Pressure maintenance

Nitrogen is used for pressure maintenance in oil and gas reservoirs for enhanced recovery. It is sometimes used as a miscible agent to reduce oil viscosity and increase recovery in deep reservoirs. Other appHcations include recovery of oil in attic formations, gas cap displacement, and a sweep gas for miscible CO2 slugs. Nitrogen competes with CO2, a more miscible gas with hydrocarbons (qv), in most of these appHcations. The production mode is typically by on-site cryogenic separation plants. In 1990, nitrogen production in enhanced recovery operations was 20 x 10 m /d (750 million SCF/d)... 

Mechanical seals vapor recovery sealing glands by oil pressure maintenance Vapor incineration Inspection and maintenance... 

Pressure maintenance Maintenance of specified (differential) pressures in spaces or pipe/duct systems. 

In addition to pressure maintenance in a resei voir, there are other ways to maintain or improve well productivity as the formation pressure falls. A pump can be used to raise the oil, a process called artificial lift. One type is the familiar beam pump with its surface power unit driving up and down one end of a center-mounted beam while the other end executes the opposite down-up motion. The second end is attached to a string of sucker rods that extend down to the bottom of the well and operate a pump arrangement, consisting of a cylinder, plunger, and one-way A alves. Other types of pumps in use eliminate the sucker rod and may have the power unit at... 

Pressure maintenance (jockey) pumps should be provided to maintain a predetermined pressure on the system and make-up normal leakage in the distribution system. Normally, the pressure maintenance pump will maintain 10-15 psi (69-103 kPa) above the starting pressure for the automatic starting of the main fire water pump. (See 7.4.4.3.9.)... 

When the fire water system will be routinely used for purposes other than firefighting (e.g., washdown), the pressure maintenance pump, typically 150-300 gpm (570-1,150 Ipm), should have sufficient capacity for such use or a separate service pump should be provided. The service pump need not meet the requirements for fire water pumps. 

All of these factors affect the number of separation trains per stage. Mechanical separation characteristics, such as foaming tendency with a large GOR drop should also be considered. The reservoir pressure maintenance program should be considered. 

Injection into an oil producing reservoir for pressure maintenance. 

The HTP is a batch process the volume treated per unit time is a function of the cycle-time (that is the sum of the times of each step sealing, pressurization, maintenance at the operating pressure, depressurization, opening, and unloading times), of the batch volume, and of the number of cells used simultaneously in parallel in the same cycle. 

Foams can also be produced during primary production because pressure is greater in the reservoir at the locations from which oil is being drained, and lower near and in the well-bore. As oil moves toward a producing well and then into the bottom of the well, the reduced pressure it experiences can cause dissolved gas to be released. When this happens to a light oil, the gas normally separates from the oil. In the case of some heavy oils, however, the gas remains dispersed in the oil as an in situ oil foam [339,698], This is called foamy-oil production, and can be associated with increased primary-oil production compared to what would be expected from non-foamy-oil production. It is thought that the formation of foamy-oil delays the formation of a continuous gas phase (increases the trapped gas saturation) and contributes a natural pressure-maintenance function [339,698],... 

Thurston, H., Swales, J. D., Bing, R. F., et al. 1979. Vascular renin-like activity and blood pressure maintenance in the rat. Studies of the effect of changes in sodium balance, hypertension and nephrectomy. Hypertension 1 643-649. 

There s a single element found in successful weight loss,cholesterol control, stress management, diabetes prevention, and blood pressure maintenance. It s something virtually everyone all over the world who has enjoyed a long life has in common, the factor that all medical authorities agree is essential for both quality and quantity of life. What is this snake oil that appears to be the cure for what ails you It s physical activity. 

My first thought in reading the article was that it must be the calcium in dairy, but that, it turned out, was not the case at all, even though calcium itself is indeed part of the electrolyte balance needed to control blood pressure. In this study, however, people getting as much calcium from other sources did not enjoy the same protection. Nor did individuals who consumed whole-fat dairy foods. Only the low-fat dairy products provided blood pressure maintenance. 

Studies in animal models using endothelin antibodies are now being reported. Miyamori et al. demonstrated in rabbits [163] that endothelin antibody administration failed to show any appreciable changes in systemic or renal haemodynamic parameters suggesting that endothelin in the circulation may not contribute to blood pressure maintenance under normal conditions. However, its role as a local modulator is as yet not defined. 

High-pressure nitrogen injection is considered an EOR process (Manrique et al., 2007). Some authors (e.g., Moritis, 2000) classify iimniscible gas injection as EOR too. In those cases, processes other than pressure maintenance are involved, and the processes result in more oil recovered. 

None Waterflood Water injection for pressure maintenance... 

Conventional (primary and secondary) recovery methods recover only a small fraction of the crude oil originally in place in a typical reservoir. The primary and secondary recovery techniques, which include pressure maintenance by gas injection and water flooding for improved recovery, leave approximately two-thirds of the original oil in the reservoir. As the conventional oil production of the United States continues to decline, enhanced oil recovery will play an important role in the utilization of our domestic resources. Conventional methods do not overcome the basic problems of oil being trapped within the rock pores and of the low mobility of the remaining oil. 

In this chapter the properties of nonaqueous hydrocarbon foams will be reviewed and the effects of foam formation on flow of oil—gas mixtures in porous media will be discussed A laboratory technique for investigating the role of foamy-oil behavior in solution gas drive is described, and experimental verification of the in situ formation of non-aqueous foams under solution gas drive conditions is presented The experimental results show that the in situ formation of nonaqueous foam retards the formation of a continuous gas phase and dramatically increases the apparent trapped-gas saturation. This condition provides a natural pressure maintenance mechanism and leads to recovery of a much higher fraction of the original oil in place under solution gas drive. 

Results of the experimental study suggest that the formation of an oil-continuous foam may be involved in flow of heavy oil under solution gas drive. Such foam formation can be very beneficial for increasing the oil recovery. It delays the formation of a continuous gas phase, and thereby acts as a natural pressure-maintenance mechanism. In terms of the conventional solution gas drive theory, it serves to greatly increase the apparent trapped-gas saturation. 

A chromatographic analysis for one oil can be used to aid in the characterization of another oil which has similar physical properties. Calculations then can be made for fluids for which a detailed analysis is not available. The characterization procedure and the equation of state presented have been used to (1) predict the saturation pressure and phase behavior for reservoir fluids (2) predict properties for estimating the quantity of reservoir fluid in place and the recovery of that fluid by primary depletion and (3) predict phase behavior during compositional model studies for primary depletion (123) pressure maintenance by gas... 

ADMINISTERING DRUGS FOR HYPERTENSIVE EMERGEN Cl ES. Nitropnisside and diazoxide are dni used to treat jiatieiits witli a hyiiertensive emergency (a systolic pressure of 120 mm Hg or more). When tliese dni are used, die nurse frequently monitors die blood pressure, heart rate, and electrocardiogram throughout die course of dierapy. Continuous monitoring is preferred. The primary care provider will order die parameters for the blood pressure maintenance... 

When gas is used as the pressure maintenance agent, it is usually injected into a zone of free gas (i.e., a gas cap) to maximize recovery by gravity drainage. The injected gas is usually natural gas produced from the reservoir in question. This, of course, defers the sale of that gas until the secondary operation is completed and the gas can be recovered by depletion. Other gases, such as N2, can be injected to maintain reservoir pressure. This allows the natural gas to be sold as it is produced. 

Sodium is the primary positive ion in extracellular fluid and is a major determinant of fluid concentration or extracellular osmolality. Sodium is present in the body in a variety of forms and is stored in the bones and, more prevalently, in body fluids. Sodium is important for blood pressure maintenance, nerve impulse conduction, and circulation of nutrients into the cell. Thus sodium imbalance (outside the 135-145 mEq/L range) can result in fluid imbalance, as well as other electrolyte imbalances. 

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