US Petroleum Holdings

title-3573714

2008-01-14T09:18:30+01:00

US Petroleum Holdings engineering has become a technical profession that involves extracting oil in increasingly difficult situations as the "low hanging fruit" of the world's oil fields are found and depleted. Improvements in computer modeling, materials and the application of statistics, probability analysis, and new technologies like horizontal drilling and enhanced oil recovery, have drastically improved the toolbox of the petroleum engineer in recent decades.

As mistakes may be measured in millions of dollars, petroleum engineers are held to a high standard. Deepwater operations can arguably be compared to space travel in terms of technical challenges. Arctic conditions and conditions of extreme heat have to be contended with. High Temperature and High Pressure (HTHP) environments that have become increasingly commonplace in today's operations require the petroleum engineer to be savvy in topics as wide ranging as thermohydraulics, geomechanics, and intelligent systems.

US Petroleum Holdings engineers must implement high technology plans with the use of manpower, highly coordinated and often in dangerous conditions. The drilling rig crew and machines they use become the remote partner of the petroleum engineer in implementing every drilling program. Understanding and accounting for the issues and communication challenges of building these teams remain just as vital to the petroleum engineer as ever.

The Society of Petroleum Engineers is the largest professional society for petroleum engineers and publishes much information concerning the industry. US Petroleum Holdings engineering education is available at 17 universities in the United States and many more throughout the world - primarily in oil producing states - but not only top producers, and some oil companies have considerable in house petroleum engineering training classes.

Petroleum engineers have historically been one of the highest paid engineering disciplines; this is offset by a tendency for mass layoffs when oil prices decline. According to a survey published in Dec 2006 the average income was $116,834.

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Abiogenic theory of gas

2008-01-13T19:17:51+01:00

Abiogenic theory
US PEtroleum Holdings

The idea of abiogenic petroleum origin was championed in the Western world by astronomer Thomas Gold based on thoughts from Russia, mainly on studies of Nikolai Kudryavtsev. The idea proposes that hydrocarbons of purely geological origin exist in the planet. Hydrocarbons are less dense than aqueous pore fluids, and are proposed to migrate upward through deep fracture networks. Thermophilic, rock-dwelling microbial life-forms are proposed to be in part responsible for the biomarkers found in petroleum.

This theory is a minority opinion, especially amongst Western geologists; no Western oil companies are currently known to explore for oil based on this theory, although Russia is known to have applied this theory with some success.[citation needed]

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Physical properties of Gas

2008-01-13T19:13:50+01:00

US Petroleum Holdings constituting a gas move essentially independently (more freely than those in a solid or liquid), with no significant forces keeping them together or pushing them apart. Their only interactions are rare and random collisions. The particles move in random directions, at high speed. The range in speed is dependent on the temperature and defined by the Maxwell-Boltzmann distribution. Therefore, the gas phase is a completely disordered state. Following the second law of thermodynamics, when no work is being done on or by a gas, the gas particles will immediately diffuse to homogeneously fill any shape or volume of space that is made available to them.

The thermodynamic state of a gas is characterized by its volume, its temperature, and its pressure. These variables are related by the fundamental gas laws, which state that the pressure in an ideal gas is proportional to its temperature and number of molecules, but inversely proportional to its volume.

Like liquids and plasmas, gases are flowing and free moving fluids: they have the ability to flow and do not tend to return to their former configuration after deformation, although they do have viscosity. Unlike liquids, unconstrained gases in a vacuum environment do not occupy a fixed volume, but expand to fill the entire space. Note that this is true in the case of empty, vacuum environments. If one sprays carbon dioxide from a fire extinguisher, for example, the gas will not expand to fill the room. Instead, the gas will pour out like a fluid and pool on the floor. This is due to the fact that it is more dense than the air surrounding it.[2]

The kinetic energy per molecule in a gas is the second greatest of the states of matter (after plasma). Because of this high kinetic energy, gas atoms and molecules tend to bounce off of any containing surface and off one another, the more powerfully as the kinetic energy is increased. A common misconception is that the collisions of the molecules with each other is essential to explain gas pressure, but in fact their random velocities are sufficient to define that quantity. Mutual collisions are important only for establishing the Maxwell-Boltzmann distribution.

Gas particles are normally well separated, as opposed to liquid particles, which are in contact. A material particle (say a dust mote) in a gas substrate moves in Brownian Motion. Since it is at the limit of (or beyond) current technology to observe individual gas particles (atoms or molecules), only theoretical calculations give suggestions as to how they move, but their motion is different from Brownian Motion. The reason is that Brownian Motion involves a smooth drag due to the frictional force of many gas molecules, punctuated by violent collisions of an individual (or several) gas molecule(s) with the particle. The particle (generally consisting of millions or billions of atoms) thus moves in a jagged course, yet not so jagged as we would expect to find if we could examine an individual gas molecule. Wikipedia

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Six Classes of Fuel

2008-01-13T10:59:55+01:00

Fuel oil in the United States is classified into six classes, according to its boiling temperature, composition and purpose. The boiling point, ranging from 175 to 600 °C, and carbon chain length, 20 to 70 atoms, of the fuel increases with number. Viscosity also increases with fuel oil number and the heaviest oil has to be heated to get it to flow. Price usually decreases as the fuel number increases. No. 1 fuel oil, No. 2 fuel oil and No. 3 fuel oil are referred to as distillate fuel oils, diesel fuel oils, light fuel oils, gasoil or just distillate. For example, No. 2 fuel oil, No. 2 distillate and No. 2 diesel fuel oil are almost the same thing. Diesel is different in that it also has a cetane number limit which describes the ignition quality of the fuel. Distillate fuel oils are distilled from crude oil. Gas oil refers to the process of distillation. The oil is heated, becomes a gas and then condenses. It differentiates distillates from residual oil (RFO). No. 1 is similar to kerosene and is the fraction that boils off right after gasoline. No. 2 is the diesel that trucks and some cars run on, leading to the name "road diesel". It is the same thing as heating oil. No. 3 is a distillate fuel oil and is rarely used. No. 4 fuel oil is usually a blend of distillate and residual fuel oils, such as No. 2 and 6, however, sometimes it is just a heavy distillate. No. 4 may be classified as diesel, distillate or residual fuel oil. No. 5 fuel oil and No. 6 fuel oil are called residual fuel oils (RFO) or heavy fuel oils. As far more No. 6 than No. 5 is produced, the terms heavy fuel oil and residual fuel oil are sometimes used as synonyms for No. 6. They are what remains of the crude oil after gasoline and the distillate fuel oils are extracted through distillation. No. 5 fuel oil is a mixture of No. 6 (about 75-80%) with No. 2. No. 6 may also contain a small amount of No. 2 to get it to meet specifications. Residual fuel oils are sometimes called light when they have been mixed with distillate fuel oil, while distillate fuel oils are called heavy when they have been mixed with residual fuel oil. Heavy gas oil, for example, is a distillate that contains residual fuel oil. The ready availability of very heavy grades of fuel oil is often due to the success of catalytic cracking of fuel to release more valuable fractions and leave heavy residue.

The US nomenclature is used in most of the world. In the United Kingdom the classes comprise 6 commonly used fuels using alphabetical designations, from Class C1 (kerosene) to Class G (heavy fuel oil). There is a Class H designation which is not yet in general use. The characteristics of these oils are specified in British Standard BS2869:1998 - soon to be updated to BS2869:2006.

Wikipedia

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Recent Outlook US Petroleum Holdings

2008-01-12T18:53:53+01:00

Official Energy Statistics from the U.S. Government

Trends in energy supply and demand are affected by many factors that are difficult to predict, such as energy prices, U.S. economic growth, advances in technologies, changes in weather patterns, and future public policy decisions. It is clear, however, that energy markets are changing gradually in response to such readily observable factors as the higher energy prices that have been experienced since 2000, the greater influence of developing countries on worldwide energy requirements, recently enacted legislation and regulations in the United States, and changing public perceptions of issues related to the use of alternative fuels, emissions of air pollutants and greenhouse gases, and the acceptability of various energy technologies, among others The Energy Information Administration projects increased consumption of biofuels (both ethanol and biodiesel), growth in coal-to-liquids (CTL) capacity and production, growing demand for unconventional transportation technologies (such as flex-fuel, hybrid, and diesel vehicles), growth in nuclear power capacity and generation, and accelerated improvements in energy efficiency throughout the economy.

Despite the rapid growth projected for biofuels and other nonhydroelectric renewable energy sources and the expectation that orders will be placed for new nuclear power plants for the first time in more than 25 years, oil, coal, and natural gas still are projected to provide roughly the same 86-percent share of the total U.S. primary energy supply in 2030 that they did in 2005 (assuming no changes in existing laws and regulations). The expected rapid growth in the use of biofuels and other nonhydropower renewable energy sources begins from a very low current share oftotal energy use; hydroelectric power production, which accounts for the bulk of current renewable electricity supply, is nearly stagnant; and the share of total electricity supplied from nuclear power falls despite the projected new plant builds, which more than offset retirements, because the overall market for electricity continues to expand rapidly in the projection.

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UsPetroleum, fuel and gas information

2008-01-12T18:52:25+01:00

DRILLING AN OIL WELL
US Petroleum Holdings
The earliest oil wells were drilled percussively (cable-tool drilling), that is, holes were drilled simply by hammering at the earth. Very soon, the limited depths which this method could attain meant that rotary drilling was introduced. Modern wells drilled using rotary drills can achieve lengths of over 12,000 meters / 38,000 feet.
US Petroleum Holdings

Until the 1970s, most oil wells were vertical (or, more specifically, were supposed to be vertical - deviations introduced by different lithology and mechanical imperfections meant that most wells were at least slightly deviated). However, modern technologies (directional drilling) allow strongly deviated wells which can, given sufficient depth, US Petroleum Holdings
actually become horizontal. This is of great value as the reservoir rocks which contain hydrocarbons are usually horizontal, or sub-horizontal. A well, therefore, which passes along a reservoir (rather than through it, as a vertical well must) can tap a larger volume with a much larger surface area (and thus a correspondingly higher production rate). Using deviated and horizontal drilling, it has also become possible to reach reservoirs several kilometers away from the drilling place (Extended Reach Drilling), allowing to produce hydrocarbons from underneath e.g. environmentally sensitive areas or offshore close to the coast line.
Drilling

The well is created by drilling a hole (5 to 30 inches wide) into the earth with an oil rig turning a drill bit. After the hole is drilled, a metal pipe slightly smaller than the hole size (called a 'casing') is run into the hole. The outside of the casing is then bonded and secured to the hole with cement. The casing provides structural integrity to the newly drilled wellbore in addition to isolating potentially dangerous high pressure zones from each other and from the surface.

With these zones safely isolated and the formation protected by the casing, the well can be drilled deeper (into potentially more-unstable and violent formations) with a smaller bit, and also cased with a smaller size casing. Modern US Petroleum Holdings
wells often have 2-5 sets of subsequently smaller hole sizes drilled inside one another, each cemented with casing.

To drill the well:

. The drill bit, aided by rotary torque and the compressive weight of drill collars above it, breaks up the earth.
. Drilling fluid is pumped down the inside of the drill pipe and exits at the drill bit and aids to break up the rock, as well as clean, cool and lubricate the bit.
. The generated rock "cuttings" are swept up by the drilling fluid as it circulates back to surface outside the drill pipe.
. The pipe or drill string to which the bit is attached is gradually lengthened as the well gets deeper by screwing in several 30' joints of pipe at surface.

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

After drilling and casing the well, it must be 'completed'. Completion is the process in which the well is enabled to produce oil or gas.

In a cased-hole completion, holes (called perforations) are made in the casing that covers the reservoir section to provide a path for the oil to flow from the surrounding rock into the well bore. In open hole completion, often 'sand-screens' or a 'gravel pack' is installed US Petroleum Holdings
in the last drilled, uncased reservoir section. These tools are to maintain structural integrity of the wellbore in the absence of casing, while still allowing flow from the reservoir into the wellbore. Screens also control the migration of formation sands into production tubulars and surface equipment, which can cause washouts and other problems, particularly in unconsolidated sand formations in offshore fields.

After a flow path is made, acids or other fluids are often pumped into the well to fracture, clean, or otherwise prepare and stimulate the reservoir rock to optimally produce hydrocarbons into the wellbore. Finally, the area above the reservoir section of the well is packed off inside the casing, and connected to the surface via a smaller diameter pipe called tubing. This arrangement provides a redundant barrier to leaks of hydrocarbons as well as allowing damaged sections to be replaced. Also, the smaller diameter of the tubing produces hydrocarbons at an increased speed, in order to overcome the hydrostatic effects of heavy fluids such as water.

In most wells, the natural pressure of the subsurface reservoir is high enough to push the oil or gas all the way to surface. However, this is not always the case, especially in depleted fields where the pressures have been lowered by other producing wells. Installing a smaller diameter tubing may be enough to help the production, but other types of artificial lift can also be used. Common solutions are downhole pumps, gas lift, or surface pump-jacks - the "nodding donkey" pumps dotting the countryside in old oil fields in Texas and Oklahoma. The use of artificial lift technology in a field is often termed as "secondary recovery" in the industry.

Production

The production stage is the most important stage of a well's life, when the oil and gas are produced. By this time, the oil rigs and workover rigs used to drill and complete the well have moved off the wellbore, and the top is usually outfitted with a collection of valves called a "Christmas Tree". These valves regulate pressures, control flows, and allow access to the wellbore in case further completion work needs to be performed. From the outlet valve of the Christmas Tree, the flow can be connected to a distribution network of pipelines and tanks to supply the product to refineries, natural gas compressor stations, or oil export terminals.

As long as the pressure in the reservoir remains high enough, this Christmas Tree is all that is required to produce the well. If the pressure depletes and it's considered economically viable, an artificial lift method mentioned in the completions section can be employed.

Workovers are often necessary in older wells, which may need smaller diameter tubing, scale or paraffin removal, repeated acid matrix jobs, or even completing new zones of interest in a shallower reservoir. Such remedial work can be performed using workover rigs-also known as puling units-to pull and replace tubing, or by the use of a well intervention technique called coiled tubing.

Enhanced recovery methods such as water-flooding, steam flooding, or CO2 flooding may be used to increase reservoir pressure and provide a "sweep" effect to push hydrocarbons out of the reservoir. Such methods require the use of injection wells (often picked from old production wells in a carefully determined pattern), and are used when facing problems with reservoir pressure depletion, high oil viscosity, or can even be employed early in a field's life; in certain cases-depending on the reservoir's geomechanics-reservoir engineers may determine that ultimate recoverable oil may be increased by applying a water-flooding strategy early in the field's development rather than later. The application of such enhanced recovery techniques is often termed as "tertiary recovery" in the industry.

Abandonment

Finally, when the well no longer produces or produces so poorly that it is a liability to its owner, it is abandoned. In this simple process the wellbore is filled with cement so that the flow path from the reservoir to the surface is plugged.

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. Unwanted natural gas can actually be quite a disposal problem at the well site. If there is not a market for natural gas near the wellhead it is virtually valueless because it must be piped to the end user. The easy way to get rid of it was to burn it away at the well site, but due to environmental concerns this practice is becoming less and less common. Often, unwanted (or 'stranded' - gas without a market) gas is pumped back into the reservoir with another 'injection' well for disposal. Another solution is to export the natural gas as LNG. Of course, in locations such as the United States with a high natural gas demand, pipelines are constructed to take the gas from the well site to the end consumer.

Another obvious way to classify oil wells is by land or offshore wells. There really is very little difference in the well itself; an offshore well simply targets a reservoir that also happens to be underneath an ocean. Also, due to logistics, drilling an offshore well is far more costly than an onshore well. By far the most common type of well is of the onshore variety. These wells dot the Southwestern United States, and are also the most common type of well in the Middle East. US Petroleum Holdings

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 when they are drilled primarily for producing oil or gas, once the producing structure and characteristics are established
. appraisal wells when they are used to assess characteristics (such as flow-rate) of a proven hydrocarbon accumulation
. exploration wells when they are drilled purely for exploratory (information gathering) purposes in a new area
. wildcat wells when a well is drilled, based on a large element of hope, in a frontier area where very little is known about the subsurface. In the early days of oil exploration in Texas, wildcats were common as productive areas were not yet established. In modern times, oil exploration in many areas has reached a very mature phase and the chances of finding oil simply by drilling at random are very low. Therefore, a lot more effort is placed in exploration and appraisal wells.

Re-Entry Projects:

Re-entry Projects involve locating well bores that were drilled in the past that were plugged and abandoned. The process generally involves finding the specific location of a previously drilled well and uncovering the site. Sites are frequently buried under several feet of soil and are often overgrown with trees and brush. Once uncovered, a rig is moved into the site and begins drilling through cement "plugs" that were placed during the plugging process. Sometimes there are numerous plugs in the well bore, each of which must be drilled out, down to the zone of interest for the re-entry.

Once the desired total depth is reached, work begins on the placement of casing, or pipe, in the hole. Frequently, casing already exists and must simply be extended or slightly modified to create a producing well.

Various other completion tasks such as perforation, stimulation (fracturing, acidizing, etc.) and swabbing are then performed to create a well bore from which hydrocarbons can be recovered.

Advantages:

Re-entry and re-completion have exciting advantages over speculation and drilling of new wells, and the United Stated Department of Energy has fully endorsed this new approach. Furthermore, the state of Texas currently has and incentive program that grants an exemption from 10 years of state severance tax for these types of wells.

New cutting-edge technologies have made re-entry a profitable venture for independent exploration companies. Geophysists can now map subterranean rock far more accurately, and new revolutionary imaging techniques greatly increase the possibilities or petroleum discovery. The newest generation of powerful microprocessors on the market is now able to support the processor-intensive imaging software.

For most re-entry candidates, exploration geologists and/or geophysicists have already identified petroleum-producing zones, and the exploration companies that abandoned the sites had only partially extracted hydrocarbons from the wells they drilled.

Re-entries usually cost much less than new drills and are procedurally advantageous. They often significantly reduce risk by using geographically known petroleum production zones, and can generate quicker returns than new drilling ventures. Re-entries average significantly less time to completion versus drilling a new well.

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Holdigns Petroleum in US

2008-01-12T12:23:21+01:00

Most geologists view crude oil, like coal and natural gas, as the product of compression and heating of ancient organic materials over geological time scales. According to this theory, it is formed from the decayed remains of prehistoric small marine animals and algae. (Terrestrial plants tend to form coal.) Over millennia this organic matter, mixed with mud, is buried under thick sedimentary layers of material. The resulting high levels of heat and pressure cause the remains to metamorphose, first into a waxy material known as kerogen, and then into liquid and gaseous hydrocarbons in a process known as catagenesis. Because hydrocarbons are less dense than the surrounding rock, these migrate upward through adjacent rock layers until they become trapped beneath impermeable rocks, within porous rocks called reservoirs. Concentration of hydrocarbons in a trap forms an oil field, from which the liquid can be extracted by drilling and pumping.

Geologists also refer to the “oil window”. This is the temperature range that oil forms in-below the minimum temperature oil does not form, and above the maximum temperature natural gas forms instead. Though this corresponds to different depths for different locations around the world, a ‘typical’ depth for the oil window might be 4 - 6 km. Note that oil may be trapped at much shallower depths, even if it is not formed there. Three conditions must be present for oil reservoirs to form: a rich source rock, a migration conduit, and a trap (seal) that concentrates the hydrocarbons.

The reactions that produce oil and natural gas are often modeled as first order breakdown reactions, where kerogen breaks down to oil and natural gas by a large set of parallel reactions, and oil eventually breaks down to natural gas by another set of reactions.

FORMATION OF OIL: Abiogenic theory

The idea of abiogenic petroleum origin was championed in the Western world by astronomer Thomas Gold based on thoughts from Russia, mainly on studies of Nikolai Kudryavtsev. The idea proposes that large amounts of carbon exist naturally in the planet, some in the form of hydrocarbons. Hydrocarbons are less dense than aqueous pore fluids, and migrate upward through deep fracture networks. Thermophilic, rock-dwelling microbial life-forms are in part responsible for the biomarkers found in petroleum.

According to the following authors; V. A. Krayushkin, T. I. Tchebanenko, V. P. Klochko, Ye. S. Dvoryanin from the Institute of Geological Sciences, Kiev, Ukraine, the modern Russian-Ukrainian theory of deep, abiotic petroleum origins is by no means simply an academic proposition. After its first enunciation by N. A. Kudryavtsev in 1951, the modern theory was extensively debated and exhaustively tested. Significantly, the theory not only withstood all tests put to it, but it also settled many previously unresolved problems in petroleum science, such as that of the intrinsic component of optical activity observed in natural petroleum. It also demonstrated new patterns in petroleum, previously unrecognized, such as the paleonological and trace-element characteristics of reservoirs at different depths. Most importantly, the modern Russian-Ukrainian theory of deep, abiotic petroleum origins has played a central role in the transformation of Russia (then the U.S.S.R.) from being a “petroleum poor” entity in 1951 to the largest petroleum producing and exporting nation on Earth, principally with the drilling and development of the oil and gas fields in the Dnieper-Donetsk Basin.

However, this theory is very much a minority opinion, especially amongst western geologists. It often pops up when scientists are not able to explain apparent oil inflows into certain oil reservoirs. However, most of these “abiotic” fields are explained as being the result of geologic quirks. No western oil companies are currently known to explore for oil based on this theory.

ALTERNATIVE MEANS OF PRODUCING oil

As oil prices continue to escalate, other alternatives to producing oil have been gaining importance. The best known such methods involve extracting oil from sources such as oil shale or tar sands. These resources are known to exist in large quantities; extracting the oil at low cost and without too deleterious an impact on the environment remains a challenge.It is also possible to transform natural gas or coal into oil (or, more precisely, the various hydrocarbons found in oil).

The best-known such method is the Fischer-Tropsch process. It was a concept pioneered in Nazi Germany when imports of petroleum were restricted due to war and Germany found a method to extract oil from coal. It was known as Ersatz (”substitute” in German), and accounted for nearly half the total oil used in WWII by Germany. However, the process was used only as a last resort as naturally occurring oil was much cheaper. As crude oil prices increase, the cost of coal to oil conversion becomes comparatively cheaper.

The method involves converting high ash coal into synthetic oil in a multistage process. Ideally, a ton of coal produces nearly 200 liters (1.25 bbl, 52 US gallons) of crude, with by-products ranging from tar to rare chemicals.

Currently, two companies have commercialized their Fischer-Tropsch technology. Shell in Bintulu, Malaysia, uses natural gas as a feedstock, and produces primarily low-sulfur diesel fuels. Sasol in South Africa uses coal as a feedstock, and produces a variety of synthetic petroleum products. The process is today used in South Africa to produce most of the country’s diesel fuel from coal by the company Sasol. The process was used in South Africa to meet its energy needs during its isolation under Apartheid. This process has received renewed attention in the quest to produce low sulfur diesel fuel in order to minimize the environmental impact from the use of diesel engines.

An alternative method is the Karrick process, which converts coal into crude oil, pioneered in the 1930s in the United States.

More recently explored is thermal de-polymerization (TDP). In theory, TDP can convert any organic waste into petroleum.

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Drill Oil by Us Petroleum Holdings

2008-01-12T12:18:19+01:00

The earliest oil wells were drilled percussively (cable-tool drilling), that is, holes were drilled simply by hammering at the earth. Very soon, the limited depths which this method could attain meant that rotary drilling was introduced. Modern wells drilled using rotary drills can achieve lengths of over 12,000 meters / 38,000 feet.

Until the 1970s, most oil wells petroleum were vertical (or, more specifically, were supposed to be vertical - deviations introduced by different lithology and mechanical imperfections meant that most wells were at least slightly deviated). However, modern technologies (directional drilling) allow strongly deviated wells which can, given sufficient depth, actually become horizontal. This is of great value as the reservoir rocks which contain hydrocarbons are usually horizontal, or sub-horizontal. A well, therefore, which passes along a reservoir (rather than through it, as a vertical well must) can tap a larger volume with a much larger surface area (and thus a correspondingly higher production rate). Using deviated and horizontal drilling, it has also become possible to reach reservoirs several kilometers away from the drilling place (Extended Reach Drilling), allowing to produce hydrocarbons from underneath e.g. environmentally sensitive areas or offshore close to the coast line.
Drilling

The well is created by drilling a hole (5 to 30 inches wide) into the earth with an oil rig turning a drill bit. After the hole is drilled, a metal pipe slightly smaller than the hole size (called a ‘casing’) is run into the hole. The outside of the casing is then bonded and secured to the hole with cement. The casing provides structural integrity to the newly drilled wellbore in addition to isolating potentially dangerous high pressure zones from each other and from the surface.

With these zones safely isolated and the formation protected by the casing, the well can be drilled deeper (into potentially more-unstable and violent formations) with a smaller bit, and also cased with a smaller size casing. Modern wells often have 2-5 sets of subsequently smaller hole sizes drilled inside one another, each cemented with casing.

To drill the well:

. The drill bit, aided by rotary torque and the compressive weight of drill collars above it, breaks up the earth.
. Drilling fluid is pumped down the inside of the drill pipe and exits at the drill bit and aids to break up the rock, as well as clean, cool and lubricate the bit.
. The generated rock “cuttings” are swept up by the drilling fluid as it circulates back to surface outside the drill pipe.
. The pipe or drill string to which the bit is attached is gradually lengthened as the well gets deeper by screwing in several 30′ joints of pipe at surface.

Completion

After drilling and casing the well, it must be ‘completed’. Completion is the process in which the well is enabled to produce oil or gas.

In a cased-hole completion, holes (called perforations) are made in the casing that covers the reservoir section to provide a path for the oil to flow from the surrounding rock into the well bore. In open hole completion, often ’sand-screens’ or a ‘gravel pack’ is installed in the last drilled, uncased reservoir section. These tools are to maintain structural integrity of the wellbore in the absence of casing, while still allowing flow from the reservoir into the wellbore. Screens also control the migration of formation sands into production tubulars and surface equipment, which can cause washouts and other problems, particularly in unconsolidated sand formations in offshore fields.

In most wells, the natural pressure of the subsurface reservoir is high enough to push the oil or gas all the way to surface. However, this is not always the case, especially in depleted fields where the pressures have been lowered by other producing wells. Installing a smaller diameter tubing may be enough to help the production, but other types of artificial lift can also be used. Common solutions are downhole pumps, gas lift, or surface pump-jacks - the “nodding donkey” pumps dotting the countryside in old oil fields in Texas and Oklahoma. The use of artificial lift technology in a field is often termed as “secondary recovery” in the industry.

Production

The production stage is the most important stage of a well’s life, when the oil and gas are produced. By this time, the oil rigs and workover rigs used to drill and complete the well have moved off the wellbore, and the top is usually outfitted with a collection of valves called a “Christmas Tree”. These valves regulate pressures, control flows, and allow access to the wellbore in case further completion work needs to be performed. From the outlet valve of the Christmas Tree, the flow can be connected to a distribution network of pipelines and tanks to supply the product to refineries, natural gas compressor stations, or oil export terminals. petroleum

As long as the pressure in the reservoir remains high enough, this Christmas Tree is all that is required to produce the well. If the pressure depletes and it’s considered economically viable, an artificial lift method mentioned in the completions section can be employed.

Enhanced recovery methods such as water-flooding, steam flooding, or CO2 flooding may be used to increase reservoir pressure and provide a “sweep” effect to push hydrocarbons out of the reservoir. Such methods require the use of injection wells (often picked from old production wells in a carefully determined pattern), and are used when facing problems with reservoir pressure depletion, high oil viscosity, or can even be employed early in a field’s life; in certain cases-depending on the reservoir’s geomechanics-reservoir engineers may determine that ultimate recoverable oil may be increased by applying a water-flooding strategy early in the field’s development rather than later. The application of such enhanced recovery techniques is often termed as “tertiary recovery” in the industry.

Abandonment

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. Unwanted natural gas can actually be quite a disposal problem at the well site. If there is not a market for natural gas near the wellhead it is virtually valueless because it must be piped to the end user. The easy way to get rid of it was to burn it away at the well site, but due to environmental concerns this practice is becoming less and less common. Often, unwanted (or ’stranded’ - gas without a market) gas is pumped back into the reservoir with another ‘injection’ well for disposal. Another solution is to export the natural gas as LNG. Of course, in locations such as the United States with a high natural gas demand, pipelines are constructed to take the gas from the well site to the end consumer.

Another way to classify oil wells is by their purpose in contributing to the development of a resource. They can be characterized as:

Re-Entry Projects:

Re-entry Projects involve locating well bores that were drilled in the past that were plugged and abandoned. The process generally involves finding the specific location of a previously drilled well and uncovering the site. Sites are frequently buried under several feet of soil and are often overgrown with trees and brush. Once uncovered, a rig is moved into the site and begins drilling through cement “plugs” that were placed during the plugging process. Sometimes there are numerous plugs in the well bore, each of which must be drilled out, down to the zone of interest for the re-entry.

Various other completion tasks such as perforation, stimulation (fracturing, acidizing, etc.) and swabbing are then performed to create a well bore from which hydrocarbons can be recovered.

Advantages:

Comments

History about US Petroleum Holdings

2008-01-12T12:16:11+01:00

Shallow production of oil was driving the exploration of the West Speaks Field in the early oil boom years. Many wells were drilled in the 1960’s and early 1970’s with oil production as the main objective, not gas. The wells were drilled and logged, showing that the intervals of our present day interest were “hydrocarbon bearing”, but the technology was not there to US Petroleum Holdings it out of the ground. Adding to this problem was typically a lack of gas pipelines to take this gas production to market and the prices that were being paid for this production was far less than $.30 per Thousand Cubic Feet of gas (MCFG). These factors killed the effort towards gas production and the exploration effort was usually short-lived. Due to increases in gas pricing over the last few years, many independent oil and gas companies have re-focuUS Petroleum Holdingssed their efforts in these types of areas that were drilled during earlier times in search of oil reserves.

The West Speaks Field has been commercially productive from shallow Yegua, Frio and Miocene are oil bearing sands and the Upper Wilcox gas bearing sections, but no real commercial production existed with the deeper Middle and Lower Wilcox series until recently. This area of prolific Wilcox production has seen substantial development US Petroleum Holdingsin the last few years with “Roeder” (Middle Wilcox) and “Migura” (Lower Wilcox) discoveries. These sections of the Middle to Lower Wilcox intervals have generated substantial commercial gas production from the field after new fracture stimulation technology was implemented during the completion operations. Larger independent companies such as El Paso Natural gas and Dominion Exploration and Production are actively developing the Roeder & Migura Wilcox sections in the area with some new wells generating gas flowsUS Petroleum Holdings in excess of 5 Million Cubic Feet of gas per Day.

We have identified many plugged well bores in the West Speaks Field that were drilled during the 1960’s and early 1970’s that were logged showing gas pay. Core samples were taken and determined to yield considerable hydrocarbons. Several of these wells had casing installed and were ceUS Petroleum Holdingsmented. While a handful of wells were tested in the Roeder Wilcox series, they flowed a nominal amount of gas at a non-commercial rate. Many of the wells were deemed as dry holes and some of the wells were re-completed in the shallower zones. The idea of “re-entering” a plugged well bore is not new, however recent prices of oil and natural gas has brought old thinking back into the light. The wells of this program will be re-entered, in some instances deepened, and then the zones of our interest will be fracture stimulated with modern technology. This type of project is typically less expensive than drilling a new well and the geologics US Petroleum Holdings are heavily in favor as the site has been logged.

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US Petroleum Holdings

2008-01-12T11:37:53+01:00

US petroleum holdings, Corp. is an independent energy company engaged in the procurement, exploitation, development, acquisition and operation of oil and natural gas properties with a geological focus in the United States. The company has implemented a business strategy that emphasizes development opportunities where the company has acquired several properties within a general area with proven reserves.

The recent up trend in the oil and natural gas market has resulted in sector investments becoming extremely beneficial. Consequently, the company has sought to procure working interests in properties that are either currently producing or will produce crude oil and natural gas within the next quarter.

Our projects implement and utilize the most innovative, state-of-the-art and cost-effective technologies that can profitably recover oil and natural gas as well as extend the productive life of US domestic reserves, reducing the reliance on energy imports.

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