RTP管在高压含硫油气环境下的应用

Application of RTP Pipe in High Pressure Sulfur Environment

非金属增强热塑性塑料复合管(RTP)在西部油气田应用中处于高压高含硫工况。为明确RTP管在高压含硫环境下的应用效果,针对服役前后RTP管高密度聚乙烯(PE-HD)内衬层材料和涤纶纤维增强材料,开展形貌分析、理化性能分析及服役后样品的承压性测试。试验结果表明,PE-HD和涤纶纤维在高压含硫环境下服役后外观和结构成分均发生了一定变化,抗拉强度显著降低。服役后PE-HD与原始样品相比硬度和氧化诱导温度也有所下降,热失重存在一定差异,维卡软化温度变化不大。油气田高压含硫服役环境对PE-HD内衬层和涤纶纤维有溶胀作用,大分子分子链和次价键作用减弱,导致材料部分性能有所降低,但服役后RTP管的整体承压性仍能满足标准要求。建议RTP管在高压含硫油气环境中应用时内衬层材料应选用耐油气介质溶胀和渗透性能更好的材料,如交联聚乙烯(PEX)或聚偏氟乙烯(PVDF)等。

Non-metallic reinforced thermoplastic composite pipe(RTP)serviced in western oil and gas fields suffers conditions of high pressure and high sulfur content.In order to clarify the application effect of RTP pipe in high pressure and sulfur environment,the morphology analysis,physical and chemical properties analysis and pressure test of samples after service were carried out for the lining material of high density polyethylene(PE-HD)and polyester fiber reinforced material of RTP pipe before and after service.The test results show that the appearance and structural composition of PE-HD and polyester fibers have changed and the tensile strength have decreased significantly after service in high-pressure sulfur-containing environment.After service,the hardness and oxidation induction temperature of PE-HD also decreased compared with the original sample.There was a certain difference in thermal weight loss,and the Vicat softening temperature did not change much.PE-HD and polyester fibers are used as the lining layer and reinforcing layer of RTP pipe,respectively.The high-pressure sulfur-containing service environment of the oil and gas field has the swelling effect on the PE-HD lining layer and polyester fiber,and the macromolecular chain and the secondary bond are weakened,resulting in a decrease in some properties of the material.However,the overall pressure bearing capacity of the RTP tube after service can still meet the standard requirements.It is suggested that the lining material of the RTP tube in the high-pressure sulfur-containing oil and gas environment should be selected with materials with better swelling and permeability of the oil and gas medium,such as cross-linked polyethylene(PEX)or polyvinylidene fluoride(PVDF).