Oil & Gas Geology ›› 2017, Vol. 38 ›› Issue (1): 197-208.doi: 10.11743/ogg20170121

Previous Articles    

Application of improved fuzzy-grey comprehensive evaluation method to quantitative reservoir evaluation: A case study of the low-permeability gas reservoirs of the lower part of 8th member of the Shihezi Formation in Su X block of Sulige Gasfield

Zhu Zhaoqun1, Lin Chengyan1, Zhang Sujie2, Ren Lihua1, Zhao Jianxuan3, Chen Shizhen1, Jia Xiaopeng4, Chen Li5, Zhang Ji6   

  1. 1. School of Geosciences, China University of Petroleum(East China), Qingdao, Shandong 266580, China;
    2. Downhole Technology Service Company, CNPC BHDC, Tianjin 300580, China;
    3. No. 1 Natural Gas Production Plant, Qinghai Oilfield Company, PetroChina, Golmud, Qinghai 816000, China;
    4. Schlumberger China, Beijing 100015, China;
    5. The Branch of Exploration and Production Corporation, PetroChina, Beijing 100007, China;
    6. Sulige Gasfield Research Center of Changqing Oilfield Company, PetroChina, Xi'an, Shaanxi 710021, China
  • Received:2016-09-18 Revised:2016-12-20 Online:2017-02-28 Published:2017-02-27

Abstract:

For the lower section of 8th member of the Shihezi Formation (Middle Permain) in the Su X block of the Sulige gasfield,significant degree of uncertainty was involved in early-stage evaluation of low-permeability gas reservoir due to immature understanding and incomplete information,which causes difficulty to a fine reservoir description.It is vital for a better reservoir evaluation to fully account for uncertainty and effectively magnify the differences of different reservoirs in evaluation results.In this paper,based on the idea of multi-information superposition,the methods of fuzzy mathematical evaluation and grey correlation analysis are linked by membership degree and are integrated to establish a more effective fuzzy-grey comprehensive evaluation model,along with differentiated and improved internal algorithm.The application of the model to reservoir evaluation in this study suggests that this method enhances the differences and precision for the low-permeability reservoir classification and characterization,with consideration of the fuzzy and grey properties of reservoir.In this case study,four types of reservoir are classified and the type Ⅰ and Ⅱ are deemed to be the favorable targets.The different reservoir categories are better separated in plane view than before.The comparison of evaluation results with the real production data and geological principles of fluvial deposition also displays good coincidence.This method may be effective and efficient for guiding the exploration and development of the gas field,and provide a new thought for similar low-permeability reservoir evaluation as well.

Key words: quantitative evaluation, fuzzy mathematics, grey theory, reservoir description, Shihezi Formation, Sulige gasfield

CLC Number: