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Orkiszewski Correlation – Theory Behind It

Orkiszewski correlation is a composite of several calculation methodologies from several published correlations with 148 field measurements. The Duns-Ros flow pattern map is used with a redefined boundary between bubble and slug flows. An improved calculation model for slug flow is presented. It is a very popular correlation, mainly due to its improved accuracy over previous calculation models.

Based upon similarity in theoretical concepts, Orkiszewaki selected five methods and compared them by determining the deviation between predicted and measured pressure drops. He selected the best two of the five methods, Duns and Ros and Griffith and Wallis upon which to base his correlation. Neither method was found to be accurate over the entire flow range. The Griffith and Wallis correlation was found to be reliable in the lower flow rate range of slug flow but not accurate in the higher range. The Duns and Ros method presented the same behavior except that it was also inaccurate for the high viscosity oils in the low flow rate range.

Of the two methods, Orkiszewaki preferred the form of the Griffith and Wallis correlation as it appeared to provide a sufficient foundation for an improved general solution. The Duns and Ros method, however, is based upon a complex set of interrelated parameters and was too difficult to relate to the physical phenomena occurring inside the pipe.

Orkiszewski extended the Griffith and wallis correlation to include the high velocity flow range by incorporation of the work of Duns and Ros. A parameter was developed to account for:

1. Liquid distribution between the liquid slug, the liquid film and entrained liquid in the gas bubble, and

2. Liquid at the higher flow velocities. This parameter was used to calculate wall friction losses and flowing density as derived from the published data of Hagedorn and Brown.

Orkiszewski concluded that the modified method was sufficiently accurate for the entire range of studied conditions, and accuracy could be improved by rigorous analysis of the liquid phase distribution.


Introduction to Orkiszewski Correlation

This is the introduction of Orkiszewski Correlation used to predict pressure transverse curve in the pipe. The most important thing about using correlation is good information. The Orskizewski correlation has several steps to determine a lot of figures in multiphase flow calculation. The lack of reliable pressure drop data and experimental flow apparatus for correlation data gathering represent the inherent problems of obtaining a general multiphase flow model.

During multiphase flow in vertical pipe, at least four distinct regimes of flow are identifiable. These are usually described as the bubble, slug, transition, and mist flow regions. The image below demonstrates the geometrical configuration of the four regions of flow. These four flow regimes are important to the Orkiszewski Correlation which will be in details later on.

Flow region

Bubble flow consists of a continuous liquid phase with little free gas in the liquid medium. When greater amount of gas evolve from the liquid phase, the gas bubbles agglomerate, and form slug-like gas pockets. This characteristic is called the slug flow region. If the greater amounts of gas are released, the transition flow region is formed in which droplets of liquid become entrained in the gas pockets. The gas pockets become distorted and approach a continuous gas form. Greater gas throughput restricts the continuous liquid phase to the well walls with a continuous gas phase flowing within the annular liquid phase. This represents the mist flow region in which the continuous gas phase is saturated with a fine mist of entrained liquid particles. Due to a lot of flow region, it will cause a complexity of the flow the Orkiszewski Correlation which we will fully discuss later.



Top 10 Oilfield Service Companies

If you are looking for oil field service jobs, you need to take a look at top 10 oilfield service companies. Those companies have their own expertise in various fields as drilling, oil field construction, oil well cementing, completion technology, formation evaluation, survey, directional drilling, solid control, drilling fluids, ect.

The top 10 oilfield service companies are as follows:

1. Schlumberger: Schlumberger is the leading oilfield services provider, trusted to deliver superior results and improved E&P performance for oil and gas companies around the world. Through our well site operations and in our research and engineering facilities, we are working to develop products, services and solutions that optimize customer performance in a safe and environmentally sound manner.

Website: http://www.slb.com/

2. Halliburton: Founded in 1919, Halliburton is one of the world’s largest providers of products and services to the energy industry. With more than 60,000 employees in approximately 80 countries, the company serves the upstream oil and gas industry throughout the lifecycle of the reservoir – from locating hydrocarbons and managing geological data, to drilling and formation evaluation, well construction and completion, and optimizing production through the life of the field.

Website: http://www.halliburton.com

3. Transocean: Transocean, the world’s largest offshore drilling contractor, provides the most versatile fleet of mobile offshore drilling units to help customers find and develop oil and natural gas reserves. Building on more than 50 years of experience with the highest specification rigs, our 18,000 employees are focused on safety and premier offshore drilling performance.

Website: http://www.deepwater.com/

4. Saipem: Saipem is a large, international and one of the best balanced turnkey contractors in the oil & gas industry.Saipem has a strong bias towards oil and gas related activities in remote areas and deepwater and is a leader in the provision of engineering, procurement, project management and construction services with distinctive capabilities in the design and the execution of large-scale offshore and onshore projects, and technological competencies such as gas monetization and heavy oil exploitation.

Website: http://www.saipem.com

5. Baker Hughes and BJ Services Company (Baker already acquired BJ service): A top-tier oilfield service company with a century-long track record, Baker Hughes delivers solutions that help oil and gas operators make the most of their reservoirs.

Website: http://www.bakerhughes.com/

6. Weatherford: Weatherford International Ltd. (NYSE:WFT) is one of the largest global providers of products and services that span the drilling, evaluation, completion, production and intervention cycles of oil and natural gas wells. Weatherford is a new breed of service company—one that can provide the industry with extended products and services, more efficient operations, more powerful research and development capabilities and greater geographic diversity.

Website: http://www.weatherford.com/

7. Fluor: Fluor is a FORTUNE 500 company that delivers engineering, procurement, construction, maintenance (EPCM), and project management to governments and clients in diverse industries around the world. For nearly a century, clients have selected Fluor as their company of choice to complete challenging projects in remote parts of the world.

Website: http://www.fluor.com

8. Petrofac: Petrofac is the global oil & gas industry’s premier facilities and infrastructure provider, admired by customers and employees for delivering consistently and rewarding excellence.

Website: http://www.petrofac.com/

9. China Oilfield Services Ltd: China Oilfield Services Limited(“COSL” )is the leading integrated oilfield services provider in the offshore China market. Its services cover each phase of offshore oil and gas exploration, development and production. Its four core business segments are geophysical services, drilling services, well services, marine support and transportation services. COSL has listed its H shares on the Main Board of the Stock Exchange of Hong Kong Limited “HKSE” since 20 November 2002 under the ticker 2883.

Website: http://www.cosl.com.cn/ens/

10. McDermott: McDermott is a leading engineering, procurement, construction and installation (“EPCI”) company focused on executing complex offshore oil and gas projects worldwide. Providing fully integrated EPCI services for upstream field developments, we deliver fixed and floating production facilities, pipelines and subsea systems from concept to commissioning.

Website: http://www.mcdermott.com/

Sorce: Internet

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In the petroleum industry, most petroleum engineers commonly use the special unit, not used in the SI metric system. These customary units are known as oil field units and the most common oil field units are listed in following table with their corresponding SI units.

Common Oil Field Units

Unit Conversions: Even many experienced engineers have difficulty with the use and conversion of units. This problem seems to be particularly troublesome in petroleum engineering because of the many non-standard units used in the discipline. Often equations are given in textbooks only in oilfield units. When trying to use other units or trying to use combinations of equations, problems often arise. This write-up will contain a few simple rules to avoid common pitfalls.

Conversion of numbers from one set of units to another is usually fairly straightforward. A technique which has been taught for many years to engineering students is to place unit conversion factors above and below a horizontal line and “canceling” units until the desired set is achieved. The following is an example showing how to convert from psi to kPa.


Dealing with units in equations always seems to create difficulties. However, if one rule is remembered, this can be done easily and correctly: Convert numbers, not equations! Article by: Dr. Mustafa V.



Properties of Market Crude Oil

Properties of Market Crude Oil are shown in the following table.

table Properties of Market Crude Oil

In fact the pricing of crude oils has become increasingly transparent from the 1990s onwards through the use of marker crudes (benchmark crude oil) such as West Texas Intermediate (WTI – USA), Brent (Europe and Africa), Dubai and Oman (Middle East), and Tapis and Dubai (in Asia) . The main criteria for a marker crude is for it to be sold in sufficient volumes to provide liquidity (many buyers and sellers) in the physical market as well as having similar physical qualities of alternative crudes. In addition the marker crude should provide pricing information.

WTI does this through its use on the New York Metals Exchange as the basis of a futures contract where trade is equivalent to many hundreds of millions of barrels per day, even though physical WTI production is less than 1 million barrels per day. A futures contract for crude oil is a promise to deliver a given quantity of crude oil but this rarely occurs as participants are more interested in taking a position on the price of the crude oil. Futures markets are a financial instrument to distribute risk among participants with the side effect of providing transparency on the pricing of crude oil.

Brent offers pricing information based more on the physical trading of oil through spot trading, and forward trading but also offers futures trading but not to the same extent as WTI.

Dubai and Oman pricing is based more on the physical trades of Dubai and Oman but due to falling production levels questions are being raised about the appropriateness of Dubai as marker crude.

In Asia there is no futures exchange where crude oil is traded and which would provide pricing information to the same extent as WTI and Brent. In Asia the pricing mechanism for say Tapis, a marker for light sweet crude in the region, is based on an independent panel approach where producers, refiners and traders are asked for information on actual trades and where there have been none, their best guess. (Any estimates that are wildly high or low are discarded and the quoted price is then an average of views on the market price for Tapis.


What is Society of Petroleum Engineers (SPE)?

Society of Petroleum Engineers (SPE) was founded in 1957. SPE is the international technical and professional association for engineers and the management of energy resources produced through the wellbore. SPE collects, distributes, and exchanges information on techniques and operations to nearly 49,500 members in 125 countries through a broad range of activities, including section meetings, publications, continuing education programs, and technical meetings and exhibitions.

Mission Statement: To provide the means for collection, dissemination, and exchange of technical information concerning the development of oil and gas resources, subsurface fluid flow, and production of other materials through wellbores for the public benefit; and to provide opportunities through its programs for interested (and qualified) individuals to maintain and upgrade their individual technical competence in the aforementioned areas for the public benefit.

 SPE website: www.spe.org


What is American Petroleum Institute (API)?

The origins of the American Petroleum Institute date back to World War I, when Congress and the domestic oil and natural gas industry worked together to help the war effort. At the time, the industry included the companies created in 1911 after the court-imposed dissolution of Standard Oil and the “independents.” These were companies that had been “independent” of Standard Oil. These companies had no experience working together, but they agreed to work with the government to ensure that vital petroleum supplies were rapidly and efficiently deployed to the armed forces. The National Petroleum War Service Committee, which oversaw this effort, was initially formed under the U.S. Chamber of Commerce and subsequently as a quasi-governmental body. After the war, momentum began to build to form a national association that could represent the whole industry in the postwar years. The industry’s efforts to supply fuel during World War I not only highlighted the importance of the industry to the country but also the industry’s obligation to the public, as the original charter shows.

The American Petroleum Institute was established on March 20, 1919. API offices were established in New York City, and the organization focused its efforts in several specific areas.

Statistics: The first was to develop an authoritative program of collecting industry statistics. As early as 1920, API began to issue weekly statistics, beginning first with crude oil production. Later the report, which was shared with both the government and the press, was expanded to include crude oil and product stocks, refinery runs and other data.

API statistics remain one of the most credible sources of industry data and they are used worldwide.

Standardization: The second was the standardization of oil field equipment. During World War I, drilling delays resulted from shortages of equipment at the drill site, and the industry attempted to overcome that problem by pooling equipment. The program reportedly failed because there was no uniformity of pipe sizes, threads and coupling. Thus, the new association took up the challenge of developing industry-wide standards and the first standards were published in 1924. Today, API maintains more than 500 standards and recommended practices covering all segments of the oil and gas industry to promote the use of safe, interchangeable equipment and proven and sound engineering practices.

Taxation: The third major area of activity was taxation. Initially the efforts included working with the Treasury Department and Congressional committees to develop an orderly, logical and easily administered way to tax oil assets. In the 1930s, these efforts extended to working state governments. Both the federal and state governments tax highways fuels to fund the building of roads, and the industry supported tougher laws against tax evasion. This led to the formation of the API state petroleum council network. API now has offices in 27 state capitals and represents members in 33 states, all east of the Rocky Mountains. In late 1969, API made the decision to move its offices to Washington, D.C., where we remain today.

 API website: http://www.api.org/



Offshore Drilling Companies That You Should Look For

Nowadays, offshore drilling plays a big part of our drilling industry therefore I would like to share top offshore drilling companies. If you are interested in working with offshore drilling companies, please check out the following companies. There are websites and company profile for each company. If you are interested in any company, we also provide you their company website links so it makes you life easy to contact the companies. Note: Information is based on the lasted information in Sep-11.

Drilling companies (drilling contractors) are people providing drilling services, equipment, experience to oil companies as Shell, BP, Exxon, Chevron, etc. Working with drilling companies has a lot of advantages as international experience, good income, job challenges, etc.

 Aban Loyd Chiles Offshore Limited, Chennai, India

Aban Loyd Chiles Offshore Limited is India’s largest offshore drilling contractor in the private sector, offering world-class drilling and oil field services for offshore exploration and production of hydrocarbons to the oil industry in India and abroad. Our innovative and cost effective solutions make us one of the most efficient international drilling contractors. Thanks to a highly qualified professional team backed by years of experience and expertise, we continue to foray into newer waters. [click to continue…]


OPEC-Organization of Petroleum Exporting Countries

OPEC (Organization of Petroleum Exporting Countries) is an international Organization of eleven developing countries, which are heavily reliant on oil revenues as their main source of income. Membership is open to any country which is a substantial net exporter of oil and which shares the ideals of the Organization. The current Members are Algeria, Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the United Arab Emirates and Venezuela. Since oil revenues are so vital for the economic development of these nations, they aim to bring stability and harmony to the oil market by adjusting their oil output to help ensure a balance between supply and demand. Twice a year, or more frequently if required, the Oil and Energy Ministers of the OPEC Members meet to decide on the Organization’s output level, and consider whether any action to adjust output is necessary in the light of recent and anticipated oil market developments. OPEC’s eleven members collectively supply about 40 per cent of the world’s oil output, and possess more than three-quarters of the world’s total proven crude oil reserves.

The Organization of the Petroleum Exporting Countries (OPEC) is a permanent, intergovernmental Organization, created at the Baghdad Conference on September 10–14, 1960, by Iran, Iraq, Kuwait, Saudi Arabia and Venezuela. The five Founding Members were later joined by eight other Members: Qatar (1961); Indonesia (1962); Socialist People’s Libyan Arab Jamahiriya (1962); United Arab Emirates (1967); Algeria (1969); Nigeria (1971); Ecuador (1973–1992) and Gabon (1975–1994). OPEC had its headquarters in Geneva, Switzerland, in the first five years of its existence. This was moved to Vienna, Austria, on September 1, 1965.

OPEC’s objective is to co-ordinate and unify petroleum policies among Member Countries, in order to secure fair and stable prices for petroleum producers; an efficient, economic and regular supply of petroleum to consuming nations; and a fair return on capital to those investing in the industry.

1960-1970: These were OPEC’s formative years, with the Organization, which had started life as a group of five oil-producing, developing countries, seeking to assert its Member Countries’ legitimate rights in an international oil market dominated by the ‘Seven Sisters’ multinational companies. Activities were generally of a low-profile nature, as OPEC set out its objectives, established its Secretariat, which moved from Geneva to Vienna in 1965, adopted resolutions and engaged in negotiations with the companies. Membership grew to ten during the decade.

1970-1980: OPEC rose to international prominence during this decade, as its Member Countries took control of their domestic petroleum industries and acquired a major say in the pricing of crude oil on world markets. There were two oil pricing crises, triggered by the Arab oil embargo in 1973 and the outbreak of the Iranian Revolution five years later, but fed by fundamental imbalances in the market; both resulted in oil prices rising steeply. The first Summit of OPEC Sovereigns and Heads of State was held in Algiers in March 1975. OPEC acquired its 11th and final current Member, Nigeria, in 1971.

1980-1990: Prices peaked at the beginning of the decade, before beginning a dramatic decline, which culminated in a collapse in 1986 – the third oil-pricing crisis. Prices rallied in the final years of the decade, without approaching the high levels of the early-1980s, as awareness grew of the need for joint action among oil producers if market stability with reasonable prices was to be achieved in the future. Environmental issues began to appear on the international agenda.1990s

1990-2000: A fourth pricing crisis was averted at the beginning of the decade, on the outbreak of hostilities in the Middle East, when a sudden steep rise in prices on panic-stricken markets was moderated by output increases from OPEC Members. Prices then remained relatively stable until 1998, when there was a collapse, in the wake of the economic downturn in South – East Asia. Collective action by OPEC and some leading non-OPEC producers brought about a recovery. As the decade ended, there was a spate of mega-mergers among the major international oil companies in an industry that was experiencing major technological advances. For most of the 1990s, the ongoing international climate change negotiations threatened heavy decreases in future oil demand.


Petroleum Engineering Optimization

Petroleum Engineering Optimization examines techniques of reservoir optimization and parameter estimation that is useful in petroleum engineering and geosciences. In regard to reservoir optimization, there are several parameters to look at such as matching reservoir models, linear and nonlinear parameter estimation, history matching and the computation of confidence intervals on estimates parameter values.

Specific parameter estimation techniques include Newton type methods (Gauss-Newton, Newton, Levenberg-Marquardt, eigenvalue modification approaches), quasi-Newton (Broyden’s algorithm), singular value decomposition (SVD) and robust (LAV and MLAV) methods.

Methods to optimize goal-oriented projects are also emphasized on this course, for instance environmental impact minimization and cost reduction, production or profit maximization, etc. Optimization techniques includes gradient-based methods such as Newton, variational approaches such as optimal control theory, direct search methods (line search, conjugate gradient and polytope), and exploration methods such as simulated annealing, taboo search and genetic algorithm. What’s more, both constrained and unconstrained methods are also studied.

What are you required for Petroleum Engineering Optimization?

If you are interested in this subject, you are required to pass several courses in regard to mathematics and computer programming for example Linear algebra, computer language C, C++, Matlab or Java.