Field Results of a Real Time Drilling Fluid Monitoring System

Abstract

AbstractAn automated system was developed to determine some physical properties of the drilling fluid in real time during drilling operations. Rheology, density, electrical stability, total solids suspended and water in oil ratio were determined in real time during onshore drilling operation. This work presented the results obtained using the system, comparing it with data obtained by standard offline methods according to API. The first stage of the development was performed in laboratory where the monitoring container was connected to a fluid flow loop was built. Rheology was determined using an inline modified concentric cylinder viscometer. The device was capable of determining shear stress at different shear rates. Density was determined by a Coriolis device, electrical stability was calculated by a self-designed device built under API technical design, water in oil ratio was provided by electromagnetic means of a commercial device and total solids suspended was calculated using a developed material balance equation, which uses real time data of density and water in oil ratio as inputs. The entire system was assembled into a skid, fully automated and controlled by in house developed software, adequate to be transported and installed at rig sites. The second stage was to test the system in onshore rig sites in northeast of Brazil. With automatic control of flow rate and pressure, the system performed measurements in the rig site drilling fluid, pumping the fluid in and out of the system, operating as a bypass of the main pressurized drilling fluid flow line. The system reported data locally on a screen and transmitted to a remote operations center. Density, electrical conductivity, total solids suspended and water in oil ratio were provided at every second. Viscosity profile was provided every 30 min with calculation at 6 different shear rates, in accordance to API. Electrical stability tests were performed every 30 min with 1 min of duration. The developed system performed measurements properly in the onshore rig sites. All technical requirements for operational safety were met, as well as environmental and electrical hazard managed. Overall statistical deviations calculated between online and offline reference data reported were considered satisfactory. The system constitutes the most complete project for real time fluid monitoring properties in real time. Several fluid properties (electrical stability, water oil ratios) were measured online for the first time. These properties are a requirement for real time diagnosis software and an essential input for autonomous drilling projects.