Dual gradient drilling: a pilot test of decanter centrifuge for CAPM technology

The article is about problem of drilling deepwater oil and gas wells that consists in complicating and increasing cost of their well design due to narrowing mud window at different depths. The authors analyse drilling technology developed and applied in practice of offshore drilling with a dual gradient drilling, which allows drilling significant intervals without overlapping an intermediate casing string. Based on analysis of these technologies and taking into account their disadvantages the authors proposed and tested a new drilling technology of dual gradient drilling with placement of all necessary innovative equipment on drilling platform. Keywords: managed pressure drilling; deepwater drilling; offshore drilling; dual gradient drilling; riser; oil and gas exploration in sea.

A History of 50 years Deepwater Drilling Activities in Indonesia (1968 - 2020)

Effort for overviewing deepwater drilling activities in Indonesia was done in 1992, which covered first activities back in 1968. However, no update since then and not many oil and gas practitioners are familiar with the history of deepwater drilling in Indonesia so far. Perhaps, this is due to less information and publications. Literature review and interview practitioners were performed to gather every information related to deepwater drilling activities in Indonesia particularly. In detail, the quantitative data which consist of 40 basins with deepwater environment and 276 drilled wells are presented in this paper. Overview of deepwater drilling activities both exploration and development projects on every basin with certain time periods are described. Moreover, the data is interpreted statistically to give a better understanding and enrich the historical overview. Finally, this research is providing comprehensive historical of deepwater drilling activities both exploration and development project in Indonesia for 50 years since 1968 to 2020. Nevertheless, the accuracy and completeness of the data can be improved for future study.

Cyberdefence of Offshore Deepwater Drilling Rigs

An alternative methodology using new preventative technology to manage cybersecurity exposure on deepwater drilling rig assets is presented. For the past two years Shell's Deepwater Wells business has been evaluating typical cyber defence approaches and undertaken cybersecurity risk assessments and penetration tests. These activities have demonstrated the challenges attaining cybersecure drilling rig environments. Whilst cyberattacks increase in frequency, adaptability, and become cheaper to launch, regulatory and liability insurance requirements are also evolving. To achieve the goal of cyber-resilience, a major Operator has collaborated with a cybersecurity firm to trial technology for rapidly and reliably protecting deepwater rigs. The paper presents aspects of the numerous challenges faced and offers a different approach using new technology applied to both supplement and accelerate the attainment of a cyber-resilient environment onboard deepwater drilling rigs. It shares the deep dive lessons learnt leading to a more comprehensive understanding of how to protect drilling rigs and their safety critical control systems. Aside from addressing technical attributes using risk vs. maturity based methods, the approach also caters to business demands of short term rig contracts, managing multi-vendor legacy systems and satisfying increasing digitalisation/remote access needs with associated reductions in overall cybersecurity CAPEX spend.

A Study on the Main Parameters That Affects the Reliability of Fatigue Failure in a Marine Drilling Riser

Advances in subsea exploration in the oceans to discover new petroleum reservoirs and sometimes different kind of minerals at the seabed in ultra deepwater, continuously introduce new challenges in offshore drilling operations. This motivates the development of increasingly safe maritime operations. In offshore petroleum, a marine drilling riser is the pipe that connects a wellhead at the sea bottom to a drillship at the sea surface, as an access to the wellbore. It serves as a guide for the drilling column with the drill bit and conductor to carry cuttings of rock coming from the wellbore drilling and its construction. Drilling riser is constantly exposed to adversity from the environment, such as waves, sea currents and platform motions induced by waves. These elements of the environment are prevailing factors that can cause a riser failure during deepwater drilling operations with undesirable consequences for the environment. In the present work, key parameters that influence the probability of fatigue failure in a marine drilling riser are identified, and a parametric evaluation with those parameters are carried out. Dynamic behavior of a riser is previously calculated and fatigue damage is estimated. Afterwards, the First Order Reliability Method (FORM) is applied to determine the probability of fatigue failure on the riser. Fundamentals of the procedure are described, and results are illustrated through the analysis for a typical riser in deepwater drilling operation. Parametric evaluations are done observing points considered as critical along the riser length, and looking to the sensitivity of key parameters in the process. For this study, the SN curve from API guidelines is applied and accumulated fatigue damage is estimated from simulations of the stress time series and applying the Palmgren-Miner’s rule. Finally, the influence of each parameter in the reliability of fatigue failure is verified and discussions given.

First MPD Project in Myanmar Successfully Completed on Deepwater Exploration Well

With the many challenges associated with Deepwater Drilling, Managed Pressure Drilling has proven to be a very useful tool to mitigate many hurdles. Client approached Managed Pressure Drilling technology to drill Myanmar's first MPD well on a Deepwater exploration well. The well was drilled with a Below Tension Ring-Slim Rotating Control Device (BTR-S RCD) and Automated MPD Choke System installed on semi-submersible rig, Noble Clyde Boudreaux (NCB). The paper will detail MPD objectives, application and well challenges, in conjunction with pore pressure prediction to manage the bottom hole pressure to drill to well total depth safely and efficiently. This exploration well was drilled from a water depth of 590m from a Semisubmersible rig required MPD application for its exploratory drilling due to uncertainties of drilling window which contained a sharp pressure ramp, with a history of well bore ballooning there was high potential to encounter gas in the riser. The Deepwater MPD package integrated with the rig system, offered a safer approach to overcome the challenges by enhanced influx monitoring and applying surface back pressure (SBP) to adjust bottom hole pressures as required. Additionally, modified pore pressure hunting method was incorporated to the drilling operation to allow more accurate pore pressure prediction, which was then applied to determine the required SBP in order to maintain the desired minimum overbalance while drilling ahead. The closed loop MPD circulating system allowed to divert returns from the well, through MPD flow spool into MPD distribution manifold and MPD automated choke manifold system to the shakers and rig mud gas separator (MGS). The automated MPD system allows control and adjustments of surface back pressure to control bottom hole pressure. MPD technology was applied with minimal overbalance on drilling and connections while monitoring on background gases. A refined pore pressure hunting method was introduced with manipulation of applied surface back pressure to define this exploration well pore pressure and drilling window. The applied MPD Deepwater technique proved for cost efficiency and rig days to allow two deeper casing setting depths and eliminating requirement to run contingency liners. MPD system and equipment is proving to be a requirement for Deepwater drilling for optimizing drilling efficiency. This paper will also capture detailed lesson learned from the operations as part of continuous learning for improvement on Deepwater MPD drilling.