松辽盆地宋芳屯油田葡萄花油层潜在的损害因素

Latency formation damage in Putaohua oil reservoir of Songfangtun oilfield, Songliao basin

宋芳屯油田葡萄花油层呈现中～低渗透性特征，容易受到伤害． 分析潜在的损害因素，可以有效地预防油层损害． 研究表明，伊利石、高岭石以及蒙皂石－ 绿泥石混层粘土是伤害储层的主要粘土矿物，平均质量分数为６ ．９５ ％ ． 储层平均阳离子交换量为１０ ．６８ ×１０ － ５ ｍ ｏｌｇ ，岩石体积膨胀为１１１ ％ ，呈现潜在水敏损害，南部地区高于北部地区． 酸敏损害表现为高岭石、绿泥石以及蒙皂石－ 绿泥石混层粘土、方解石和长石产生二氧化硅凝胶、氟铝酸盐、氢氧化铁胶体、氟硅酸盐和氟化钙沉淀，以及长石骨架颗粒解体． 主要渗流孔喉半径小于８ μｍ ，粒径小于５ μｍ 的地层微粒平均质量分数为７ ．１９ ％ ，潜在的微粒运移损害严重． 其它潜在损害因素包括井筒和地层内碳酸钙结垢以及石蜡沉淀等．

The Putaohua Oil Reservoir in Songfangtun Oilfield presents characteristic of lower to medium permeability, and therefore will tend to be easily damaged. The latency analysis of formation damage will aid for effectively preventing the formation from being damaged. The investigation shows that the dominant components of clay minerals are illite, kaolinite, and mixed\|layer clay mineral of smectite to chlorite, with total average mass fractions of 6.95 percent. The average content of cation\|exchange capacity in the reservoir is 10 -5 mol/g. The sandstones are of 111 percent expanding fractions of volume, show a hint of potential formation damage from water susceptivity, with most intense water susceptivity in the southern part of the oil field. The processes of acid susceptivity acting on kaolinite, chlorite and mixed\|layer clay mineral of smectite to chlorite will possibly cause the formation damages in the form of precipitation of silicon dioxide, fluoaluminate, iron hydroxide gel, fluosilicate, calcium fluoride, and disaggregation of feldspar frame particles as well. The dominant radii of flowing throats in the reservoir are smaller than 8 μm. The formation particulates which are smaller than 5 μm in diameter are of 7.19 percent of mass fractions. The particulates migration will severely harm the reservoir. The other coming harmful events include the precipitation of calcium carbonate in the well hole or inside the formation, the deposition of paraffin and so on.