1. Text “Well testing”. Glossary

2. Grammar: Participle

1). Read, translate and retell the text Text “Well Testing”

In producing gas and oil, efficient performing of the producing wells has more and more importance. A variety of tests must be made to determine the performing of an oil or gas well. This procedure is called testing. There are a large number of types of well tests and each is needed to obtain certain information about the well. Various personnel make many well tests, some of them are routine and some are complicated. Depending upon the type of test to be performed, the standard lease producing equipment may be all that is necessary for the test. In other tests, specially designed apparatus may be necessary. In any event, it is very important that the test be done accurately since well test data presents the true history of a well and the reservoir in which it is completed.

Potential test: the most frequently conducted well test is the potential test, which is a measurement of the largest amount of oil and gas, produced by a well in a 24-hour period under certain fixed conditions. The produced oil is measured in an automatically controlled production and test unit. It can also be measured by wireline measurement in lease tank. Produced gas is measured at the same time with equipment such as an orifice meter or an orifice well tester. The major items of equipment needed for a test of this type are usually available as standard equipment at the lease tank farm.

The potential test is normally made on each newly completed well and often during its production life. The information obtained from this test is required by the state regulatory group, which assigns a producing allowable, which must be followed by the operator of the well. It is necessary to make the tests from time to time and producing allowables are adjusted according to the results of the tests. Very often these tests are performed by the producer to help in establishing proper production practices.

Bottom-hole pressure test: this test is a measure of the reservoir pressure of the well at a specific depth or at midpoint of the producing interval. The purpose of this test is to measure the pressure in the zone in which the well is completed. In making of this test, a specially designed pressure gage is lowered into the well by means of a wireline. The pressure at the selected depth is recorded by the gage. After that gas is pulled to the surface and is taken from the well. Regular bottom-hole tests will provide valuable information about the decline or depletion of the zone in which the well has been producing.

Productivity tests are made on both oil and gas wells, and include both the potential test and the bottom-hole pressure test. The purpose is to determine the effects of different flow rates on the pressure within the producing zone. In this way, it is possible to establish some certain physical characteristics of the reservoir and to calculate maximum potential rate of flow. This test mitigates risk of damaging the well, which might occur if the well were produced at its maximum possible flow rate.

Special tests: two types of special tests are fluid level determination and bottom-hole determination. The first is required for wells, which will not flow and must be made to produce by pumping or artificial lift. The bottom-hole determination is normally made along with the bottom-hole pressure test and is made to determine the temperature of the well at the bottom of the hole. It is necessary to lower a specially designed recording manometer into the well on a wire line. The temperature tests are used by the engineer in solving problems about the nature of oil or gas that the well produces. It is also useful in locating leaks in the pipe above the producing zone. Other special tests are performed with flow rate indicators and radio active tracers.

As we know, one of the parameters of effective oil production is quality of investigation works and methods of production rate increasing1, applied in the results of well testing. Well state diagnostics also is very important for geotechnical activities, especially on the last stage of deposit development. While testing a well it is very important to know reservoir pressure. Under the reservoir pressure there is fluid and gas, which fills pore space or reservoir fractures. It is the most important parameter which characterizes producing energy of oil, gas, and water beds. Deposits where reservoir pressure higher than hydrostatic pressure are called deposits with abnormally high reservoir pressure. Its formation, change and state in oil and gas deposits depend on hydrostatic, geostatic, and geotectonic pressure, and also on chemical interaction of waters and rocks.

In the process of well exploitation areas with lower pressure can take place. Pressure in the well in work is called dynamic and pressure in the well when the work is stopped is called static. In the course of deposit development (if methods of keeping pressure are not applied) reservoir pressure reduces.

Answer the following questions:

What must be done to determine the performing of an oil or gas well?

Why is it very important that the test be done accurately?

What is a potential test?

How is the information obtained from potential test used?

What is the purpose of the bottom-hole pressure test?

What makes it possible to establish some certain physical characteristics of the reservoir and to calculate maximum potential rate of flow?

Describe two types of special tests.

What equipment is used for special test?

Why is it so necessary to know reservoir pressure in the well?

What factors cause formation, change and state of pressure in the well?

How can pressure in the well be measured?

Exercise 1. Translate the following sentences into Kazakh, using the above text:

1. Some tests must be made to determine the performance of an oil or gas well. 2. There are a large number of types of well tests and each is needed to obtain more information about the well. 3. The standard lease producing equipment may be all that is necessary for the test. 4. It is very important that the test be done accurately since well test data presents the true history of a well. 5. The produced oil is measured in an automatically controlled production and test unit. 6. The tests are performed by the producer to help in establishing proper production practices. 7. A specially designed pressure gage is lowered into the well by means of a wire line. 8. The temperature tests are used by the engineer in solving problems about nature of oil or gas that the well produces.

Read and learn by heart the following oil and gas glossary

naphta: an oil distillate. Naphta is an intermediate product between gasoline and kerosene. It is known as a light product because of the low molecular weight of the hydrocarbons making it up.

coke: a solid material similar to coal that can be produced from processing of heavy oil.

coking: a refining process by which the denser, heavier products of the distillation process (residuals) are converted to lighter products such as cat feed and naphtha, and petroleum coke, a solid, coal-like fuel. The coking unit, or coker, heats hydrocarbons to near 800 degrees Fahrenheit, at which temperature all the lighter products vaporize and the coke solidifies in a large drum called a coke drum from which it is removed by means of high-pressure jets of water.

distillation curve: a graph which plots the percentage (by volume) of a given grade of crude which boils off as a function of temperature. Since the boiling points of the various crude cuts are constant, the distillation curve shows the percentage of each compound in a given grade or batch of crude.

gas cap: upper portion of reservoir rock of a gas-containing field. The gas extracted during oil production is sometimes injected into the gas cap in order to boost hydrocarbon recovery.

field: set of porous rocks containing hydrocarbons.

flare bleeder: device for evacuating and burning unused gases.

fractionation: the separation of crude oil into its more valuable and usable components through distillation.

geophone: acoustical sensor for collecting reflected waves, in seismic exploration.

gravity: a property of a material that compares its weight to its volume.

distillation tower: a tall column-like vessel in which crude oil is heated and its vaporized components distilled by means of distillation trays. Also used to remove impurities added during the refining process.

drill: making a hole by means of whatever mechanism.

echo sounder: device used to calculate the distance of an obstacle based on the time a soundwave takes to travel to the obstacle and back.

effluent: mixture of oil, gas, water and sand discharged from a well.

electron: an elementary particle carrying a negative electric charge. An electron's mass is negligible compared with that of protons and neutrons.

enhanced recovery: recovery techniques designed to extract more hydrocarbons from a reservoir by physical, chemical or thermal means.

drill string: set of drilling tools, comprising pipes connected to each other, the bit, and the different tools. In drilling the drill string is rotated by the rotary table.

drilling mud: mixture of water and special additives circulating within the well for the purpose of cooling the drill-bit, removing rock cuttings and transporting them back up to the surface, preventing the well wall from caving in, maintaining sufficient pressure at the well bottom to avoid hydrocarbon blowout.

completion (well): all operations (tubing, installation of valves, wellhead, etc.) to bring a production well into operation.

loading flange: Installations required to deliver crude oil to a refinery.

jacket: steel structure placed on the seabed with a deck supporting drilling and/or production facilities.

jet fuel: a fuel used in aircraft. Jet fuel is obtained by distillation and sweetening. The latter removes all trace of mercaptans (very light molecules containing sulfur atoms). Jet fuel is a white product, so-called because it is transparent.

derrick: metal tower erected vertically above a well for the purpose of lifting and lowering tubes and tools into the well.

derrick-man: member of the drilling crew who works at the top of the derrick.

well: hole drilled underground for oil exploration and operation. By extension any apparatus used for this purpose.

wellhead: all connections, valves, nozzles, pressure gages, thermometers, and so forth, installed at the exit from a production well.

well-logging: electrical recording of physical characteristics of rocks traversed by a well.

white product: a term used to refer the lightest products resulting from the refining process, because of their transparent appearance.

desalting: removal of salt from crude oil. Desalting is preferably performed prior to commercialization of the crude, and must be performed prior to refining.