The Research and Application of Foam-Dewatering Technology in Xujiahe Gas Reservoir of Mid-Sichuan Gas Field

Xujiahe gas reservoir of mid-Sichuan gas field is one of the most important exploration and development area and the main supersede layer system. With the development of the gas reservoir, some wells of gas yield is lower produce unconventionally and some wells can only produce intermittently, because their water-unloading ability can't completely lift the formation water from the wells and accumulate in the downhole. In allusion to the character of high salinity, containing Ba²⁺ and condensate oil, we develop the foam-dewatering matched technology. We develop a CT5-7CⅢ foaming agent, which can bear high salinity, Ba²⁺ and condensate oil, and a water-solubility CT1-12A demulsifying agent that can break the emulsion quickly and entirely in environment temperature, can mix with the de-foaming agent. At the same time, we develop a spot application technology. Using these agents, we had made foam-dewatering field experiments in seven wells and de-emulsion field experiments in three gas stations, increase daily gas 2.8×10⁴m³ and formation water 40m³. The field experiments indicate that the foaming agent's characters of foam-dewatering are very well, the emulsion is broken quickly and entirely, and the spot technics is very predigest.