Lab study on hyperhaline cationic polymer drilling fluid for deepwater drilling

The condition of deepwater drilling is very complicated. If the natural gas hydrate is formed in the drilling fluid, the fluid can not be circled normally thus resulting in the increase of drilling time. For this problem, the study has optimized the hyperhaline cationic polymer drilling fluid for deepwater drilling by a lot of experiments. This system is formulated with 20%NaCl as hydrate inhibitors, high molecular weight polymer as flocculant, low molecular weight polymer as clay inhibitor, and combining with fluid loss control agent, viscosifier, lubricant and so on. The lab test results show that it performs good rheology capability and high antipollution capability as well as the high inhibition and good reservoir protection capability. At the same time, it can inhibit the gas-hydrate formation at low temperature effectively to meet the requirement for deepwater drilling.