Abstract
Since Conductor Sharing Technology became prominent in the 1990s, the technology has evolved to accommodate the associated well design and construction complexities. In the redevelopment of Brownfield "S", under an alliance between PETRONAS Carigali and other operator, the technology has enabled the number of potential new wells to be increased. However, the technology has been constrained in terms of the available conductor and casing size options. The objective is to advance the current technology to meet the well design and construction requirements.
This paper presents the challenges and solutions for conductor sharing technology to accommodate a higher specification conductor (36"×1.5" wall thickness), which is required to meet the fatigue life requirement in Field "S" Phase 3 redevelopment project. Since mid-2018, when PETRONAS took over the operatorship, further conductor analyses have been required. These studies confirmed the requirement for 36" conductor with 1.5" wall thickness, to meet the target fatigue life of 20 years. This paper focuses on a range of key engineering considerations related to well construction including geometrical separation, integration between CWD (casing while drilling) and directional, cementing, and diverter requirement to CWD surface casing.
Since there is no existing system that can accommodate this wall thickness and still be able to meet the well construction requirements, a collaboration with the equipment provider has led to the design and manufacture of the world's first splitter wellhead system used for 36" (1.5" WT) × 13-3/8"(2X) × 9-5/8"(2X) × 3-1/2"(4X) with 10,000 psi working pressure rating. The splitter wellhead has allowed two infill wells to be drilled and completed on Platform "A". The system has maximized oil recovery with the additional well. The successful installation and production from this wellhead provide opportunity to reduce construction cost and maximize utilization of existing well slots for future development of brown fields.
The improved technology has created more value by allowing surface casing to be installed by CWD in directional sections and the cementing program to be enhanced under diverter system. This solution will be beneficial to similar brown fields which have limited remaining slots and where it is unjustifiable to construct a new platform. In addition, it provides opportunity to lower the wellhead platform cost for green fields by optimizing the number of well slots and platform design.
Water Well Design and Construction