First Deployment of a New Integrated Expandable Under Reamer Technology With a Conventional Drilling BHA in a Vertical Well in KSA

Abstract

Abstract This paper presents and discusses the results of a field application where a new integrated expandable under reamer technology was deployed in the Uthmaniyah field located in Saudi Arabia. The wells in the Uthmaniyah field usually are vertical and high interface severity is encountered in hard Dolomite/Limestone intervals. Conventional directional drilling bottom hole assemblies (BHA) are deployed in these wells. This interface severity is likely to initiate axial and lateral vibrations causing bit and BHA damages. The 12¼-in. bore hole section of a Utmaniyah well was planned to be opened up to 14-in. For the first time in this field a new intelligent under reamer technology was used for the under reaming application. The new on-command digital, expandable under reamer is fully integrated into the BHA and can be monitored and controlled from the surface. The real-time feedback from the reamer includes tool vibration and stick slip (VSS) data, and confirmation of blade activation status and position, reducing operational uncertainty during reaming and saving time for a shoulder test. The under reamer tool has unlimited activation cycles that provide the capability of selective reaming. The flexible placement of multiple reamers in the BHA enables near-bit and main reaming applications, and a combination of both. When used for near-bit reaming service, the reamer can reduce the rat-hole length to 4 m, compared to an application where it is placed 40 to 70 meters behind the bit. Significant time savings can be achieved by eliminating the dedicated rat-hole run. In the mentioned application in the Uthmaniyah field the new reamer achieved a high rate of penetration and reliable hole enlargement across a long section containing Minjur formation in one run. The BHA was designed as a pendulum assembly to keep the borehole vertical with the reamer positioned 63 ft behind the bit. A second run was planned to eliminate the remaining 63 ft rat hole by repositioning the reamer below the Measurement While Drilling (MWD) and Logging While Drilling (LWD) suite, resulting in a final rat-hole of approximately 12 ft. The technology proved its effectiveness as a reliable main reamer as a part of conventional non-rotary steerable BHA in an interbedded hard formation with Dolomite/Limestone intervals. Drilling optimization services were utilized to illustrate and optimize weight distribution, minimize vibrations and match bit and reamer aggressiveness. The paper will summarize and describe the results and features in detail, and demonstrate how they can help the operators to reduce operational risks and save cost.