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Lost Circulation: Challenges and Solutions

20 – 22 May 2014

Dubai, UAE | Hilton Dubai Jumeirah Resort

Technical Agenda

Session 1: Geological/Operational Perspective

Session Chairs: John Cook, Schlumberger; Phil Green, Occidental Oil and Gas International

Lost circulation is a problem that has been with us since the dawn of the petroleum industry, and continues to plague us. A number of factors in the past 20 years have generated increased attention on lost circulation—the need to drill into or through depleted reservoirs, increasing use of non-aqueous drilling fluids, the ever-rising cost of rig time, a growing focus on well integrity, the availability of new fluid additives and mechanical remedies, and the development of engineered solutions to the problem, such as the various wellbore strengthening techniques.

This session will set the stage for the detailed discussions of the workshop. The session discussion will include: geological environments where we expect lost circulation problems, the role of previous production and depletion, primary and secondary effects of lost circulation, and the impact of lost circulation on field planning and development.

Session 2: Physics, Mechanics and Chemistry of Lost Circulation

Session Chairs: Alexandre Lavrov, SINTEF Petroleum Research; Fersheed Mody, Apache Corporation

Mitigation of lost circulation requires a good grip on both  the mechanisms that play a central role in generating induced fractures or re-opening of existing fractures, along with the various  mechanisms that assist in healing these losses, be it mechanical plugging, chemical sealing, etc. Lost circulation is a multi-physics phenomenon and a result of complex interplay between physical, rock mechanical, and chemical processes. Drilling fluid can be lost into porous media or fractures. In addition, new fractures can be created when drilling above the fracture gradient. The objective of this session is to provide an overview of our current understanding of lost circulation mechanisms in different types of rocks: high-permeability, vugular, depleted, and naturally-fractured with low matrix permeability. Understanding these mechanisms is essential for our ability to tailor solutions that are effective in particular formations.

Session 3: Diagnosis and Data Collection

Session Chairs: Rob Elder, DNO International; Sharath Savari, Halliburton

With lost circulation being one of the major contributors to drilling non-productive time (NPT), any efforts spent on understanding the factors that lead to it would translate to tremendous savings (in terms of time and money). This exactly is the purpose of this session. The topics of this session include the different signs of lost circulation that can be monitored on surface at a very early stage. Well-known methods as well as others being left out or ignored in the field which could be considered as a potential sign might also be included. Current formation characterisation techniques and data that would help identify a potential lost circulation zone, and tag it as reservoir or non-reservoir zones well in advance would also be discussed. Finally, with information from the potential signs of lost circulation and formation information, we may discuss the best use of this information for better planning of LCM and other solutions.

Session 4: Current Mitigation of Lost Circulation–Drilling Engineering Perspective

Session Chairs: Ken Gray, University of Texas at Austin; Mohamed Haddad, ADMA-OPCO

This session will cover things the drilling engineer can do to avoid or mitigate subsurface losses so as to reduce non-productive time (NPT), while drilling as fast as circumstances warrant. Mud losses to a subsurface formation can occur in several ways, with each type of loss requiring a different response and solution dictated by the type and severity of the loss, as well as rock formation and wellbore fluid type and constituents. Field examples will be used in discussing engineering procedures, hardware, software, and logistics currently used in drilling practices, ECD management, hole cleaning, back reaming, and casing design for lost circulation prevention or mitigation. A comprehensive strategy, beginning with well planning and continuing through unexpected outcomes encountered during operations, offers the best chance to avoid or deal with losses during drilling operations.

Session 5: Mechanical Solutions

Session Chairs: Moji Karimi, Weatherford; Scott Petrie, Managed Pressure Operations

The industry has adopted a number of advanced drilling and completion technologies in its quest to mitigate the effects of lost circulation. This session will attempt to present some of the most current applicable to surface, intermediate, and reservoir sections respectively. Many of those described including managed pressure drilling, casing while drilling, expandable casing technologies are called niche but they are all viable drilling techniques which have found a market in areas where they are commercially justifiable by eliminating the NPT caused by lost circulation. Others are relatively low cost alternatives like circulation subs, mechanical stage tools, and BHA management whose application is going on without a great deal of learning and feedback reported to the drilling community.

Session 6: Fluid Solutions

Session Chairs: Jim Friedheim, M-I SWACO; Mohammed Mehtar, ADMA

The role that drilling fluids and fluid solutions play in controlling and possibly avoiding losses downhole is tremendous. The key here is not just in the materials or chemistries of these fluids, but also in the design and implementation of these solutions to ensure success. This session will review some of these fluids solutions along with the criteria used to validate and study their performance as well as critical engineering guidelines related to effective application of fluid solutions in the field.

Session 7: Constraints /Considerations /Consequences for the Reservoir

Session Chairs: Arnoud Meyer, Schlumberger; Marwa Al-Qutt, Agiba Petroleum Company

During drilling and completions operations through reservoir sections, damage can occur to the producing formation. Although this damage - in normal cases - is limited to the near-wellbore region of the reservoir, it plays a major role in productivity impairment. Severe or complete loss of circulation can complicate the problem as the damage will be more extended inside the reservoir.

Fractured reservoirs present a big challenge during drilling and completion operations, because permanent plugging of these fractures is not acceptable. Sometimes new wells are drilled or completed using high density fluids due to wellbore stability or well control issues, which presents other challenges, including reduced pore and fracture pressures, and increased chances to induce fractures, resulting in massive damage to the producing formation.

This session will cover consequences, prevention, and mitigation of lost circulation during drilling and completion operations when reservoir damage is an important consideration. Topics may include the impact of lost circulation and LCM on formation, the effects on production, how to recover wells back from damage, non-damaging versus acidizing treatments, how much damage can be tolerated, and whether the impact of the damage to the reservoir is understood.

Session 8: Lost Circulation Effects on Zonal Isolation

Session Chairs: Essam Abdelhamid, Total; Mohammad Amanullah, Saudi Aramco

Massive loss of circulation while drilling and cementing is a major problem in well construction, especially in the Middle East. It also triggers other problems and thus is a serious drilling hazard for safe and economic drilling operation. Conventional LCMs, controlling methods and practices rarely work in these loss zones. Hence, the industry needs out-of-the-box ideas and innovative thinking to find a viable solution to moderate to severe loss circulation problems and to understand how problems during drilling relate to future problems in cementing and reliable zonal isolation. Discussion topics might include how lessons learnt from the drilling phase might influence the cement job, how to assess the reliability of zonal isolation after lost circulation incidents, and advances in fluid additives and placement techniques.

Session 9: Wrap-Up: Mapping the Type of Loss and Choosing the Treatment

Cochairs: Fred Growcock, Occidental Oil and Gas International; John Cook, Schlumberger

We have heard a lot of discussion of why lost circulation happens, its consequences and how to (try to) deal with it. This session is aimed at tying things together, from clarifying the types of losses we might encounter in a given well or field, understanding their likely impact when they occur, and choosing the best approach to solve the problem.

Session 10: Wrap-Up: Well Planning, Strategy, and Forward Direction

Cochairs: Don Whitfill, Halliburton; Fersheed Mody, Apache Corporation

Successful prevention and remediation of lost circulation requires a comprehensive strategy to avoid or deal with losses that begins at the well planning stage and continues through the unexpected outcomes encountered during operations. This session addresses the elements of a comprehensive lost circulation strategy, and then will take a look at the future direction the industry is or should be taking. In addition, this session will provide an opportunity for further discussion on issues raised during the workshop where sufficient time was not available and the issue was placed in the “parking lot.”