Research on deepwater synthetic drilling fluid and its low temperature rheological properties

With the rapid development of deepwater drilling operations, more and more complex technical challenges have to be faced due to the rigorous conditions encountered. One of these challenges is that the drilling fluid used must had good rheological properties at low temperatures and high ability to inhibit hydrate formation. Synthetic drilling fluid has been widely applied to deepwater drilling operations due to its high penetration rate, excellent rheological properties, good ability to prevent hydrate formation, and high biodegradability. A synthetic drilling fluid formulation was developed in our laboratory. The rheological properties of this drilling fluid at low temperatures (0-20 °C) were tested with a 6-speed viscometer and its ability to inhibit hydrate formation was evaluated at 20 MPa CH₄ gas and 0 °C by differential scanning calorimetry (DSC). Several factors influencing the low temperature rheological properties of this synthetic drilling fl uid were studied in this paper. These included the viscosity of the base fluid, the amount of CEMU and organic clay, and the water volume fraction.