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HELMS Completed a Challenging Kasawari Campaign in Offshore Sarawak

HELMS Completed a Challenging Kasawari Campaign in Offshore Sarawak

Miri, 18 April 2022 – Helms Geomarine Sdn Bhd (HELMS) has successfully completed a geotechnical pipeline route survey campaign for PETRONAS’ Kasawari carbon capture and storage (CCS) project. This will be one of the largest CCS projects in the world with a capability of capturing around 3.5 million tonnes of carbon dioxide annually. The field development plan includes laying a new 135 km carbon steel pipeline that would be built to transport the CO2 to the M1 field.

The geotechnical pipeline route survey was performed using a gravity mode CPT (gCPT) and gravity corer, dropped along the proposed pipeline route from a 60m vessel called MV Tegas Tara. A total of 47 gravity cores and 47 gravity CPTs (gCPTs) were performed over a period of approximately 11 days at water depths ranging from 110m to 140m.

The gCPT system was supplied by TDI Brooks (TDI) of Texas, USA together with TDI’s experienced CPT Operator, Brian Scherer who flew in from Houston to Miri to provide supervision for the installation, operation and data acquisition of the gCPT. The gravity corer is HELMS owned equipment fitted with 300kg weights and 4m core barrel.

All CPT data processing were performed at TDI’s data centre in College Station, Texas by a team of CPT experts led by Dr. Bernie Bernard who developed the innovative gCPT system. The purpose of the Gravity CPT tool is to transport a piezocone penetrometer down to the seabed to gather dynamic PCPT cone data from the mudline to typically 3m below the mudline. In addition to its 300-kg driving head with lifting bale and coupling, the rig comprises a self-contained PCPT cone penetrometer that measures tip resistance, sleeve friction, and pore pressure using standard ASTM cone protocols.

The gCPT system is deployed using the same winch, pedestal crane, and process as for piston coring. When about 5m above mudline, the tool is triggered by a freefall winch like a piston corer to ballistically insert itself into the soil. Once the cone insertion into the soil is complete, the system is immediately retracted from the seabed and retrieved to the deck. Cone data are downloaded from the probe for evaluation and analysis.

CPT Specialist, Nazrin Ridhwan said, “The gCPT was selected to be deployed on this project as the end user was specifically looking for soil data at 0m to 0.5m below mudline which can only be achieved via a free fall system. Any seabed CPT deployment will cause a loss of data due to the immediate settlement of the seabed CPT unit. By using the free fall dropping mechanism, any disturbance by the placement of a heavier Seabed CPT is totally avoided and this is particularly of significance when the seabed is found to be generally very soft to soft in consistency at almost all testing locations.”

The number one challenge coming from this project was the enormous difficulty in obtaining Local Work Permits (LWP) for the non-Sarawakian crew. The delay and uncertainty of obtaining the LWPs in time forced HELMS to embark on a localization initiative to train Sarawakian technicians to perform the operation with guidance from Brian Scherer of TDI and HELMS senior personnel. In addition, innovative shore support solutions were introduced, made possible via the vessel’s high-speed internet connection, to overcome the LWPs limitations.

This campaign not only marks HELMS’ first project carried out under the 3-year offshore soil boring contract with PETRONAS, but also a showcase of HELMS’ ability as an offshore geotechnical solution provider.