Cheats On Bloons Level Pack 3 Level 28

CLASS 01

PVT PARAMETERS

Basics: field, pressure, temperature, saturation, normal conditions, gradient pressure geothermal gradient, bubble pressure, pressure dew.

PVT tests aim to provide the data needed to perform a material balance in the reservoir.

For data analysis carried out tests with samples of the deposit. A simple way to understand how to perform the tests is to think of a soda bottle. At first, when the bottle is closed only observe one phase, liquid, any gas containing drink is dissolved in it. But what happens if we open the bottle? We note that begins to release gas and liquid can see small bubbles move surface and released, why is this happening? Well, when we opened the drink, which had a certain internal pressure higher than the environment, generate a pressure differential and fully gas saturated solution is released because the drink to that pressure and temperature and does not dissolve in it completely.

The same happens when you alter a site, usually with the drilling of a well. In the basement oil mixed with gas at a certain pressure solution depends on the pressure gradient, depth and a temperature which in turn depends on the geothermal gradient, opening a well, produce a pressure differential and compounds, from the lightest to the top, to the heaviest, migrate to areas of lower pressure (the well and then the surface).

To find oil with gas in solution is important to consider a fundamental property of the latter, the solubility, which is the ease with which the dissolved gas in crude oil and is closely linked to the pressure, temperature and composition of both the crude oil as gas.

Depending on the amount of dissolved gas and pressure to which we are, there may be different types of deposits. One classification is more general sites saturated and undersaturated reservoirs. Saturated fields are those where a small differential pressure I can feel the release of gas. Undersaturated fields are where the pressure to reduce observed no release of gas. It is very important to know the type of site we have, as this determines the mechanism of production will go.

Returning to the concept of PVT tests, that we show some parameters such as volumetric factors training, relations between the amount of gas and oil and gas properties of hydrocarbons. Then explain some of the most important

Value solution gas - oil (Rs)

is linked to the solubility of gas and can be understood as the ratio between the volume of a standard cubic foot (measured at standard conditions) in solution and the volume of a typical barrel of oil, at a certain temperature and pressure condition.

is represented as follows in a plot vs Rs. Pressure. From an initial pressure P> Pb, until the bubble pressure, the graph shows a steady linear behavior, because all the possible gas is dissolved in the liquid to reach Pb is released the first drop of gas and gradually releasing gas constant, ie the amount of dissolved gas decreases, so also Rs, and does so in a linear fashion. The arrows indicate the direction of increase of the parameters.

Rsi
When we talk about is the Rs for pressures greater than Pb and when we speak of Rs, Rs is a pressure less than Pb.

Factor Petroleum Training volume (βo)

This parameter relates the volume of oil with a corresponding volume of dissolved gas at reservoir conditions from the corresponding volume on the surface.


While we are in the phase region, the value of βo increases because oil is expanding as we reduce the pressure. When you reach the bubble pressure, this parameter decreases because the volume of oil now going steadily losing the dissolved gas is released.

Factor Gas Training volume (βg) Consider

βo the same concept but in this case is the relationship between the volume of gas in reservoir volume and its corresponding surface.

Whereas the conditions of the gas we have in the reservoir can be modeled by the equation of ideal gas (PV = ZηRT). In this way we will find values \u200b\u200bof P, VZ, η, R and T in terms of reservoir and surface conditions. If we solve the volume of the ideal gas equation and substitute into the equation βg, we obtain:


temperature in the reservoir and the compressibility factor Z are constant, the pressure varies reservoir, then the graph represents a function f (x) =, of course only takes the positive part of the graph, resulting as follows.

Volumetric Factor Total Training (βt)

is the volume occupied by a barrel of oil along with gas initially dissolved at any temperature and pressure condition.

Βt = Βo + βg (Rsi - Rs)

The graph shows how both before and after the βt bubble pressure increases, this is due to expansion gas and oil.

Value gas - oil production (Rp)

The concept is similar to Rs only this time, the relationship is between the cubic feet of gas produced and cubic feet of oil produced. The following chart shows the performance this value.

To obtain these parameters is necessary to submit samples of certain test site. Usually we take the sample and introduce in a cell that can change the volume and we'll apply pressure differentials on the value of pressure can be greater than or equal to Pb. There are two forms of testing, is releasing a flash and the other is the instant release.

flash in the release we started with a P> Pb and varying the pressure until we get to Patmos. The gas that is released will always be in contact with oil. The mass sample remains constant and measuring the volume consider the gas and oil together. In this test we obtain mainly Pb and βt.

Stages of flash release or Solvent Based

The release begins at P = differential Pb and in this case with each differential pressure, the gas that is released is removed from the sample so that we also Patm. With her we get Z, βt, βo, βg, γg, ρo and Rs.

Stages instant release



Liberation and Gas Field Surface

In reservoir to achieve a flash gas release is necessary that the gas saturation is lower than the critical for the gas does not move and always be in contact with the petroleo.Si gas saturation is above criticism, then moves and the release occurs Differentiation. are always surface in the presence of instantaneous release if the gas production flow lines and separators is in contact with oil.

Fluid Phase Diagram in Field

Such diagrams allow us to evaluate the composition of a system for classifying it under certain criteria you choose. In general, the phase diagram for a site is as follows:

The envelope is composed the bubble curve indicates the saturation line for liquid, mist line that shows the saturation line for gas. Within it can be seen Isocal lines representing the percentage of sample fluid and decrease from left to right. The critical point is the point where liquid and gas phase are in equilibrium. Cricondenbárico point represents the point of greatest pressure which are in equilibrium liquid and gas, cricondentherm point represents the maximum temperature that are in equilibrium liquid and gas. Finally we look at areas where we can find only oil, gas and only mixture of both.

According to this chart, depending on reservoir conditions and drilling can find the following types of sites:

dry gas Sites

I get only dry gas surface . The blue dotted lines represent the path from the reservoir surface. Whenever the initial temperature is higher than the temperature cricondentherm. The components of this gas are usually light, mainly methane. To qualify for this production fluid would have to undergo cryogenic processes.

Wet Gas Reservoirs

In this case we can obtain only dry gas or gas with a minimum of liquid. Following the trajectory always obtain 1-2 dry gas at the surface. Through the path 1-2'podemos obtain a minimum percentage of liquid in the pipe occurs. The temperature is higher than the temperature cricondertérmica compounds and consists of a little heavier than dry gas.

gas condensate

Production takes place at a temperature which is among the cricondentherm and criticism. The production path part in the gas-only area and into the enclosure. The reservoir temperature is between cricondentherm temperature and the critical point.

The retrograde condensation zone: if that occurs as we enter the part of the envelope which is among the critical point and the temperature cricondentherm, it will be condensed liquid, very good quality but I can not reach its saturation critical, so do not moving and we can not recover. For this reason we try to avoid getting into that area in two ways, or not allow to reach the spray pressure or reduce pressure. Usually we choose the first option injecting gas.

volatile oil fields

Formed by the lighter components, is in the area closest to the critical point and a lower pressure change can get faster to the saturation conditions . When I'm in the small pressure changes surround me produce large changes in quality. The reservoir temperature will to locate near the critical point, but slightly lower.

crude oil fields

In these fields we are far from the critical point. When we apply small pressure differentials quality does not vary much. They consist of heavier compounds. The main benefit of this oil find is that we used for PVT analysis because its composition does not vary significantly. The reservoir temperatures are much lower than the critical point.

The phase diagrams may change as we produce the oil because the pressure conditions vary and the important points as the critical point, temperature and pressure cricondentherm cricondenbárica change value. Then the bubble and dew pressures may also vary. An important point to note is that the deposits have always considered as a constant temperature, unless you have very large thicknesses where the geothermal gradient comes into play.