The SPE Foundation through member donations and a contribution from Offshore Europe

Primary funding is provided by The SPE Foundation through member donations and a contribution from Offshore Europe The Society is grateful to those companies that allow their professionals to serve as lecturers Additional support provided by AIME 1

Ways to Successfully Reduce Well Blowout Events Otto Luiz Alcantara Santos Petróleo Brasileiro S.A. - Petrobras Society of Petroleum Engineers Distinguished Lecturer Program www.spe.org/dl 2

Motivation for the Lecture 6 6 5 Before 1988 After 1988 5 Number of Blowouts 4 3 2 Blowouts in Brazil During Drilling Operations 4 3 2 1 1 0 1980 1990 2000 2010 Year 0 3

Lecture Objective To show how a major oil company can act to preserve its personnel, assets and image from the consequences of a well blowout in drilling and production operations 4

Presentation Outline Introduction Well Control Training and Certification Program Well Control in Drilling and Production Operations Well Control in Deep and Ultra-Deep Waters Research and Development in Well Control in Ultra-Deep Waters Conclusions 5

Kicks and Blowouts Definitions Kicks Undesirable flow from the formation into the well that happens when the pressure inside the well becomes less than the pressure of that formation. Blowouts Uncontrolled flow from the formation into the well and then to the atmosphere, sea bottom or other uncased formations. 6

Blowouts Classification Surface Blowout Underground Blowout Cratering 7

Examples of Blowouts 8

Consequences of a Blowout Loss of Human Lives Loss of Reserves Loss of Equipment Production Discontinued Environmental Aggression 9

Human Factors Review for Offshore Blowouts Source: Aberdeen Drilling School HPHT Manual 10

Presentation Outline Introduction Well Control Training and Certification Program Well Control in Drilling and Production Operations Well Control in Deep and Ultra-Deep Waters Research and Development in Well Control in Ultra-Deep Waters Conclusions 11

Certification and Training Program in Well Control Well control training starts in 1971 In 1993, the Well Control Certification and Training Program is created and conducted by Petrobras University The program is accredited by WellCAP of IADC in July, 1996 12

WellCAP Certificates Issued Until 31 December, 2009 LEVEL INTRODUCTORY FUNDAMENTAL SUPERVISION TOTAL SURFACE 1006 974 1194 3174 COMBINED (SURFACE/ 266 494 2003 2763 SUBSEA) TOTAL 1272 1468 3197 5937 13

Trained/Certified People 600 600 Number of Certified/Trained People 500 400 300 200 100 500 400 300 200 100 0 1980 1990 2000 2010 Year 0 14

600 500 400 300 200 100 0 Cumulative Blowouts in Brazil per 1000 Drilled Wells Blowouts in Brazil per 1000 Drilled Wells X Trained/Certified People 4.00 3.50 3.00 2.50 2.00 1.50 1.00 0.50 0.00 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Year 15 1982 Trained/Certified People Blowouts per 1000 Drilled Wells Trained/Certified People Cumulative Blowouts/1000 Drilled Wells

Presentation Outline Introduction Well Control Training and Certification Program Well Control in Drilling and Production Operations Well Control in Deep and Ultra-Deep Waters Research and Development in Well Control in Ultra-Deep Waters Conclusions 16

Well Control in Drilling and Production Operations Personnel (Well Control Team) Monitoring of well control certificates Drills at the rig site Well Control Equipment (Well Control Team) Rig inspections upon receiving it Monitoring of well control equipment and kick detection tests 17

Development of Well Safety Standards Well Control in Drilling and Production Operations Creation of a committee to review, elaborate and approve internal well safety standards There are 17 standards approved and in use Operations (Well Control Team) Elaboration and approval of operational procedures especially in deep waters Reinforcement of the use of these operational well safety procedures and standards 18

Presentation Outline Introduction Well Control Training and Certification Program Well Control in Drilling and Production Operations Well Control in Deep and Ultra-Deep Waters Research and Development in Well Control in Ultra-Deep Waters Conclusions 19

Peculiarities of deepwater and ultra-deepwater well control Low fracture gradients Excessive frictional pressure inside the choke line Low temperatures Hydrate formation Gas in riser 20

Subsea Configuration 21

Low Fracture Gradients Fracture pressures in deep waters are lower than those found onshore or in shallow waters The overburden pressure is lower due the seawater Narrow operational window for the mud weight 22

23 Low Fracture Pressure 11,6 1580 2890 12 10,0 1580 1940 11 14,1 1940 4630 10 10,8 1940 2670 9 10,8 1770 2650 8 10,8 1380 2470 7 104 1380 1740 6 9,8 1530 2600 5 11,0 1580 4400 4 10,4 1580 2900 3 9,3 1580 2100 2 11,4 1590 2390 1 Fracture Pressure (lb/gal) Water Dept (m) Shoe Depth (m) Well

Narrow Operational Window Pore Pressure Shallow Water Fracture Pressure...Sea Level Sea Floor Deep Water 24

Excessive Frictional Pressure Losses Inside the Choke Line The frictional pressure losses inside the choke line can be excessive during a kick circulation Small inside diameter of the choke line and its long length The problem is aggravated by the low seawater temperature 25

Hydrate Formation High pressure and low temperature at the wellhead are favorable for hydrate formation Hydrate can plug the kill and choke lines, the annulus space and the BOP cavities. Hydrate formation can be prevented using inhibitors such as salt and glycol. 26

Gas Inside the Riser After BOP Closure In ultra-deep waters, there are chances of the gas has passed through the BOP and into the riser before well closure The use of synthetic oil based mud increases these chances 27

Presentation Outline Introduction Well Control Training and Certification Program Well Control in Drilling and Production Operations Well Control in Deep and Ultra-Deep Waters Research and Development in Well Control in Ultra-Deep Waters Conclusions 28

Research and Development A strategic in-house corporate research program dedicated to ultra-deepwater exploitation systems has been created Important research projects portfolio in well safety: Drilling Hydraulics and Gas Migration Gas Solubility in Synthetic Oil Based Mud Kick Simulator for Field Application Study of Ultra-Deepwater Blowouts 29

Drilling Hydraulics and Gas Migration Objective: to obtain downhole pressures and temperatures during simulated drilling operations Issues Addressed: riser hydraulics and temperatures; critical pressure effects (surge and swab); and gas migration Results: comparison of gathered data with computer models 30

Drilling Hydraulics and Gas Migration Research conducted through a JIP coordinated by RF - Rogaland Research that used a drillship Campos Basin (Brazil) in a water depth of 2714 m The drilling string was equipped with six sensors for recording pressures and temperatures Gas migration experiments were done through nitrogen injection with the bit just above the BOP 31

Drilling Hydraulics and Gas Migration Sensor # 6-1 acquisition/3s - 1706 m 28 DP Stands (25.6) 3 DP Stands (19.5) Sensor # 5-1 acquisition/3s - 2596 m 54 DP Stands (19.5) Sensor # 4-1 acquisition/s - 4135 m 1 DP Stand (19.5) 2 DP Stands (19.5) Sensor # 3-1 acquisition/s - 4166 m 1 DC Stand Sensor # 2-1 acquisition/s - 4254 m 4 DC Stands Bit Sub+X-over Sensor # 1-1 acquisition/s - 4368 m Bit @ 4370 m 32

Drilling Hydraulics and Gas Migration 7350 7300 Measuered Measured Values values Filtered Simulated Simulation 7250 7200 Pressure (psi) 7150 7100 7050 7000 6950 6900 0 72 144 216 288 360 432 504 576 648 720 Time (s) 33

Objective: to understand the interaction between a gas kick and a synthetic oil based mud Issues Addressed: experimental determination and modeling of thermodynamic properties Gas Solubility in Synthetic Oil Based Mud Results: experimental data of gas solubility (methane), density and formation volume factor for n-paraffin, ester, emulsions and drilling fluids 34

Gas Solubility in Synthetic Oil Based Mud Research conducted at UNICAMP (Campinas State University) in a PVT cell with an operating capacity of 177 ºC and 10000 psi The current experiments aim at expanding the ranges of pressure and temperature using a new PVT cell with an operating capacity of 200 ºC and 15000 psi 35

The New PVT Cell 36

Gas Solubility in the Unweighted Drilling Fluid at 70ºC Rs [m³std/m³] 200 160 120 80 40 63% NP no additives 63% NP with additives 78% NP no additives 78% NP with additives 10 MPa => 1450 psi 0 0 10 20 30 40 Pressure [MPa] 37

Density of the Unweighted Drilling Fluid at 70ºC 0.95 78% NP no additives 78% NP with additives 63% NP no additives 63% NP with additives 0.85 ρ [g/cm³] 0.75 10 MPa => 1450 psi 0.65 0 10 20 30 40 Pressure [MPa] 38

Development of a Kick Simulator Objective: to develop a software to assist the drilling engineer in well control issues on an ultra-deepwater drilling rig Issues Addressed: estimation of pressure behavior inside an ultra-deepwater well during a gas kick circulation and calculation of kill sheets Result: a software to be used by the drilling personnel at rig site 39

Kick Simulator Output 40

Study of Ultra-deepwater Blowouts Objective: to study ultra-deepwater blowouts and their control through the dynamic kill method using relief wells Issues Addressed: pressure behavior and gas flow rate during blowouts and the application of the dynamic kill method Products: two simulators, one for blowout events and the other for dynamic kill method 41

Subsea Blowout 42

9000 8000 7000 6000 0 400 800 1200 1600 2000 2400 Time (s) T I ME (s) 43 Bottonhole PRESSÃONO FUND Pressure DOPOÇO (psi) 5000 Subsea Blowout 600 md 400 md 200 md BOTTOMHOLE PRESSURE (psi)

250 200 150 100 50 0 Dynamic Kill from a Relief Well 1000 gpm 2000 gpm 1500 gpm 0 400 800 1200 1600 TIME (s) 44 GAS FLOW VAZÃO degás RATE (mmscf/day) (mmscf/dia)

Conclusions Effective preventive actions make onshore and offshore drilling and production operations safer Training, well control equipment tests and elaboration of safety standards are some of these actions that were responsible for the decrease of the number of blowouts in Brazil Research projects enhanced the understanding of the well safety processes 45

Questions? 46

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