Survey and Workflow for HorizontalCompletion Procedures

Randy AndressPrincipal Engineering Consultant

Completion Methods

Open Hole Cased Hole

Open Hole Completions

Bare Foot Slotted Liner Mechanically Staged

Process Packers Plus DirectStim Delta Stim Sleave Zone Select Frac-Point

Bare Foot Completions

Advantages Lowest Cost

Simple

Non-exact Geology/Geophysics

No cementing Zonal Isolation Issues

Limitations Poor Isolation or Staging Options

Borehole Integrity

Open Hole No Tubulars

Slotted Liner

Advantages

Low Cost

Simple

Non-exact Geology/Geophysics

No cementing Zonal Isolation Issues

Maintains Borehole Integrity

Limitations

Poor Isolation or Staging Options

Open Hole Slotted Tubulars

Mechanically Staged Process

Advantages

Excellent Stage or Zonal Isolation

Simplified Pumping Operations

Significantly Reduces Completion Time

Extensive Track Record and Multiple Suppliers

No cementing Issues

System of Isolation Packers and Ball Actuated Ports or Sleeves

Mechanically Staged Process

Mechanically Staged Process

Limitations

Significantly More Expensive

System Subject to Damage While RIH

Tubular ID Restricts Injection Rates

More Precise Geology/Geophysics Required

Utilize Coiled Tubing to Mill Out Ball Seats

Limited Ability to Perform Fracture Diagnostics

System of Isolation Packers and Ball Actuated Ports or Sleeves

Cased Hole Completions

Pump Down Plug and Perf Annular Coiled Tubing Fracturing External Casing Perforating Process

Advantages

Excellent Stage Isolation

Simplified Pumping Operations

Significantly Reduces Completion Time

Extensive Track Record and Multiple Suppliers

Ability to Perform Individual Stage Fracture Diagnostics

Composite Bridge Plug is Mounted to Wireline Perforating Guns and RIH to Setting Depth. The Plug is Charge Set then Gun is Pulled to

the Next Perforating Depth.

Pump Down Plug and Perf

Limitations

Plugs Require Coiled Tubing Mill-Out

Plug May Bridge or Prematurely Set While RIH

More Precise Geology/Geophysics Required

Integrity of Cemented Casing

Composite Bridge Plug is Mounted to Wireline Perforating Guns and RIH to Setting Depth. The Plug is Charge Set then Gun is Pulled to

the Next Perforating Depth.

Pump Down Plug and Perf

Advantages

Excellent Stage Isolation

Multiple Stages Treated Per Day

Reduces Completion Time

Ability to Reverse Out

Ability to Perform Individual Stage Fracture Diagnostics

Utilizes Coiled Tubing and a Jetting-Packer Assembly to Isolate From Previous Stages and Convey a Jetting Slurry to the Depth of Interest.

Fracture Treatments are Then Pumped Down the Annulus.

Annular Coiled Tubing Fracturing

Limitations

Coiled Tubing May Stack-Out Short of TD

Rate Restrictions Due to Annular Size

Depth/CT Size Limitations

Potential Tool Sticking Due to Low Side Proppant Build-up

More Precise Geology/Geophysics Required

Integrity of Cemented Casing

Coiled Tubing adds Significant Costs

Annular Coiled Tubing Fracturing

Advantages

Excellent Stage Isolation

Multiple Stages Treated Per Day

Significantly Reduces Completion Time

Hydraulic Line Can be Used as Dead String

External Perforating Guns and Integral Isolation Valves are Attached to the Casing and RIH Prior to Cementing Casing. The Guns are Individually Fired Using an Attached Hydraulic Line and Pre-set

Hydraulic Pressures.

External Casing Perforating Process

Limitations

Coiled Tubing Mill-Out of Isolation Valves

Rate Restrictions Due to Tubular Size

System Subject to Damage While RIH

Very Precise Geology/Geophysics Required

Integrity of Cemented Casing

More Expensive Than Other Methods

External Casing Perforating Process

So, Whats Best?

Depends

Open Hole vs. Cemented Casing Stress Direction Formation Height, Fluid Contacts, Frac

Barriers

Permeability Reservoir Petrophysical Knowledge Offset or Field Data

Open Hole vs. Cemented Casing

Undulating Directional Profile Could Impact Sweep Efficiency During the Cementing Process and Compromise Zonal Isolation

Loss Zones Could Steal Cement Slurry and Compromise Zonal Isolation

Extended Reach Horizonal Boreholes Could Present ECD Issues Which Impact Full Circulation

Waiting on Future Reservoir or Petrophysical Data May Dictate Casing and Cementing Open Hole

Stress Direction

Stress direction is the key determinate of hydraulic fracture orientation in horizontal wells

Wells drilled in the direction of maximum horizontal stress will yield longitudinal fractures (Parallel to the wellbore). While this might be desirable in moderate permeability reservoirs, it is not ideal for micro-perm formations.

Conversely, wells drilled perpendicular to the maximum horizontal stress will facilitate transverse fractures. Multiple transverse fractures will contact a much larger volume of reservoir rock.

Formation Height, Fluid Contacts, Frac Barriers

Reservoirs containing gas-oil or gas-water contacts are better suited for multiple small longitudinal fractures to control fracture growth thru the fluid contacts.

Reservoirs with thin pay sections or with solid fracture barriers are more economically completed and stimulated with longitudinal fractures.

Permeability

Reservoirs with micro-permeability will require multiple transverse fractures to contact as much rock as possible.

Reservoirs with moderate permeability will not require the massive stimulation. Two to four properly spaced longitudinal fractures will be adequate to cover the horizontal section. This will also apply to reservoirs with moderate to good vertical permeability.

Reservoir Petrophysical Knowledge

If the level of reservoir and petrophysical knowledge is high, the mechanically staged process will be the most effective method to maximize reservoir coverage and minimize drilling and completion time. However, if the level is low, this could be the most costly and inefficient choice.

If the level of reservoir and petrophysical knowledge is low, (or waiting on data), cementing casing and then utilizing the Pump Down Plug and Perf method will be more effective. This method will allow individual stimulation and testing prior to moving to the next interval.

Offset or Field Wide Data

Run casing and cement if waiting for: Offset well to be drilled Additional reservoir or petrophysical data Micro-seismic operations