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July 5, 2008
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Home / Issue Archive / 2008 / April #4 / Lufkin Controllers Can Resolove Production Problems on Many Levels

№ 4 (April 2008)

Lufkin Controllers Can Resolove Production Problems on Many Levels

NGDU (Oil-and-gas producing division) Almetyevneft took the lead in introduction of Lufkin Automation controllers for sucker-rod pumps at Tatneft, having suggested their testing at one of the leading oil-producing fields of the company

By Vladimir Fadeev, Manager of Production Department, Tatneft, Deputy Chief Engineer, Candidate of Science (Engineering)

Working as a leading technologists at Almetyevneft oil field, I happened to participate in tests of the first controller which were performed in spring of 1996. The controller showed itself well and was recommended for application; however, at that time because of high price, controllers did find wide application. At present, both in respect of quality and price, the situation has become more favorable for consumers.

The range of controller application is very wide, and, in my opinion, there is lack of understanding on this issue now. To fill in this gap, a trip of a group of Tatneft specialists to Houston was arranged for experience exchange in 2007.

Americans have such an approach: efficiency is related to the period between maintenance of the wells equipped with sucker-rod pumps. I was amazed that this factor at some companies abroad has reached 4-5 years.  At Tatneft this period for wells equipped with sucker-rod pumps is now on average 880 days, being one of the highest in the country. Our equipment operating conditions are somewhat tougher, oil is more viscous, and hydrogen sulfur content is higher.

Pressure of 20-30 Atm is usually maintained at the pump intake during well operation. Americans run the pump directly to the depth of the producing bed, and, without any limitations, recover as much liquid as it is flowing from the formation.  In addition, they provide certain reserve of the pumping unit capacity, so that to do minor maintenance, having stopped the equipment, or to pump in inhibitor solutions without losing liquid recovery. The main thing in this operating mode is to reduce shock loads on the valve actuating gear, and on the pump itself, which is achieved by appropriate control parameter setting.

Thus, within 3-4 years, the period between maintenance in the U.S. increased from 1-2 to 4-5 years. This is the main issue we paid attention to, and we believe that it is possible to increase the period between maintenance at Tatneft to at least 1,000 days by means of utilization of Lufkin Automation controllers.
Controllers make it possible to solve problems of the optimal use of downhole pumping equipment. It is possible to save on reduction of hanger length, and amount of rods. While standard tubing and rod hanger is 1,200-1,300 meters long, use of Lufkin Automation controllers will make it possible to reduce hanger length by 100-200 meters, which, in money terms, is about 55,000-110,000 rubles per well with the same liquid recovery. Optimization of downhole pumping equipment hangers results in reduction of power consumption for liquid lifting.

Lufkin Automation software makes it possible to select a setting for the necessary production recovery regime, or to automate the process.
Use of Lufkin Automation controllers is related not only to control of downhole pump and surface equipment operation, but to control of the field development process. It is planned to arrange control over the liquid withdrawal and bottomhole pressure, monitoring of their interaction in the dynamic of the injection and producing well stock operation as a pilot project at the fields of Almetyevneft and Yamashneft.

Recently, at the workshop of chief engineers of Tatneft, it was suggested that Almetyevneft should equip with controllers about 100-150 wells in the Berezovskaya area, Romashkinskoye field, and develop “an intelligent” area. Controllers are also used on dually completed wells to realize control over liquid withdrawal volumes and bottomhole pressure of the bed below М1-X packer. By the way, controllers with autonomous power supply found wide application in injection well operation in the United States. I would like to mention several positive aspects of application of М1-X packer which is a joint product of the U.S. company Smith Services, and Tatneft. Over 2000 М1-X packers have been introduced at Tatneft in the short period of time. Fabricated under a license agreement, this effective tool found wide application as a packer element in both injection and producing wells, and also in dual completion technologies which enable simultaneous production from several pay beds.

It should be mentioned that Tatneft is at the new stage of development of the system of well automation which is based on decision-making by the automation devices directly on wells on the basis of the process information and algorithms of equipment operation control with provision of information to the level of the technological service of the field. Information should be provided to the level of the oil field management only in case of deviation from the set well operation mode, which will help to minimize the data transmission system load.

Information adequacy is another important factor. Scheduled well surveys once every three months provide only fragmentary information, and here, due to telemechanization of well operation, continuous monitoring is performed by radio channel. Telemechanization enables on-line well operation monitoring, which significantly reduces well downtime due to timely detection and elimination of the problems.

To be able to move farther, it is necessary to certify a set of downhole pumping equipment and controller as a well production rate metering device. This course is taken in Canada, where a temporary permit was issued for use of controllers with the aim of crude oil fiscal metering. The matter is that there can be several well owners at one and the same oil field, and profit is distributed among them based on the amount of the produced oil. By installing an appropriate software-hardware system on the well, it becomes possible to get real-time information on the amount of hours of the well operation, and accumulating production mode.

A large number of questions arise in connection with the company’s reorganization. We have removed power service, mechanical service, transportation department from the company’s structure, are removing drilling and well workover departments, some other sectors are next in turn. We have transferred the pumping units to the managing company Tatneft-MechService.

The next step will be transfer of the downhole pumping equipment (tubing, rods, pipes), then we will be able to pass over to a new type of contractual relations. Controllers will help us in relationship with the partners (which are now third parties) to determine the reasons of the equipment downtime and responsibility criteria. This is a very important issue in the part of interrelations. This can result in significant increase of amount of Lufkin Automation controllers ordered by the service company itself. Service companies should themselves purchase controllers now, understanding that they provide an information “shield” against non-productive losses. Why were controllers of Lufkin Automation selected?

Because the “finer” controller algorithms of this company are most efficient at present. There are other control means, but they involve more costs. There is a mechanical service and a power one available at present but there is no automation service. In my opinion, it is necessary to set up an automation service structure as promptly as possible. Everything should be concentrated in the same hands; highly qualified specialists should be attracted who would do both assembly and commissioning work, and keep track of failures.

In the result of a number of energy conservation activities including application of controllers, operating costs of Tatneft for production of 1 ton of oil are almost the lowest among the Russian oil-producing companies. This makes us “maintain our reputation”, purchase controllers which get repaid rather quickly, often within less than a year. At present, 496 controllers are used at the fields of the company, and it is planned to purchase 667 more in 2008.

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