刘振通 1庄建山 1郭文猛 1宋元洪 1习胜利 1和建勇1
作者信息
摘要
Abstract
Well PN-0085 is one gas well which is located at Block EL ROBLE, in ANACO Oil and Gas Field, Venezuela. In the third section of ?311.2 mm borehole, the density of oil-based drilling fluid is 1.48 g/cm3, and the safe density window of drilling fluid is narrow. During the drilling of this section, multiple sets of high-pressure gas reservoirs and leakage zones were dilled from top to bottom, and serious leakage and overflow happened frequently. As a result, the drilling of the third section was completed by carrying out plugging and killing simultaneously. Then, ?244.5 mm intermediate casing was run to the depth of 3 127.13 m. During the circulation after the casing was run to the bottom, serious gas invasion and overflow happened. In this situation, well killing of low displacement was carried out and after 13 cycles of circulation with choke, the density of drilling fluid was adjusted to 1.51 g/cm3and the fragile balance was established, but the tendency of mud loss occurred in the borehole. Considering the complicated borehole situation that overflow and leakage coexisted, a series of measures were taken to complete the well cementing operation, such as taking sodium silicate as the cementing prepad to prevent and control leakage and improve the interface bond strength, applying dual-cementing, dual-density, an-ti-gas channeling and invasion cement slurry system, conducting low displacement operation, and waiting on cement with the wellhead annulus closed, etc. It is shown from the cementing inspection results that the top of cement slurry reaches the designed height and the cementing quality is good, satisfying the cementing requirements of gas wells.关键词
固井/高压/井漏/防气窜/静胶凝强度/硅酸钠/前置液Key words
cementing/cement slurry/mud loss/anti-gas channeling/static gel strength/sodium silicate/prepad fluid分类
能源科技
