Ryan Hieronymus, OXY
OBJECTIVES/SCOPE:
The presentation will review a new modeling workflow utilizing dynamic, iterative nodal analysis with cumulative-based IPR indexing to generate production profiles for different operating scenarios for a given base-case production forecast. Output profiles can be tested for value in an
economic model. This workflow has been used to rebase the high-pressure gas lift strategy in Delaware Basin and evaluate production impacts of other initiatives (surface-controlled gas lift and smaller annular areas).
METHODS, PROCEDURES, PROCESS:
The workflow starts with a production profile reflecting a base-case operating mode (type curve or production forecast). A reservoir pressure profile is generated based on EUR, cumulative production, and initial pressure. A flowing bottomhole pressure (FBHP) profile is calculated. The
combination of reservoir pressure and FBHP profiles provides IPRs at each point in cumulative production. A parallel profile is then calculated for the alternative case: for each point, IPR is consistent with the base profile at the same cumulative production. Injection depth and production rates are calculated for each day of the alternative case.
RESULTS, OBSERVATIONS, CONCLUSIONS:
Direct comparisons of offset well performance are often obscured by differences in well characteristics (depletion, drilling quality, completion execution, operations). Reservoir simulation, an alternative, is time-intensive and not typically performed outside specific cases. An evaluation
technique was needed to fill the gap between offset comparison and reservoir simulation. This new workflow was first utilized to assess production impact of high-pressure gas lift in Delaware Basin, and found that the value of high-pressure gas lift is more dependent on fluid composition and productivity than on oil EUR (prior metric for selecting high vs. low pressure). Application of the workflow catalyzed a pivot in strategy: high-pressure gas lift was removed from scope on new wells where it was found not to be value accretive, resulting in cost savings. On a smaller set of new wells, the workflow affirmed that high pressure gas lift was value accretive and was maintained in scope. The workflow was also utilized to support field development by assessing production impacts of other initiatives (surface-controlled gas lift and smaller annular area during annular gas lift).
NOVEL/ADDITIVE INFORMATION:
The workflow has been a valuable tool to assess early-life production acceleration opportunities. These opportunities, by definition, do not lead to incremental EUR (no change to late life artificial lift method and terminal FBHP), but rather serve only to accelerate barrels from later years into
earlier years. In evaluation of such opportunities, the time-value of the production acceleration must justify the additional cost (which is usually not an acceleration but is additive to existing cost structures). This workflow has provided insight into which factors have larger impacts on
production acceleration, and which have lower impacts.