9Project Background Reservoir Candidate Screening Initial Reservoir SimulationsInitial Pilot SelectedResults of Original PilotSecond Pilot SelectedResults of Second Pilot
10Preliminary Reservoir Screening Estimating OOIPIf there was only primary production thenCum Production / 0.1 = OOIPIf there was primary + secondary production thenCum Production / 0.2 = OOIPEstimating Remaining Oil= OOIP - Cum Production - 25% SRO
11Initial Simulation Results Is there sufficient remaining oil?
12Preliminary Reservoir Screening Single layer or stratified reservoir?“C” %“D” %
13Initial Reservoir Simulation Obtain History Including Offset LeasesEvaluate Technical InformationOpen and Cased Hole LogsCore ReportsEngineering ReportsOsage Agency ReportsModel ReservoirNote I added Osage to Agency…
14Initial Simulation Results Vertical Permeability vs. Horizontal Permeability
24Wolco Heel -to -toe configuration Reverse order on pics for animation after print
25Geologic Interpretations Key Project Decision PointsHorizontal wells should be drilled parallelto the predominate fracture orientationIn the Bartlesville reservoir, horizontalwells can be drilled with air using andcompleted open hole
26Planning the Project Log Review Blake 3A Saturation – 30’ Assume total reservoir to be 80’ Thick
27Planning the ProjectLocation with pilot horizontal well plans in relation to existing wells
28Drilling the Horizontal Wells 1. Drill the Vertical Well 2. Move Out Drilling Rig 3. Move In Workover Rig 4. Drill the Curve and Horizontal Sections
29Drilling the Horizontal Wells Short Radius Horizontal Drilling TechniqueAmoco (BP) Licensed Rotary SteerableSystem70 ft. Radius of Curvature1000 ft. Lateral SectionBased on Formation StabilityOpen Hole CompletionAir/Foam Drilling Fluids
30Drilling the Horizontal Wells Advantages of These TechniquesLow costDrilling with air minimizes formationdamage in low-pressure, sensitive reservoirsUse of air hammer permits rapidpenetration ratesShort-turning radius (70ft) permits wellsto be conventionally completed withrod-pump set with low pressure headon the formation
31Drilling the Horizontal Wells Drill the Vertical WellSet pipe 70 ftabove target formationKOP70 ftTarget Formation
32Drilling the Horizontal Wells Drill the CurveTrip in Hole with Curve Drilling Assembly(CDA)Run Gyro to Orient CDA DirectionDrill Curve
33Drilling the Horizontal Wells Drill the Curve70 ft Radius
43Drilling the Horizontal Wells Drilling and Completion CostsWolco 4A - $257,000Wolco 5A - $214,000Wolco 6A - $202,000In 2001 a nearby 1200 ft. horizontal wellwith a 300 ft. radius curve had an estimatedcompleted cost of $700,000.Note I changed it to $700,000
44The Initial Project Results Initial Production98% Water CutVERYDISAPPOINTING RESULTS
46The Initial Project Results Initial Production High initial water cut was the problem. The following questions needed to be answered:Note change to text
47The Initial Project Results 1. Why is the oil production below expectations?2. Is water injection occurring belowthe parting pressure?3. How can we increase oil production torealize economic operations?
49The Initial Project Results Step Rate Test ResultsOpened Fractures at 573 psi BHP1725 BWPDFracture gradient of 0.35 pst/ft which isless than a column of water
50The Initial Project Results Significance of Step-Rate TestLow fracture gradient of 0.35 psi/ft helps to explain why conventional waterfloods operating in the range of 0.70 psi/ft have often failed.Low fracture gradient provides additional support for the concept of using horizontal injection wells.
51The Initial Project Results Step Rate Test Operations ChangesInjecting at approximately 1200 BWPDSurface pressure = Vacuum
62The Initial Project Results Reconfigure the Field Pilot ProjectChange from a horizontal waterfloodto oil rim recovery
63Pilot Production Summary MonthlyBefore Pilot ChangeHorizontal Waterflood
64Pilot Production Summary MonthlyAfterPilot ChangeOil Rim Recovery with Vertical Injection
65This pilot was discontinued. Conclusions1. The original pilot recovered very little oil making the results uneconomical.This pilot was discontinued.
66Conclusions2. The pilot was modified by re-drilling the two horizontal wells into the oil rim and using an existing vertical well injecting into the bottom high permeability zone.
67Conclusions3. Simulations with the current reservoir characteristics match the present performance.Year 1
68Conclusions4. In old or abandoned fields where conventional waterfloods were inefficient, production may possibly be re-established with:Horizontal wells placed in the oil rimIn areas of adequate oil saturationReservoirs with sufficient bottom hole pressure
70Horizontal Waterflooding Specific Lessons LearnedInitial production results were disappointing, with an oil cut of 1 to 2%, but total fluid withdrawal and injection rates were as predicted.Use Lessons Learned as title text drop HZ Waterflooding. Replace text: 1. The Bartlesville reservoir has the rock strenght to allow underbalanced air drilling and openhole completions
71Horizontal Waterflooding Specific Lessons LearnedDiagnostic tests on the horizontal injector determined injection parameters, which led operation procedures to keep the injection rates below fracture parting pressure.Use Lessons Learned as title text drop HZ WaterfloodingAdd text: Underbalanced air drilling resulted in no damage to the productivity of the reservoir
72Horizontal Waterflooding Specific Lessons LearnedThe injection profile survey indicated that all of the injected fluid was exiting at the heel of the horizontal injection well. Negating the value of Wolco 4A pressure support.Use Lessons Learned as title text drop HZ Waterflooding note the text added then drop the end of the sentence after end.
73Horizontal Waterflooding Specific Lessons LearnedThe 0.35 psi/ft fracture gradient was much lower than expected. And confirmed the necessity of using bottomhole pressure gauges when conducting step rate tests.Use Lessons Learned as title text drop HZ Waterflooding drop the end of the sentence after expected
74Horizontal Waterflooding Specific Lessons LearnedFractures are dynamic and can take large volumes of water; obtaining injection profiles and step rate test information is vital.Use Lessons Learned as title text drop HZ Waterflooding note text added
75Horizontal Waterflooding Specific Lessons LearnedThe high permeability providing high injection capacity and location of the disposal well, Blake 1A, supplied pressure support for the re-drilled horizontal producers.Use Lessons Learned as title text drop HZ Waterflooding. Note text added
76Horizontal Waterflooding Specific Lessons LearnedRe-drilling the producers (Wolco 6A-4 and 5A-4) up structure (heading NE) and away from the original pilot area was successful because by-passed oil was encountered in compartments.Use Lessons Learned as title text drop HZ Waterflooding Note text added
77Horizontal Waterflooding Specific Lessons LearnedA bottomhole pressure of 125 psi is enough to have adequate withdrawal rates with horizontal producers at ~ 5% oil cut to generate a satisfactory economic rate of return.Use Lessons Learned as title text drop HZ Waterflooding note text added
78Horizontal Waterflooding Specific Lessons LearnedThe character of the layered reservoir with high and low permeabilities was able to be managed by injecting into the high permeability “D” zone in a vertical well and producing the oil rim at top of the lower permeability “C” zone with horizontal wells.Use Lessons Learned as title text drop HZ Waterflooding Note modified text
79DOE Horizontal Project Conclusion Low cost horizontalsNo problem with hole stabilityLow cost logging techniqueLow cost horizontal redrills