China Petroleum Exploration ›› 2017, Vol. 22 ›› Issue (3): 96-103.DOI: 10.3969/j.issn.1672-7703.2017.03.012

• PETROLEUM ENGINEERING • Previous Articles     Next Articles

Low-contrast reservoir identification method based on double formation water resistivity and its application

Zhong Jibin1,2, Shi Yujiang1,2, Wang Changsheng1,2, Zhang Shaohua1,2, Li Weibing1,2   

  1. 1. Research Institute of Exploration and Development, PetroChina Changqing Oilfield Company;
    2. National Engineering Laboratory of Low-permeability Oil & Gas Exploration and Development
  • Received:2016-02-26 Revised:2017-03-12 Online:2017-05-10 Published:2017-05-15

Abstract: The apparent formation water resistivity (Rwa) is an important parameter of well logging interpretation. It is usually used, together with the true formation water resistivity (Rw), to identify the properties of reservoir fluids. For low-contrast continental reservoirs, however, the properties of formation water vary greatly, thus the wrong conclusion is often reached if the same Rw is used in the same area to identify oil reservoirs. In this paper, the formation water resistivity (Rw_sp) was calculated layer by layer on the basis of spontaneous potential curve. Then, Rw_sp, as the substitute for Rw, was used for comprehensive interpretation combined with Rwa. This method is quite capable of identifying lowcontrast oil layers in continental reservoirs with remarkable practical results.

Key words: low-contrast reservoir, apparent formation water resistivity, formation water resistivity based on spontaneous potential, amplitude of spontaneous potential curve, irreducible water resistivity, conductive ion concentration, mud property

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