Managed Pressure Drilling (MPD) has been deployed in Vietnam for six (6) years since 2007 to address a number of drilling and reservoir challenges, and has delivered considerable success in many cases. Twenty five (25) separate projects have been performed over the six (6) year period, in a range of formations and with different types of rigs. The main application of MPD Technology has been in the following reservoir and formation types where the challenges are being encountered: granite basement, fractured and vugular carbonates, High Pressure High Temperature (HPHT) and over pressured clastics. MPD has not been applied as yet in deepwater, but its application is being viewed with interest by operators in Vietnam planning deep water operations, following its successful deployment in other regions of South East Asia. The types of rigs on which the technology has and is being applied are all offshore, and include Jack-Ups, Semi-Submersibles and a Platform rig supported by Semi-Submersible Drilling Tender Assist barge. The paper will examine and discuss the different procedural approach of MPD Technology used today including Constant Bottom Hole Pressure – Equivalent Circulating Density (ECD) management, Early Kick Detection, and Pressurized Mud Cap Drilling (PMCD). MPD has mainly been used in reservoir sections, but by no means exclusively, for example in carbonate loss zones which may or may not contain gas, for Rate of Penetration (ROP) gain and ECD management in intermediate hole sections. Three (3) case histories will be presented within the paper addressing the different applications and formations in which the technology has been applied in Vietnam. This includes achieving an additional 800 meters of a granite basement reservoir section, reducing the fluid losses, improving ROP, reduction of Non – Productive Time (NPT) and post drilling clean up, by 60 – 70%, compared with previous wells in the field. The drilling of HPHT and over pressured clastic formations with an extremely narrow kick – loss tolerance, where there is a high risk of fracturing the formation or inducing a serious kick, if the hydraulic profile of the well is not successfully managed. The pre-planning, engineering, equipment utilized, and adaption of the drilling rig to facilitate the successful deployment of MPD Technology will all be discussed, to clearly demonstrate what is required to deliver a successful MPD project and the well objectives.

Managed Pressure Drilling (MPD), with the installation of Rotating Control Device (RCD) and MPD Choke has been identified as an time saving value added technology to two different operators in Vietnam when mitigating well control situations. Conventional well control approach is to shut in the annular BOP and circulate out influx by using either the Driller's or Weight & Wait methods. However, these methods can only be used when the bit is on bottom and circulation is possible. In cases when it is unsuitable to use the standard well control methods, alternative such as: stripping to maintain BHP constant plus Volumetric to control gas migration to surface is considered. Referencing two HPHT wells drilled in offshore Vietnam with MPD equipment; both influxes were encountered when the bit was completely out of the hole and the other when the bit was halfway from bottom of the well. The operators used the RCD bearing assembly and the MPD Choke Manifold to strip the drillstring back to total depth and performed standard well control procedures. The MPD stripping technique allowed the operators to regain well control, enhanced operational safety and significant time savings. This paper will discuss the methodology of MPD well control techniques based on the experience from the two HPHT wells in Vietnam. The main objectives of the paper is to define, document, and develop workflows to successfully implement well control procedures using MPD in future HPHT wells.

A managed pressure drilling (MPD) and early influx detection system is gaining worldwide acceptance as an enabling technology for drilling wells with challenges that can lead to tremendous nonproductive time (NPT), significant unplanned costs, and increased risk exposure. MPD counteracts the high cost of these wells by delivering significant savings when eliminating fluid losses or well control events that cause NPT. MPD technology has proven that is used to not only reduce NPT but also enable access to reserves previously considered un-drillable. In this case history, MPD helped to reach reserves that could not be reached in the first well. Client planned to drill the well A, which is its second offshore exploration well. Early on in 2019, the campaign encountered significant problems because of high temperatures and a narrow pore-pressure/fracture-pressure (PP/FP) gradient window. Additionally, using conventional drilling methods in offset wells led to problems relating to kicks, loss scenarios, and stuck pipe. Before drilling the second exploration well, the relevant parties considered that the first well-presented multiple drilling issues, and they drew from past success. The latter job had ended with reaching all the well targets despite high-pressure/high-temperature (HP/HT) conditions using a continuous circulating device in conjunction with an MPD system. Therefore, this combination of technologies was chosen to drill the well A. The operator used the MPD system, from the start when drilling the 14 3/4-in × 16-in. hole section to the end when drilling the 8 1/2-in. hole section, in offshore Vietnam. Applying MPD technology on this well resulted in many benefits, including the main benefit of always controlling the bottomhole pressure through the challenging zones. MPD also helped to maintain the equivalent circulating destiny (ECD) and equivalent static density (ESD) during drilling, connections, and a logging operation to mitigate the risk of any gas breaking out at the surface and to drill the well to the desired target depth. This paper focuses on using MPD technology in conjunction with the continuous circulation system, in offshore Vietnam. It goes into detail by describing the experience and providing some of the lessons learned.

Managed Pressure Drilling (MPD) technology has effectively proven that it can overcome the operational obstacles encountered when drilling difficult and challenging wells. MPD has helped many operating companies reach target depth by accurately managing the annular pressure profile of the wells in which it is deployed. However, well construction operations do not stop when target depth is reached. The well still has to be cased, cemented, and completed in order to produce and returns the initial spend on these investments. In high-pressure, high-temperature (HPHT) well conditions where very narrow margins between the pore and fracture pressures are prevalent, conventional cementing operations become a complicated task. The tendency of inducing losses is very common, specifically during running of casing or liners, which is then further aggravated during the displacement of the cement slurry. This was the case in one of the HPHT wells in Vietnam where losses were encountered during previous liner running operations. This situation led the operating company to decide to utilize MPD technology to improve, enhance and optimize the cementing operation. Pre-modeling to determine the correct parameters and the utilization of MPD technology allowed the mud weight to be reduced while managing equivalent circulating density (ECD) through the application of surface backpressure (SBP) to stay within the limits of the well. The application of MPD closed loop cementing on this HPHT well proved effective and provided correct parameters to successfully complete the cementing operations. This paper will discuss the application of MPD closed loop cementing on this HPHT well in Vietnam. Specifically, it will examine the following: (1) reasons and concepts associated with MPD closed loop cementing; (2) MPD closed loop cementing pre-planning and engineering; (3) MPD closed loop cementing execution; (4) MPD closed loop cementing challenges; and (5) lessons learned and best practices. The paper will also detail how the MPD closed loop cementing technique can be further refined and improved to be able to address other pertinent concerns experienced by other HPHT operations in Vietnam, thereby realizing the full potential and impact that the technology can help bring about in terms of drillability, efficiency, and above all safety.

The paper discusses two gas condensate development projects in Vietnam, which have and are deploying Managed Pressure Drilling (MPD) Technology. Bien Dong POC in 2010 commenced planning for the Bien Dong 1 High Pressure High Temperature (HPHT) gas condensate development project offshore Vietnam, with bottom hole pressures of 15.2lb/gal - 17.2lb/gal, and with bottom hole temperatures in the range of 155 deg C - 180 deg C. With very narrow kick loss margins inside 0.5 lbs/gal, the probability of serious kick loss issues during the drilling of the reservoir sections looked to be very high. The Bien Dong 1 development is a complex HPHT project ranking one of the most difficult and challenging HPHT projects in Asia Pacific currently. As a remedy for such potential drilling hazards, Managed Pressure Drilling techniques and technology were selected, and implemented. This technology gives the option for accurate early kick detection and if required Constant Bottom Hole Pressure (CBHP) drilling coupled with ECD management. The second project which deployed MPD Technology is the gas condensate development for Cuulong JOC, with lower pore pressures than Bien Dong 1 the range of 12.5lb/gal - 14.0lb/gal but with bottom hole temperatures up to 190 deg C static. The paper will examine the following Reasons and conceptions to use managed pressure drilling technologyPreplanning and engineering of the projectManaged pressure drilling equipment adaption into a new build semi-submersible tender assist, quad mast rig, including modifications to the hook up of the 15K BOP stack and expanded mud gas separator systemImplementation of the project once the rig was on location in readiness to commence drilling the first wellRig crew familiarization and training in MPD techniquesAnalysis of the early results in the project