Technology Focus: Drilling and Completion Fluids (November 2010)

Abstract

Technology Focus Last year, I wrote about the science-based approach to fluids and the increased level of knowledge required of drilling-fluids-related professionals. This year, I want to emphasize the importance of drilling and completion fluids in well control, lost-circulation mitigation, and wellbore stability. One of the first things you learn as a drilling engineer or rig supervisor is that the most important aspect in drilling is the drilling fluid (this may be a little biased coming from a fluids specialist). It is like the blood in our circulatory system! It serves many functions and can be either friend or foe, depending upon how it is maintained. The primary function of drilling or completion fluids is to control subsurface pressures. With the challenge of drilling in ever-increasing water depths and into higher-pressure and temperature reservoirs in the pursuit of hydrocarbons, this becomes even more important and more difficult to accomplish. Additionally, the fluid density required to control formation pressures often is very close to the fracture gradient, so that there is a delicate balance between well control and lost returns. Another issue to consider is the effect that fluids have on wellbore stability. With the increased complexity of the wells being drilled, higher fluid densities are needed to prevent the hole from becoming mechanically unstable, thus narrowing the “safe drilling window” between borehole stability and lost returns. Various techniques are used to address this issue. Factors such as formation type and characteristics, type of loss, and others should be considered when selecting the most appropriate solution. There is no “one size fits all” approach that works. The papers in this feature address issues in the preceding discussion. Please take time to read them along with the papers listed for additional reading. Drilling and Completion Fluids additional reading available at OnePetro: www.onepetro.org SPE 130413 • “Vital Role of Nanopolymers in Drilling- and Stimulation-Fluid Applications” by Subodh Singh, University of Oklahoma, et al. SPE 125708 • “Remote Real-Time Monitoring of Particle-Size Distribution in Drilling Fluids During Drilling of a Depleted HP/HT Reservoir” by Egil Ronaes, SPE, M-I Swaco, et al. SPE 130421 • “Utility-Calculation Method of New Four-Parameter Rheological Model for Drilling Hydraulics” by Guo Wang, China University of Petroleum, Beijing, et al. SPE 128405 • “Salinity-Based Pump-and-Dump Strategy for Drilling Salt With Supersaturated Fluids” by T.J. Akers, SPE, ExxonMobil