Oil & Gas Geology ›› 2017, Vol. 38 ›› Issue (1): 144-151.doi: 10.11743/ogg20170115

• Petroleum Geology • Previous Articles     Next Articles

Pore types and characteristics of volcanic reservoirs of the Jiamuhe Formation in Jinlong oilfield, Junggar Basin

Wang Xiaojun1, Zhao Fei1, Zhang Qin2, Wang Dongxue1, Xia Jinjie1, Wu Xingzhou1, Li Chenxi2, MeiXiaohan2, Lyu Dehong3   

  1. 1. Research Institute of Petroleum Exploration & Development, PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China;
    2. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China;
    3. Mudlogging International Department, CNPC Greatwall Drilling Company, Beijing 100101, China
  • Received:2016-06-29 Revised:2016-12-20 Online:2017-02-28 Published:2017-02-27

Abstract:

Volcanic rocks in the Jiamuhe Formation are favorable reservoirs in Jinlong oilfield.It is a key step for exploration and development of volcanic reservoirs to analyze the characteristics of volcanic reservoir and define the distribution of favorable reservoir facies belts.Based on core,thin section,high pressure mercury injection and reservoir property data,this paper defined the characteristics of lithology and property of the volcanic rocks,and predicted the distribution of favorable volcanic reservoirs.The results show that the volcanic reservoirs consist of volcanic lavas,volcaniclastic lavas,volcaniclastic rocks and depositional volcaniclastic rocks.The volcanic reservoirs in Jinlong Oilfield are characterized by medium to low porosity and low to extra low permeability.The reservoir spaces are divided into pore vs. fracture classes according to their shapes in the rock,and primary vs. secondary categories on the basis of genesis,of which the contraction pores and fractures are the main reservoir spaces of the volcanic reservoirs in Jiamuhe Formation.Volcanic rocks with different lithologies and petrofacies have different types of mercury-injection curves.There are 3 curve types featuring respectively in fine pore throat with bimodal positive skew distribution,fine-micro pore throat with unimodal positive skew distribution,and micro pore throat with unimodal negative skew distribution.Overall, the micro-fine pore throats are predominant and the sorting is poor to moderate.Lithologically,the volcanic breccias,basalt and andesite are the most favorable reservoirs in the study area,while as to petrofacies,the best reservoirs occur in the explosive facies and the upper part of the effusive eruption facies.The best favorable reservoir facies belt is located at the middle part of the study area and is in NW-SE-trending banded distribution.

Key words: reservoir property, pore type, distribution of pore throat, volcanic reservoir, Jiamuhe Formation, Jinlong oilield, Junggar Basin

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