Influence Factors Of Calcium Sulfate Scaling And Synthesis Of Chemical Scale Inhibitor

Water injection development is a common development way to improve oil recovery in the process of oilfield production.But in the process of water injection,it is easy to cause the problem of formation pore and scaling because of the incompatibility of injected water and formation water.The common scale in the development of oil and gas field is CaC03,CaSO4 and BaSO4.The formation of these dirt blocks blocked the pore throat,reduced the permeability of the reservoir,increased the seepage resistance and increased the operating pressure of the pump.If we do not pay attention to the problem of scaling in the process of water injection,it may bring serious harm to the production of oil field.At present,chemical scale inhibitor has been widely used in the field of petroleum as its good effect and low cost.In this paper,the molecular design of the synthesized scale inhibitor is carried out.According to the sift of monomer material,we ultimately determine the scale well 4 monomer itaconic acid,vinyl acetate,AMPS and 2,2-dimethylol propionic acid.Through the experimental study on optimization of initiator dosage,reaction temperature and reaction time,we can get the reaction conditions for the best scale inhibition effect of inhibitors:synthesis of 85 degrees Celsius temperature,initiator dosage of the total mass of monomer 8%,reaction time 3h.By the orthogonal experiment,inhibition rate reached a maximum of 92.49%under the condition that the monomer ratio is 2:1.5:1:0.75,the reaction time is 3h,the reaction temperature is 85 degrees celsius,initiator dosage of the total mass of monomer is 8%.Through infrared spectroscopy analysis,the synthetic scale inhibitor contains carboxylic acid functional groups,ester functional groups and sulfonic acid functional groups,etc.It can be complexed with metal ions to achieve scale inhibition.The synthesis of scale inhibition and evaluate the effect of industry standard results indicated that:scale inhibitors have good hydrolytic and thermal stability,solid content is 55.04%,density is 1.182g/cm3;with the increase of temperature,the scale increased first and then decreased,the inhibition rate reach the maximum when the temperature is 70 degrees celsius and the PH is 7.5;with increasing salinity,the scale of the calcium sulfate scale rate increases first and then decreased slowly.The oilfield water analysis data of Jiudong Oilfield,Hujianshan Oilfield and Jiyu Oilfield were used as the basic data,and ScaleChem software was used to predict the scale and scale types.Combining with experiments,the synthetic scale inhibitors were used to evaluate the scale inhibition effect of the above three blocks of oilfields.It was found that the synthesized scale inhibitors have good scale inhibition effect on calcium sulfate scale,barium sulfate scale and calcium carbonate scale.This synthesized scale inhibitors can meet the application of oil field.