Modern drilling technologies enable to complete tremendous borehole trajectories, despite well control risks and unpredicted sticking issues. Nevertheless when it comes to formation sampling the development wells and deviated drains are excluded from the program due to high risk of getting stack with heavy logging suit. The high costs of rig time nowadays practically exempted drilling the pilot holes for PVT sampling acquisition and to reduce rig time as much as possible. Therefore, new technologies are demanded to enhance formation testing (FT) and sampling in deviated hole while mitigating the risks of getting stuck.

The Sirikit and Suphanburi fields are in different provinces of Thailand and usually required the complete set of open hole logging suit, including formation pressure and sampling. However some deviated sections are usually experiencing high wash out and solids key seating where no tools could pass through using the standard wireline (WL) conveyance technique. The only viable option in those cases is to run in hole with slim FT through drillpipe logging (TDL), that allow slimmer WL suits conveyance through drillpipe open-ended bottom hole assembly.

The slim FT is a 2.4" outer diameter (OD) tool with pump out and sampling capabilities. The tool was already tested in several jobs with WL and shows reliable results. Three wells with 8.5" section and up to 47 deg wellbore deviation were selected for testing the sampling TDL. This was a first trial as such in the entire Asia Pacific region. The end of drillpipe was positioned around 50m below the high inclination and dogleg severity zone to prevent WL from key seating. Once WL tool ran through drillpipe and engaging openhole, the entire string was moved to the pressure testing and sampling stations. Maximum allocated time of one hour per depth was sufficient for successful fluid identification and sampling. Due to articulated centralized design with single point contact with formation, no differential sticking or cable key seating were experienced during operation. The downhole real time monitoring was completed using the basic capacitance and resistivity sensors, which enable appropriately, distinguish between formation water and hydrocarbons during pump out and sampling. The sampling bottles were extracted on surface and verified the collected oil. The results of all cases were successful and fit for purpose.

Drilling deviated development wells are a world-wide established practice, however no slim sampling tool were available through bit. Drilling deviated wells are a world-wide established practice that post challenge to WL formation testing and sampling operation. The successful combination of through drillpipe logging method with slim formation testing and sampling WL tool opens the new horizon solutions for evaluation of the hydrocarbons in place without need to drill the pilot holes or redrill the damaged section.

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