In the last two decades, hydraulic fracturing has become a routine completion practice in most oilfields producing from the low- and medium-permeability Jurassic formations in western Siberia. To optimize hydraulic fracture conductivity, operators and service companies were progressively decreasing polymer loading in fracturing fluids, developing new polymer-free fluids, implementing foams as fracturing fluids, increasing proppant size and concentration, enhancing polymer breaker performance, increasing breaker concentration, and implementing the tip screenout technique. All these methods have some positive impact on proppant pack conductivity but lead to higher risk of premature screenout. The intrinsic limitations stem from the fact that conductivity is created by the proppant pack, which physically limits permeability. The new channel fracturing technique allows development of an open network of flow channels within the proppant pack; thus, the fracture conductivity is enabled by such channels rather than by flow through the pores between proppant grains in the proppant pack. The channel fracturing technique is capable of increasing fracture conductivity by up to two orders of magnitude. Talinskoe field, located near Nyagan, Russia, produces from a series of Jurassic sublayers at depths of 2270 to 2700 m. Several oil-saturated sandstone sublayers are separated by shale barriers, and their development is conducted separately. For some wells, production from bottom sublayers JK10 and JK11 became uneconomical due to injection water breakthrough or low liquid rates. Production in these wells was switched to upper layers JK2 through JK9 after perforation and stimulation operations. Five of these wells were stimulated with the channel fracturing technique. Six-month of post-frac production data were compared with production data from eight offset wells stimulated recently via conventional hydraulic fracturing. The wells stimulated with the channel fracturing technology showed an average productivity index about 51% higher. This production effect still remains positive. The absence of screenouts confirmed reliability in proppant placement observed in other projects worldwide. The successful implementation of the channel fracturing technique in brownfield development is described in detail with a theoretical and operational review, results from laboratory experiments, and analysis of the production results in comparison with conventional fracturing.

Application of horizontal multiple-stage fracturing is becoming the standard completion technique for oil and gas developments both in shale and tight sands. This technology has proven to be a game-changer within the US oil and gas industry to the point of creating an oversupply of gas in the US. Predictions indicate that the supply of oil related to this technology could allow the US to become self-sufficient within the decade. Globally, shale and tight-sand exploration activities are also increasing. This concept was successfully suited for and applied within a Russian tight-oil play in the Em-Egovskoe license area in western Siberia.This paper provides the case history of how a horizontal multiple-fracturing completion methodology helped unlock the potential reserves in the western Siberian Em-Egovskoe tight oil field. This very heterogeneous and lenticular sand oil play was known for years for its complexity and arduous nature. The completion technique employed a proven North America multiple-stage fracturing technique using a combination of swellable packers and sliding-sleeve frac ports. The fracturing design for the Em-Egovskoe field is discussed. This design is an adaptation of an alternating hybrid fluid system composed of proppant slugs during the pad stage and a high-concentration proppant ramp in the main frac stage.The well is currently flowing at commercial rates synonymous with early production in a typical North American oil shale well. The various monitoring techniques for measuring fracturing efficiency are also discussed. A production curve fit analysis using early production data allowed the operator to evaluate how the project was being commercially realized. Results and recommendations are presented.

No abstract

Slugs-fracs is one of new-to-field approaches which changed the conditions of wells for fracturing increasing the number of candidates in Kamennoe field Western Siberia. Placing fracturing jobs by slugs of proppant pumped in linear gel successfully implemented in stimulating pay zones in near water intervals with small stress contrast between zones and barriers. A few technical specifics had been used to contribute the success of this methodology such as earlier pumping with near matrix rate to allow more fluid filtration ahead of the main proppant stages before fracture is fully formed. Proppant setting according to Stokes law and dune effects theory were evaluated and considered for design strategy. The slugs-fracs allowed pumping regardless of the wellbore deviation and height of perforated intervals. Post-fracturing results from 120 wells were used for analysis. Significant decrease in initial water cut and sustainable oil production were reported. First slugs-fracs were introduced in the beginning of 2010 and in following 2 years more than 200 hundreds jobs have been pumped across the field. This allowed to drill spots of the field that were previously suspended as result of ineffective fracturing treatments mostly due to high risk of fracture breaking down the water zones.

Application of horizontal multiple stage fracturing is becoming the standard completion technique for oil and gas developments both in Shale and Tight Sand. This technology has proven to be a game-changer for the United States oil and gas industry to the point of creating an oversupply of gas in United States. Predictions indicate that the supply of oil related to this technology could allow the United States to become self-sufficient within this decade. Globally, shale and tight sand exploration activities are also increasing. This concept was successfully suited to one of the Russian Tight Oil plays within the Em-Yoga license area in Western Siberia. This paper provides the case history of how horizontal multiple fracturing completion methodology helped to unlock the potential Western Siberian Em-Yoga Tight Oilfield. This very heterogeneous and lenticular sand oil play was known for years for its complexity and arduous nature to extract oil from. The completion technique employed the proven North America multiple stage fracturing using a combination of swell-able packers and sliding sleeve frac ports. The fracturing design for the Em-Yoga field will be discussed in this paper. This design is an adaptation of an alternating hybrid fluid system composed of proppant slugs during the pad stage and a high concentration proppant ramp in the main frac stage. The well is currently flowing at commercial rates synonymous with early production time in a typical North American oil shale well. In this paper, the authors describe the various monitoring techniques of how fracturing efficiency was measured. Earlier production allowed providing of fit curve production analysis to evaluate how the project is being commercially realized.