No abstract

Sulfate-reducing bacteria (SRB) corrosion is the main type of corrosion that occurs when steel for transportation gas pipeline (X70) passes through the soil.Based on the actual corrosion data of hanging pieces in an engineering site and SRB preparation liquid experiments, the corrosion characteristics of X70 pipeline steel under the action of SRB were studied, and the safety of gas transmission pipelines was evaluated. The weight-loss method and scanning electron microscope analysis method were being used. According to the industry standards, the SRB biofilm protection efficiency was selected as the evaluation index to analyze the pipeline safety capabilities. The research results are as follows: (1) Considering the main control factors for SRB, it is found that the corrosion behavior of X70 steel was related to biofilms, SRB metabolism and the formation of corrosion products; (2) the railway crossing section had the highest degree of corrosion, and the areas adjacent to it were also seriously corroded. There was a certain connection between stray current and SRB corrosion, so as to determine the promotion effect of stray current on SRB corrosion. The processing capability was assessed to be severely insufficient, requiring and corrosion and pressure resistance tests. In engineering, high-performance materials or temporary coatings can be used, but targeted microbial control based on the SRB corrosion mechanism has greater engineering value.

In this paper, the problems of high refrigerant line differential pressure and uneven distribution of cold energy in cold box regulation under C3-MR process are studied. Five reasons are predicted by engineering performance. Using gas chromatography experiment and grey system pure mathematics analysis, it is determined that the main causes of the problem are unreasonable distribution ratio of each group of mixed refrigerants and disordered latent heat of vaporization of refrigerants. Furthermore, the grey system model is used to study: 1. grey relation analysis model shows that the correlation degree of T3 temperature measuring point is 0.8552, which is the only main factor. The abnormal working condition is determined by the project to be caused by incorrect proportion of N2 components. 2. According to GM(1,N) model, the driving term of T3 temperature measuring point is 3.8304, which needs to be supplemented with N2 component to eliminate the problem. 3. After adding N2 to 10% (mol component), abnormal working conditions disappeared. The GM(1,N) model is used again to verify that the difference of driving results is small, the average relative error is 24.91%, and the accuracy of the model is in compliance.

The development process of oil and gas fields is affected by engineering and geology. Reservoir damage is significant as a bridge connecting these two disciplines. The life cycle of oil and gas fields can be prolonged by making development plans that consider reservoir damage. Therefore, this study performed experiments and discusses a Cretaceous reservoir development in the Chun17 block of the Chunguang Oilfield. We have carried out five sensitivity experiments on typical cores from the block, and analyzed lithology, physical properties, and crude oil. A mathematical model based on the Analytic Hierarchy Process (AHP) was then established based on the core data.Overall, the reservoir in the study area has ultra-high porosity and high permeability. The reservoir has moderately strong water sensitivity (damage rate is 38 ~ 90%) and moderately strong alkali sensitivity (damage rate is 22 ~ 75%). The crude oil belongs to extra-heavy oil reservoirs (containing 2.43% wax, 0.96% sulfur, 20.25 m% gum, 7.35 m% asphalt, 38.26 m% saturated hydrocarbon, and 27.51 m%). The crude oil is sensitive to temperature changes. Based on the AHP model analysis, the development scheme chooses the third (weight 0.1757) of the conventional analytic results of AHP; the Thermal oil production C1 scheme has the most stable future trend and appears to be the best option. In the next step, using fire flooding technology to develop the reservoir will benefit the most economically. The workflow consisting of "conclusion of reservoir experiment → AHP mathematical modeling → verification of relative permeability of high-temperature oil and water → verification of trial production" is simple and effective. The findings of this study can help to better understand the idea and process of making development plans for sensitive oil and gas fields through reservoir evaluation. Combining experimental data with mathematical modeling can find a balanced combination point in qualitative and quantitative analysis. Whether this combination point is correct can be verified by field engineering practice.

No abstract