Drilling in High-Density and Thin-Pressure-Windows Complex Formation

摘要

Super-high pressure gas fields in Tarim Oilfield mostly lie inrnthe area of Tianshan mountains. The upper cap rock of theserngas fields is salt gypsum formation which is deeply imbedded,rnthis salt gypsum formation contains not only many differentrnpressure systems but also soft mudstone and salt-water bedrnwith super-high pressure, 80 percent of all accidents andrncomplex situations take place in this section. Tarim Oilfieldrnarranges well Dina-11 in Dina structure in order to change thisrnadverse situation; all results and achievements during drillingrnoperation are as follows:rn1) Drill through salt gypsum formation about more thanrn1,000 m, and salt-water bed with super-high pressurern2) Drill through two low pressure formation with underbalancedrndrilling technologyrn3) Perform 16 times of blocking leakages operation withrnhigh density drilling fluid successfullyrn4) Perfect well control technology for super-high pressurerngas reservoirrn5) Find Dina gas field finallyrnConsummate the drilling technology for Shanqian structurernand reduce the possibility of accidents and complex situations,rnquicken the speeds of exploration and development throughrndrilling operation in well Dina-11