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Circulation

1. 1 Lost Circulation Measurable loss of whole mud (liquid phase and solid phase) to the formation. Lost circulation can occur at any depth during any operation

2. 2 Lost Circulation ADVERSE EFFECTS ON DRILLING OPERATIONS SURFACE HOLE LOSS OF DRIVE PIPE OR CONDUCTOR SHOE HOLE CLEANING PROBLEMS HOLE BRIDGE OR COLLAPSE STUCK-PIPE WELL CONTROL PROBLEMS LOSS OF THE WELL

3. 3 Lost Circulation ADVERSE EFFECTS ON DRILLING OPERATIONS INTERMEDIATE HOLE LOSS OF FLUID LEVEL MONITORING LOSS OF FORMATION EVALUATION HOLE CLEANING PROBLEMS HOLE BRIDGE OR COLLAPSE EXTENDED WELLBORE EXPOSURE TIME STUCK-PIPE WELL CONTROL PROBLEMS UNDER GROUND BLOWOUT ADDITIONAL CASING STRINGS

4. 4 Lost Circulation ADVERSE EFFECTS ON DRILLING OPERATIONS PRODUCTION HOLE LOSS OF FLUID LEVEL MONITORING LOSS OF FORMATION EVALUATION HOLE CLEANING PROBLEMS HOLE BRIDGE OR COLLAPSE EXTENDED WELLBORE EXPOSURE TIME

5. 5 Lost Circulation ADVERSE EFFECTS ON DRILLING OPERATIONS PRODUCTION HOLE STUCK-PIPE WELL CONTROL PROBLEMS UNDER GROUND BLOWOUT ADDITIONAL CASING STRINGS PRODUCTION ZONE DAMAGE

6. 6 Lost Circulation LOST CIRCULATION MECHANISIMS “PRESSURE INDUCED FRACTURE” WELLBORE PRESSURE EXCEED THE FRACTURE PRESSURE OF THE FORMATION CAUSING THE ROCK TO CRACK OPEN (FRACTURE)

7. 7 Lost Circulation PRESSURE INDUCED FRACTURE

8. 8 Lost Circulation LOST CIRCULATION MECHANISIMS “NATUARLLAY EXISTING FRACTURES/ HIGH PERMEABILITY” OVER BALANCED WELLBORE PRESSURE IS EXPOSED TO A FORMATION WITH UNSEALED FRACTURES OR HIGH PERMEABILITY

9. 9 Lost Circulation “NATUARLLAY EXISTING FRACTURES/ HIGH PERMEABILIY”

10. 10 Lost Circulation CAUSES OF LOST CIRCULATION “PRESSURE INDUCED FRACTURE” EXCESSIVE MUD WEIGHT ANNULAR FRICTION LOSS WELLBORE PRESSURE SURGES IMPOSED OR TRAPPED PRESSURES SHUT-IN PRESSURES LOW FORMATION PRESSURE

11. 11 Lost Circulation CAUSES OF LOST CIRCULATION “NATURAL FRACTURES/PERMEABILITY” UNCONSOLIDATED FORMATIONS FISSURES/FRACTURES UNSEALED FAULT BOUNDARY VULGAR/CAVERNOUS FORMATION

12. 12 Lost Circulation PRESSURE INDUCED FRACTURE CAUSE WELLBORE PRESSURES ARE GREATER THAN FORMATION FRACTURE PRESSURE THE FORMATION FRACTURES ALLOWING MUD LOSS

13. 13 Lost Circulation PRESSURE INDUCED FRACTURE WARNING PROGNOSED LOSS ZONE EXCESSIVE MUD WEIGHT LOW FRACTURE STRENGTH POOR HOLE CLEANING WELLBORE PRESSURE SURGES

14. 14 Lost Circulation PRESSURE INDUCED FRACTURE INDICATORS MAY BEGIN WITH SEEPAGE LOSS OR POSSIBLY TOTAL LOSS PIT VOLUME LOSS EXCESSIVE HOLE FILL IF SHUT-IN A SUDDEN LOSS OF PRESSURE

15. 15 Lost Circulation PRESSURE INDUCED FRACTURE FIRST ACTION (TOTAL LOSS) REDUCE PUMP SPEED TO APPROXIMATELY ½ SPEED PICK-UP OFF BOTTOM AND STOP THE PUMPS ZERO THE STROKE COUNTER AND FILL THE ANNULUS WITH WATER OR LIGHT MUD RECORD THE STROKES IF/WHEN THE ANNULUS BEGINS TO FILL UP MONITOR THE WELL FOR FLOW

16. 16 Lost Circulation PRESSURE INDUCED FRACTURE PREVENTITIVE ACTION MINIMISE MUD WEIGHT AND MAXIMISE SOLIDS REMOVAL CONTROL RATE OF PENETRATION MINIMSE WELLBORE PRESSURE SURGES AVOID IMPOSED OR TRAPPED PRESSURE

17. 17 Lost Circulation NATURAL FRACTURES/HIGH PERMEABILIY CAUSE WELLBORE PRESSURE IS OVERBALANCED TO THE FORMATION PRESSURE MUD LOST TO NATURAL FRACTURESAND/OR HIGH PERMEABILITY

18. 18 Lost Circulation NATURAL FRACTURES/HIGH PERMEABILIY WARNING PROGNOSED LOSS ZONE LOST CIRCULATION CAN OCCUR AT ANY TIME DURING ANY OPEN HOLE OPERATION

19. 19 Lost Circulation NATURAL FRACTURES/HIGH PERMEABILIY INDICATORS MAY BEGIN WITH SEEPAGE LOSS OR POSSIBLY TOTAL LOSS PIT VOLUME LOSS STATIC LOSSES DURING CONNECTIONS OR SURVEYS

20. 20 Lost Circulation NATURAL FRACTURES/HIGH PERMEABILIY FIRST ACTION (TOTAL LOSS) REDUCE PUMP SPEED TO APPROXIMATELY ½ SPEED PICK-UP OFF BOTTOM AND STOP THE PUMPS ZERO THE STROKE COUNTER AND FILL THE ANNULUS WITH WATER OR LIGHT MUD RECORD THE STROKES IF/WHEN THE ANNULUS BEGINS TO FILL UP MONITOR THE WELL FOR FLOW

21. 21 Lost Circulation NATURAL FRACTURES/HIGH PERMEABILIY PREVENTIVE ACTION MINIMISE MUD WEIGHT CONTROL RATE OF PENETRATION MINIMSE WELLBORE PRESSURE SURGES PRE-TREAT WITH LCM

22. 22 Lost Circulation LOSS SEVERITY CLASSIFICATIONS SEEPAGE LOSS ( < 20 BBLS/HOUR) PARTIAL LOSS ( > 20 BBLS/HOUR) TOTAL LOSS (NO RETURNS) GRADUAL LOSSES OPERATION NOT INTERUPTED POSSIBLE WARNING OF INCREASED LOSS SEVERITY IMMEDIATE DROP IN FLUID LEVEL WHEN PUMPING IS STOPPED SLOW TO REGAIN RETURNS WHEN STARTING CIRCULATION OPERATIONS USUALLY INTERUPTED REMEDIAL ACTION REQUIRED RETURN FLOW STOPS IMMEDIATELY PUMP PRESSURE DECREASE STRING WEIGHT INCREASE OPERATIONS SUSPENDED REMEDIAL ACTION REQUIRED

23. 23 Lost Circulation METHODS FOR LOCATING LOSS DEPTH SUCCESSFUL TREATING OF LOST CIRCULATION DEPENDS GREATLY ON LOCATING THE DEPTH OF THE LOSS ZONE

24. 24 Lost Circulation METHODS FOR LOCATING LOSS DEPTH SURVEY METHODS TEMPERATURE SURVEY ACOUSTIC LOG RADIOACTIVE TRACER SPINNER SURVEY PRESSURE TRANSDUCER HOT WIRE SURVEY PRACTICAL METHODS OFFSET DATA GEOLOGISTIC/LOGGER IDENIFIES POTENTIAL LOSS ZONE MONITORING FLUID LEVEL TRENDS WHILS DRILLING

25. 25 Lost Circulation CONSIDERATIONS FOR SURVEY METHODS SURVEY TOOLS ARE NOT ALWAYS AVAILABLE CONSIDERABLE TIME REQUIRE TO RUN THE SURVEY SURVEYS REQUIRE LARGE VOLUMES OF MUD RESULTS ARE OFTEN DIFFICULT TO INTERPRET POSSIBILITY OF LOSING THE SURVEY TOOL IN THE HOLE

26. 26 Lost Circulation GUIDELINE FOR LOST CIRCULATION SOLUTIONS ACTION RESULTS CONSIDERATIONS MINIMISE MUD WEIGHT REDUCE WELLBORE PRESSURES, (THE DRIVING FORCE PUSHING MUD INTO THE LOSS ZONE) MORE SUCCESSFUL WITH PRESSURE INDUCED FRACTURES POSSIBLE WELL CONTROL AND HOLE STABILITY PROBLEMS FORMATION “HEALING TIME” REACTIVE CLAYS SWELL WITH WBM PRODUCING A PLUGGING EFFECT MORE SUCCESSFUL WITH FRESH WATER MUD LOST TO SHALE BETTER RESULTS WITH LCM NORMAL 6-8 HOURS WAITING TIME WITH THE STRING INSIDE THE CASING

27. 27 Lost Circulation GUIDELINE FOR LOST CIRCULATION SOLUTIONS ACTION RESULTS CONSIDERATIONS LOSS CIRCULATION MATERIAL (LCM) EFEECTIVELY BRIDGES, MATS AND SEALS SMALL TO MEDIUM FRACTURES OR PERMEABLITY LESS EFFECTIVE WITH LARGE FRACTURES OR FAULTS INEFFECTIVE WITH CAVERNOUS ZONES INCREASE THE LCM LBS/BBL WITH LOSS SEVERITY SPECIAL TECHNIQUES A PLUG BASE IS PUMPED INTO THE LOSS ZONE FOLLOWED BY A CHEMICAL ACTIVATOR. THE TWO MATERIALS FORM A SOFT PLUG CAN BE USED IN PRODUCTION ZONES INCREASED RISK OF PLUGGING EQUIPMENT PLUG BREAKS DOWN WITH TIME

28. 28 Lost Circulation GUIDELINE FOR LOST CIRCULATION SOLUTIONS ACTION RESULTS CONSIDERATIONS CEMENT CEMENT SLURRY IS SQUEEZED INTO THE LOSS ZONE UNDER INJECTION PRESSURE PROVIDES A “FIT TO FORM”SOLID PLUG AT OR NEAR THE STRESS OF THE SURRONDING FORMATION DRILLING BLIND IN SOME CASES THE ONLY PRACTICAL SOLUTION IS TO DRILL WITHOUT RETURNS NOT A CONSIDERATION WHERE WELL CONTROL PROBLEMS POTENTIALLY EXIST SET CASING IN THE FIRST COMPETENT FORMATION

29. 29 Lost Circulation GUIDELINES FOR SUCCESSFUL LCM RESULTS LOCATING THE LOSS ZONE AND ACCURATE PILL DISPLACEMENT IS VITAL. POSITION THE STRING +/- 100 FEET ABOVE THE LOSS ZONE, DO NOT STOP PUMPING UNTIL THE PILL CLEARS THE BIT. INSURE THAT THE BASE MUD VISCOSITY WILL SUPPORT THE LCM VOLUME ADDED. ADD FRESH WATER GEL TO A PREMIXED LCM PILL IMMEDIATELY BEFORE PUMPING, FRESH GEL CONTINUES TO YIELD AFTER SPOTTING.

30. 30 Lost Circulation GUIDELINES FOR SUCCESSFUL LCM RESULTS AN EFFECTIVE LCM PILL BRIDGES, MATS AND THEN SEALS OFF THE LOSS ZONE, PARTICLE SIZE DISTRIBUTION AND PILL FORMULATION MUST SATISFY THESE REQUIREMENTS. CONSULT THE LCM PRODUCT GUIDE PRIOR TO APPLYING THE PILL. USE LARGE NOZZLE SIZES IF THE LOSS POTENTIAL IS HIGH. KEEP THE STRING MOVING DURING THE PILL SPOTTING OPERATION TO AVOID STUCK-PIPE.

31. 31 Lost Circulation LOSS CIRCULATION MATERIAL (LCM) MATERIAL DEFINITION GRADES FINE (F) A PORTION OF THE MATERIAL WILL PASS THROUGH THE SHAKER SCREENS MEDIUN (M) MAJORITY OF MATERIAL WILL SCREEN-OUT AT THE SHAKERS COARSE (C) ALL MATERIAL WILL SCREEN OUT AT THE SHAKER. WILL PLUG JETS AND DOWNHOLE TOOLS. RECOMMENDED WITH OPEN-ENDED PIPE FIBROUS & FLAKED NON-RIGID MATERIALS THAT FORM A MAT ON THE HOLE TO PROVIDE A FOUNDATION FOR NORMAL FILTER CAKE DEVELOPMENT GRANULAR RIGID MATERIAL THAT PLUG THE PERMEABLITY OF THE LOSS ZONE

32. 32 Lost Circulation LOSS CIRCULATION MATERIAL (LCM) MATERIAL DEFINITION LCM BLEND A COMBINATION OF FIBROUS, FLAKED AND GRANULAR MATERIALS IN ONE SACK CELLULOSTIC SIZED WOOD DERIVED MATERIALS USED TO PREVENT SEEPAGE/PARTIAL LOSSES CALCIUM CARBONATE SIZED LIMESTONE OR MARBLE (ACID SOLUBLE) USED FOR SEEPAGE/PARTIAL LOSS IN PRODUCTION ZONES. SIZED SALT GRANULATED SALT (WATER SOLUBLE) DEVELOPED FOR SEEPAGE/PARTIAL LOSS IN PRODUCTION ZONES IN SALT-SATURATED SYSTEMS

33. 33 Lost Circulation SEEPAGE LOSS SOLUTIONS ( < 20 BBL/HOUR) FIRST ACTION RECOVERY REDUCE ROP TO LIMIT CUTTING LOAD MINIMISE MUD RHELOGY MINIMISE GPM MINIMISE WELLBORE SURGES MINIMISE MW CONSIDER PULLING INTO THE SHOE AND WAITING 6 TO 8 HOURS ADD LCM PILL IN 5-10 PPB INCREMENTS. EVALUATE RESULTS OVER 2 CIRCULATIONS BEFORE INCREASING TO THE NEXT LEVEL OF LCM CONCENTRATION. MIX 30 TO 50 BBL BATCHES AS DICTATED BY THE HOLE SIZE. CONSIDER SPOTTING LCM PILL BEFORE POOH. NON-PRODUCTIVE INTERVALS WBM: OBM/SBM LCM BLEND (F) 5-15 PPB CELLULOSIC (F/M) 2-25 PPB LCM BLEND (M) 5-15 PPB LCM BLEND (F/M) 10-20 PPB PRODUCTION ZONE EXPOSED WBM: OBM/SBM LIMESTONE (F/M) 5-30 PPB CELLULOSIC (F/M) 2-25 PPB LIMESTONE (F/M) 5-15 PPB

34. 34 Lost Circulation THE LCM MIXTURES SHOWN ARE INTENDED AS A GUIDE WHERE NO FIELD EXPERIENCE EXIST. SOME SOLUTIONS MAY REQUIRE 2 – 6 PPB CONCENTRATION IN THE TOTAL MUD SYSTEM. CONSULT YOUR MUD COMPANY FOR AVAILABLE PRODUCTS AND PILL FORMULATIONS BEST SUITED FOR THE AREA

35. 35 Lost Circulation SEEPAGE LOSS SOLUTIONS ( < 20 BBL/HOUR) FIRST ACTION RECOVERY REDUCE ROP TO LIMIT CUTTING LOAD MIMINISE MUD RHELOGY REDUCE GPM MINIMISE WELLBORE PRESSURE SURGES MINIMISE MW CONSIDER POOH TO SHOE AND WAITING 6-8 HOURS ADD LCM PILL IN 5-10 PPB INCREMENTS. EVALUATE RESULTS OVER 2 CIRCULATIONS BEFORE INCREASING TO THE NEXT LEVEL OF LCM CONCENTRATION. MIX 30 TO 50 BBL BATCHES AS DICTATED BY THE HOLE SIZE. CONSIDER SPOTTING LCM PILL BEFORE POOH. NON-PRODUCTIVE INTERVALS WBM: OBM/SBM LCM BLEND (M) 15-25 PPB CELLULOSIC (F/M) 10-25 PPB LCM BLEND (C) 15-25 PPB CELLULOSIC (C) 10-25 PPB WALNUT (M/C) 10-20 PPB WALNUT (M) 5-15 PPB PRODUCTION ZONE EXPOSED WBM: OBM/SBM LCM BLEND (F) 15-25 PPB CELLULOSIC (F/M) 2-25 PPB LCM BLEND (M) 5-15 PPB LIMESTONE (F/M) 5-15 PPB CELLULOSIC (M) 5-15 PPB

36. 36 Lost Circulation TOTAL LOSS SOLUTIONS FIRST ACTION RECOVERY PULL OFF BOTTOM AND KEEP THE STRING MOVING FILL ANNULUS WITH WATER OR LIGHT MUD RECORD STROKES IF/WHEN ANNULUS FILLS UP CONSIDER POOH TO SHOE MINIMISE WELLBORE PRESSURE SURGES FORMULATIONS FOR SPECIAL PILLS AND CEMENT ARE DICTATED BY THE CONDITIONS OF EACH INCIDENT NON-PRODUCTIVE INTERVALS WBM: OBM/SBM 40 PPB LCM PILL 30-40 PPB LCM PILL SPECIAL PILL SPECIAL PILL CEMENT SQUEEZE CEMENT SQUEEZE PRODUCTION ZONE EXPOSED WBM: OBM/SBM 40 PPB LCM PILL 30-40 PPB LCM PILL SPECIAL PILL SPECIAL PILL CEMENT SQUEEZE CEMENT SQUEEZE ADDRESS RESERVOIR NEEDS

37. 37 Lost Circulation THE LCM MIXTURES SHOWN ARE INTENDED AS A GUIDE WHERE NO FIELD EXPERIENCE EXIST. SOME SOLUTIONS MAY REQUIRE 2 – 6 PPB CONCENTRATION IN THE TOTAL MUD SYSTEM. CONSULT YOUR MUD COMPANY FOR AVAILABLE PRODUCTS AND PILL FORMULATIONS BEST SUITED FOR THE AREA

38. 38 Lost Circulation SPOTTING PROCEDURES FOR LOST CIRCULATION MATERIAL (LCM) LOCATE THE LOSS ZONE MIX 50 TO 100 BBLS OF MUD WITH 25 – 30 PPB BENTONITE AND 30 – 40 PPB LCM POSITION THE STRING +/- 100 FEET ABOVE LOSS ZONE IF OPEN-ENDED, PUMP ½ OF THE PILL INTO THE LOSS ZONE. STOP THE PUMP, WAIT 15 MINUTES AND PUMP THE REMAINDER OF THE PILL

39. 39 Lost Circulation SPOTTING PROCEDURES FOR LOST CIRCULATION MATERIAL (LCM) IF PUMPING THROUGH THE BIT, PUMP THE ENTIRE PILL AND FOLLOW IT WITH 25 BBLS OF MUD IF RETURNS ARE NOT REGAINED, REPEAT THE PROCEDURE. IF RETURNS ARE NOT REGAINED AFTER THIS, WAIT 2 HOURS AND REPEAT THE PROCEDURE IF RETURNS ARE NOT REGAINED AFTER PUMPING THREE PILLS, CONSIDER OTHER OPTIONS TO REGAIN CIRCULATION

40. 40 Lost Circulation SPOTTING PROCEDURES FOR SPECIAL PILLS IF POSSIBLE DRILL THROUGH THE LOSS INTERVAL. THEN POOH AND RIH OPEN-ENDED DRILLPIPE POSITION THE STRING +/- 100 FEET ABOVE LOSS ZONE CLEAN THE MIXING PIT THOROUGHLY. MIX 50 BBLS OF DESIRED PILL PUMP DOWN THE DRILLSTRING AND PLACE IN THE SUSPECTED ZONE. IF ANNULUS IS NOT FULL, PUMP MUD DOWN THE ANNULUS WHILE PUMPING THE PILL DOWN THE DRILLSTRING

41. 41 Lost Circulation SPOTTING PROCEDURES FOR SPECIAL PILLS WHEN THE ANNULUS IS FULL, PREPARE TO PERFORM SQUEEZE JOB. APPLY 150 TO 200 PSI ON THE ANNULUS. THIS WILL “SOFT SQUEEZE” THE MATERIAL INTO THE LOSS ZONE

42. 42 Lost Circulation SPOTTING PROCEDURES FOR A GUNK PLUG IF POSSIBLE DRILL THROUGH THE LOSS INTERVAL. THEN POOH AND RIH OPEN-ENDED DRILLPIPE POSITION THE STRING +/- 100 FEET ABOVE LOSS ZONE MIX 100 SX OF CEMENT AND 100 SX OF BENTONITE WITH 50 BBLS OF DIESEL (SLURRY WEIGHT 11.5 PPG - 1.39 CUBIC FEET PER SACK) PUMP DOWN STRING 15 BBLS OF WATER-FREE DIESEL AHEAD AND BEHIND THE GUNK PLUG

43. 43 Lost Circulation SPOTTING PROCEDURES FOR A GUNK PLUG WHEN THE LEAD DIESEL SPACER REACHES THE BIT, CLOSE THE BOP AND PUMP DOWN THE ANNULUS PUMP AT 4 BBL/MIN DOWN THE STRING AND 2 BBL/MIN DOWN THE ANNULUS UNTIL THE TAIL SPACER CLEARS THE BIT RECIPROCATE THE STRING SLOWLY, DO NOT REVERSE CIRCULATE PULL THE STRING CLEAR OF THE SQUEEZE. PLACE THE SQUEEZE WITH THE CEMENT UNIT.

44. 44 Lost Circulation SPOTTING PROCEDURES FOR A GUNK PLUG WAIT + 8 HOURS FOR THE GUNK PLUG TO CURE, REPEAT THE PROCEDURE IF RETURNS ARE NOT REGAINED. IT MAY BE NECESSARY TO DRILL OUT THE GUNK BEFORE REPEATING THE PROCEDURE.

45. 45 Lost Circulation SPOTTING PROCEDURES FOR CEMENT IF POSSIBLE,DRILL THROUGH THE ENTIRE LOST CIRCULATION INTERVAL POOH AND RIH WITH OPEN-ENDED DP POSITION THE OPEN-ENDED DP 100 FEET ABOVE THE LOSS ZONE MIX AND PUMP 50 TO 100 BBLS OF CEMENT SLURRY FOLLOW THE SLURRY WITH ENOUGH VOLUME OF MUD OR WATER TO BALANCE THE “U” TUBE WAIT 6 TO 8 HOURS AND ATTEMPT TO FILL THE ANNULUS

46. 46 Lost Circulation SPOTTING PROCEDURES FOR CEMENT REPEAT THIS PROCEDURE IF RETURNS ARE NOT REGAINED IT MAY BE NECESSARY TO DRILL OUT THE CEMENT BEFORE REPEATING THE PROCEDURE. NOTE THE CEMENT FORMULATION MUST BE TESTED BY THE CEMENT COMPANY TO DETERMINE THE CEMENT THICKENING TIME

47. 47 Lost Circulation LOST CIRCULATION PREVENTION GUIDELINES THE PREVENTION OF LOST CIRCULATION MUST ALWAYS BE CONSIDERED IN THE WELL PLANNING, DRILLING AND POST ANALYSIS PHASES.

48. 48 Lost Circulation LOST CIRCULATION PREVENTION GUIDELINES DESIGN THE CASING PROGRAMME TO CASE-OFF LOW PRESSURE OR SUSPECTED LOST CIRCULATION ZONES MAINTAIN THE MUD WEIGHT TO THE MINIMUM REQUIRED TO CONTROL KNOWN FORMATION PRESSURES. HIGH MUD WEIGHTS ARE ONE OF THE MAJOR CAUSES OF LOST CIRCULATION MAINTAIN LOW MUD RHEOLOGY VALUES THAT ARE STILL SUFFICENT TO CLEAN THE HOLE.

49. 49 Lost Circulation LOST CIRCULATION PREVENTION GUIDELINES PRE-TREAT THE MUD SYSTEM WITH LCM WHEN DRILLING THROUGH KNOWN LOST CIRCULATION INTERVALS ROTATING THE STRING WHEN STARTING TO CIRCULATE HELPS TO BREAK THE GELS AND MINIMISE PUMP PRESSURE SURGES START CIRCULATION SLOWLY AFTER CONNECTIONS AND PERIODS OF NON-CIRCULATION MINIMISE ANNULAR RESTRICTIONS

50. 50 Lost Circulation LOST CIRCULATION PREVENTION GUIDELINES USE THE MINIMUM GPM FLOW RATE TO CLEAN THE HOLE WHEN DRILLING THROUGH KNOWN LOST CIRCULATION ZONES CONTROL ROP WHEN DRILLING KNOWN LOST CIRCULATION ZONES TO AVOID LOADING UP THE ANNULUS WITH CUTTINGS REDUCE TRIP SPEEDS TO MINIMISE SWAB AND SURGE PRESSURES PLAN TO BREAK CIRCULATION AT 2 OR 3 DEPTHS WHILE TRIPPING INTO THE HOLE

51. 51 Lost Circulation LOST CIRCULATION PREVENTION GUIDELINES CONSIDER USING JET SIZES OR TFA THAT WILL ALLOW THE USE OF LCM PILLS (+ 12/32” JETS) BE PREPARED FOR MUD LOSSES DUE TO THE SHAKER SCREENS PLUGGING

52. 52 Lost Circulation PRECAUTIONS WHILE DRILLING WITHOUT RETURNS INSURE AN ADEQUET WATER SUPPLY IS AVAILABLE USE ONE PUMP TO DRILL AND THE SECOND TO ADD WATER TO THE ANNULUS ASSIGN A PERSON TO MONITOR THE FLOWLINE AT ALL TIMES CLOSELY MONITOR TORQUE AND DRAG TO DETERMINE WHEN TO PUMP VISCOUS SWEEPS

53. 53 Lost Circulation PRECAUTIONS WHILE DRILLING WITHOUT RETURNS CLOSELY MONITOR PUMP PRESSURE WHILE DRILLING FOR INDICATIONS OF PACKING-OFF CONTROL ROP (IF POSSIBLE) AT ONE JOINT PER HOUR PICK UP OFF BOTTOM EVERY 15 FEET (3 METRES) DRILLED TO ENSURE THE HOLE IS NOT PACKING-OFF KEEP THE PIPE MOVING AT ALL TIMES

54. 54 Lost Circulation PRECAUTIONS WHILE DRILLING WITHOUT RETURNS MAINTAIN 400 – 500 BBLS RESERVE OF VISCOUS MUD READY TO PUMP CONSIDER SPOTTING HI-VIS PILLS ON BOTTOM PRIOR TO TRIPPING OR LOGGING STOP DRILLING AND CONSIDER POOH TO THE SHOE IF PUMP REPAIRS ARE REQUIRED START AND STOP MOVING THE PIPE SLOWLY TO MINIMISE PIPE SPEED

55. 55 Lost Circulation PRECAUTIONS WHILE DRILLING WITHOUT RETURNS CONSIDER SPOTTING A HI-VIS PILL ABOVE THE BHA PRIOR TO EACH CONNECTION PRIOR TO EACH CONNECTION, CIRCULATE AND WIPE THE HOLE THOROUGHLY DO NOT RUN SURVEYS WILL DRILLING BLIND IF CIRCULATION RETURNS, STOP DRILLING. RAISE THE STRING TO THE SHUT-IN POSITION. STOP THE PUMPS AND CHECK FOR FLOW

56. 56 Lost Circulation PRECAUTIONS WHILE DRILLING WITHOUT RETURNS IF FLOW IS OBSERVED, CLOSE THE BOP AND OBSERVE THE SHUT-IN PRESSURES: 1. NO SHUT-IN PRESSURE - SLOWLY CIRCULATE BOTTOMS-UP THROUGH TWO OPEN CHOKES 2. PRESSURE OBSERVED - SLOWLY CIRCULATE THE KICK WITH THE DRILLERS METHOD. BE PREPARED FOR AN UNDERGROUND BLOWOUT

57. 57 Lost Circulation SEALING MATERIALS USED FOR LOST CIRCULATION MATERIAL TYPE DESCRIPTION CONCENTRATION LBS/BBL LARGEST FRACTURE SEALED (INCHES) NUTSHELL GRANULAR 50% - +3/16 10 MESH 50% - +10 100 MESH 20 0—4—8—12—16—20 PLASTIC GRANULAR 50% - +3/16 10 MESH 50% - +10 100 MESH 20 LIMESTONE GRANULAR 50% - +3/16 10 MESH 50% - +10 100 MESH 40 SULPHUR GRANULAR 50% - +3/16 10 MESH 50% - +10 100 MESH 120

58. 58 Lost Circulation SEALING MATERIALS USED FOR LOST CIRCULATION MATERIAL TYPE DESCRIPTION CONCENTRATION LBS/BBL LARGEST FRACTURE SEALED (INCHES) NUTSHELL GRANULAR 50% - +10 16 MESH 50% - +30 100 MESH 20 0—4—8—12—16—20 EXPANDED PERCITE GRANULAR 50% - +3/16 10 MESH 50% - +10 100 MESH 60 CELLOPHANE LAMINATED ¾” FLAKES 8 SAWDUST FIBROUS ¼” PARTICLES 10 PRAIRIE HAY FIBROUS ½” PARTICLES 10

59. 59 Lost Circulation SEALING MATERIALS USED FOR LOST CIRCULATION MATERIAL TYPE DESCRIPTION CONCENTRATION LBS/BBL LARGEST FRACTURE SEALED (INCHES) BARK FIBROUS 3/8” PARTICLIES 10 0—4—8—12—16—20 COTTONSEED HULLS GRANULAR FINE 10 PRARIE HAY FIBROUS 3/8” PARTICLES 12 CELLOPHANE LAMINATED 1/2” FLAKES 8 SHREDDED WOOD FIBROUS 1/4” FIBERS 8 SAWDUST FIBROUS 1/16” PARTICLES 20

60. 60 Lost Circulation