Open AccessA comprehensive approach for fracability evaluation in naturally fractured sandstone reservoirs based on analytical hierarchy process method
Author(s) -
He Rui,
Yang Zhaozhong,
Li Xiaogang,
Li Zhanling,
Liu Ziyuan,
Chen Fei
Publication year - 2019
Publication title -
energy science and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.638
H-Index - 29
ISSN - 2050-0505
DOI - 10.1002/ese3.303
Subject(s) - brittleness , geology , analytic hierarchy process , hydraulic fracturing , petrophysics , petroleum engineering , geotechnical engineering , tight gas , permeability (electromagnetism) , natural gas field , matrix (chemical analysis) , porosity , natural gas , engineering , materials science , operations research , membrane , biology , composite material , genetics , waste management
The tight sandstone gas reservoir in southern Songliao Basin is naturally fractured and is characterized by its low porosity and permeability. Large‐scale hydraulic fracturing is the most effective way to develop this tight gas reservoir. Quantitative evaluation of fracability is essential for optimizing a fracturing reservoir. In this study, nine fracability‐related factors, particularly mechanical brittleness, unconfined compressive strength ( UCS ), mineral brittleness, cohesion, internal friction angle ( IFA ), natural fracture, fracture toughness, horizontal stress difference, and fracture barrier were obtained based on a series of petrophysical and geomechanical experiments. Taking above factors into consideration, a modified comprehensive evaluation model is proposed based on analytic hierarchy process ( AHP ) method. The UCS and IFA were removed from the AHP model based on the results of factor correlation analysis. The transfer matrix in the weighting procedure was applied to improve the consistency of judgment matrix, and the fuzzy matrix was employed to promote the objectiveness of final decision. The fracability evaluation of four reservoir intervals in Jinshan gas field was analyzed. Field fracturing tests were conducted to verify the feasibility of the proposed evaluation model. Results showed that the tubing pressure curve is more fluctuated in the reservoir interval with more developed natural fractures, and gas production is higher in the reservoir interval with greater fracability coefficient. The field test data coincide with the results of the proposed evaluation model.