Achimov deposits extend over 12,000 square kilometers around the city of Novy Urengoy. These deposits are characterized by high reservoir pressures, and a narrow range of drilling fluid densities that creates complicated conditions for drilling and completion of wells. Due to the high accident rate of drilling horizontal wells only S-shape wells were drilled for this formation. The first successful horizontal production well was drilled in 2013 in cooperation Arcticgaz, ERIELL, Schlumberger. The first well to drill a horizontal wellbore on Achimov formation, has been planned to open Ach3,4 and Ach5 layers of Achimov formation. In close cooperation with project operator - Arcticgaz company, engineering group of Schlumberger drilling contractor and drilling contractor developed and successfully implemented comprehensive solutions for drilling and completion of horizontal wells Achim. One of the key factors of success was the use of drilling muds Megadril-D with constant control of equivalent circulating density. Application of rotary steareable system with optimally balanced PDC bits, allowed to drill horizontal wells through Achimov deposits in record time. An additional factor for drilling risks reduction was implementation of geomechanic model, as in the preparation of the preliminary model and real-time control for wellbore stability with the latest technology logging measurements (LWD) – acoustic and density neutron formation properties. In the period for 2013 to the 2nd quarter of 2014 have been successfully constructed more than 10 similar wells. Esteblished new records: maximum closure – 2403 meters, the length of the longest subhorizontal section reached 1233 meters. Set a record duration of well construction time of 62 days vs 100 planned, which could not been reached before by anyone in the region (formerly similar wells with shorter intervals of subhorizontal sectionhave been constructed in evarage about 150 days). Recently were successfully run two completion liners for 3-stage hydraulic fracturing (MSF) and one of MSF was successfully done. For completion purposes was used OBM with the weighting agent of mikro size, provided an unprecedented stability to settlement for a long time. This article devoted to the description of technologies and solutions that have been used for the construction of sub-horizontal wells. Preliminary production index of subhorizontal wells shows that current PI higher than S-shape wells (even with frac). Positive experience in the construction of subhorizontal wells change plans to develop Achimov deposits and opens new perspectives of hydrocarbon production in the region.

The interaction of NOVATEK, Investgeoservice (IGS) and Schlumberger allowed to deliver 2 complex extended reach wells (ERD), including the longest ever drilled in Russian mainland, well number 373, in the Yurkharovskoye field located in Arctic Yamal peninsula, as part of the offshore development plan from onshore locations. A geomechanical model was developed to address the main challenges, including optimum equivalent circulating density window and drilling regimes for wellbore quality and stability. Drilling & Measurements key technologies, multipole sonic-while-drilling, latest high-speed telemetry service, multifunction logging-while drilling technologies were used for real time Geomechanics service to prevent costly wellbore stability issues. In addition the combination of rotary steerable technology with customized polycrystalline diamond compact bits and drilling fluid system, delivered superior drilling performance, resulting in high performed drilling of these complex wells. Positive experience in the construction of these ERD wells, gives grounds to include options for developing the region, similar wells in the planning stage of various development scenarios. This article devoted to the description of technologies and solutions that have been used for the construction of these wells.

E&P operating companies starting develop deeper production intervals with poorer formation properties due to depletion of the upper productive layers. This is a global trend worldwide. In connection with this it is very critical to optimize well construction and at the same time increase productivity of wells.Purpose to this work was to increase the productivity of six deviated gas condensate wells drilled for the achimov tight-gas deposits of the Urengoy gas condensate field. Integrated approach to well construction, completion and two-stage stimulation as well as the other technologies were used In order to achieve high production objectives.Because of the complex geological conditions of the achimov formation associated with the presence of abnormal pressure, narrow driling window, construction and completion of wells was associated with the risk of complications and emergencies.The paper describes an integrated project approach to planning, construction and the stimulation of the six wells in low permeable gas-condensate formation.The following technologies had been used during the wells construction: improved design of well completion (retrievable packer, the use of "floating" of the sealing arrangement, the use of the landing nipple below the packer to be able to cut off the producing formation, the use of premium gastight connections). Expanded set of logging (standard logging, NMR (Nuclear Magnetic Resonance), crossdipole acoustic measurements), a special thee component cement slurry, fracturing technology with high conductive channels, coil tubing service and drilling pipes make up.Due to integrated approach and new technology involved in well construction and completion of the six-deviated wells, construction time reduced and wells productivity increased by 30%. Urengoyskoe gas condensate fieldUrengoyskoe gas condensate field is supergiant gas field, third in the world by reserves, which is achieving 10 trillion of cubic meters (10 13 m 3 ). This field located in Yamalo-Nenetskiy area of Tyumen region of Russia, slightly to the south from polar Ural. Please see Fig. 1 Urengoyskoe gas field started developing at 1966 and it is more than 45 years in production. The length from south to north is 220 km and area of gas field 6 000 square kilometers.

The objective of this study was to identify efficiencies and prospects for future implementation of an advanced fracturing system for horizontal wells in which fracturing operations are combined with coiled tubing (CT) operations and are run together with CT inside the well. This results in decreased operation time for multistage fracturing (MSF) jobs. Nowadays, in Western Siberia extensively used following workflow at wells: preoperational work (which include casing drifting, bottom-hole cleaning with sludge trap, coiled tubing slack off for opening a frac-port, pulling the coil out of the hole and following fracturing operation). The method of pumping fracturing operations through the annulus of a CT had been given especially for elimination of extra operationsat wells during jobs at Vinogradova field. The method implemented with a modern completion system that includes special four-way union and protector for coiled tubing and coiled tubing 50.8 mm. The paper contains the analysis of executed MSF jobs with coil tubing inside the well and special equipment which were used in order to implement all the operations during fracturing. The innovative approach to cooperative work between the hydraulic fracturing and CT fleets enabled to reduce the operational timeline by 40% at the first well. As this technology comes into greater use in Russia and abroad, there will need to be sophisticated study and correct implementation. For future success, it will be necessary to perform an in-depth analysis to achieve further reduction in the operating timeline reduction and to eliminate complications in the process.

Horizontal drilling and multistage fracturing completions are becoming widespread practices in the development of Western Siberia’s low-permeability oil fields. More than 100 wells have been completed to date—with success from both operational and production perspectives. The majority of applications were applied in newly drilled wells, where it is possible to install openhole packers and frac ports for isolating fracture stages. The concept of multistage fracturing was transferred to old areas of brownfields, where sidetracks drilling was the main method of increasing oil recovery. Traditional sidetracks were associated with risks of production underachievement in low-permeability environments - even after stimulation treatments. The ability to drill sidetracks with a considerable horizontal section, and stimulating them with several fracturing stages would improve production significantly. However, slim wellbores of sidetracks significantly restrict completion option choice and abrasive perforating via coiled tubing (CT) becomes a universal enabler for multistage fracturing treatments. One of the greatest challenges in such a process is isolation between the stages. Fiber-enhanced proppant plugs were used for better proppant grains suspension, which sets the plug in the most efficient, homogeneous way. The first well was recently completed with this method. Three stages of fracturing stimulation were performed with CT abrasive perforation; fiber-enhanced proppant plugs were placed at the tail-in of the first two fractures. In both of the fractures, reliable isolation was achieved at first attempt. After all three stages were placed, wellbore cleanout with CT was performed, followed by nitrogen kickoff. Oil production has exceeded expectation by 30%. Multistage fracture (MSF) stimulation in the horizontal section of a sidetrack well completed with cemented liner with the utilization of abrasive perforating and fiber-enhanced proppant plugs has demonstrated unique value, as it is the only effective solution currently available for these conditions. The decision-making and candidate-selection processes, execution and lessons learnedare described.