Complex Fracture Geometry Investigations Conducted on Western-Siberian
Oilfields at Rosneft Company

Никитин, А. А.; Shirnen, Alexander; Manière, Jérôme

doi:10.2523/109909-ms

Cited by 3 publications

(1 citation statement)

References 7 publications

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“…Many wells have simultaneous production from several intervals in which massive hydraulic fracturing treatments were placed since 2002 to maximize production. A history of the propped fracturing designs evolution was written by Timonov et al 2006 andNikitin et al 2007. Priobskoe was always a primary target for new stimulation technologies, since it is relatively well-studied; fullsuite logs, core analysis, geomechanics studies and fracture geometry measurements are available for dozens of wells.…”

Section: Introductionmentioning

confidence: 99%

First Steps of Channel Fracturing in Russia Set New Directions for Production Increase of the Oil Fields

et al. 2013

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Channel fracturing technique changes the concept of proppant fracture conductivity generation by enabling hydrocarbons to flow through open channels instead of the proppant pack. The new technique is based on four main components: proppant pulsing at surface with fracturing equipment and software, a special perforation strategy, fibrous material to deliver stable channels, and a set of models to optimize channels geometry. Channel fracturing in Russia's oil fields began in 2008 as field testing operations in tight collaboration with the development team. Full-suite logs provided geomechanical models and ensured fracture channels optimization. An important result of those first treatments was long-term channels stability. The treated wells continue to show stable productivity over a fouryear period. As of today, more than 90 channel fracturing treatments have been pumped in Russia with no screen-outs. A very low screenout risk has become one of the most important advantages of the technology; the fibers make fluid more stable while the presence of clean pulses around proppant structures ensure bridging-free flow. As the channel's conductivity does not depend on proppant size to hold channels open, treatments can be performed with smaller proppants (20/40 or 16/20 mesh) instead of larger proppants (12/18 mesh) that have an increased risk of screenout. In combination with abrasive jetting perforations, channel fracturing has proven to be an efficient stimulation solution for Russia's multi-layered reservoirs. This completion technique ensures proper flow distribution into perforation clusters according to the channel's specific requirements. It also allows reliable proppant admittance through jetted caverns. Channel fracturing increases the effective half-length with increased treatment size. A considerable number of channel fracturing jobs with proppant mass equal to standard fracturing designs have been performed-significantly increasing channeled length and providing better production in low permeability (1 to 3 mD) oil reservoirs. Based on production analysis of stimulated wells in five different areas, a correlation between incremental channel fracturing productivity over the conventional stimulation technique and kH value of the formation can be made: the higher the kH the more significant the advantage of the channel fracturing is in oil wells.

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Section: Introductionmentioning

confidence: 99%

First Steps of Channel Fracturing in Russia Set New Directions for Production Increase of the Oil Fields

et al. 2013

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Analogous Reservoirs to Chicontepec, Alternatives of Exploitation for this Mexican Oil Field

Gachuz-Muro

Sellami

2009

EUROPEC/EAGE Conference and Exhibition

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The giant Chicontepec field contains oil from 18 to 45 oAPI in laminated sandstones of 0.1 to 10 mD at a depth of around 2500 meters (8202 ft). Original Oil in Place (OOIP) is estimated to be 140, 900 MMSTB. The complex geology (complicated structural and stratigraphic nature of the reservoirs), lack of reservoir information and lack of technology availability caused a gap between discovery and development. Throughout a period of several decades some exploration wells were drilled based on 2D seismic and log correlations of the reservoirs. The exploitation of the Paleonchannel was postponed because most of the wells showed poor productivity. The reasons for the low recovery (around 3%) have never been thoroughly understood. Various hypotheses have been proposed to explain the deficient performance such as partial closing of the fractures with declining reservoir pressure (bubble-point pressure is near initial pressure), inadequate comprehension of the geological model, deficiency in the fracturing technology, oil-wetted or intermediate-wetted reservoirs, applicability of unconventional wells (horizontal wells, casing drilling technology), etc. Today, the Chicontepec Paleochannel is an intermediate stage. Due to the experience of different fields with similar characteristics, this paper describes an analysis of alternatives that may be considered to resolve the problems of exploitation at the Chicontepec field. Advanced technologies, hydraulic fractures, artificial lift systems, all of them combined with secondary and enhanced oil recovery, may be feasible to sustain or increase production. A number of hurdles will have to be overcome. This field, the second most important oil field in Mexico, should take advantage of the experience learned from these analogous reservoirs. Chicontepec Paleochannel Geographically, it is located in east-central Mexico in parts of the states of Veracruz, Puebla and Hidalgo. Chincontepec system was deposited under complex tectono-stratigraphic conditions. Geologically, it covers an area of 957,534 acres (Figure 1). Aproximately half of Chicontepec consists of shales or silty shales with the rest of the formation made up of multiple thin sandstones beds and zones of sandstones beds. Typically, between 8 and 16 major reservoirs are present. These set of reservoirs is composed of channel complexes that are flanked by, and rest on, lobe sandstones that grade into distal fan and basin floor deposits, resulting in high heterogeneity. Throughout a period of several decades some exploration wells were drilled based on 2D seismic and log correlations of the reservoirs. The 3D seismic allowed the identification of sand bodies with viable pay thickness. Some wells produce small amounts of water, in general, water-oil contacts have not been identified. X-ray diffraction analysis showed that the clay cointains dominantly kaolinite with a content of 1 to 5 %. The sandstones are immature litharenites consisting of quartz grains, abundant carbonate fragments, and granitic fragments. Because of the abundance of carbonate in the system, the sediments are highly cemented by ferroan calcite and ferroan dolomite, in addition to quartz overgrowths. Core analyses show that the reservoirs are characterized by both low porosity and low permeability, Figure 2. All the reservoirs have permeabilities of 0.1 to 10 mD and porosities ranging from 5 to 15 %. The effective permeability, as determined from build up, fall off, drawdown and step rate test or advance decline analysis, varies from 0.01 to 15 mD.

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Hydraulic Fracture Geometry Investigation for Successful Optimization of Fracture Modeling and Overall Development of Jurassic Formation in Western Siberia

Nikitin

Yudin

Латыпов

et al. 2009

Asia Pacific Oil and Gas Conference &Amp; Exhibition

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The focus of our research is on a remote oilfield in western Siberia, currently in the initial stages of development. There are two producing horizons of Jurassic age with a shale barrier in between them and variable oil/water contact (OWC). Each new well of the field is a candidate for a hydraulic fracturing treatment. Depending on well location, there is an option to perform the fracturing treatment on the lower formation only, the upper formation only, or to conduct two separate fracturing operations. Fracture breakthrough on any of the jobs can lead to significant production underperformance. With a goal to calibrate fracture modeling and identify the most critical parameters for fracture treatments, the decision was made to implement an independent measurement of frac geometry for an ongoing fracturing campaign. A total of 11 fracturing treatments are described in detail where differential cased-hole sonic anisotropy (DCHSA) measurements as well as bottomhole pressure gauges (BHPG) were implemented to enable precise modeling and to determine reliable fracture geometry. DCHSA, using a dipole shear sonic imager tools, allows for direct measurement of propped fracture height and fracture orientation azimuth. Provided with fracture height and using bottomhole pressure data, it was possible to accurately model resulting fracture half-length and propped width. In addition to DCHSA measurements, a study to describe the geomechanical properties of the formations was also undertaken to further enhance the understanding of fracture height growth in the reservoirs. Advanced open-hole logging was performed on four wells, which served as the basis for creating a geomechanical model for other wells in the field. The methodology used to model stress distribution from acoustic logging was developed using a correlation created from density logs run on offset wells. This tool allowed for reliable fracture modeling at the design stage, and enabled optimization of fracture treatments. By coupling the enhanced geological understanding obtained from the fracturing campaign with advanced geometry measurement technology, an effective geomechanical modeling method was successfully applied for future field development and production optimization. This research's technical workflow can be used as a comprehensive guideline in any field where precise placement of hydraulic fracture makes a significant difference in the overall development of a field. Introduction Kinyaminskoe oilfield is a remote field in western Siberia, located in the middle of forests and bogs, about 200 kilometers from the nearest town. Because access to the field is difficult, exploration and development of Kinyaminskoe started considerably later in time than development of closer fields, despite relatively better formation properties and production potential. Eventually, operators managed to build roads to the remote fields through the very tight Siberian taiga forests. Many of these fields are accessible only by winter roads when bogs become frozen at temperatures below -30 °C.

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Complex Fracture Geometry Investigations Conducted on Western-Siberian Oilfields at Rosneft Company

Abstract: fax 01-972-952-9435.

Cited by 3 publications

References 7 publications

First Steps of Channel Fracturing in Russia Set New Directions for Production Increase of the Oil Fields

First Steps of Channel Fracturing in Russia Set New Directions for Production Increase of the Oil Fields

Analogous Reservoirs to Chicontepec, Alternatives of Exploitation for this Mexican Oil Field

Hydraulic Fracture Geometry Investigation for Successful Optimization of Fracture Modeling and Overall Development of Jurassic Formation in Western Siberia

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