Translate the sentences into English

1. После спуска обсадной колонны следующей задачей становится цементирование спущенной колонны.

2. Оборудование хранения рассыпного цемента и по работе с ним доставляют к скважине, получая возможность приготовления большого количества цементного раствора на месте работ.

3. В определенное время бурильные трубы убирают, и к скважине прибывает бригада для спуска обсадной колонны.

4. Спуск обсадной колонны во многом напоминает спуск бурильной трубы намного больше, и поэтому требуются специальные элеваторы, ключи и клиновые захваты.

5. Центраторы устанавливают на обсадной трубе, и, поскольку они имеют дугообразные пружины, они удерживают обсадную трубу в центре скважины после ее спуска.

6. Контейнерная цементировочная головка устанавливается на самой верхней трубе обсадной колонны.

7. Оцентрованная обсадная колонна позже обеспечивает более эффективное  цементирование.

8. Нижняя пробка останавливается или «садится» в муфте с обратным клапаном.

9. Скребки улучшают качество цементирования за счет удаления со стенки корки, образованной буровым раствором, что проделывается движением колонны вверх и вниз, либо ее вращением.

10. После закачки цемента наступает время ожидания затвердения цемента.

 

1. Study the following vocabulary before reading.

sack             a weight measure. One sack contains 94 pounds of cement, 100 pounds of bentonite, 100 pounds of barite.

density         weight of a volume of a material.

slurry density the density of slurry expressed in either pounds per gallon or pounds per cubic foot. Suitable additives are used to modify slurry density.

weight          refers to the density of a drilling fluid or slurry.

fluid loss   the volume of fluid lost to a permeable material due to the process of filtration.

slurry yield   volume of slurry when one sack of cement (94 pounds) is mixed with desired amount of water containing any other additives such as accelerators, fluid-loss control agents, etc.

unpumpable unable to be pumped.

 

Reading

 

Read the text.

According to physical properties and chemical composition, the American Petroleum Institute (API) has identified nine types of cement. They are:

● API Class A and B (Portland cement)

● API Class C (High early strength cement)

● API Class D, E and F (Retarded cement)

● API Class G and H (Basic cement)

● API Class? (Special order only)

API Classes G and H cements are commonly used across a large geographical area. Classes A, B and C are used in specific geographic locations where down-hole conditions require special cement properties. Classes D, E and F are pearly used and only in special situations. You may hear the terms Standard, Premium and Premium Plus when referring to oil field cements.

The properties of cements used in the oil field depend on the factors like geographic location, downhole conditions (depth, temperature, etc.), type of cement job, and type of mixing water.

The properties of cement slurry are influenced by factors such as water ratio of cement slurries (gal/sk), slurry density (lb/gal), and slurry yield (ft3/sk). One must remember that if there is too much water in the slurry free water appears on top of the slurry and retards setting. If there is too little water the slurry is thick and difficult to pump and accelerates setting.

 

Slurry density (or cement slurry weight) must be always carefully monitored, too. While on the job, one must be alert to slurry property changes that can be the result of improper slurry density. The slurry properties most affected by changes in density are thickening time, flow characteristics (pumpability), drilling fluid displacement efficiency, free water, settling, compressive strength, fluid loss.

What about slurry yield, too much cement rather than too little is always advisable.

The thickening time is the time required for a cement to become unpumpable. Such well conditions like bottomhole circulating temperature (BHT), well depth and well pressure influence the thickening time. One must always remember that temperature, rather than depth has the greatest effect on cement thickening times. It can also be affected by conditions such as water invasion, loss of water to the formation, shutdown during cement slurry placement and contamination.

Compressive strength is the amount of strength required to support a string of casing. It provides the basis for most WOC regulations. It is a generally accepted rule that a compressive strength of 500 psi is the minimally acceptable standard for most cement operations.