Successful Application of Managed Pressure Drilling MPD Technology to Reach TD in a Narrow Margin HPHT Well in the North Sea – A Case History

2021 ◽  
Author(s):  
Babar Kamal ◽  
Emil Stoian ◽  
Graeme MacFarlane
Keyword(s):  
Pore Pressure ◽  
North Sea ◽  
Back Pressure ◽  
Lessons Learned ◽  
The North ◽  
Pull Out ◽  
Bottom Hole ◽  
Managed Pressure Drilling ◽  
Integrity Tests ◽  
Remedial Work

Abstract This paper reviews the recently concluded successful application of a Managed Pressure Drilling (MPD) system on a High-Pressure High-Temperature (HPHT) well with Narrow Mud Weight Window (NMWW) in the UK sector in the Central North Sea. Well-A was drilled with the Constant Bottom Hole Pressure (CBHP) version of MPD with a mud weight statically underbalanced and dynamically close to formation pore pressure. Whilst drilling the 12-1/2" section of the well with statically under-balanced mud weight, to minimize the overbalance across the open hole, an influx was detected by the MPD system as a result of drilling into a pressure ramp. The MPD system allowed surface back pressure to be applied and the primary barrier of the well re-established, resulting in a minimal influx volume of 0.06 m3 and the ability to circulate the influx out by keeping the Stand Pipe Pressure (SPP) constant while adjusting Surface Back Pressure (SBP) through the MPD chokes in less than 4 hours with a single circulation. After reaching the 12-1/2" section TD, only ~0.025sg (175 psi) Equivalent Mud Weight (EMW) window was available to displace the well and pull out of hole (POOH) the bottom hole assembly (BHA) therefore, 3 × LCM pills of different concentrations were pumped and squeezed into the formation with SBP to enhance the NMWW to 0.035sg EMW (245 psi) deemed necessary to kill the well and retrieve BHA. MPD allowed efficient cement squeeze operations to be performed in order to cement the fractured/weak zones which sufficiently strengthened the well bore to continue drilling. A series of Dynamic Pore Pressure and Formation Integrity Tests (DPPT and DFIT) were performed to evaluate the formation strength post remedial work and to define the updated MMW. Despite the challenges, the MPD system enabled the delivery of a conventionally un-drillable well to target depth (TD) without any unplanned increase/decrease in mud weight or any costly contingency architecture operations, whilst decreasing the amount of NPT (Non Productive Time) and ILT (Invisible Lost Time) incurred. This paper discusses the planning, design, and execution of MPD operations on the Infill Well-A, the results achieved, and lessons learned that recommend using the technology both as an enabler and performance enhancer.

First MPD Project in Myanmar Successfully Completed on Deepwater Exploration Well

2021 ◽  
Author(s):  
Harpreet Kaur Dalgit Singh ◽  
Bao Ta Quoc ◽  
Benny Benny ◽  
Ching Shearn Ho
Keyword(s):  
Pore Pressure ◽  
Control Device ◽  
Back Pressure ◽  
Deepwater Drilling ◽  
Hole Pressure ◽  
Bottom Hole Pressure ◽  
Bottom Hole ◽  
Managed Pressure Drilling ◽  
Pore Pressure Prediction ◽  
Exploration Well

Abstract 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.

1300 Tons Grouted Integrity Support Installation Case Study

2020 ◽  
Author(s):  
Beatriz Alonso Castro ◽  
Roland Daly ◽  
Francisco Javier Becerro ◽  
Petter Vabø
Keyword(s):  
North Sea ◽  
Structural Integrity ◽  
High Strength ◽  
Regulatory Compliance ◽  
Lessons Learned ◽  
Oil Field ◽  
The North ◽  
Future Production ◽  
Heavy Lift ◽  
The North Sea

Abstract The North sea Yme oil field was discovered in 1987, production started in 1996 and ceased after 6 years when it was considered no longer profitable to operate. In 2007 a new development was approved, being Yme the first field re-opened in the Norwegian Continental Shelf. The concept selected was a MOPUStor: comprising a jack-up unit grouted to a subsea storage tank. Due to compromised structural integrity and lack of regulatory compliance that came to light shortly after installation, the platform was required to be removed [1]. The remaining riser caisson and the future 1050 t wellhead module required a support to allow the re-use of the facilities and tap the remaining oil reserves. The innovative tubular frame support was designed as a braced unit, secured to the existing MOPUstor leg receptacles and holding a grouted clamp larger than typical offshore clamps for which design guidance in ISO is available. The existing facilities had to be modified to receive the new structure and to guide it in place within the small clearances available. The aim of this paper is to describe the solutions developed to prepare and verify the substructure for installation; to predict the dynamic behavior of a subsea heavy lift operation with small clearances around existing assets (down to 150 mm); and to place large volume high strength grouted connections, exceeding the height and thickness values from any project ever done before. In order to avoid early age degradation of the grout, a 1 mm maximum relative movement requirement was the operation design philosophy. A reliable system to stabilize the caisson, which displacements were up to 150 mm, was developed to meet the criteria during grouting and curing. In the stabilizer system design, as well as the plan for contingencies with divers to restart grouting in the event of a breakdown, the lessons learned from latest wind turbine industry practices and from the first attempt to re-develop the field using grouted connections were incorporated. Currently the substructure is secured to provide the long term integrity of the structure the next 20 years of future production in the North Sea environment.

Drilling the Un Drillable: A Case Study of the Bela Well in Makran Accretionary Prism

2021 ◽  
Author(s):  
Umair Ahmed Baig ◽  
Ghulam Nabi Agha
Keyword(s):  
Pore Pressure ◽  
Accretionary Prism ◽  
Well Being ◽  
Lessons Learned ◽  
Planning Stage ◽  
Lost Circulation ◽  
Hole Pressure ◽  
Bottom Hole Pressure ◽  
Fracture Pressure ◽  
Bottom Hole

Abstract The Bela Well is situated on Makran accretionary prism with several active mud volcanoes that makes conventional drilling challenging due to the extremely high pore pressure i.e. in excess of 15,000 psi and a very narrow window between pore pressure and fracture pressure. This adverse condition was observed in the 9 offset wells drilled within this basin with problems related to wellbore instability, lost-circulation zones and over-pressured formations leading to kick/loss well control scenarios that resulted in the well being abandoned prior to reaching the geological target. The constraint to drill the planned and 8-3/8" section in the well was the unpredictability of the pore/fracture pressure in the Panjgur formation representing a high-level operational risk. Solutions to tackle such a high pressure well included incorporating heavy grade casing i.e. 9-7/8"- 72 ppf in the planning stage, utilization of a 3000 HP rig to cater to extreme axial and hydraulic loads. Whereas MPD was planned as a technique to cater to the narrow window between pore pressure and fracture pressure. A managed pressure drilling (MPD) system was utilized to enable drilling the 8-3/8" hole section. An MPD system that applies constant bottom hole pressure enabled drilling the section with statically underbalanced mud weight by keeping a constant surface back pressure to prevent any influx. The drilling window for MPD was validated by determining the Bottom Hole Pressure where both, an influx from the formation and fluid losses occurred. These values were later used to establish the target Equivalent Circulating Density-ECD to drill the hole accordingly. Trips for BHA change or BOP test were performed by placing a pressurized mud cap in the wellbore. This paper describes in detail the successful MPD application resulted in the first well being drilled in the Makran accretionary prism to a depth of 5000 m. Lessons learned and challenges encountered will also be discussed in this paper

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