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DEMO2000-Prosj.ret tekn.utv. petro.virk

At-the-Bit Mud Loss Control - well piloting of a new drilling tool to combat severe mud losses by converting mud to a downhole pill.

Alternative title: At-the-Bit Mud Loss Control - pilotering av det nye boreverktøyet for å håndtere store slamtap ved å omgjøre boreslam til nedihulls pille.

Awarded: NOK 3.8 mill.

Project Number:


Application Type:

Project Period:

2022 - 2023


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Curing severe mud loss during drilling is a big challenge to the oil industry. Todays solutions are time consuming and costly. The At-the-Bit Mud Loss Control innovation include down hole technologies for on-demand and instant treatment of such losses. The key features of the new tool involve down hole storage and release of a highly swellable granular mixture that swells around 60 times when exposed to drilling mud. The current solution is tailor made for use together with water based drilling fluids. The development project is in Phase 4 for well piloting and qualification. The petroleum industry recognize the high value potential related to safe and cost efficient drilling and reduced logistics. Two well pilots were conducted during phase 4 as planned. The first pilot was carried out at the Catoosa Test Facility in Oklahoma during the summer/fall of 2022. Drilling was performed with all the At-the-Bit components along with a commercial Bottom Hole Assembly (BHA) consisting of a PDC-bit, Rotary Steerable System (RSS), and Measurement While Drilling (MWD) tools. The pilot's objective was to demonstrate the drillability and functionality upon activation of the polymer-release tool. The well was drilled as planned, designed as a high-deviation well, penetrating various geological formations with high Dog Leg Severity (DLS). It was demonstrated that the tool components can withstand downhole loads, vibrations, temperatures, and pressures. The tool was activated as scheduled after 10 days of drilling operation, but the swellable granular polymer mixture was only partially released from the At-the-Bit tool in the borehole. This was due to that the granular polymer mixture was forming a bridge and lead to tool plugging. Based on the experiences from the well pilot in Catoosa, a new flow diverter was designed and manufactured for further piloting in Oman. This flow diverter, along with the other At-the-Bit components, was successfully demonstrated in a functional commercial oil well in Oman in May 2023. In parallel, efforts were made to modify the granular polymer mixture to improve the displacement.

The At-the-Bit Mud Loss Control technology has been successfully demonstrated through two well pilots in Oklahoma and Oman. The first pilot was demonstration of drilling a highly deviated well and activation of downhole tool. The second pilot demonstrated a further development of the downhole tool in a commercial well. As a result of these two pilots interest for further use of the technology has been confirmed from the JIP members. This relates to drilling in potentially lossy formations at NCS, Oman and deep water Brazil. The value potential of the technology as a service has been proven through business cases. The business impact is related to reduced NPT, less logistics costs and environmental footprint. In addition, new hydrocarbon reserves may be unlocked which are not drillable with todays technologies. Infill drilling in mature and depleted fields is one important application of this technology.

The At-the-Bit Mud Loss Control technology aims at on-demand and instant downhole solution for treatment of severe and total mud loss. The circulating drilling mud will be converted downhole to a swelling pill by use of a super absorbent polymer. A special designed superabsorbent polymer has been developed for use in water based mud (WBM) together with suitable carrier fluids. The tool prototype consists of several components inserted as a part of the drillstring. From top to bottom, the tool assembly consists of; pressure compensator, flow diverter (ball operated), dual pipe concentric polymer carriers, release sub and ball catcher. The total length of the tool is around 30 m and is located above bottom hole assembly (BHA). The polymer with carrier fluid payload is around 400 litres which will give a downhole pill of around 12 cubic meters when fully swelled. The prototype has been functionality tested both at the yard and in an experimental well at the EnergyX and Xrig facilities at Ålgård outside Stavanger during a DEMO2000 project (2020-2021). This new application is a continuation for well piloting in oil wells. A one year program is anticipated with two pilots. This will include onshore wells in USA and the Middle-East. The R&D challenges include the investigation of the drillability of the innovations with use of concentric dual casing tubulars. Also, finding appropriate well candidates to demonstrate the sealability of lossy formations needs much attention in the well planning phase. The thief zones may include both natural and induced fractures. Karstified carbonate formations may give special challenges with potential high mud losses.

Funding scheme:

DEMO2000-Prosj.ret tekn.utv. petro.virk