China Petroleum Exploration ›› 2024, Vol. 29 ›› Issue (2): 147-157.DOI: 10.3969/j.issn.1672-7703.2024.02.012

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Important role of seismic data in gas reservoir logging interpretation and evaluation: a case study of M Gas Field in Siberian Basin

Wu Guohai1, Hu Xin2, Guo Zhenhua1, Ni Guohui1, Jiang Ren3, Yang Yuanqi1, Wang Kun1   

  1. 1 International Company, CNPC Logging Co., Ltd.; 2 China National Oil and Gas Exploration and Development Co., Ltd.;3 PetroChina Research Institute of Petroleum Exploration & Development
  • Online:2024-03-15 Published:2024-03-15

Abstract: The low-resistivity gas layers are observed in HM1 and HM2 sandstone reservoirs in the upper part of the Cretaceous in M Gas Field. Due to the incomplete logging data and lack of density and neutron porosity curves, there are great challenges in gas layer interpretation and evaluation. In the process of logging and well test data interpretation, it is found that there is a good correlation between the bright spot reflection feature in seismic profile and gas-bearing property of the reservoir. AVO technology is applied to process the pre-stack seismic data such as noise reduction and amplitude compensation, and the high-precision AVO profile is obtained with five channels. The analysis of the relationship between amplitude and offset further proves that the bright spot seismic reflection is caused by gas layer, and confirms the feasibility of using seismic data in assisting logging interpretation and gas layer prediction. After effectively scaling and calibrating seismic profile and eliminate lithology factors unrelated to gas enrichment in seismic reflection features by logging data, the direct relationship between seismic reflection features and gas-bearing property of the reservoir is established. By fully tapping and utilizing natural gas information contained in seismic data, the reflection features of seismic profile such as bright spot reflection, pot bottom reflection, and shield-absorption are used to assist logging interpretation, which not only makes up for the lack of logging data, but also further verifies the logging interpretation conclusions. Based on the distribution range of bright spots, the gas-bearing range of HM1 and HM2 layers is precisely delineated, achieving the combination of well and seismic data. In addition, the amplitude variation of bright spots plays a significant role in predicting the high-abundance gas-bearing zone, predicting the thickness variation of gas layers, and estimating the gas-water contact. In the process of gas reservoir interpretation and evaluation, superior results have been obtained by the method of well and seismic data combination, providing a reliable basis for the optimal selection of well location, which has been confirmed by production practice.

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