RESEARCH AND APPLICATION OF CEMENTING TECHNOLOGY IN BAKE OILFIELD

Bake oilfield of Tuha has a low formation pressure and bottom hole temperature, its formation is easy to collapse. So lost circulation easily occurred during cementing to pollute oil/gas formation; And back pressure can not be applied when cement solidifies so that oil/gas emits outside casing after cementing. After laboratory experiment, the formulation system of lightweight conduct cement slurry, retarded cement and accelerated cement were optimized and corresponding measures were taken. No lost circulation, large flow resistance and oil/gas emitting outside casing occurred after experiment in 12 wells. The high grade rate for intermediate casing is 83.3%,for production casing is 100%, increased 47. 7% and 48. 8% compared to pre - experiment respectively. Not only was cementing qualityimproved, but more important, prevented payzone from belng polluted,