Abstract Aqueous phase trapping (APT) that causes vital damage has not attracted attention in production yet. In this paper, the APT damage is evaluated based on imbibition and backflow experiments via studying six factors (imbibition pressure difference, liquid types, initial permeability and porosity, initial water saturation, clay minerals and natural crack). Experimental results show that the imbibition pressure difference is positively correlated with APT damage, and the damage extent is still medium (Permeability Damage Ratio (PDR) is 0.32) even for underbalanced conditions. Compared to the 3%KCl solution and 0.01% scale inhibitor solution, the 0.1% foam fluid presents the weakest damage (PDR is only 0.14) because of its lower interfacial tension ( σ = 22.1 m N / m ) and higher contact angle ( θ = 20.5 ° ). A lower initial water saturation can result in more serious APT damage. The APT damage increases with the declination of permeability, but the increase of porosity. The content of kaolinite is positively correlated with the damage extent and plays a significant role because of the largest adsorption capacity compared to other studied clay minerals (maximum adsorption volume and specific surface area of kaolinite are 120.28 cm3/g and 24.63 m2/g, respectively). The APT damage extent of natural crack is lower than that of matrix pores (PDRs are 0.10 and 0.32 for the natural crack and matrix pores, respectively). However, the natural crack can strengthen APT damage in matrix pores because the crack face provides a larger imbibition area for the matrix pores. Three unfavorable engineering responses can be induced by APT damage in production, which are the reduction of production flow rate, increase of residual liquid in wellbore and the elevation of the pressure difference between casing and tubing, respectively. This paper provides new insights for the APT damage and presents a great significance for the diagnostics and control of APT damage for tight sandstone gas reservoirs.

中文翻译：

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致密砂岩气藏生产中水相圈闭损伤机理与工程响应

摘要 水相捕集（APT）在生产中尚未引起人们的重视。本文通过研究渗吸压差、液体类型、初始渗透率和孔隙度、初始含水饱和度、粘土矿物和天然裂缝6个因素，基于渗吸和回流实验对APT损伤进行了评估。实验结果表明，渗吸压差与APT损伤呈正相关，即使在欠平衡条件下，损伤程度仍为中等（渗透性损伤比（PDR）为0.32）。与 3%KCl 溶液和 0​​.01% 阻垢剂溶液相比，0.1% 泡沫液由于其较低的界面张力 (σ = 22.1 m N / m ) 和较高的接触角 ( θ = 20.5°）。较低的初始含水饱和度会导致更严重的 APT 损害。APT 损伤随着渗透率的下降而增加，但随着孔隙度的增加而增加。高岭石的含量与破坏程度呈正相关，因为与其他研究的粘土矿物相比，其吸附容量最大（高岭石的最大吸附量和比表面积分别为 120.28 cm3/g 和 24.63 m2/g），因此起重要作用）。天然裂缝的APT损伤程度低于基质孔隙（天然裂缝和基质孔隙的PDR分别为0.10和0.32）。然而，天然裂纹可以加强基质孔隙中的 APT 损伤，因为裂纹面为基质孔隙提供了更大的吸水面积。生产中的 APT 损坏会引起三种不利的工程反应，分别是生产流量的降低、井筒残余液的增加和套管与油管压差的升高。该论文为APT损伤提供了新见解，对致密砂岩气藏APT损伤的诊断和控制具有重要意义。