Research on the genesis and identification of low resistivity gas reservoirs in unconsolidated sandstone gas reservoirs:A case study of the Sebei gas field,Qaidam Basin
Duan-Yang GU1, Wen-Bo DOU2, Fu-Shou DING3, Li YAN3, Hao LYU3
1. Exploration and Development Research Institute of Qinghai Oilfield Branch of CNPC,Dunhuang 736202,China 2. The 11th Oil Production Plant of Changqing Oilfield Branch Petrochina,Qingyang 745000,China 3. No.3 Oil Production Plant of Qinghai Oilfield Branch Petrochina,Mangya 816400,China
The Sebei gas field is a Quaternary Huxiang sedimentary biogas reservoir with shallow burial and poor diagenesis.The reservoir has "four highs" background of "high porosity,high salinity,high clay content,and high conductivity of (yellow/magnetic) iron ore".A low gas barrier layer and a special ultra-low gas barrier layer were formed.Based on the electrical response characteristics of the low-resistance gas layer logging curve,the authors studied its spatial distribution and its influence on production characteristics,and made a mechanism analysis of the low-resistance gas layer.The results are as follows:First,geological backgrounds such as high porosity,high salinity,and high clay content are the main factors leading to the low resistivity of the gas layer in the Sebei gas field,and the thin interbeds of sand and mudstone also have a certain effect;Second,the existence of special conductive minerals is the direct factor responsible for the abnormal low-resistance gas layer;Third,the natural gamma-resistance intersection method can effectively identify the low-resistance gas layer formed by geological background and reservoir characteristics;as for lateral and induction logging,the double-resistance cross section improves the recognition effect of thin sand bodies;Fourth,on the basis of fine logging interpretation,it seems that strengthening the study of the planar distribution of iron ore layers and using dynamic methods to form plane monitoring by means of gas testing can improve the precision of the interpretation of low-resistance gas layers.
顾端阳, 窦文博, 丁富寿, 严力, 吕浩. 疏松砂岩气藏低阻气层成因及识别研究——以柴达木盆地涩北气田为例[J]. 物探与化探, 2020, 44(3): 649-655.
Duan-Yang GU, Wen-Bo DOU, Fu-Shou DING, Li YAN, Hao LYU. Research on the genesis and identification of low resistivity gas reservoirs in unconsolidated sandstone gas reservoirs:A case study of the Sebei gas field,Qaidam Basin. Geophysical and Geochemical Exploration, 2020, 44(3): 649-655.
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