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

Abstract

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.

Re-fracturing Considerations of Horizontal Well Multi Stage Fractured Completions in Mid Permeability Formations

“…This can be confirmed, between others methods, by microseismic measurements in a horizontal well or post-frac cross dipole acoustic logging interpretation in sub-vertical well (15)(16)(17) .…”

Горизонтальный Стресс И Его Влияние На Морфологию Газовой Залежи На Примере Месторождения Адамташ (Республика Узбекистан)

“…Проведенные исследования показали, что направление максимального горизонтального стресса в большинстве скважин субпараллельно простиранию основного разлома, ограничивающего месторождение с севера, на основе чего можно предположить, что данный разлом является проводящим для пластовых флюидов и его пересечение с покрышкой (соляноангидритовой пачкой верхней юры) определяет положение ГВК и морфологию газоконденсатной залежи. В коллекторах, расположенных ниже линии пересечения указанного разлома и покрышки, в результате движения флюидов по разлому отсутствуют условия для накопления газа [10].…”

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

“…Coupled with precise pressure history match using a bottom-hole memory gauge, it was possible to calculate fracture width and half-length with relatively high accuracy. This fracture modeling method which is based on cross-dipole sonic was detailed in case studies for Priobskoe wells was described by Nikitin et al 2006 and for Kinyaminskoe wells -by Nikitin et al, 2009 and is common for the area. This calculated geometry was used in a numerical simulator which confirmed the stability and high conductivity of the channels.…”