Investigation of service life and corrosion mechanism of tubing in production well on polymer flooding

Abstract

The corrosion behaviour and the remaining safe service life of tubing in simulating production well of polymer flooding in Xinjiang oilfield which located in China was investigated using weight loss measurement and surface characterisation. The results showed that as the chloride ion concentration, temperature and H 2 S content increased, the corrosion rate of N80 steel gradually increased in the hydrolysis of anionic polyacrylamide (HPAM)/H 2 S/CO 2 environment. The tubing of production well met the requirements of oilfield in polymer flooding. The corrosion scales had two layers: the outer O-rich layer and the inner S-rich layer. The chloride ion concentration and temperature affected the location and the thickness of the S-rich layer. The corrosion scales of N80 steel were composed of FeS, FeS 2 , FeCO 3. Polyacrylamide adsorbed on the surface of steel to form a network film blocked the contact between metal and solution and then inhibited the anodic dissolution of metal.

Effects of silty sand and pH on the formation of corrosion film and corrosion behaviour of low-Cr steel in the CO2 environment

“…As observed, all polarisation curves showed that the corrosion process was controlled by anodic reaction. Compared to no obvious distinction of corrosion potential among different conditions, the wide potential domain occurred in the anodic process, and an active current peak appeared, which was related to the formation of Cr oxides [21,22]. The potential domain of 1Cr steel without silty sand was the lowest.…”

How to Choose the Suitable Steel of Wellhead, Wellbore, and Downhole Tools for Acid Gas Reinjection Flooding

“…According to the weight-loss corrosion rate and pitting corrosion rate, the remaining corrosion life calculation model of tubing is established [33][34][35]. The core idea of the theory is that when the remaining wall thickness reaches its minimum allowable wall thickness, the service time of the tubing is its finite life.…”

Insight into polymer concentration, temperature, CO2 content, and Cl− content on corrosion of N80 steel tubing in polymer flooding

“…Moreover, the corrosion factors of tubing in polymer flooding production wells also include wellbore temperature, CO 2 content, and Cl − content. [11][12][13][14] As is well known, temperature plays an important role in the process of tubing corrosion. [15][16][17] Generally, scholars have proposed that the corrosion rate peak is usually between 80°C and 90°C in CO 2 corrosion where the temperature accelerates the reaction process and increases the corrosion rate of bare steel at the initial stage of corrosion.…”