Tatneft Field-Tests Lufkin’s SAM Intelligent Well Technology

The accuracy and precision of data is key when it comes to measuring oil and gas production volumes and flow rates

By Elena Zhuk

This applies to all stages of field development and well life, from pilot production onward. Such data also backs up decision making on when and how to apply well intervention technologies. Russian standards governing measurement and quality of production for individual wells and license blocks are regulated by GOST R 8.615-2005 “Measurement of the Amount of Recovered Oil and Petroleum Gas; General Metrological and Technical Requirements.” And to comply with those standards, Russian producers are putting the best technologies available world wide to the test. In 2007, Lufkin Automation, a global leader in intelligent well technologies based in East Texas, initiated the process of obtaining GOST certification of its SAM series of controllers which Tatneft started buying two years earlier. Partnering with Tatneft, Lufkin is field-testing on the 60-year old Romashkinskoye field in Tatarstan.

Oil&Gas Eurasia’s Technology Editor, Elena Zhuk, visited the oil capital of Tatarstan - the City of Almetyevsk - where Tatneft and its production subsidiary, Almetyevneft, are located near to the oilfields of Tatarstan, some of them in production since World War II. There, Zhuk saw first hand how Russian production engineers are implementing 21st Century intelligent well technology.

Almetyevneft: from tests to large-scale implementation

The introduction of Lufkin’s SAM line of controllers is today a major-league project of state-owned Tatneft, one of Lufkin’s best customers globally. Tatneft specialists began to familiarize themselves with foreign-made equipment for production control in the mid 1990s when tests performed by Almetyevneft, one of several Tatneft production units, proved the efficiency of using Lufkin’s DeltaX controllers and others.

However, at that time, the equipment was too costly for Tatneft to buy and install the systems on a large scale. And Russian manufacturers were entering the market with cheaper alternatives; firms such as Lint in Kazan and Intek in Ufa. Further competition was felt from Rosemount, a division of Emerson Process Management, which assembles some of its products in Chelyabinsk at the Metran plant, also a part of Emerson. Tatneft spent several years in search of the optimal solution until 2004 when specialists from the Production Department of Tatneft visited Lufkin Automation’s exhibition stand during the June international oil and gas show in Moscow.

Lufkin specialists described in detail how Bealrusneft had applied an earlier version of Lufkin’s line of intelligent well technology at the 40 year old Rechitskoye field (see OGE No 8, 2006, p. 16-27 in “archive” on www.oilandgaseurasia.com). Following a preliminary analysis, Tatneft in 2005 began a phased in test of Lufkin’s SAM Well Manager, a new generation product. It differs from its predecessor applied in Belarus by more advanced capabilities in well operation optimization.

Investment payback comes in reliability and efficiency

Tests performed in 2005 on the first batch of 10 controllers, eight of which were installed in fields operated by Almetyevneft, showed good results, high consumer characteristics and operational reliability. The new Lufkin controllers not only transfers all the information to the work stations of specialists who need it, but the system also performs its analysis and well control according to a set criteria. Tatneft found the experience of Almetyevneft important to its making a decision to expand the project to a large scale. “We had to study the area of application and performance of Lufkin controllers in various conditions,” said Airat Rakhmanov, Almetyevneft’s Manager of Oil Production and Business Development, said. By the end of 2006, Tatneft had tripled its commitment to 30 controllers; by yearend 2007, a total of 75 Lufkin systems were in place. In 2008, Tatneft will buy and install another 100 controllers.

“Though Lufkin controllers are more expensive compared to the domestic ones, they provide wider possibilities in combination with high reliability,” said Lufkin Automation’s representative in Tatarstan, Peter Dmitriev. Specialists of Almetyevneft confirm that the controller has wide capabilities which they list as follows: the system enables optimization of operational parameters of the oil bed pump system, ensures well productivity control, equipment diagnostics, and continuous monitoring of the status of pumping and surface equipment.

Controller operation is based on mathematical processing of the readings of three sensors (position, revolutions and load) which are installed at the crank, electric motor shaft and polished rod.

Since 2006, XSPOC software product of Theta Enterprise, Inc., California-based specialists in rod pumping software, has been included in the system of automated production control; all controllers are now connected to this product. XSPOC software enables remote monitoring and analysis of the well and equipment status. At present, specialists of the company, for whom user places were developed for interaction with the system, can work with the Russified version of this product.

One solution to various problems

Rustem Latfullin, Deputy Manager of Department on Oil Production and Business Development of Almetyrevneft has first-hand knowledge of the efficiency of controllers – technologies of application of this equipment at the fields of NGDU were tried out under his leadership and with his direct participation. “We selected certain groups of wells: intermittently producing wells are, first of all, marginal and low water-encroached ones which cannot be producing continuously due to poor reservoir properties; wells which are frequently under workover operations (at least three workover operations a year) – wells having asphaltic-resinous paraffin deposits and water-oil emulsion problems,” Latfullin said. “Another group includes wells with unstable formation pressure. Pressure stability is maintained with the help of the reservoir pressure maintenance system; injection wells are needed. Wells operated without production measuring devices can be singled out as a separate group.

Intermittently producing and frequently serviced wells

“We have developed a control algorithm for intermittently producing wells with a standard controller setting: shutting-off by certain pump filling percentage,” he continued. “We determined experimentally for each well, what pump filling percentage corresponds to the minimum admissible bottomhole pressure, and set an operating regime: as the pump filling percentage reaches a certain value, the well will automatically stop. After a certain period of accumulation mode, the well will automatically restart production. Thus, rational operation is ensured by optimization of intermittent production with the aim of achieving maximum recovery, i.e. we recovery all oil which comes to the wellbore On average, we managed to increase production from these wells two times already in 2005,” Latfullin, said regarding the efficiencies achieved by installing controllers at intermittently producing wells.

Standard controller capabilities are used at Almetyevneft with application of the gained experience and expertise. Creative strategy of specialists makes it possible to talk about “know-how”, new technologies developed with application of Lufkin equipment as an effective tool of the production process control.

The problem of asphaltic-resinous paraffin deposits was resolved at Tatneft by use of rods with special scrubbers. However, at a number of wells, these asphaltic-resinous paraffin deposits are in a thick-flowing form, so the mechanical method is not sufficient to solve the problem. The most complicated, frequently serviced wells were equipped with controllers. Before the Lufkin controllers were installed, up to six paraffin cleaning treatments needed to be made per year in these wells, and even in this amount they were mostly ineffective. “We were late with treatments, performing them when there was already a critical mass of paraffin deposits. So as to not aggravate the situation, we had to service the wells. The period between servicing was very short, according to Latfullin. “At present, the amount of preventive treatments was reduced to four treatments a year due to their timeliness and efficiency,” he said. “As a result, the well utilization factor increased from 0.89 to 0.96, and the average daily production rate rose.”

The main thing is not to interfere

Here is an illustrative example of intelligent well operation. Fig. 1 shows dynamics of well 11326 operation from November of 2007 to the present, where the red curve represents the number of cycles of production and accumulation, and the green one – daily production. Stability of the formation and bottomhole pressure in this well depends significantly on the stability of the operation of the injection wells. In April 2007, the injection well which directly affects this well was stopped for workover operations until November as a result of an accident with downhole equipment. Formation pressure dropped from 140 to 100 atmospheres, and the production rate from fell from 19 to 3 m3/day.

The availability of a controller at this well enabled the automatic transfer of the well to the self-controlled mode of production based on the set bottomhole pressure, which appeared to be the optimal option, and on some days the number of cycles reached 17. As one can see, within 35 months, the producing mode of the well was completely restored. It should be mentioned that this process took place without any participation of the specialists, field personnel, and additional hydrodynamic surveys. The only thing which was specified by the specialists beforehand was the pump filling setting.

Controllers provide additional possibilities

In the near future, Almetyevneft plans even more wide-spread expansion of its intelligent well project using Lufkin controllers, particularly with respect to protecting equipment from external corrosion by the use of cathodic protection stations. By connecting the cathodic protection station to a vacant analog input of the Lufkin controller, it will be possible to operate the cathodic protection from the control panel.

Apart from control of sucker-rod pumps, Tatneft is also exploring possible ESP operation control, with control stations connected to an XSPOC software and hardware complex . At present, Almetyevneft technologists can judge the status of three wells equipped with ESP by receiving remote data on the dynamics of well operation, pressure at the pump intake, temperature, electric motor vibration, load and voltage.

At four areas of the Romashkinskoye field – Almetyevskaya, Severo-Almetyevskaya, Berezovskaya and Minnibaevskaya, and also at the Bukharskoye field, in the Devonian horizons and sour oil pools, Lufkin controllers showed reliability and capabilities limited only by the imagination of petroleum engineers at Almetyevneft.

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The operator Victor Naumov, who last February marked the 30th anniversary of his employment on Almetievneft (Almetiev oil) oilfields, has been featured many times in stories appearing in “Znamya truda” (Labor Banner), “Nefnyanik Tatarstana” (Tatarstan Oilman), “Neftyanye Vesti” (Oil News). Naumov believes that “the equipment from Lufkin is a good thing. Previously, in case of pump starvation, the drilling equipment did not get turned off, became overheated, the mud balls were “burning”… Now the Lufkin controllers sense it and tune the operation of the drilling equipment. Often it happened so that the holes were in operation mode for 24 hours, and then stayed idle for two days – in wintertime it resulted in steaming off, restarting of the engine. Previously switchers personally obtained well-hole dynamometer cards, checked how the pump was working – presently you can see all this on the control panel, just by finding on the computer wells that you need. This makes easier the work of technicians and switchers. We can learn the debit of a well even in barrels.
Normally control centers are all self-triggering, but Lufkin controllers give off a warning sound signal to the switcher 15 seconds before they start off. You have time to take some safety measures. For sometimes the feeder stops, there is a power shortage, and as you walk by, the pumping gear nearby would get triggered making you bounce! But this one sings like a nightingale: “I’m starting off.” Very convenient. Excellent control centers! It’s a pity though that there are few of them, we should have more.”

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