砂砾岩人造裂缝导流能力物理模拟

Physical Modelling of Artificial Fracture Conductivity of Glutenite

由于砂砾岩储集层结构复杂、孔隙度低、非均质性和各向异性强,导致油藏开发具有一定的难度。为了实现砂砾岩油藏的高效开采,进行砂砾岩裂缝导流能力研究。通过分析影响砂砾岩裂缝导流能力的各个因素,从支撑剂含量和砾石含量两方面进行实验,在此基础上研究纤维和支撑剂粒径变化对导流能力的影响。支撑剂在裂缝中的分布方式有3种:与砾石接触、与基质和砾石接触、与基质接触。低闭合压力时,砂砾岩裂缝导流能力与砾石含量呈正相关,此时纤维对导流能力影响不大;随着闭合压力增大,导流能力随砾石含量增加出现下降趋势,纤维的存在也使导流能力下降。导流能力与支撑剂含量呈正相关,闭合压力越大,导流能力越弱,在一定砾石含量时,支撑剂粒径越大,导流能力越强。综上分析,在一定闭合压力下,砂砾岩裂缝导流能力与砾石含量和支撑剂含量呈正相关,增大闭合压力,导流能力出现下降趋势。

It is difficult to develop glutenite reservoir due to its complex structure,low porosity,strong heterogeneity and anisotropy.In or⁃der to realize the efficient exploitation of glutenite reservoir,the fracture conductivity of glutenite is studied.Through analyzing the factors affecting the fracture conductivity in glutenite,this paper starts from the experiments on proppant and gravel contents and studies the influ⁃ences of fiber and proppant particle size on fracture conductivity.It is found that there are three contacts for proppants in fractures:contact⁃ing with gravel,contacting with gravel and matrix,and contacting with matrix.When the closure pressure is low,the fracture conductivity of glutenite is positively correlated with gravel content,at this time,the fiber has little impact on the conductivity;with the increase of the clo⁃sure pressure,the fracture conductivity decreases with the gravel content,and the presence of fiber also decreases the conductivity.The conductivity is positively correlated with the content of proppant,and the greater the closure pressure,the weaker the fracture conductivity.If the content of gravel is fixed,the larger the particle size of proppant is,the stronger the flow conductivity will be.To sum up,under a cer⁃tain closure pressure,the flow conductivity of fractures in glutenite is positively correlated with the contents of gravel and proppant.With the increase of closure pressure,the fracture conductivity tends to decrease.