Shell Exploration & Production Breakout Session Low Rate Wells, Gas Wells, Unloading after Stimulation

Post-Stimulation Unloading and Operation Hydraulic Fracturing Acid treatment Coiled Tubing / Bullhead Concern about unloading due to unaerated liquids Cannot do slickline work if acid in tubing Nitrogen / Fluid Commonly no problems unloading because of nitrogen assisting the flowback production

Acid – Bullhead treatment method Common procedure Set Plug, test tubing If tubing test is good, pump acid job If tubing test is bad, replace GLVs, pump acid job If acid job does not complete, switch to flush fluid and frac way acid.

Acid – Bullhead treatment method Alternative procedure Install new valves (AFLAS packing) in all mandrels, designed to unload acid / flush fluids No need to frac fluids if job fails Unload / kickoff well Run Flowing Gradient Survey Re-design / replace valves for new conditions

Hydraulic Facture Treatment Produce liquids a high rate to clear proppant from wellbore before installation of rod pump equipment Use multi-rate design for shallow lift at high rate, but ability to lift deeper if rate is lower than desired

Gas Wells Wellhead Backpressure Reduction Chemical treatment Gas Lift Wellsite compression Chemical treatment Foam / surfactant Gas Lift increase mixture vertical velocity with gas Reduce hydraulic flow area Velocity string, Siphon string, Diptube, Tubing extension Can lift / produce from below perfs if desired

Low Liquid rate gas lift Conventional and retrievable equipment used May have conventional above, retrievable on bottom Pulling units in high demand, so more retrievable equipment is being used. Like to have lift pressure of 100 psi per 1000 ft. of lift depth Common pressures are 750 to 850 or 1000 psi

Low Liquid rate gas lift Economic issue, not a mechanical / physical limitation. How much gas are you willing to expend for the liquids produced. Consider $60/bbl oil and $15/mcf gas Compression costs Wellhead compression is relatively inexpensive $1300/month for 15 mcfd additional production Higher compression ratio costs ~ $0.20/mcf $2700/month for 600 mcfd @ 1100 psi