New Era of Cementing

Cementing complexes produced in Russia nowadays (including the commonly known cementing units CA-320) are based on a regular stirrer operation. Cement entering mixing tank is clumped, but at that time non-homogeneous mixture is created whose density is very difficult to control. Due homogeneity of the slurry produced is achieved in a separate cement surge process which takes place in a special unit the operation of which is based on cement recycling in a large volume tank (about 20 m3). Cement pumping is carried out from the same tank. Cement is made for future use. This way of mixing the slurry for well cementing was used by several generations of oil-industry workers. The overwhelming majority of wells on the CIS territory was built with the help of this method. This usual, obvious and therefore apparently reliable way of cementing is understood by many experts as the only possible.

However, if we try to consider carefully the details of this process and both qualitative and quantitative components, none of experienced pluggers can be completely sure that cemented string is in full conformance with the design-project. Commonly used methods of cementing operations do not allow us to carry out full control of working mixture parameters at any stage of operational procedures. Besides, it is difficult to assess the exact amount of the slurry to be pumped.

In conditions of severe competition oil producing companies during well construction often try to choose service companies which can offer not only comparatively low cost of works but their high quality and speed of execution. Such combination is possible only under complex application of modern equipment and progressive technologies.

Nowadays, the most popular cementing complexes among overwhelming majority of international and Western service companies are complexes using twin pumping cementing units with automatic slurry mixing system. There are several types of these units but they have a common principle of operation (two independent lines and a deck-based motor- transmission- high pressure pump) and a system of automatic cement and water mixing. Since 2010 HC1000-10 unit has been manufactured by a world known producer of high-tech equipment for oil and gas service NOV FIDMASH.

HC1000-10 unit is equipped with two separate drivelines of three triplex plunger pumps SPM (as part of Allison transmission and Caterpillar motor) and a system of automatic mixing and control. In addition, the lines are in fact separate because hydraulic drive of for all the pumps also has two separate wet kits, and the low pressure pipe layout is arranged in a way that makes it possible to continue pumping under any emergency situation and failure of any centrifugal pump.

Mixing units of JetMixer type produced by NOV FIDMASH are based on the principle of ejection, where cement is added into liquid with uniform humidification. Mixing takes place under high speed recycling of the slurry that passes 3 – 6 cycles before entering the pumping line. This fact allows preparing the slurry of the needed density during very short period of time. The slurry has uniform consistency because the mixing principle prevents cement sedimentation. Therefore, the units produced by NOV FIDMASH do not need cement surge tanks and there is no need to prepare cement for future use.

While discussing the components of the cementing complex with HC1000-10 units, it is worth mentioning that the units can be used practically with any cement-transporting device based on the principle of air feed. Examples of such equipment can be mobile cement bulk storage of CT-40 type and cement trucks CТ-25 manufactured by Sibneftmash CJSC and practically any similar imported machines. Unlike traditional complexes, those including HC1000-10 units do not need separate cementing control stations, cement surge units and reservoirs. The quantity of equipment units used for cementing decreases 3 – 4 times, and the quantity of maintenance staff can be decreased up to 5 (!) times.

Not long ago NOV FIDMASH held its regular customers’ conference dedicated to operation of equipment manufactured by the company. HC1000-10 cementing unit was presented to experts and excited great interest. Here is the opinion of a department manager of an international service company: “I liked the cementing unit with twin pumps very much. It is an ideal option to have two independent working pumps and not one, because you have to fulfill very important operations, which in case of emergency may lead to loss of a well, and in case of operating only one pump, especially in Arctic environment, one cannot exclude the possibility of failure. That is why an additional pump is an excellent solution!”

ADVANTAGES OF HC1000-10 CEMENTING UNITS
MANUFACTURED BY NOV FIDMASH

- material cost optimization. The unit makes it possible to prepare the needed quantity of cement. If you use a special automatic density control system together with JetMixer, you will be able to make cement slurry in real-time mode;
- personnel cost optimisation. When operating the cementing complex you will need only 3 – 4 people;
- equipment optimisation. The unit does not need any additional cement surge tank(-s) and additional cementing control station;
- multifunctionality. The unit allows to carry out works relating to massive pumping, acid treatment, etc.
- worldwide experience. Similar units have been produced by NOV for decades and used throughout the world;
- company image. Use of progressive equipment will allow to strengthen positions on oil services market, achieve technological efficiency of cementing operations in conformance with international standards and become an example for other service companies.