| Cementing operation is one of the important working procedures in oil and gasmining,the poor quality of it will result in the occurrence of interlayer channeling andpipe out of the interlayer,and seriously affect the subsequent mining of oil and gasbesides well life.The study in recent years found that in the later mining period of oilfield, the poor quality of two interfaces of cement in the cementing operation is one ofthe main causes of interlayer channeling and pipe out of the interlayer.This paper presents the new method to improve the he quality of two interfacescement by applying carboxylated styrene-butadiene rubber latex as the interfacialreinforcing agent after the modifiability of it according to the analysis of the actionprinciple of drilling fluid cake and two interfaces、the analysis of the action principleof improving the intensity of two interfaces by flushing spacer fluid usingcarboxylated styrene-butadiene rubber latex.We composed a kind of modified carboxylated styrene-butadiene rubber latex asinterfacial reinforcing agent by the way of emulsion polymerization with styrene、butadiene and functional monomer A acting as polymerization of monomer.Besides,we also determined the synthesis conditions of interface agent: the proportion ofstyrene and butadiene is1:1，the dosage of chain transfer agent is about0.5%，polymerization temperature is65-70℃，the proportion of the third monomer is7%.The evaluation of interfacial reinforcing agent shows that the agent can reducethe cement penetration and improve the cement stone barrier ability, and it isbeneficial to improve the cementing quality，The agent can improve the recovery rateof debris, and it is beneficial to maintain the stability of the wall of well.The agent canimprove the compatibility conditions among cement slurry, mud cake and the wall,and achieve the purpose of improving the quality of cementing quality of twointerfaces.Based on this,we formed the interfacial reinforcing agent after prioritizingthe other treatment agent with better compatibleness.The basic formula is base mud+ 0.15%FA368+1.0%JM-1+0.5%NPAN+1.0%OSAM-K+0.1%JN-A.The formula hasgood reology， inhibitory characteristic， and its rolling recovery rate reaches86.55%.Its overall performance is good in the pollution of6%of bentonite or20%ofdebris, and it has better compatibility with slurry on site.We field tested the interface strengthening drilling fluid in XiDing5-P3well,Qian1-320-18well, Qian1-332-22well, Zhong362-32well and Zhong333-29well indifferent geological conditions of the5wells tested. The performance of drilling fluidis stable, cementing acoustic variable are all of high quality. The average cementintensity formed by interface strengthening drilling fluid acting on permeability coreis0.576MPa.The two interfaces strengthening average cement intensity formed bylow permeability core is0.76MPa, and the bond strength of interface formed by thetwo core is0.76MPa on average, They are both significantly higher than those inother drilling fluid, and it further proves that the interfacial reinforcing agent helps toimprove the quality of two interfaces cement.This paper studies on the impact of thetwo interfaces interface enhancer cementing quality has important theoreticalsignificance and application value for cementing quality. |
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