Study On Pressure Lightening Agent And Low Density Cement Slurry System

With the speeding up of the exploration and development speed,high temperature and low pressure leakage well more and more easily,low density cement slurry system is the main way to solve the low pressure easy leakage formation cementing.By conventional low density cement slurry to reduce material of fly ash,silicon,bentonite,slag on cement slurry density lower ability is limited;Nitrogen,ordinary drift beads has low pressure resistance;Hollow glass microsphere,the high cost.According to this problems,developed the bearing capacity of less than or equal to 60 MPa low cost composite reducing agent,has carried out 180? high temperature resistance,density is 1.20g/cm3?1.60g/cm3 between low density cement slurry system research.Based on actual accumulation form particles,three particles close packing model and uncertainty four particles close packing model From three grading model for grading of three particle size ratio of 1:0.464:0.464.System developed close packing voidage test device,and testing voidage accumulation system,the results show that the primary particles and secondary particles,level three small particles when the volume ratio of 6:13,that particles close packing system voidage,as 34.01%.Triple particle volume of three-level particles close packing system for fine-tuning,it is concluded that large,medium and small three particle volume in[7?10]:[1?2]:[2?2.5]between voidage accumulation system when the difference is small,particle accumulation is more closely.Combining theoretical model and experimental verification,the developed the density is 0.87g/cm3?1.04g/cm3 and 1.01g/cm3?1.23g/cm3,bearing capacity of 40 MPa and 70 MPa,respectively applicable scope of slurry density in 1.20g/cm3?1.60g/cm3 between composite reducing agent JQ-1 and JQ-2,it's cost less than 16900 yuan/ton.Through a large number of experiments prove that this composite reducing agent and conventional oil well cement slurry additive compatibility good,strong resistance to high temperature performance.This article also developed by using composite reducing agent was carried out by density of 1.20g/cm3?1.40g/cm3 and 1.60 g/cm3 low density cement slurry system bearing capacity,high temperature stability,rheological property,permeability cement,cement stone at high temperature properties,such as the strength development of the research.The research results show that this kind of low density cement slurry system has good resistance to high temperature stability,slurry fluctuation is less than 0.02g/cm3 density difference;Better rheological properties,fluidity is greater than 20 cm;API fluid loss is small,less than 50ml;In cyclic temperature 140??180? under the condition,thickening time adjustable between 154min?527min,thickening curve is good,the basic right angle thickening The cement paste,high compressive strength,density of 1.20g/cm3?1.40g/cm3 and 1.60g/cm3 three kinds of low density cement slurry system of 75? water bath atmospheric maintenance two days compressive strength were 16.28MPa?26.46MPa?30.25MPa;Paper also for three kinds of low density cement slurry,high temperature resistance of cement stone compressive strength and bond strength is influenced by temperature,such as cement permeability performance were studied.Results show that the composite reducing agent of routine low density cement slurry system performance and density cement slurry systerm routine performance difference is not big,can improve the quality of low density cementing slurry system,reduce the cementing cost,improve the corrosion resistance of the cement,extend the life of the oil and gas Wells.