Minimum miscibility pressure is where gas injection projects are won or lost technically. Above it the displacement is miscible and residual oil saturation approaches zero in the contacted region; below it the displacement is immiscible and a substantial residual remains. The margin between reservoir pressure and MMP therefore determines the recovery mechanism, and MMP determination methods disagree with each other by amounts that can straddle the reservoir pressure. Slim tube testing is the accepted standard and is slow and expensive; correlations are fast and imprecise; equation of state calculation depends on how well the fluid model is tuned near the critical region.

Mobility ratio makes sweep the limiting factor. Gas is far less viscous than oil, which produces a mobility ratio strongly unfavourable to stable displacement, and the consequence is viscous fingering: the gas advances in narrow channels rather than a uniform front, breaks through early and thereafter recycles. Gas is also far less dense than oil, which produces gravity override in which the gas rises to the top of the reservoir and sweeps only the upper part. Miscible displacement is efficient at the pore scale and can still recover poorly if the gas contacts only a fraction of the reservoir.

Water alternating gas exists to address this. Alternating slugs of water and gas raise the average injected fluid mobility, reducing fingering, and the water helps suppress gravity override. The design variables, WAG ratio, slug size, cycle count and tapering, determine how effectively it works, and they interact with reservoir heterogeneity, wettability and hysteresis in the relative permeability curves. WAG also reduces injectivity and introduces three-phase flow, which simulation represents poorly.

Finally, gas injection is a supply and facilities project as much as a reservoir project. The injected gas must come from somewhere, produced gas must be separated and recompressed for reinjection, and the recycle volume grows as breakthrough progresses until compression becomes the binding constraint. Projects have been limited not by reservoir performance but by compression capacity that was sized on early-life recycle volumes.

By the end of this training, participants will be able to:

• Explain miscibility development mechanisms and identify which applies to a given gas and oil system
• Determine minimum miscibility pressure using slim tube, rising bubble, correlation and equation of state methods
• Assess the reliability of MMP determinations and the consequence of the margin to reservoir pressure
• Evaluate immiscible and miscible displacement behaviour and their expected recovery
• Analyse mobility ratio, viscous fingering and gravity override and their effect on sweep
• Design gravity stable and gravity assisted gas injection where reservoir geometry permits
• Design water alternating gas schemes including ratio, slug size, cycling and tapering
• Diagnose conformance problems and evaluate foam, gel and mechanical control options
• Specify compositional simulation requirements for gas injection processes
• Plan field implementation including gas supply, recycle, compression and facility requirements

The training develops the phase behaviour and displacement physics and then applies them to design decisions using field and laboratory data. Participants perform MMP calculations by correlation and compare them with slim tube results, calculate mobility ratios and assess fingering and override risk, and design WAG schemes for defined reservoir conditions. Compositional simulation behaviour is examined for the sensitivities that matter. Gas injection projects, including CO2, hydrocarbon and nitrogen floods, are examined for the recovery achieved and the technical factor that determined it.

Organisations sending participants to this training will:

• Screen gas injection opportunities correctly against miscibility and sweep criteria
• Avoid projects designed on MMP determinations that do not support the assumed mechanism
• Improve sweep and recovery through better WAG and conformance design
• Size compression and recycle facilities against realistic late-life gas volumes
• Improve the technical basis of gas injection investment decisions
• Build capability applicable to CO2 injection and storage projects as well as hydrocarbon gas

Participants will:

• Determine and defend a minimum miscibility pressure
• Predict whether a gas flood will be sweep limited and by what mechanism
• Design WAG schemes with a technical basis for each parameter
• Specify compositional simulation studies that will represent the process correctly
• Anticipate gas recycle and facility constraints
• Build a specialist capability shared with CO2 EOR and storage work

• Reservoir engineers working on gas injection and enhanced recovery
• Simulation engineers modelling compositional processes
• Production and facilities engineers supporting gas injection projects
• Development engineers evaluating recovery options
• Technical staff working on CO2 EOR and storage projects
• Reserves and evaluation engineers assessing gas flood reserves
• Asset managers considering gas injection investment

Upon successful completion of this training course, delegates will be awarded an official Certificate of Completion issued by the Petroleum Engineers Association (PEA), an ISO 9001:2015 certified training organization. The certificate carries 10 Credits and formally records the total learning hours completed.

Each certificate is signed by the Course Facilitator and the CEO of the Petroleum Engineers Association, and serves as verifiable proof of professional training that delegates can present to employers and professional bodies worldwide.