一种稠油热采井用抗硫套管试验研究

为了保证稠油热采井工况下石油套管的性能，采用低碳Cr-Mo钢和V、Ti等元素微合金化的设计，利用纯净钢冶炼技术，并配合适当的“高频电阻焊+热张力减径+热处理工艺”的生产工艺，设计出了一种稠油热采井用抗硫套管。对试制套管的几何尺寸、力学性能、高温性能、腐蚀性能等进行了检测分析。结果表明:试制套管的几何尺寸精度高，椭圆度≤0.25%，壁厚不均度≤6%；强韧性匹配好，具有较高的高温强度和低的线膨胀率，在350 ℃高温时屈服强度折损率≤15%，拉伸强度折损率≤10%，线膨胀率≤15%；抗硫化氢应力腐蚀性能优异，依据NACE TM 0177标准中A法A溶液，在加载496 MPa应力下H2S应力腐蚀720 h后试样不开裂；同时，还具有优异的抗外压挤毁和内压至失效性能。

Study on a H2S Stress Corrosion Resistance Casing for Heavy Oil Thermal Recovery Wells

In order to ensure the performance of casing in heavy oil thermal recovery wells, a new kind of casing product with sulfur stress corrosion resistance for heavy oil thermal recovery wells was developed by using low carbon Cr-Mo steel-based chemical composition, micro-alloying with addition of V and Ti, adoption of clean-steel metallurgical technology and appropriate production process on the basis of high frequency electrical resistance welding and forming-hot stretch reducing-heat treatment technology. The performances were tested and analyzed such as geometry dimension, mechanical properties, high temperature performance, linear expansion coefficient and sulfide stress corrosion cracking and so on. The results show that the geometric size of the trial casing product is accurate, less than 0.25% in ovality and less than 6% in eccentricity. The casing has high strength and toughness, good high temperature strength and low linear expansion rate. At 350 ℃, the yield strength loss rate is less than 15%, the tensile strength loss rate is not more than 10%, the linear expansion rate is lower than 15%. Excellent， hydrogen sulfide stress corrosion resistance was proved by experiment that the specimen loaded about 496 MPa stress by using a method has no crack after 720 h in a solution according to NACE TM 0177 standard. And it has also excellent practical properties of some full-length casing like bursting and collapse.