Using Real Time Fluid Properties Data in Providing Accurate Results for Managed Pressure Drilling and Improved Drilling Control

摘要

Narrow mud windows often cause a lot of trouble when using conventional drilling techniques due to the difficulty of maintaining the bottomhole pressure between the maximum pore pressure and minimum fracture pressures of the exposed formations. This can lead to wellbore influx, formation damage and fluid loss. Managed pressure drilling (MPD) is an adjustable drilling technique that will help balance and maintain the annulus pressure, within a desired margin. Using MPD will enhance drilling performance, reduce nonproductive time (NPT), and increase safety. Operators usually acquire fluid property measurement by either PVT analysis to account for downhole effect of pressure and temperature on density and rheology, or using experimental lab data with downhole fluid properties. These measurements are used to calculate the equivalent circulating density, and control surface back pressure (SBP) via MPD surface choke. Acquiring real-time downhole data for fluid properties like density and rheology, at a high frequency, will lead to precise calculations of the equivalent circulating density (ECD), and the annular frictional losses. Real-time monitoring of ECD and pressure drop allows for optimal control over the annular pressure throughout the drilled section, which in turn reduces the risk of kick occurrence and lost circulation. Satisfactory results were achieved with the use of real-time data in MPD; where no stuck pipe or well control incidents were recorded. In this paper, we will demonstrate the steps taken to obtain real-time data measurements of the properties and the operational details that led to improved performance of MPD.