Technology Of The Compatibility Of Oil-field Water And Study Of Reservoir Sensitivity About Representative Blocks On Yanchang Oil-field

This paper mianly discusses the problems about the compatibility of oil-field water, reservoir sensitivity, and protections of water sensitivity formation.By analyzing the reasons for scaling and sensitive damage, good recipes for scale inhibitors and anti-swelling agents are introduced in this thesis.Results of the experiments impile that the clear water has good compatibility with oil-field water which comes from Chang7 layer, Chang8 layer, Chang9 layer in Wuqi oil-field. In addtion to this, when the dosage of inorganic flocculant PAC is 30mg/L and the dosage of HPAM is 2mg/L,the results of flocculation is perfect.Except this, this paper also finds PESA, PBTCA and PESA have good effect in Yan10 oil-field water of Dingbian oil-feild.Further studys show the mixture of PESA and PBTCA or ATMP have bettter scale inhibition effect, which impiles that different side groups in PESA, PBTCA, ATMP just exsit synergistic effect, and the mixtrue of PESA and PBTCA have quiet thermal stability in 60℃.XRD analysis shows that the main mineral of Chang2 layer, Yan 8 layer, Yan 10 layer of Dingbian oilfeild and Wuqi Yan9 rock-oil mainly be consisted of quartz crystal, albitite, and albitite, the clay minerals include ceramics, illite, chlorite,and other minerals,the content of wchich is 5% to 8%.Scanning electron microscopy shows that the pore types of Chang2,Yan8, Yan10 mainly is intergranular pores, solutional voidand cracking hole, but Yan9 of Wuqi oil-feild mainly contains intergranular pores. Generally speaking, the connectivity and distribution of clay minerals is different in the selected blocks. Sensitivity experiments show that Chang2 layer, Yan8 layer and Yan10 layer are weak velocity sensitivity and moderate water-sensitive formations, but Yan9 layer of Wuqi oil-field is strong water-sensitive formation, and the damage of water sensitivity is 86.2%, thus some measures should be taken to protect this formation.And some clay stabilizers such as PDADMAC, PTA, PCD, small organic cations are evalued by static experiment.Experimental results suggest that when the ratio of NH4Cl and PTA is 3:2, the ratio of anti-swelling is 91.2%.The stable period and the ability of bearing the washout about clay stabilizer is carried out by dynamic experiment.The data of research tells us the appropriate injecting quantity of clay stabilizer is 5PV, and under this condition the stable period of clay stabilizer is more than 100PV. Further study indicates that the loss of the rock permeability reduces from 58.27% to 13.01%, which shows the clay stabilizer has good protection on Yan9 layer.