Researches Of Formation Damage Mechanism And Drilling Fluid Technology Of Xingzichuan Chang 10

The reserves of low permeability oil fields are rich in our country.According to the preliminary statistics,the untouched reserves of the low permeability reservoirs permeability of which is less than 50×10-3?m2 account for more than 50%of the total,and the outputs of low permeability oil fields in the proportion of the total yields are rising year by year.Though the geologic conditions of low permeability oil fields are bad and their development is difficult,the rich reserves of low permeability oil fields are paid more and more attentions to with the rapid development of our country's economy and the growing demand for oil in our country.With further exploration and development,formationtype is becoming more and more complicated and diversified,the corresponding exploration and development is more and more difficult.and the requirement for formationprotection technique is higher.Formation damage has corresponding characteristics according to local conditions,so studying the Xingzichuan oil and gas layer damage mechanism is necessary.The Xingzichuan oil field belongs to mesoporosity and low permeability oil field,which has high clay content and complicate pore texture.Evaluating the formationsensitivity exactly and analysing the formation damage mechanism will provide the valuable reference for planning the oil drilling engineering scheme.This article analysed the type and number of clay minerals,according to the characteristics of reservoirs in Xingzichuan.Combined particles migration,predicting the condition of velocity sensibility could play a guiding role in the experiment.On the basis of the clay minerals analysis,sensitivity experiments were done.The overall characteristics of the Xingzichuan block included:speed sensitivity was strong,water sensitivity and acidic sensitivity were from medium to strong,salt sensitivity and stress sensitivity were medium.On the basis of the sensitivity analysis,the drilling fluid composition of the region were studied,the mechanisms of tackifier?high-temperature resistant fluid loss additives and calcium carbonate were also studied and their performance was evaluated in the laboratory,and then reagents that were efficient had been screened out and the optimal added amount was determined.The optimized drilling fluid system was evaluated from heological properties?fluid losing and wall building property?anti-pollution?high pressure stability?lubricity and core dynamic damage,and then a set of the drilling fluid system that was suitable for Xingzichuan region had been established These efforts provided direction forXingzichuan region in drilling fluid technology research and developmenting and perfecting the drilling fluid system.