Study On Preparation And Properties Of Plugging Fluid Loss Additive

Based on the investigation of the inert materials suitable for oil field application,a new exploration of the filter reducing agent is made from the angle of change of high temperature water.The effect of blocking and filtering loss of five kinds of ultra-fine inert materials and the applicability of two kinds of nanomaterials in drilling fluids were systematically studied,and four new types of blocking and filtration loss agents were prepared from laboratory materials.Based on the new sealing type filter reducing agent,2 sets of 4 kinds of sealing drilling fluids suitable for super high temperature and high salt were developed.In this paper,artificial sand core is used to simulate the microcracks and microporosity loss in the well in the high temperature and high pressure filter,and as a new method to evaluate the filter loss of the blocked drilling fluid filter,several common sealing materials and systems are evaluated.The experimental selection of flaky ultrafine mica powder,spherical ultrafine talc powder,fibrous sepiolite,wood fiber powder,and wood pulp system was studied in which they were aggravated to?=2.00 g/cm³,and aggravated by 30%Na Cl+1%Ca Cl₂ salt.Loss performance.It is found that the material has good resistance to ultra-high temperature and salt,and each material has its own characteristics,but the effect of reducing filtration failure is very limited.It was found that mica powder,sea foam powder,and wood fiber powder had a good effect.Talcum powder was more suitable for aggravating system,and other blocking filter reducing agents must be prepared for compound use.The applicability of the most common nanocrystalline cellulose and nanocrystalline silicon dioxide in drilling fluid was verified,and it was found that they were not suitable for the high temperature and ultra-high temperature system.Calcium humic acid(CaHA₂),aluminum humic acid(AlHA₃),cross-linked starch(CS)and polystyrene(PS)powder were made and evaluated.They were found to have good filtration loss and high temperature and salt resistance.Using cross-linked starch and calcium humic acid as the main filter reducing agent,two sets of anti-high temperature anti-salt sealing drilling fluid systems were developed.They are:clear water+3%cross-linked starch+2%mica powder+2%wood fiber powder+1%sea foam powder+1.5%PS(150°C);Clear water+3%cross-linked starch+2%mica powder+2%wood fiber powder+1%sea foam powder+1.5%PS+1%talc+200%barite(150°C,2.0g/cm³);Water+5%CaHA₂+2%mica powder+2%sea foam powder+1%wood fiber powder+1.5%PS(250?);Water+5%CaHA₂+2%mica powder+2%sea foam powder+1%wood fiber powder+1.5%PS+1%talc+200%barite(250°C,2.0 g/cm³).These sealed drilling fluid systems perform well in salt-adding and aggravating environments,and can be used under high temperature,high temperature,high salt,and aggravated conditions.