Lost Circulation: A New Approach to An Old Challenge

Salim Taoutaou is the founder of Taoutaou Consulting LLC and currently serves as its managing director. Prior to this, he was the cementing and well integrity technical adviser for Schlumberger in Paris, where he managed the global development of technologies and solutions for oil and gas sector. Throughout his 24 years in the oil and gas industry, Taoutaou has held various managerial and technical global positions, as well as regional ones in North Africa, the North Sea, the Middle East, and Asia Pacific.  He has authored more than 58 international journal and conference papers and holds several patents.  In 2014, Taoutaou received the SPE Asia Pacific Regional Technical Award in Drilling Engineering.  He also served as SPE Distinguished Lecturer for the 2017–2018 season. He received his MS degree in mechanical engineering from Guelma University and an Executive MBA from the Quantic School of Business and Technology.

John Cook retired from Schlumberger Cambridge in 2018, after 35 years in research and development there. His main focus was with geomechanics and its use in drilling planning and optimization, wellbore instability control, lost circulation, stimulation, sand production, and field and reservoir management. Cook is the author or co-author of many technical papers for SPE and other journals, co-author of a chapter in the SPE-published Advanced Drilling and Well Technology handbook, and assignee on a number of patents.  Before joining Schlumberger, Cook worked on materials science and electron microscopy, with a BS degree in natural sciences and a PhD in physics, both from Cambridge University.

Ken Russell has been geomechanics adviser and director of Russell Geomechanics, based in Aberdeen, Scotland, since 2014. He has gained more than 45 years of experience working for a variety of oil service companies in wireline operations, management, and formation evaluation. Since 2000, Russell principally has worked in real-time geomechanics operations and developing acousto-geomechanical applications. He was one of Schlumberger’s principal instructors, delivering geomechanics training at operating company locations, training centers, and operational centers worldwide.  Through extensive operational and wellsite experience in the North Sea, Europe, Africa, South America, and the Far East, Russell has gained a broad-based knowledge of drilling, production, log data acquisition, analysis, and interpretation that has allowed him to develop and deliver pragmatic solutions to the geomechanical challenges of drilling, sand production, fracturing, and unconventional reservoirs faced by operators. His principal interests include the development and application of acousto-geomechanical techniques for the evaluation of anisotropic formations and fracture systems and the identification and prevention of wellbore instability.  Russell holds a BSc (Hons) degree in physics from Aberdeen and has been a member of SPE since 1984.

1. Lost Circulation: Definition, Challenges, and Consequences 1
1.1. Definition and Challenges 1
1.2. Consequences 2
1.2.1. Drilling 2
1.2.2. Well Integrity 2
1.2.3. Production and Reservoir Damage 3
1.2.4. Economics: Unplanned Spending 3
1.3. References 4

2. Mechanics of Rocks and Fractures 5
2.1. Geomechanics Primer 5
2.1.1. Stresses and Mohr’s Circle 5
2.1.2. Elastic Rock Properties and Failure Criteria 6
2.1.3. State of Stress and Pore Pressure in the Subsurface 8
2.1.4. Driller’s Fracture Gradient and the Mud Weight Window 12
2.2. Geological Aspects of Natural Fractures 13
2.2.1. Characterization of Natural Fractures 14
2.2.2. Mineralization of Natural Fractures 16
2.3. Rock Mechanical Properties of Natural Fractures 17
2.3.1. Fracture Toughness and Fracture Propagation 18
2.3.2. Fracture Width 19
2.3.3. Fracture Compliance 19
2.3.4. Natural Fracture Networks 20
2.4. Induced Fractures 20
2.4.1. Drilling-Induced Fractures at the Wellbore Wall 20
2.4.2. Induced Fractures due to Reservoir Pressure Depletion 24
2.5. Fluid Flow and Particle Transport in Fractures 28
2.5.1. Mud Rheology 29
2.5.2. Mud Losses to the Formation—Leakoff 29
2.5.3. Hydraulic Conductivity 29
2.5.4. Particle Transport 31
2.5.5. Interaction of Drilling-Induced and Natural Fracture Systems 31
2.6. Vugs and Solution Features 32
2.7. Nomenclature 36
2.8. References 38

3. Lost Circulation Mechanisms 40
3.1. Leakage Into Intact Formations 40
3.2. Vugular Formations 41
3.3. Natural Fractures 42
3.4. Induced Fractures 43
3.5. Borehole Breathing 45
3.6. Depleted Reservoirs 45
3.7. Lost Circulation During Casing and Cementing 46
3.8. References 47

4. Measurement, Prediction, and Diagnosis 48
4.1. Data—Interpretation and Action 48
4.2. Detecting and Measuring the Losses 48
4.3. Location and Identification of the Loss Zone 50
4.3.1. Temperature, Flow, and Tracer Measurements 51
4.3.2. Resistivity Logs 51
4.3.3. Resistivity Imaging Tools 53
4.3.4. What the Driller or Cementing Engineer Needs to Know 53
4.4. Diagnostics 53
4.5. Real Time Data and Decision-Making Software 57
4.6. References 59

5. Preventing and Curing Lost Circulation 61
5.1. Planning the Well 61
5.2. Drilling and Well Engineering Solutions 61
5.2.1. Managed Pressure Drilling (MPD) 62
5.2.2. Casing While Drilling (CWD) 67
5.2.3. Expandable Tubulars 68
5.2.4. Lost Circulation Materials and Fluids 69
5.3. Real-Time Techniques During Drilling, Casing, and Cementing 83
5.3.1. Drilling 83
5.3.2. Running Casing 83
5.3.3. Cementing 84
5.3.4. Placement of Lost Circulation Treatments 85
5.4. References 87