REDUCING COMPLETION FAILURE RISK IN THE SLIM HOLE WORLD USING FPWD TOOLS

摘要

Shell continues to push the LWD slim hole envelope at its Gulf of Mexico Brutus field with world firsts by running Sperry Sun’s 4 ?” GeoTap FPWD (Formation Pressure While Drilling) and Rotary Steerable tools. Developing slim hole technology is critical in fields such as Brutus with only an eight slot TLP and field redevelopment limited primarily to a slim hole (5 ?” casing) environment. In addition, acquiring pressures to identify differentially depleted layers in completion intervals is critical to completion integrity. Acquiring formation pressures while drilling has become the method of choice to acquire pressures in highly depleted sands while minimizing borehole exposure and cost by eliminating wire line runs and wiper trips.The GeoTap/Quad combination was used on four wells at Brutus. In the A-3 well, with 6000 psi overbalance, 11 pressures were acquired to identify a differentially depleted layer within the J2 interval. Data acquired was used to modify the completion interval to reduce the failure risk associated with differential depletion. The well was cased and completed with no issues and has performed above expectations. In the A-7 wells FPWD/Quad evaluation strings were run and fifteen pressures were acquired. No differential depletion was observed and the entire zone was completed and is producing as expected. The A-5ST3 well was also drilled and evaluated with an FPWD/Quad and 20 pressures were acquired. Formation pressure data while drilling was used to modify mud weights, evaluate zones for possible uphole recompletions, and confirm the presence of differential depletion. As with the A-3 well, the FPWD data was used to modify the completion interval and the well has performed above expectations.Over the course of four slimhole FPWD runs at Brutus, numerous advancements in operational procedures have been implemented. These include the use of three versus two drawdowns to reduce or eliminate minor supercharging, along with monitoring the difference between pumps-on versus pumps-off pressure acquisition, which indicated a difference of less than one psi in Brutus type (half-Darcy to Darcy unconsolidated Plio-Pliocene) sands. This knowledge enabled the team to acquire high quality data, reduce the risk of sticking the BHA, and increase hole cleaning while continuously circulating.