利用干扰试井判断特低孔渗裂缝-孔隙型砂砾岩油藏连通性——以准噶尔盆地红153井区为例

Research on Connectivity of Extra-low Porosity and Permeability Fracture-Pore Type Glutenite Oil Reservoir in Interference Well Test Way——A Case Study of the Area of Well Hong153 in Junggar Basin

砂砾岩油藏储层变化快、非均质性强,油藏连通性的判断一直是国内外研究的难点。红153井区块二叠系夏子街组油藏属于特低孔渗的裂缝-孔隙双重介质油藏,且纵向上隔夹层不发育,油层跨度平均347m。为了判断油藏平面上及纵向上连通性,以寻求合理的开发方式及井距,在该区进行了干扰试井。利用红153井的开井和关井以及新投产井的压裂作为激动信号,在相邻生产井下入高精度存储式压力计,通过测得的井底连续流压的变化情况,来判断各井之间的连通性。此次打破常规将干扰试井应用于砂砾岩油藏开发中,取得了较好的效果。观测结果证实当激动井进行关井作业或者压裂时,监测井的地层压力明显上升;当激动井开井时,监测井的地层压力明显下降。其中平面上最远监测距离达1.5km,纵向上最大监测跨度达176m,大大超过一般的测试井距500m,也用实际数据证明了该特低孔渗油藏在平面上及纵向上连通性好,为油藏的开发部署提供了有利依据,表明该油藏适宜采用较大生产井距、一套井网进行开发。

The reservoirs in glutenite oil reservoirs are characterized by rapid changes and severe heterogeneity.Judgment of reservoir connectivity has always been a difficulty at home and abroad.The Permian Xiazijie Formation reservoir in the area of Well Hong153 is the one with extra-low porosity and permeability fracture-pore double-medium.The interlayers don′t develop in the vertical and average span between oil layers was 347m.Interference well test was carried out in this area for knowing the reservoir connectivity and seeking reasonable development way and well spacing.Using the opening and closing of Well Hong153 and fracturing of the new producers as an activation signal,a high-precision memory manometer was applied to the adjacent production well,and the connectivity among wells was judged by the measured continuous bottomhole pressure.The interference well test was applied to the development of glutenite reservoirs achieving good results,which broke the conventional practice.The observations confirmed that the formation pressure of the monitoring wells increase significantly when the active well is activated for well closure or fracturing and decrease significantly when the active well is opened.The farthest observation distance is as much as 1.5 km on the plane,and maximum observation span is up to 176m in the vertical,which greatly exceeds the average measuring distance of 500m.Actual data proved the good connectivity in this extra-low porosity and permeability reservoir,which provides favorable foundation for the development and deployment of the oilfield.This oil reservoir may be developed with larger well spacing and one set of well pattern.