Successful Application of Deepwater Dual Gradient Drilling

Ziegler, Robert F.; Ashley, Paul; Malt, Roar; Stave, Roger; Toftevåg, Kjell Rune

doi:10.2118/164561-ms

Cited by 13 publications

(3 citation statements)

References 1 publication

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“…The experience from first use of EC-Drill in 3 deepwater wells in GOM where this method was used [7] [8] confirmed this. Several studies have been performed by independent 3 rd parties to fully understand and evaluate the potential and inherent risks to personnel and structures.…”

Section: Gas In Evacuated Risermentioning

confidence: 85%

Drilling Depleted Reservoirs using Controlled Mud Level Technology in Mature Subsea Fields

Fossli

Stave

2014

All Days

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Many subsea fields on the NCS are now entering maturity. As reservoir pressure declines, this inherently introduces significant well construction and well delivery challenges. Wells are the biggest driver for increased recovery. Depletion and increased formation pressure heterogeneity in mature fields are driving costs and slowing well delivery. For fields developed with fixed platforms, conventional pressurized Managed Pressure Drilling (MPD) techniques developed on land has been used for some time to combat these challenges. For floaters with subsea Blow Out Preventers (BOPs) and Low pressure marine drilling risers in harsh environment, other technologies are needed. EC-Drill is a new technology developed by AGR Enhanced Drilling specifically for floaters which will regulate the drilling fluid level in the marine riser in order to manage the wellbore pressures. A subsea mud pump is connected to the marine drilling riser and is used to manage the fluid level within the riser up or down. The drilling fluid is pumped back to surface from a lower level on the riser so that the hydrostatic pressure in the wellbore can be managed more effectively. This also enables using conventional mud weight to drill depleted reservoirs. The technique also allows for precise control of wellbore pressures and enables drilling with close to constant bottom hole pressure. The technology will ensure improved hydraulics which can result in; improved hole cleaning, higher rate of penetration, improved casing/liner cementing, less downtime (NPT) due to formation pressures heterogeneity and longer horizontal sections may now be drilled in depleted reservoirs, etc.This paper discusses the challenges related to drilling in depleted reservoirs and outline the new drilling technique that is available to solve these and other drilling challenges on the Norwegian Continental Shelf (NCS).

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Section: Gas In Evacuated Risermentioning

confidence: 85%

Drilling Depleted Reservoirs using Controlled Mud Level Technology in Mature Subsea Fields

Fossli

Stave

2014

All Days

Self Cite

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“…Controlled annular mud level (CAML) technology is an extension of RMR technology and is used after the installation of riser pipes and blowout preventer assemblies [13]. This technology can detect kick and leakage earlier and achieve controlled pressure cementing [14,15]. It has been successfully used in Brazil and the Mediterranean offshore as well as in the North Sea, the Barents Sea, and other seas.…”

Section: Introductionmentioning

confidence: 99%

Research on the Stability of the Spacer Fluid Interface in Dual-Layer Pipe Dual-Gradient Drilling

Wang,

Li,

Zhong

et al. 2023

Processes

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Dual-layer pipe dual-gradient drilling technology is an emerging technology for solving the problem of the narrow safety density window in deepwater drilling. The unstable spacer fluid interface in this technology directly affects the dual-gradient pressure system in the annulus, causing changes in the drilling mud performance and affecting the control of bottom hole pressure and rock removal with drilling mud. Therefore, the key to the stable operation of dual-layer pipe dual-gradient drilling technology is to maintain the stability of the spacer fluid interface. Based on this, a seawater-spacer fluid-drilling mud annular flow model was established in this study, with a bottom hole pressure control step of 0.2 MPa, and the spacer fluid height after a single control was used as the evaluation index to study the influence of annular flow velocity, the spacer fluid properties, and the drill string rotation speed on the stability of the spacer fluid interface. The results show that in the determined conditions of the seawater and drilling mud system, the annular fluid flow rate and the physical parameters of the spacer fluid are the main factors affecting the stability of the spacer fluid interface. When the annular fluid flow rate increased within the range of 0.04~0.2 m/s, the liquidity index of the spacer fluid increased between 0.5 and 0.9, the consistency coefficient increased in the range of 0.6 to 1.4 Pa⋅sn, and the stability of the spacer fluid interface decreased. However, the stability of the spacer fluid interface increased with the increase in its density in the range of 1100~1500 kg/m3. The results obtained in this study can provide a reference for selecting the operating parameters to ensure the stable operation of dual-gradient pressure systems.

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“…Here we refer to a common definition of the karst, introduced to describe the landscape, which contains caves, underground channels, and other features associated with soluble rocks [2]. Encountering karsts while drilling can cause critical safety incidents including uncontrollable losses of drilling fluid and gas kicks as reported in speciality reports [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Real-Time Detection of Karstification Hazards While Drilling in Carbonates

2022

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The nature of carbonate deposition can cause the development of unique geological features such as cavities and vugs called karsts. Encountering karsts while drilling can lead to serious consequences. To improve drilling safety in intervals of karstification, it is important to detect karsts as early as possible. The use of state-of-the-art geophysical methods cannot guarantee early or even real-time detection of karsts or karstification zones. In this paper we demonstrate, based on an analysis of 20 wells drilled in karstified carbonates in the Barents Sea, that a karst that is dangerous for drilling is often surrounded by one or more other karstification objects, thus forming a karstification zone. These zones can be detected in real time through certain patterns in drillstring mechanics and mud flow measurements. They can serve as indicators of intervals with a high likelihood of encountering karsts. The identified patterns corresponding to various karstification objects are summarized in a table and can be used by drilling engineers. Apart from that, these patterns can also be utilized for training machine learning algorithms for the automatic detection of karstification zones.

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Successful Application of Deepwater Dual Gradient Drilling

Cited by 13 publications

References 1 publication

Drilling Depleted Reservoirs using Controlled Mud Level Technology in Mature Subsea Fields

Drilling Depleted Reservoirs using Controlled Mud Level Technology in Mature Subsea Fields

Research on the Stability of the Spacer Fluid Interface in Dual-Layer Pipe Dual-Gradient Drilling

Real-Time Detection of Karstification Hazards While Drilling in Carbonates

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