Prepare And Study Of Micro-nano Sized Plugging Agent With Lubrication And Anti-sloughing

Oil and gas reservoir of Shanbei are micro fracture reservoir. It is easy to cause lost circulation when drilling process, causing severe damage on reservoirs. The size distribution of micro-nanometer blocking agent researched from my experiment is matching the structure of the oil reservoir, It could solve the problems of serious leakage of drilling fluid and damage to the oil reservoir, The polyethylene wax(PE wax) with high melting point and high hardness was chosen as the main agent of blocking agent; different types of surfactant compound systems were chosen as the emulsifier; water was chosen as dispersion agent. The plugging agent which was made of polyethylene wax, water and emulsifier has a good dispersion performance in water. The influencing factors of the properties of blocking agent have been researched, including emulsifier HLB value, emulsifier content, emulsifying time, wax content, stirring speed. The stability property and size distribution have been studied. The results showed that when the emulsifier HLB value is 10.5, the mixed emulsifier dosage was 9.6%, the wax content was 30.21%, the stirring speed was 1000 r/min, the emulsifying time was 30 min and emulsifying temperature was 130℃, It can get that average particle size of blocking agent has only 1.6 μm and It owns the best stable performance. It can’t change on the condition of centrifuging for 10 min and 3000 r/min,or staying for 90 days. In addition, the specific gravity, rheology, filter loss, shale inhibition and lubricity of some drilling fluids have been researched, the results showed that apparent viscosity and the plasticity viscosity increase by 10% and 17% singly, at the same time the dynamic shear fell by 7.5%, the API filtration and the HTHP filtration volume fell 19.6% and 27.2% as well when the content of plugging agent was 1.5%. Friction coefficient and shale swelling reduced by 62.9% and 35% singly when the content of plugging agent was 3.0%, which showed that the plugging agent has a good plugging property and anti-sloughing, It can inhibit shale swelling and effectively protect the oil reservoir.