phenomenon has been confirmed to raise the average global temperature by

about 0.5°C within the last century. The flaring stations in the Niger – Delta area has been

blamed for smoke and flames that damage the air and soil quality in the ecologically fragile delta

and contribute to the global green house gases. The gas flaring in Nigeria has for years been

criticized by environmental groups as the world’s largest sources of global warming pollutants

this acts, which experts attributes to the rise in sea level. In Nigeria however, environmental

policies and regulations can be conveniently characterized as minimal and poor, as the Nigerian

government puts profits ahead of the environment and the welfare of its citizens. Nigeria, which

according to UN economic commission for Africa is categorized as a gas – surplus country, still

has limited associated gas sales as 68% of the gas is flared and as a result has been associated

with climate change and related warming, deforestation and acid rain with attendant impact on

agriculture and other physical infrastructure. Heat and noxious gases may contribute to

environmental health problem in the Niger – Delta region. Also, there has been timely warming

and an increasing global awareness on the need to protect our environment and improve our

economy. Typical gas flare in Nigerian oil field are located at ground level and surrounded by

thick vegetation, farmland and villages huts 20 – 30m from the flare. The heat radiation is a

function of the flare temperature, gas flow rate and geometrical design of flare stack. There is a

great physiological impact on crops planted in the vicinity of the gas flare. The soil mantle of the

earth is indispensable for the maintenance of the plant life, affording mechanical support and

supplying nutrient and water.

Also, the soil constitutes a major storage location for heat, acting as sink for energy during the

day and a source to the surface at night. Soil temperature is one of the most critical factors that

influence important physical, chemical and biological processes in soil and plant. Soil

temperature affects plant growth first during seed germination. Metabolically regulated plant

processes, such as water and nutrient uptake can be diminished below optimum rates at both low

and high temperature, resulting in temperature dependent growth and yield pattern. For instance,

corn yields were observed to increase almost linearly as a function of soil temperature between

15 – 25°C, above 25°C the yield decreases. With respect to the gas flaring, its effect on

vegetation, health and microclimate are equally searing. The free disposal of gas through flaring

generates tremendous heat, which is felt over an average radius of 0.5 kilometer thereby causing

thermal pollution. It has been reported that there could be about 100% loss in yield of crops

cultivated 200m away from the flares, 45% loss in yield of crops at 600m away and 10% loss in

yield for crop planted 1000m away.

3.2 ATTEMPTS TO STOP/REDUCE GAS FLARING IN THE NIGER DELTA

Nigeria is endowed with abundant natural gas resources, which in energy terms, is in excess of the nations proven crude oil reserve. More so, the gas was discovered whilst searching for crude oil, as no deliberate effort had been made to search for natural gas then. The current reserved estimate of the Nigerian gas is over 120 trillion cubic feet, with about 50/50 distribution ratio between Associated Gas (AG) and Non Associated Gas (NAG). Only a small fraction of this quantity is currently being utilized.

A large fraction (about 63%) of the AG produced during the production of crude oil is currently being flared. Even then this is a considerable improvement of between 7% - 17% from what it used to be three years ago, when it was flared between 70% to 80%.

In order to diversify its revenue base and reduce the huge wastage of valuable resource as well as the degradation of the environment as a result of flaring, the Nigerian Government, through the NNPC, is vigorously pursuing a number of natural gas utilization projects with its joint venture partners whereby associated gas would be harnessed to achieve these objectives.

The government is sufficiently concerned about the issues of environmental degradation so much so that it has targeted 2010 as the deadline year when all gas flares must be extinguished. In line with this target therefore, all the Joint Venture partners have also set their own targets in order to meet this deadline.

These targets range from year 2005 to 2010. This means that the gas sector in Nigeria is going to be a beehive of activities, and a lot of room exists for investment in this area. Some of these are: LNG (Liquefied Natural Gas), IPP (Independent Power Plant), GTL (Gas to Liquid Conversion), NGL (Natural Gas Liquids) and Methanol. Gas supply to local industries, is indeed an industry with great potentials and future in the 21st century.

While a number of gas utilization projects have already been completed, commissioned and in operation, several other projects are at various stages of execution. In addition, local industries have started converting from the use of fuel oil to gas due to increase in awareness.

3.2.1 Domestic Gas Market:

On the domestic front, NNPC through its subsidiary, Nigerian Gas Company (NGC), currently supplies gas for power generation, either as source of fuel or as feedstock to cement and fertilizer plants, glass, food and beverages, manufacturing industries and so on. More local industries are now aware of the advantages and benefits of using gas, hence the demand for gas is increasing. The Nigerian gas market is a profit oriented market awaiting potential investors.

3.2.2 Export- Oriented Gas Projects:

For the international market, NNPC and its Joint Venture partners are currently embarking on several gas utilization projects, which include the following:

3.2.3 Escravos Gas Project:

This project was executed by NNPC/Chevron JV. The plant is located in the Southwestern part of the country and it produces mainly LPG for export from its first phase. Detailed engineering for the second phase has reached advanced stage, while a third phase is being proposed.

3.2.4 Oso NGL Project:

The NNPC/Mobil JV recently commissioned an NGL plant located at its OSO field in the South Eastern part of Nigeria. It started production for export in the third quarter of 1998.

3.2.5 LNG Projects:

Nigeria, through NLNG (Nigeria Liquefied Natural Gas) Ltd., is currently embarking on the construction of its first LNG plant in collaboration with three partners, namely, ELF, AGIP, and SHELL. The LNG plant site is located at Finima in the Eastern region of Nigeria and, these three companies in joint venture with NNPC, will also supply up to 1 billion standard cubic feet of natural gas for feed stock/fuel to the plant from their Obite, Obiafu and Soku fields respectively. It is expected that flaring will be substantially reduced by the time these projects come on stream, in addition to the expected huge revenue.

3.2.6 Ekpe Gas Compression Projects:

The NNPC/MOBIL JV executed this project in order to gather the gas that was being flared in this field for enhancement of oil production by gas lifting and gas re injection.

3.2.7 Oso 2Y2 Project:

This project is also being executed by the NNPC/MOBIL JV. The objective is to provide additional gas make-up for the Oso NGL as well as maintain condensate production at the expected plateau.

3.2.8 Belema Gas Injection Project:

The NNPC/SHELL Joint Venture is executing this project with an objective to reduce gas flares in Five flow stations by re-injecting some of the gas, some for gas lifting, some for use as fuel by local industries and the excess for backing out NAG that is currently used to meet various existing contractual obligations. The contracts for the execution of the EPC and gathering pipelines have reached advanced stages of execution. About 80mmscf/d of gas is expected to be utilised.

3.2.9 Odigbo Node Gas Project:

The objective of this project is to gather about 113mmscf/d of AG from about Six flow stations in the NNPC/Shell Eastern Nigeria Fields, for supply (about 92mmscf/d) to ALSCON (Aluminum Smelting Company of Nigeria) as feed gas and for gas lifting.

Odidi AGG Project: This project is also being executed by the NNPC/Shell JV in the South Western part of Nigeria. The objective of the project is to gather gas and inject into the ELP (Escravos to Lagos Pipeline), which will eventually form part of the West African Gas Pipeline that will supply gas to some West African Countries.

3.2.10 Cawthorne Channel Gas Injection Project:

The objective of this project is to gather the gas that is currently being flared in this field for re-injection and for supply to a third party for LPG extraction. The conceptual design is currently on-going.

3.2.11 The West African Gas Pipeline Project:

The objective of this project is to supply gas to some ECOWAS countries, pursuant to Nigeria's commitment to Article 48 of the ECOWAS Treaty, which encourages member nations to co-operate, consult and co-ordinate their polities regarding energy and mineral resources.

Following deliberations by member-states on improving co-operation on energy, the governments of Nigeria, Ghana, Benin and Togo, through their ministries and departments responsible for energy matters, signed Heads of Agreements (HOA) in 1995, to provide a framework for the construction of a Ministerial Steering Committee (MSC), and Project Implementation Committee to monitor the development of the project.

A commercial group has also been set up comprising Nigerian Gas Company (NGC), Ghana National Petroleum Corporation (GNPC), SOBEGAZ (Benin) and SOTOGAZ (Togo); and two gas producers Chevron Nigeria Ltd. (CNL) and Shell Petroleum Development Company of Nigeria. (SPDC). In 1998, the commercial group retained a German company to conduct a feasibility study and the final report was submitted in March 1999. The report showed that the WAGP was commercially viable and technically feasible. Negotiations are currently on-going with a number of prospective buyers in the sub region which now include companies in Senegal.

In order to achieve the flare-out target date of 2010, NNPC and some of its partners, have drawn up activities and strategic programmes for the utilization of all gas that is currently being flared as well as future gas production resulting from growth in oil production. These programmes included: NNPC/Elf JV had set its flare-out target year at 2006, and some of their planned projects include Amenam/Kpono, Ofon (Phase-2) and 4-bar integrated oil and gas projects.

NNPC/Shell JV's flare-out target year was 2008. Some of their planned projects include Akri/Oguta, S. Forcados, EA, Bonga, Ubie, Bomu etc, and gas gathering and utilization projects. NNPC/Chevron JV's flare-out target year was 2006 and their planned projects are EGP phases 2 and 3.

4.0 CONCLUSION

From this study the following conclusions have been deduced:

Gas Flaring is still a major factor to be looked at in the Nigerian oil and gas industry The measures and efforts made by the Nigerian government have proved positive as gas

flaring rates have reduced drastically from what it used to be about three years ago. In order to further reduce gas flaring in the Niger Delta, associated gas should be

continually exploited and should be used as an alternate energy source. Even with all the measures taken so far, Nigeria still remains largest gas flaring

community in the world.

5.0 APPENDIX

 

Smoke from giant gas flares hovers above Ebocha-Egbema

Nigeria flares enough gas per year to power a good portion of Africa.

.

Color composite of the nighttime lights of the Nigeria region. The vector polygon drawn around

the gas flares associated with Nigeria are shown in white