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The Influx Management Envelope (IME) assists in identifying influx conditions which could compromise the primary well barrier and fluid handling capacity on surface. IME boundaries are influenced by changes in parameters such as mud weight, wellbore depth and geometry, pump rate, surface pressure, etc. Thus, any changes to these parameters will change the acceptable influx volume and intensity for Dynamic Influx Management. It is, therefore, critical to understand how changes in each of these variables affect IME limits so that its validity can be established within parameter ranges, rather than only for discrete values.
This work presents an in-depth discussion of how IME limits are determined, with both detailed philosophical and practical guidance on methods to calculate the surface and subsurface limits. Recent deepwater applications of the IME are used to represent baselines for presenting methods of calculating IME limits, including a basic single bubble approach, through to the most robust approach of including transient, multiphase simulations. Parameter sensitivity analyses are performed to determine reasonable ranges for which an IME is valid, with the goal of understanding the required IME update frequency during operation.
Gabaldon, O. R. (Blade Energy Partners) | Brand, P. R. (Blade Energy Partners) | Culen, M. S. (Blade Energy Partners) | Haq, I. U. (Blade Energy Partners) | Gonzalez-Luis, R. A. (Blade Energy Partners) | Silva, T. Pinheiro Da (Blade Energy Partners) | Puerto, G. (Blade Energy Partners) | Bacon, W. (Blade Energy Partners)
The Influx Management Envelope (IME) proposed by Culen et al. (2016) is an advanced, innovative way to assess influx conditions in Managed Pressure Drilling operations, offering an improved tool for the decision making process. This work presents the process of developing the IME concept on a real deepwater MPD operation for the first time. Limiting factors such as: shoe integrity, maximum surface pressures, and mud gas separator (MGS) flow rates (gas and liquid) have been taken into consideration in the process of developing a set of Influx Management Envelopes for three different hole sections. Two methods were used for developing the IMEs: Single bubble approach, as described by Culen et al.; and hydraulic modeling using a commercial transient, multiphase flow simulation software package. A comparison of the results from the single bubble calculation versus simulation methods is presented, highlighting the impact of gas dissolution and dispersion on the manageable influx volumes in MPD. Additionally, the IME design process includes provision for advanced alternatives for safe handling and removal of influxes within the limits of the primary barriers and those of the surface equipment.
To safely plan and execute MPD Influx Control operations, the limits of the primary barrier envelope must be communicated and understood. These safe operating limits have historically been represented with an MPD Operations Matrix. More recently, the development of the Influx Management Envelope (IME) has provided a means of communicating the primary barrier limits with improved accuracy and clarity. However, the generation of the IME currently requires performing a series of complex well control simulations with specialist engineering support. Because drilling operations are dynamic in nature, a practical method to generate the IME boundaries at the wellsite is required so that changes to mud weight, flowrate, surface and bottom hole circulating temperatures, trajectory, and bit depth can be accounted for, and the IME kept up to date.
This paper describes the development of a novel tool to quickly and automatically generate IMEs at the wellsite without the need for sophisticated modelling software and specialist personnel. The single bubble derivation that was originally presented by Culen et al was analysed further to obtain a more accurate and explicit relationship rather than an implicit one, which forms the basis for the calculations. The IME can be updated based on any well parameter changes, which allows field engineers to maintain an up to date and accurate IME throughout MPD operations.
Gabaldon, Oscar (Blade Energy Partners, Ltd.) | Gonzalez Luis, Romar (Blade Energy Partners, Ltd.) | Brand, Patrick (Blade Energy Partners, Ltd.) | Saber, Sherif (Blade Energy Partners, Ltd.) | Kozlov, Anton (Blade Energy Partners, Ltd.) | Bacon, William (Blade Energy Partners, Ltd.)
In high pressure high temperature (HPHT) reservoirs and exploratory wells, especially in deep water, there is a higher degree of uncertainty, which can increase the operational costs due to non-productive time (NPT) and operational problems due to the unpredictable nature of these wells. For these challenging wells with narrow windows, Managed Pressure Drilling (MPD) techniques offer cost-effective tools to increase the odds for achieving well and cost objectives assurance. There are significant benefits from early implementation of MPD in the project life cycle. These benefits include from improving operational efficiency to risk mitigation and safety enhancement. However, there is an enormous potential that many operators have been missing. This is related to the incorporation of MPD as a driver in optimizing the well design, which could greatly increase the possibilities of reaching target depth, and potentially prepare to eliminate one or more casing strings. Current well design process hinges on the ability to manage uncertainties by company or regulatory requirements, such as kick tolerance and safety factors. This work addresses the value added from implementing MPD in early stages in the project life cycle through the analysis of case studies. The cost savings from the impact on the well design are also discussed. This work also presents a in depth discussion on the benefits, and enablers of this approach. Furthermore, it presents considerations by taking advantage of dynamic processes facilitated with MPD. Finally, new guiding criteria to aim to constitute a systematic and integrated approach to ensure well integrity and optimize well design while also considering the operational implications and integral cost benefits is proposed to the industry. This paper represents the initial phase of a compressive long-term project to integrate two main components of well design. These are MPD adaptive well design, and statistical analysis based on variations of load and/or strength.
Managed Pressures Drilling (MPD) offers the capability to detect very small influxes when compared to using conventional rig equipment. Furthermore, the potential exists to control and circulate out the influx with the MPD equipment, without shutting in and performing conventional well control. When executed appropriately, this approach to managing an influx represents a higher degree of safety and enormous cost savings. However, managing an influx with MPD, particularly when a subsea BOP is in place, is quite different to conventional well control. A critical part of implementing MPD is to ensure that there is a clearly defined procedure for determining when MPD influx management must cease, and well control be initiated.
A typical approach, regulated in some regions and voluntarily followed in others, is to create an MPD Operations Matrix before the operation begins, which outlines procedures that should be followed based on identifiable parameters following an influx. This matrix clearly identifies when it is appropriate to carry on with normal MPD operations, perform specific MPD influx control strategies, or shift to conventional well control. Forming the MPD Operations Matrix, however, can be challenging and has frequently been created inappropriately for the situations in which its use is intended. Development of a good understanding of how the well pressures and flow rates behave during MPD influx management is critical to ensuring a seamless handover between MPD influx management and Well Control.
In this work, extensive transient multiphase simulation is used to demonstrate the sensitivity of surface pressures to well, drilling and influx characteristics and their resulting importance in the development of an operations protocol. Particular attention is given to influx volume, intensity and dispersion within a water based drilling fluid. Also considered are multiple wellbore geometries with primary focus on deepwater applications, oil based drilling fluid, pump rate and drilling fluid density and rheology. Where possible, findings are validated using recorded field data.
This paper discusses and defines the transition between MPD influx management and conventional well control. The key parameters for calculating the boundaries of MPD influx management are determined and a protocol developed for smooth handover to well control operations. The protocol enables guidance to varying levels of influx management ranging from full influx detection and removal using the MPD equipment, to assisted shut in.