Publications

Nowadays, gas field development is playing an important role in the petroleum industry to produce lower carbon emission in supporting energy transition era. Drilling execution is part of the process, to construct the well to produce oil and gas from earth to surface where drilling operators are currently competing to minimize additional emissions due to non-productive time (NPT). For drilling with jack up rigs, punch through failure comes as one of the most frightening risks apart from shallow gas blow out or blow out. The operation to recover from a Punch Through incident will extend planned days, increase carbon emissions and drag the company further from its net zero carbon emission optimization resolution. Although rig placement in a green field with limited historical data may increase its likelihood, the effort to minimize this occurrence should start early in the planning phase. After the soil characteristic is obtained through geotechnical survey in the intended location, the Leg Penetration Analysis (LPA) for jack up rig is conducted to further identify Punch Through risk. The uncertainty of rig to be used for a long future campaign, which shall comply to procurement regulation in accordance with the country’s “Cost Recovery Scheme”, will consequently compound the said risk. Initiating jack up rig market survey is the key driver to observe and anticipate the available rig specification for future drilling campaign. From the market survey, the LPA sensitivity analysis is conducted with obtainable multiple rig spudcan properties i.e. spudcan area, effective diameter, elevation of tip below widest section, etc., as well as other rig specifications i.e. maximum preload and lightship dimension, and can be referenced to reduce risk rating and determine the best way forward. This paper will analyse the green gas field case study where jack up rig data analysis results in avoidance of possible rapid leg penetration at port leg as the load approaches critical values. It will also provide a flow process to manage potential punch through risk as a practical guideline, and combating anticipated emission by applying mitigations in jack up rig operation for front-end well engineering.