Study On Scale Mechanism And Scale Inhibition Technology

Due to long period of water injection,NE oilfield has been suffering serious scaling problems.Wells and pipelines scaled to different extents,even worse some were pluged by scaling.To find an effective way to resolve this problem has been like an arrow on the bow.According to the record of this oilfield’s scaling history and the data which our experiment collected,including water components data, water samples and scale samples,it can be deemed the cause of scaling in NE oilfield was that injection water is not compatible with the groundwater in reservoir which contains a large amount of Ca2+、Mg2+、 Ba2+、Sr2+、HCO3-、SO42、that comprise scales.Two scale inhibitors were selected and remixed with a most appropriate proportion in consideration of the particular case in NE oilfield.The test which simulated oilfield water revealed the mixed scale inhibitor was specifically effective for the eliminating scale of this oilfield;Even the most obstinate scale consists of SrSO4and BaSO4could be removed to an extent of90%.Following experiments studied how the scale inhibition rate was affected by temperature,CO2concentration and pH value fluctuation.In addition, being testified with other chemical reagents used in NE oilfield,the remixed inhibitor acted compatible.Based on laboratory experiments,the process of scale inhibitor injection and monitoring method to the scale inhibitor’s effection in wells and pipelines in NE oilfield are given in this paper.Field test results explicated the scale inhibition rate of remixed scale inhibitor could be kept over95%against CaCO3and85%against BaSO4.