Well testing provides useful data for reservoir characterization during various stages of field life, from exploration, development to production. The key information that are typically can be obtained are, information on reservoir properties, deliverability, and pressure data. However, if the data acquisition during the well testing is compromised it can also lead to incorrect data and could lead to a wrong understanding of the reservoir and could results in sub-optimal field development. Therefore, it is important to emphasize on the quality of the data being acquired. This paper captures the experiences gained for a high-pressure-high-temperature (HPHT) exploration well DST where data acquisition was compromised in the 1st well drilled in the structure. A combination of temperature transient effect and tubing movement in the well during shut in resulted in data quality which can't be interpreted with confidence. The lessons learnt from the same was captured and addressed successfully in the subsequent well which enabled quality data acquisition. The objective of this paper is to share the challenges and mitigation strategies for a HPHT DST with the help of two DST operation where the challenges resulted in less-than-optimum data quality and the one where they were mitigated. The range of challenges came from planning, to gauge placement, to identify potential problems early, and even having proper contingency plans to cater for unplanned events. The paper also deals with some of the best practices which can help with any DST program. Key examples are pre-job modeling, accurate temperature measurement and modeling, real-time data acquisition, and a special focus on sampling as a part of a successful DST program. Disclaimer All parameters cited in this paper are purposely made in ambiguous manner to maintain confidentiality of the data.

HPHT wells are typically associated with high complexity, technically challenging, long duration, high risk and high NPT as many things could go wrong especially when any of the critical nitty- gritty details are overlooked. The complexity is amplified with high risk of losses in carbonate reservoir with high level of contaminants compounded by the requirement of high mud weight above 17 ppg during monsoon season in an offshore environment. The above sums up the challenges an operator had to manage in a groundbreaking HPHT carbonate appraisal well which had successfully pushed the historical envelope of such well category in Central Luconia area, off the coast of Sarawak where one of the new records of the deepest and hottest carbonate HPHT well had been created. This well took almost 4 months to drill with production testing carried out in a safe and efficient manner whereby more than 4000m of vertical interval was covered by 6 hole sections. With the seamless support from host authority, JV partners and all contractors, the well was successfully delivered within the planned duration and cost, despite the extreme challenges brought about by the COVID-19 pandemic. This paper will share the experience of the entire cycle from pre job engineering/planning, execution and key lesson learnt for future exploitations.

HPHT wells are typically associated with high complexity, technically challenging, long duration, high risk and high NPT as many things could go wrong especially when any of the critical nitty- gritty details are overlooked. The complexity is amplified with high risk of losses in carbonate reservoir with high level of contaminants compounded by the requirement of high mud weight above 17 ppg during monsoon season in an offshore environment. The above sums up the challenges an operator had to manage in a groundbreaking HPHT carbonate appraisal well which had successfully pushed the historical envelope of such well category in Central Luconia area, off the coast of Sarawak where one of the new records of the deepest and hottest carbonate HPHT well had been created. This well took almost 4 months to drill with production testing carried out in a safe and efficient manner whereby more than 4000m of vertical interval was covered by 6 hole sections. With the seamless support from host authority, JV partners and all contractors, the well was successfully delivered within the planned duration and cost, despite the extreme challenges brought about by the COVID-19 pandemic. This paper will share the experience of the entire cycle from pre job engineering/planning, execution, key lesson learnt and optimization plan for future exploitations which includes an appraisal well and followed by more than a dozen of development wells.

This paper deals with the lessons learned during the completion design for a HPHT gas field (Field-X) offshore Sarawak, Malaysia. It is a carbonate reservoir with more than 500 meters of the gas column containing between 6-10 tcf of OGIP making it one of the major discoveries in recent years in this region. However, the combination of HPHT and the presence of about 18% CO2 and 2% H2S in the gas makes it a complex development, particularly for well and completion design. To address the challenges associated with the development of this field, a taskforce was formed with personnel from all relevant disciplines to come up with an appropriate design that can help produce from this reservoir safely. The project is now in the detailed design phase where the final aspects of the completion designs are being formulated. Considering that this will be one of the first development in this area with this combination of reservoir conditions, it is expected that the lessons learned from this project will support other future developments too. The paper discusses lessons learned during the design process specifically related to material selection for the highly sour environment, temperature modeling, identification of annulus pressure envelopes and their management, perforation philosophy, and surveillance methods for both reservoir management and well integrity. Another aspect which affects the overall well and completion philosophy for a complex development is the challenges associated with procurement and component qualification. At this stage, the key issues are being identified and will be briefly covered in this paper.