Revitalizing Mature Oilfields
Extracting the Last Economic Barrel from Mature and Marginal Oil Fields — Bypassed-Pay Identification, Artificial-Lift Optimization, and Waterflood Redesign — Worldwide
Assign your company's mature or marginal oil fields to A&A, and let the high-level, seasoned consultants of the A&A Consulting Team find the economic barrels your field's current operating plan is leaving behind.
Avasthi & Associates, Inc. (A&A) is an independent petroleum engineering and geoscience consulting firm. A&A does not sell logging tools, artificial-lift equipment, or injection-system hardware — our only business is expert technical consulting, which means our recommendations for revitalizing your field are never influenced by a stake in any particular vendor or technology.
Much has been written about revitalizing mature oilfields. Operators occasionally get fortunate by finding a bypassed oil zone that was never perforated, resulting in a burst of new oil production. That production, however, is often short-lived, limited by the size of the bypassed pay.
A&A's Three-Pronged Approach to Field Revitalization
The high-level, seasoned consultants of the A&A Consulting Team have worked for many years extracting the last economic barrel from mature and marginal oilfields, and can quickly identify whether a field still has good potential. A&A's consultants have also developed unconventional techniques that can considerably extend a field's productive life. These methods include:
• Bypassed-Pay Identification: Running pulsed neutron or carbon/oxygen (C/O) logs behind casing to locate bypassed oil zones
• Fluid-Recovery Maximization: Using gas lift or electrical submersible pumps (ESPs) to raise total fluid withdrawal, so that economic oil production can be sustained even at higher water cuts
• Waterflood Redesign: Injecting water to raise reservoir pressure and alter production streamlines, sweeping bypassed oil toward the producing wells
Why So Much Oil Is Still Behind Pipe
Many wells were plugged back when oil prices were low — even when they were still producing at rates that would be considered attractive by today's standards. Many operators were also constrained by their existing mode of production (flowing, rod pumping, or gas lift) and could not justify producing the reservoir at higher withdrawal rates because of the high upfront capital investment required. Few operators would have considered injecting water into a moderately strong waterdrive reservoir to alter the flow streamlines and improve oil recovery. At today's oil prices, several of these alternatives are attractive again.
The first step in assessing the potential of a mature or marginal oil field is to compile thorough well histories — perforations and production records for every zone. A 20 BOPD producer in the 1950s or 1960s looked unattractive next to the zones further up the wellbore, but that same zone can provide substantial cash flow today. Many wells were plugged back early in their life because of higher anticipated production from the zones above them, leaving behind many barrels of bypassed oil that can now be recovered at today's oil prices.
Maximizing Fluid Recovery
The economics of low-oil price period often prevented the installation of large gas-lift systems or submersible pumps in small fields, which limited fluid withdrawal rates and reduced the oil percentage that could be considered economic. By installing sand control where required, and producing wells at higher fluid rates today, operators can achieve increased oil reserves from the same wellbores.
Redesigning the Waterflood
Although not the most obvious method for increasing oil recovery from a mature oilfield with a strong waterdrive, injecting water into selected wells can alter the flow regimes (streamlines) within the reservoir. A&A's consultants have seen this firsthand: in one strong-waterdrive reservoir, water injection ahead of CO2 injection achieved higher oil recovery than either method could have achieved alone. The water injection not only raised reservoir pressure — increasing well productivity — but also pushed bypassed oil, held back by well spacing, toward the producing wells. As reservoir pressure increased, the wells' high productivity index allowed for increased production, while the water injection pushed oil away from faults and unswept areas of the reservoir to increase overall oil recovery.
What A&A Delivers
A field-revitalization study from the A&A Consulting Team is built around the practical decisions your company needs to make, including, but not limited to:
• A well-by-well and zone-by-zone screening of bypassed-pay candidates, ranked by estimated economic potential
• Artificial-lift and fluid-recovery optimization recommendations (gas lift, ESP, and sand control) tailored to your field's wells and facilities
• Waterflood pattern redesign and streamline analysis to sweep bypassed oil toward existing producers
• Where applicable, an integrated evaluation of CO₂ EOR potential alongside waterflood redesign
• Presentation-ready recommendations and economic justification for your company's management, partners, and investors
The high-level, seasoned consultants of the A&A Consulting Team have extensive experience revitalizing mature and marginal oil fields, and will be delighted to help your company maximize oil production rates and reserves from its mature or marginal oil field assets.
A&A can assemble teams of high-level, seasoned consultants — with extensive experience revitalizing mature and marginal oilfields — to work on our clients' field-revitalization projects, around the world, whenever required.
To find out how A&A can help your company on its mature/marginal oil field revitalization projects, around the world, please contact us (Contact@AvasthiConsulting.com) or click here.
