Support technologies for the clean drilling prodution in Sulige Gasfield

In order to satisfy the requirements of clean drilling in the Sulige Gasfield, the key equipment suitable for drilling fluid and no landing drilling cuttings treatment process are developed, and a complete set of construction process and operation flow for no landing of drilling fluid are established, so as to avoid the environmental pollution caused by the leakage of drilling fluid. In addition, a kind of natural macromolecular environmental drilling fluid is developed. It is non-toxic (biotoxicity EC₅₀ 17.4×10⁵ mg/L) and can be biologically degraded easily (BOD₅/COD≥0.05) and its other indicators satisfy the requirements of environment protection. In this way, the qualified environmental performance of the drilling fluid can be guaranteed from the very beginning. What’s more, the solid-liquid separation and recycling technology for waste drilling fluid is developed. And it has been applied to 400 wells. And its application alleviates the environmental pressure of ecologically weak areas and the pressure of fresh water shortage in the Sulige Gas Field.