Sunday, August 30, 2009
Oil reserves
The total estimated amount of oil in an oil reservoir, including both producible and non-producible oil, is called oil in place. However, because of reservoir characteristics and limitations in petroleum extraction technologies, only a fraction of this oil can be brought to the surface, and it is only this producible fraction that is considered to be reserves. The ratio of producible oil reserves to total oil in place for a given field is often referred to as the recovery factor. Recovery factors vary greatly among oil fields. The recovery factor of any particular field may change over time based on operating history and in response to changes in technology and economics. The recovery factor may also rise over time if additional investment is made in enhanced oil recovery techniques such as gas injection, water-flooding[2], or microbial enhanced oil recovery.
Because the geology of the subsurface cannot be examined directly, indirect techniques must be used to estimate the size and recoverability of the resource. While new technologies have increased the accuracy of these techniques, significant uncertainties still remain. In general, most early estimates of the reserves of an oil field are conservative and tend to grow with time. This phenomenon is called reserves growth.[3]
Many oil producing nations do not reveal their reservoir engineering field data, and instead provide unaudited claims for their oil reserves. The numbers disclosed by some national governments are suspected of being manipulated for political reasons.
Classifications
discovered through one or more exploratory wells[6]
recoverable using existing technology[6]
commercially viable[6]
remaining in the ground[6]
All reserve estimates involve uncertainty, depending on the amount of reliable geologic and engineering data available and the interpretation of those data. The relative degree of uncertainty can be expressed by dividing reserves into two principal classifications - proved and unproved.[6] Unproved reserves can further be divided into two subcategories - probable and possible to indicate the relative degree of uncertainty about their existence.[6] The most commonly accepted definitions of these are based on those approved by the Society of Petroleum Engineers (SPE) and the World Petroleum Council (WPC) in 1997
Proved reserves
Proved reserves are further subdivided into Proved Developed (PD) and Proved Undeveloped (PUD).[9][10] PD reserves are reserves that can be produced with existing wells and perforations, or from additional reservoirs where minimal additional investment (operating expense) is required.[10] PUD reserves require additional capital investment (e.g. drilling new wells) to bring the oil to the surface.[8][10]
Proved reserves are the only type the U.S. Securities and Exchange Commission allows oil companies to report to investors. Companies listed on U.S. stock exchanges must substantiate their claims, but many governments and national oil companies do not disclose verifying data to support their claims.
Unproved reserves
Probable reserves are are attributed to known accumulations, and claim a 50% confidence level of recovery. Industry specialists refer to this as P50 (i.e. having a 50% certainty of being produced). Referred to in the industry as 2P (proved plus probable).[8]
Possible reserves are attributed to known accumulations which have a less likely chance of being recovered than probable reserves. This term is often used for reserves which are claimed to have at least a 10% certainty of being produced (P10). Reasons for classifying reserves as possible include varying interpretations of geology, reserves not producible at commercial rates, uncertainty due to reserve infill (seepage from adjacent areas), projected reserves based on future recovery methods. Referred to in the industry as 3P (proved plus probable plus possible).
Oil, gas reserves discovered
Oil refinery
Exploration methods of Oil
Oil and Gas Companies All Over The World
Abu Dhabi National Oil Company (ADNOC).
AGIP (Azienda Generale Italiana Petroli) since 1998 ENI-Agip Exploration and Production.
Anglo Siberian Oil Company plc.
Anonima Petroli Italiana (API)
AnzoilARCO (Atlantic Richfield Company) = BP-Amoco.
Australian Oil & Gas Corporation Ltd.
Australian Worldwide Exploration LimitedBay State Gas.
Bentec Drilling (Preussag DE).Benton Oil & Gas Company.
BHP Billiton.BJ Services Company.
Black Hills Exploration and Production.
(US).BP Amoco ARCO.
Chieftain International (now: Huntoil).
Chinese Petroleum Corporation (Taiwan TW).
Compagnie Générale de Géophysique (CGG).CONOCO (US) (incl. Gulf Canada).
ConocoPhillips.CSIRO Exploration and Mining.
Dana Petroleum plc.Deutag Drilling (Preussag DE) (now: KCA DEUTAG Drilling Limited)Devon Energy Corporation (US) (incl. Santa Fe Snyder Corporation, PennzEnergy).
Dominion Exploration & Production.Elf Aquitaine (TOTAL FINA ELF).
Empresa Colombiana de Petróleos (ECOPETROL).
Empresa Nacional del Petróleo - Chile (ENAP).
Encana.Energy Africa EA.Eni.Enterprise Oil plc. (UK).
Equity Oil Company.ESSO DeutschlandEvergreen Resources (US)ExxonMobilFINA (now:
Oil well
Life of a well
The creation and life of a well can be divided up into five segments:
- Planning
- Drilling
- Completion
- Production
- Abandonment
Drilling
The drill bit, aided by the weight of thick walled pipes called "drill collars" above it, cuts into the rock. There are different types of drillbit, some cause the rock to fail by compressive failure. Others shear slices off the rock as the bit turns.
Drilling fluid (aka "mud") is pumped down the inside of the drill pipe and exits at the drill bit. Drilling mud is a complex mixture of fluids, solids and chemicals which must be carefully tailored to provide the correct physical and chemical characteristics required to safely drill the well., Particular functions of the drilling mud include cooling the bit, lifting rock cuttings to the surface, preventing destabilisation of the rock in the wellbore walls and overcoming the pressure of fluids inside the rock so that these fluids don't enter the wellbore.
The generated rock "cuttings" are swept up by the drilling fluid as it circulates back to surface outside the drill pipe. The fluid then goes through "shakers" which strain the cuttings from the good fluid which is returned to the pit. Watching for abnormalities in the returning cuttings and monitoring pit volume or rate of returning fluid are imperative to catch "kicks" (when the formation pressure at the depth of the bit is more than the hydrostatic head of the mud above, which if not controlled temporarily by closing the blowout preventers and ultimately by increasing the density of the drilling fluid would allow formation fluids and mud to come up uncontrollably) early.
The pipe or drill string to which the bit is attached is gradually lengthened as the well gets deeper by screwing in additional 30-foot (10 m) joints (i.e., sections) of pipe under the kelly or topdrive at the surface. This process is called making a connection. Usually joints are combined into 3 joints equaling 1 stand. Some smaller rigs only use 2 joints and some rigs can handle stands of 4 joints.This process is all facilitated by a drilling rig which contains all necessary equipment to circulate the drilling fluid, hoist and turn the pipe, control downhole pressures, remove cuttings from the drilling fluid, and generate onsite power for these operations.
Completion
Production
Abandonment
Types of wells
Oil wells come in many varieties. By produced fluid, there can be wells that produce oil, wells that produce oil and natural gas, or wells that only produce natural gas. Natural gas is almost always a byproduct of producing oil, since the small, light gas carbon chains come out of solution as it undergoes pressure reduction from the reservoir to the surface, similar to uncapping a bottle of soda pop where the carbon dioxide effervesces. Unwanted natural gas can be a disposal problem at the well site. If there is not a market for natural gas near the wellhead it is virtually valueless since it must be piped to the end user. Until recently, such unwanted gas was burned off at the wellsite, but due to environmental concerns this practice is becoming less common. Often, unwanted (or 'stranded' gas without a market) gas is pumped back into the reservoir with an 'injection' well for disposal or repressurizing the producing formation. Another solution is to export the natural gas as a liquid.Gas-to-liquid, (GTL) is a developing technology that converts stranded natural gas into synthetic gasoline, diesel or jet fuel through the Fischer-Tropsch process developed in World War II Germany. Such fuels can be transported through conventional pipelines and tankers to users. Proponents claim GTL fuels burn cleaner than comparable petroleum fuels. Most major international oil companies are in advanced development stages of GTL production, with a world-scale (140,000 bbl/day) GTL plant in Qatar scheduled to come online before 2010. In locations such as the United States with a high natural gas demand, pipelines are constructed to take the gas from the wellsite to the end consumer.Another obvious way to classify oil wells is by land or offshore wells. There is very little difference in the well itself. An offshore well targets a reservoir that happens to be underneath an ocean. Due to logistics, drilling an offshore well is far more costly than an onshore well. By far the most common type is the onshore well. These wells dot the Southern and Central Great Plains, Southwestern United States, and are the most common wells in the Middle East.Another way to classify oil wells is by their purpose in contributing to the development of a resource. They can be characterized as:
- production wells are drilled primarily for producing oil or gas, once the producing structure and characteristics are determined
- appraisal wells are used to assess characteristics (such as flow rate) of a proven hydrocarbon accumulation
- exploration wells are drilled purely for exploratory (information gathering) purposes in a new area
- wildcat wells are those drilled outside of and not in the vicinity of known oil or gas fields.
Financial Times and Business Week recognises MBA Oil and Gas Management in 2009 distance learning rankings
Studying the MBA Oil and Gas Management degree will enable you to develop not only advanced skills in strategy and management, but also a sound knowledge of energy management and an understanding of its importance in social, political, economic, cultural and technological respects to national and international strategy and the ability to apply this knowledge to inform decision-making.
The MBA Oil and Gas Management degree is designed to provide experienced practitioners in the oil and gas sector with the advanced business, management and leadership skills needed to function at a strategic level as a contemporary energy manager.
The course is aimed at middle to senior managers or those aspiring to these positions within the Oil and Gas industry.
This master of business administration degree offers significant choice to you in terms of oil and gas subject breadth, study mode and career path. The choice of energy industry focused modules caters for the full spectrum of oil and gas strategic management activities.
The MBA Oil and Gas Management degree is available full-time, part-time executive with online support or in an online study mode
The online MBA course has been listed in The Financial Times and Business Week as one of the Top Distance Learning MBAs available globally.
The MBA Oil and Gas Management curriculum is structured so that you will initially gain experience of all kinds of key decision-making in a range of business functions. This fundamental knowledge will then be applied at a strategic level in the strategic management module.
Within the specialist energy management modules you will gain a comprehensive knowledge of the theory, practice and execution of business decisions in the energy industry.
The project module will have an energy management focus and will give the you an opportunity to further synthesise and apply specialist knowledge to professional practice.
The choice of specialist modules are as follows:
- Energy Policy and the Environment
- Health, Safety and Risk in an Organisational Context
- Leadership, Communication and Change
- Change Management
- Oil and Gas Contract Law
- Oil and Gas Management
- Operations Management: Oil and Gas
- Petroleum Economics and Asset Management
- Project Fundamentals
You will be required to attend a Leadership Week and you will have the option of participating in a study tour to IAE Aix en Provence Université in the South of France.
Benefits and Aims of the MBA Oil and Gas Management Course
You will certainly develop better subject knowledge and how to apply strategic principles within the Oil and Gas industry. You will acquire improved communication skills, writing skills and leadership skills through the MBA experience. At a personal level you should gain higher levels of self-confidence, self esteem and improved individual strengths and abilities. Ultimately this will lead to more business experience which in turn will result in a better chance of a more responsible job, higher satisfaction with your current job or the opportunity to change or focus your career.
Leadership Workshop
Study Tour - IAE Aix-en-Provence: Graduate School of Management
Day 1: Intercultural Communication Process and Styles Flash Session Day 2 - 5: Business at the Intersection: An interdisciplinary way to look at business
This study tour is delivered by speakers from IAE Aix-en-Provence Graduate Management School, Washington University’s John M. Olin School of Business and the Allen Center for Executive Education at Northwestern University.
MBA Tutoring and Professional Development
Career Counselling
MBA Alumni Association
Petroleum geology
Sedimentary basin analysis
Petroleum geology is principally concerned with the evaluation of seven key elements in sedimentary basins:
- Source
- Reservoir
Seal - Trap
- Timing
- Maturation
- Migration
In general, all these elements must be assessed via a limited 'window' into the subsurface world, provided by one (or possibly more) exploration wells. These wells present only a 1-dimensional segment through the Earth and the skill of inferring 3-dimensional characteristics from them is one of the most fundamental in petroleum geology. Recently, the availability of cheap and high quality 3D seismic data (from reflection seismology) has greatly aided the accuracy of such interpretation. The following section discusses these elements in brief. For a more in-depth treatise, see the second half of this article below.
Evaluation of the source uses the methods of geochemistry to quantify the nature of organic-rich rocks which contain the precursors to hydrocarbons, such that the type and quality of expelled hydrocarbon can be assessed.
Major subdisciplines in petroleum geology
Analysis of source rocks
If the likelihood of there being a source rock is thought to be high, the next matter to address is the state of thermal maturity of the source, and the timing of maturation. Maturation of source rocks (see diagenesis and fossil fuels) depends strongly on temperature, such that the majority of oil generation occurs in the 60° to 120°C range. Gas generation starts at similar temperatures, but may continue up beyond this range, perhaps as high as 200°C. In order to determine the likelihood of oil/gas generation, therefore, the thermal history of the source rock must be calculated. This is performed with a combination of geochemical analysis of the source rock (to determine the type of kerogens present and their maturation characteristics) and basin modelling methods, such as back-stripping, to model the thermal gradient in the sedimentary column.
Analysis of reservoir
Exploration geophysics
Exploration geophysics is the practical application of physical methods (such as seismic, gravitational, magnetic, electrical and electromagnetic) to measure the physical properties of rocks, and in particular, to detect the measurable physical differences between rocks that contain ore deposits or hydrocarbons and those without.
Exploration geophysics can be used to directly detect the target style of mineralisation, via measuring its physical properties directly. For example one may measure the density contrasts between iron ore and silicate wall rocks, or may measure the conductivity contrast between conductive sulfide minerals and barren silicate minerals.
Geophysical Methods
The following techniques are used:
- Seismic methods, such as reflection seismology, seismic refraction, refraction microtremor
- (ReMi) and seismic tomography.
- Magnetotellurics
- Scientific drilling
- Transient electromagnetic (EM) (see, e.g. Geonics instruments)
- Radio frequency electromagnetic propagation (e.g., ground penetrating radar)
- Electrical techniques, including Electrical resistivity tomography and induced polarization
- Magnetic techniques, including aeromagnetic surveys and magnetometers.
- Gravity and Gravity Gradiometry
- Geodesy
- Remote sensing
- Seismoelectrical Method
Uses
Methods devised for finding mineral or hydrocarbon deposits can also be used in other areas such as monitoring environmental impact, imaging subsurface archaeological sites, ground water investigations, subsurface salinity mapping, civil engineering site investigations and interplanetary imaging.
Mineral exploration
The most direct method of detection of ore via magnetism involves detecting iron ore mineralisation via mapping magnetic anomalies associated with banded iron formations which usually contain magnetite in some proportion. Skarn mineralisation, which often contains magnetite, can also be detected though the ore minerals themselves would be non-magnetic. Similarly, magnetite, hematite and often pyrrhotite are common minerals associated with hydrothermal alteration, and this alteration can be detected to provide an inference that some mineralising hydrothermal event has affected the rocks.
Gravity surveying can be used to detect dense bodies of rocks within host formations of less dense wall rocks. This can be used to directly detect Mississippi Valley Type ore deposits, IOCG ore deposits, iron ore deposits, skarn deposits and salt diapirs which can form oil and gas traps.
Electro-magnetic (EM) surveys can be used to detect a wide variety of base metal sulphide deposits via detection of conductivity anomalies which can be generated around sulphide bodies in the subsurface. EM surveys can also be used to detect palaeochannel-hosted uranium deposits which are associated with shallow aquifers, which often respond to EM surveys in conductive overburden. This is an indirect inferrential method of detecting mineralisation.
Regional EM surveys are conducted via airborne methods, utilising either fixed-wing aircraft or helicopter-borne EM rigs. Surface EM methods are based mostly on Transient EM methods utilising surface loops with a surface receiver, or a downhole tool lowered into a borehole which transects a body of mineralisation. These methods can map out sulphide bodies within the earth in 3 dimensions, and provide information to geologists to direct further exploratory drilling on known mineralisation. Surface loop surveys are rarely used for regional exploration, however in some cases such surveys can be used with success (eg; SQUID surveys for nickel orebodies).
Electric-resistance methods such as induced polarisation methods can be useful for directly detecting sulphide bodies, coal and resistive rocks such as salt and carbonates.
Oil and gas
Downhole geophysics tools are used within oil and gas exploration for several purposes;
- density tools measure rock density and porosity
- caliper tools measure hole diameter
- gamma-logging tools measure the radioactivity of the wall rocks in the bore hole
- EM tools measure wall-rock conductivity - to inform on porosity, sulphide content, lithology, etc.
Civil engineering
Civil engineering can also utilise remote sensing information for topographical mapping, planning and environmental impact assessment. Airborne electromagnetic surveys are also used to characterise soft sediments in planning and engineering roads, dams and other structures.
Archaeology
Ground magnetometric surveys can be used for detecting buried ferrous metals, useful in surveying shipwrecks, modern battlefields strewn with metal debris, and even subtle disturbances such as large-scale ancient ruins.
Sonar systems can be used to detect shipwrecks.
Exploration geophysics in society
Exploration Geophysics careers are in such widely varying industries as oil & gas exploration, mining, environmental studies, planetary physics and even archaeology.