本文選題：連續(xù)油管 + Ni-W合金鍍層�。� 參考：《西安石油大學(xué)》2015年碩士論文

【摘要】：模擬某油田腐蝕環(huán)境,通過高溫高壓腐蝕試驗(yàn)和實(shí)物機(jī)械疲勞試驗(yàn),采用金相顯微鏡、SEM和EDS等現(xiàn)代分析手段,結(jié)合QT-900連續(xù)油管“入井—空氣中放置—再次入井”的實(shí)際作業(yè)過程,分析了Ni-W合金鍍層對連續(xù)油管理化性能的影響,研究了H2S和CO2共存環(huán)境下連續(xù)油管在井下不同井段的腐蝕行為和CO2環(huán)境下Ni-W合金鍍層對連續(xù)油管耐蝕性的影響,并探討了在H2S環(huán)境下連續(xù)油管和Ni-W合金鍍層的抗SSC性能。研究結(jié)果表明:連續(xù)油管的組織主要為珠光體和多邊形鐵素體。與基體連續(xù)油管材料相比,Ni-W合金鍍層中Ni和W元素的含量較高,Fe元素含量較低,外壁鍍層厚度平均值為54.0μm,內(nèi)壁鍍層厚度平均值為98.0μm,鍍層與基體結(jié)合良好。Ni-W合金鍍層對連續(xù)油管的拉伸性能影響不大,但是能顯著提高連續(xù)油管的硬度和疲勞壽命。疲勞失效的Ni-W合金鍍層油管的裂紋均起源于表面鍍層,裂紋逐漸貫穿鍍層,最后擴(kuò)展至基體。刺口附近裂紋較為密集,距刺口350mm處裂紋較為稀疏。模擬井口(即井深0m)、1500m、3300m和4400m,對應(yīng)H2S分壓分別為0.020MPa、0.030MPa、0.037MPa和0.040MPa,CO2分壓分別為0.97MPa、1.10MPa、1.24MPa和1.33Mpa的腐蝕環(huán)境進(jìn)行不同井段腐蝕規(guī)律研究,結(jié)果表明,井下油管腐蝕是應(yīng)力和環(huán)境介質(zhì)綜合作用的結(jié)果。一次入釜試驗(yàn)后,連續(xù)油管在1500m井段腐蝕最嚴(yán)重,局部腐蝕速率達(dá)到4.4627mm/a,腐蝕產(chǎn)物主要為Fe S和Fe CO3的混合物。二次入釜導(dǎo)致連續(xù)油管腐蝕明顯加劇,試樣表面腐蝕產(chǎn)物Fe S含量明顯降低,局部腐蝕產(chǎn)物膜脫落嚴(yán)重,平均腐蝕速率達(dá)到1.5549mm/a,約為一次入釜的3倍,屬于極嚴(yán)重腐蝕。模擬CO2分壓為1.07MPa、溫度為60℃、加載拉應(yīng)力為439MPa的腐蝕環(huán)境研究Ni-W合金鍍層的耐蝕性能,結(jié)果表明,Ni-W合金鍍層顯著提高了連續(xù)油管的耐CO2腐蝕性能,鍍層油管的平均腐蝕速率為0.0160mm/a,約為普通連續(xù)油管的1/40,屬于輕度腐蝕。在H2S應(yīng)力腐蝕標(biāo)準(zhǔn)試驗(yàn)中,連續(xù)油管和鍍Ni-W合金層油管表面均出現(xiàn)裂紋,未通過抗SSC性能檢測。
[Abstract]:In order to simulate the corrosion environment of an oil field, by means of high temperature and high pressure corrosion test and physical mechanical fatigue test, modern analysis methods such as metallographic microscope, EDS and so on are used. The effect of Ni-W alloy coating on the physical and chemical properties of QT-900 continuous tubing was analyzed. The corrosion behavior of continuous tubing in different well sections under the co-existence of H _ 2S and CO2 and the effect of Ni-W alloy coating on the corrosion resistance of continuous tubing under CO2 environment were studied. The anti-SSC properties of continuous tubing and Ni-W alloy coating in H _ 2S environment were also discussed. The results show that the structure of continuous tubing is mainly pearlite and polygonal ferrite. Compared with the coiled tubing material, the content of Ni and W in Ni-W alloy coating is higher than that in coiled tubing material. The average thickness of outer coating is 54.0 渭 m, while the average thickness of inner coating is 98.0 渭 m. The coating has little effect on the tensile properties of coiled tubing, but it can significantly improve the hardness and fatigue life of coiled tubing. The cracks of fatigue failure Ni-W alloy coated tubing originated from the surface coating, and the cracks gradually penetrated through the coating and finally spread to the substrate. The cracks near the spines are denser than those near the 350mm. The corrosion law of different well sections in the simulated wellhead (I. e., the depth of the well is 0. 0mm / 1500mN 3300m and 4400m respectively) corresponding to the partial pressure of H _ 2S is 0.020 MPA / m ~ (0.030) MPA and 0.040 MPA / m ~ (2) CO _ 2 is 0.97 MPA / 1. 10 MPA and 1.24 MPA / 1.33Mpa respectively. The results show that the corrosion of tubing is the result of comprehensive effect of environmental medium and stress. The corrosion rate of continuous tubing was 4.4627mm / a after the first test in 1500m well, and the corrosion product was mainly the mixture of Fe S and Fe CO3. The corrosion of the coiled tubing was obviously aggravated by the secondary reactor, the content of Fe S on the surface of the sample was obviously decreased, and the local corrosion product film fell off seriously. The average corrosion rate was 1.5549 mm / a, about 3 times of that of the primary autoclave, and the corrosion was extremely serious. The corrosion resistance of Ni-W alloy coating was studied under simulated CO2 partial pressure of 1.07MPa, temperature of 60 鈩，

本文編號：1926177