涩北一号气田第四系储层特征研究

RESEARCH ON CHARACTERISTICS OF RESERVOIR BED IN QUATERNARY OF SEBEI-1 GAS FIELD

涩北一号气田是柴达木盆地东部浅层生物气田,通过对涩3-15井岩样的系统实验分析,结合气井的测试资料,研究了涩北一号气田第四系储层的岩石特征、孔隙结构和物性特征,发现岩石以粒间孔为主,具有高孔隙度、中低渗透率的特点,孔隙度主要分布在25%～40%的范围内,渗透率主要分布区间为(1～100)×10-3μm2,孔渗相关性不强;虽然该储层岩石疏松,但部分高泥质疏松砂岩中微裂缝发育,具有较好的渗透性,其产气能力甚至比泥质含量低的Ⅰ、Ⅱ类储层还强,因此可作为有效产层。这一认识为涩北一号气田的储层研究提出了新的观点,对气田的储量增长和产能建设具有积极意义。

Sebei-1 gas field in eastern Qaidamu Basin, the largest shallow biogas field in China, is characterized by unconsolidated reservoir with fine grain size and high content of shale. Based on systematic experimental analysis of rock samples in Well Se3-15 and in combination with analysis of well test data, rock characteristics, pore structure and poroperm characteristics of the reservoir in Sebei-1 gas field are studied. The rock pores are dominated by intergranular pores. The porosity is high in the range from 25% to 40% and the permeability is from medium to low in the range of 1×10 -3 to 100×10 -3μm2, and the correlativity between porosity and permeability is not strong. Although the reservoirs in this gas field are unconsolidated, some reservoirs with high shale content have well-developed microfractures thus relatively good permeability and their gas deliverability is even higher than the typeⅠand Ⅱ reservoir with lower shale content, therefore they can be considered as effective reservoirs. This new understanding provides a new concept for studying reservoirs in Sebei-1 gas field, and is of positive significance to reserves growth and construction of production capacity.