June 1, 2009
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Home / Issue Archive / 2009 / April #4 / Modified Izmeron Complexes Help Increase Oil Production in TNK-BP and Rosneft

№ 4 (April 2009)

Modified Izmeron Complexes Help Increase Oil Production in TNK-BP and Rosneft

Today artificial lift methods are used on the well stock, which have been producing for several decades. In such wells the production casing is either in need of a full repair or very close to this state.

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   To prolong the wells’ service life, to reduce repair and insulation costs related to production casing leak elimination, and to increase the oil flow rate, oil may be produced from under a packer installed in a pay zone above the perforation interval. In this case the packer isolates production casing from the produced fluid, starting from the formation and up to the wellhead. However, the following challenges had to be overcome to make this technology work:

   The NPF Izmeron Plant succeeded in resolving all these problems in March 2008 based on the experience of operation of a wide model and size range of packers installable mechanically or hydraulically for hydraulic fracturing, reservoir pressure maintenance, production casing repair and isolation, and also of manufacturing the first equipment sets for oil production from two intervals with the help of a single string Р the two zones flow production technology.

   The first packer with seals for electric cable from the ESP, which was to be installed below the packer, was manufactured in May 2008 (Patent #77634, issued July 10, 2008). Simultaneously, a bottom-hole assembly was designed to eliminate all problems related to oil production with the application of the above technique. This gave birth to the “Equipment Set for Oil Production from Below the Leak Interval (KDN NN), (Patent #76965, issued June 09, 2008).

The set includes:

   The equipment set was installed for test in Nizhnevartovsk in September in Well 3805, Cluster 42a, Van-Yogan Field, and it is still being tested. The equipment performance results are amazing.

   The underbalance in the well’s pay interval under the packer resulting from the ESP performance enabled increasing the pay zone permeability and the mobility ratio. Due to these factors, the flow rate also increased. That fact eliminated any doubt about the advantages of the equipment set, although some design elements, which proved to be insufficiently safe or inconvenient for assembly, would have to be modified. The most difficult problem, which had to be resolved, was the packer itself, namely its cable seal. The cable had to be sealed-off in the wellhead and the procedure took too much time Р nearly eight hours. Low ambient temperature made it even more complicated. Also, continuous start-ups and shutdowns of the ESP, which affected the cable seal during hydraulic shocks, had not been not taken into the account.

   In 2008, the efforts resulted in the creation of a packer with a seal, which enclosed three insulated cable cores with operating temperature 230 C and 25 sq.-mm cross-section passing through the packer’s special chambers filled with dielectrical oil. That ensured safe electrical insulation and heat removal from the cable. Borets Plant had manufactured two standard sockets to be used in pumps. Having been installed in the packer, they eliminated the need for the cable seal assembly in the  well. To protect sockets from pressure drops occurring during the packer running-in, oil heating and underbalance below the packer during the ESP operation, a compensation system was used. In addition to the packer, a KDN NN set included a cable extension device ensuring the compensation of length difference for the cable between the ESP and the packer, as well as the compensation of a length difference for the liner string between the packer and the ESP. All those modifications enabled to run-in the equipment set within 1 hour, including filling of cable seal chambers with oil (application for a patent #2008151387; favorable action for issue of a patent dated January 22, 2009). Currently the first four modified sets have been manufactured: two for the TNK-BP Nizhnevartovsk unit and two for the Rosneft’s Yuganskneftegaz.

   The above reveals that the packer with a cable seal, as well as the entire equipment set, is a complex unit to be operated by the skilled personnel. And so, experts of the plant conduct personnel trainings of the Customer and ensure technological support of the equipment at coach operation phase.

   Yet, its production may be of interest for service companies, which would be able to appreciate both the equipment’s unique design and potential advantages of cooperaВtion with the plant.

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