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Home / Issue Archive / 2009 / March #3 / Gazpromneft Cuttings Injected Into Reservoir for the First Time in Russia

№ 3 (March 2009)

Gazpromneft Cuttings Injected Into Reservoir for the First Time in Russia

Like people, every oil field has its own personality and each block of oil fields brings new challenges for oil specialists. With people, one can't expect to win every argument. With oil, even today, successful drilling still accepts a five percent failure rate for wells. 

By Alexei Chesnokov

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   Gazpromneft’s specialists were reminded of this while carrying out operations in the Priobskoye field in the Khanty-Mansi Autonomous District (KMAD).  The bottomland section of the field is a floodplain and often under 8-meters of water.  It is impossible to construct wells using the cuttings pit technology under such conditions.  Toxic drilling cuttings would be swept away by the floodwaters into the Ob River.  After long discussions, the company’s specialists made a decision to inject cuttings into the reservoir.  This technology had not been yet applied in mainland Russia, or under severe climatic conditions when temperatures drop below minus 50 degrees Celsius in the winter and rise to plus 40 degrees Celsius in the summer. To accomplish this task, it was required to drill wells and break those in receiving reservoirs and to install equipment for cuttings treatment and injection. The treatment includes the reduction of cuttings into fine condition by milling tools. Schlumberger was the only contractor who succeeded in accomplishing this task. They fabricated and installed the equipment to inject cuttings into the reservoirs. The company has been working at Priobskoye Field since October 2008 and provides services to six drilling crews. No cutting pits are used – all drilling waste and cuttings, as well as fluids for well drilling or repair and waste water, are treated and injected into the reservoir.

   Approved by the state environmental expertise committee, the company was issued the state license. The site, where cuttings are injected into reservoirs, is elevated above the ground surface so that floodwater does not cover it.
The inspiration and implementation of this idea came from Roman Fetsenets, Head of Well Building Management, Gazpromneft-Khantos. 

   Another "outside the box" approach to drilling challenges was demonstrated by Gazpromneft’s specialists at Urmanskoye field, in the Tomsk region. A complicated subsoil geological structure provided an additional challenge to oil specialists. High reservoir permeability and fracturing held out a hope of high yields in this section. However, highly permeable reservoirs are not good for drilling purposes. The pay zone is comprised of unstable cobblestones; but this layer is well saturated with oil and highly permeable. Such layers are prone to cave-ins, thus complicating the drilling process and reducing oil flow. This problem had to be eliminated. 

   The company’s specialists, under the leadership of the head of Gazpromneft's Drilling Department, Vladimir Tataurov, reviewed two options.  The first option was to apply underbalanced drilling. However, the method was not selected, because it would require significant spending and an additional feasibility study.  The second, approved option, suggested a casing drilling method. A conventional casing pipe is applied instead of drill pipes and is left in the well after drilling is completed. The technology and equipment was provided by Weatherford and is suitable for structures comprising fractured reservoir that are prone to cave-ins and collapsing.

   Department Chief of Gazpromneft RDC, Alexander Ukhov, shared his opinions with OGE regarding modern drilling technologies, problems and approaches to their solution.

   Oil&Gas Eurasia: Can the domestic scientific and engineering capabilities of drilling companies be compared with that of foreign companies?
Alexander Ukhov: Before the 1990s, engineering policies in the industry was defined by the Ministry and by the industry scientific research and design institutes. There were both strengths and weaknesses in that system. Its advantages included stability and clear plans for developing the engineering potential of the industry.

   These advantages gradually turned into disadvantages such as seclusion of the industry and zero contacts with the world's leading scientific and production centers. One more deficiency is absenting real price formation in the industry, which made it impossible to evaluate efficiency of a technology or production and complicated selling domestic technologies and equipment abroad. Technologies were “boiling inside” with no opportunity for “escape”.
When the “Curtain” was up, there was no demand for domestic developments. Major companies such as Rosneft, Lukoil, or Surgutneftegaz selected advanced western technologies despite the added expensive. Domestic well drilling and completion equipment/technologies were too far behind despite achievements in drilling, such as construction of Kola SG-3 superdeep borehole and other technologies. Currently major companies such as Lukoil Overseas, Rosneft and Gazprom integrate western and Russian technologies and drilling equipment and successfully operate both in Russia and abroad.

OGE: What engineering policy does your company pursue with regard to drilling?
Ukhov: We work as follows; we have both drilling contractors and we have service contractors that support drilling operations. There are five drilling contractors at the moment: Service Drilling Company (SBK), Eurasia Drilling Company, SSK, Pioner, and Integra; and over 10 service companies including the largest international ones such as Halliburton, Schlumberger, Baker Hughes, Smith, and Weatherford. In addition there are local service companies that at the moment gradually forcing out foreign contractors from the local market. This is of benefit for our company as well: if our national contractors provide high quality services at a lower rate, then why not to use these?
OGE: Are there any competitive manufacturers of rig top drives and other drilling equipment in Russia?
Ukhov: Today, about 99.9 percent of power heavy duty top drives used in our country are manufactured in the USA, Canada or Germany.  This equipment is quite complicated. Therefore there are no manufacturers of this equipment in our country that could compete with leading western companies in this market segment. But, some other home-produced equipment successfully forces out western competitors from the Russian market in the recent few years; these are downhole hydraulic motors by Perm Branch of VNIIBT, Kungur machine building plant, or Radius Service (Perm company). There is another example. Over 60 percent of drilling bits applied in our company are made in Russia. Our suppliers, namely Volga-Burmash (Samara Plant) and Burintekh (Ufa Scientific and Production Association), offer a complete range of different bit types.  Our domestic companies such as Vyksunsky Metallurgical Plant mastered production of high quality drill pipes that are reliable and withstand various loads. Our company widely applies aluminum drill pipes that are a 100 percent domestic development.
OGE: What can you say about the drilling rig market in Russia?
Ukhov: A drilling rig is a core setting the pace of the well construction process. Today, about 90-95 percent of drilling rigs used in our company are made in Russia.  These are Uralmash drilling rigs BU3000EUK and BU4000EUK, which are basic and equipped with modern production equipment (pumps and hoists).
OGE: What is the decision-making process for selecting service contractors?
Ukhov: This is a significant process and decisions are made based on open and transparent tenders.  We have established the Tender Committee and Tender Commissions in our company; so it is a multi-stage procedure taking into account all aspects of contractors’ activities.
OGE: Where does well construction begin?
Ukhov: A selected contractor is provided with an approved well construction program.  The work is superintended by our supervisor who monitors efficient implementation of the project. The contractor also provides their supervisor to control quality of work. Strict control is exercised at each well construction stage.
OGE: What is the purpose of constructing horizontal and horizontally branched wells?
Ukhov: I believe that horizontal wells or wells with increased deviation from the axis ensure much higher oil withdrawal rates than vertical ones, because they ensure a larger area of the pay contact with the well bore. However, drilling and completion of such wells require more spending and that is why their application was restricted.  The situation changed after significant progress was made in drilling technologies and in particular in technologies of downhole measurement while drilling. A new type of oil wells has been developed – horizontally branched wells.  It is a revolutionary stage in the oil and gas industry development. Horizontally branched wells are placed on production with actual flow rates that at least by 20 times exceed flow rates of adjacent conventional wells.  But what is more important, the ultimate oil recovery of reservoirs also doubles.  For example, in the aging field with an average daily flow rate of conventional wells of 5 tons, the daily flow rate of a horizontally branched well will be at least 100 tons.  A higher drilling costs of a horizontally branched well (by 2-2.5 times higher than that of a conventional one) pays already in the first months of its operation.  The cost of oil production using horizontally branched wells is by 3 to 5 times lower compared to conventional wells.
OGE: What tendencies are observed in selecting drill bits and diamond tools?
Ukhov: Low drilling rate and short drilling life of cone rock bits in geological sections of oil and gas fields required to revise approaches to selecting these tools.  Diamond drill bits or polycrystalline diamond (PCD) bits enable significant reduction in well drilling costs due to reduction of round-trip operations that take a significant time of the well construction process. Cutting is the most efficient technique of destructing shale and sulfated carbonate rocks, since their tensile strength is usually less than compression strength.  Besides, rock destruction by cutting requires less energy input than rock destruction by compression; and zero run-up of rock-bit teeth on downhole mud pad allows avoiding mud balls formation on the bit working surface.  The service life of bits with PCD plates is by 3 to 5 times longer than that of cone bits.

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