| As the development of oil and gas exploration constantly goes deeper, the oil and gas fields with high content of sulfur are getting more and more. Most of Chinese natural gas resources contain H2S, Sichuan’s gas field is a typical sour gas field. As there are a lot of corrosive environments in the exploitation process of gas field and more than70%gas wells are sour wells, most of oil fields will encounter many problems in the development process, for example, the sour corrosive mediums such as H2S and CO2in the ground layers will influence the sealing effect of oil and gas well’s cement sheath. These sour corrosive mediums will at first corrode the cement sheath column, and then corrode and damage the casing fast.Based on the grain composition technology, this paper remixes the class G cement with micro-cement by the sand with particle sizes of80mesh,120mesh and160mesh separately. The influences of mixing amount, particle size and grading way of sands on the comprehensive performances of anticorrosion cement slurry are discussed in detail, the anticorrosion cement slurry system with the best comprehensive performances is developed, the comparative study of anti-H2S corrosion performance of anti corrosion cement stone and common class G grade cement stone is done, and the changes of the appearance, corrosion depth and compressive strength are determined. The microstructure and composition of the cement stone after corrosion is analyzed by SEM and X-ray diffraction. The results show that the anticorrosion performance of cement stone obviously improves by using the technology of anticorrosion cement slurry system based on grain composition.The anticorrosion cement slurry system in this paper is successfully applied in the cementing construction of Yuanba drilling liner of Sichuan’s Northeast Yuanba area, which effectively controls the pollution of H2S, reaches the original design objective and has a broad promotion prospects. |
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