Multiphase Measurement Technology and Sampling Increase Auto Gas Lift Well Production by 40% | SLB
Case Study
Location
Onshore, Offshore
Details

Challenge: Control gas inflow and maximize oil production by optimizing inflow control valve (ICV) configuration and accurately measuring flow rates

Solution: Use PhaseTester portable multiphase well testing equipment with Vx multiphase well testing technology to measure flow rates and acquire surface samples during flow to characterize effluents and confirm production after performing auto gas lifting processes

Result: Brought wells back on production, increasing total field production by 40% and minimizing well interventions

Multiphase Measurement Technology and Sampling Increase Auto Gas Lift Well Production by 40%

PhaseTester equipment with Vx technology quantifies performance of artificial lift method, enabling successful recompletion in Middle East

Seeking production enhancement solution for underperforming wells

An operator in the Middle East was producing from mature oil wells drilled in fields with clastic reservoirs. Over time, substantial amounts of gas and water production had choked back the oil, impairing production from the wells to the point that they were unable to maintain natural production for long periods of time. Because of substantial reductions in oil production, the operator was considering various artificial lift methodologies to revitalize these underperforming wells.

Conventionally, gas lift would be the optimal method because of the field’s GOR and flow rate fluctuations as well as early water breakthrough. This method, however, requires developing and building an extensive pipeline network at a higher cost and a two-year lead time.

Reliably measuring multiple phases with portable test equipment

To decrease time and associated costs, the operator collaborated with Schlumberger and decided to use auto gas lifting (AGL), an artificial lift system that uses existing gas from an associated or nonassociated gas reservoir to enable or improve production from an oil reservoir. AGL is an attractive alternative to conventional gas lifting because the method

  • reduces capex by eliminating the need for a compressor and gas lift piping
  • reduces opex by minimizing well interventions, compressor power, and maintenance
  • has simple installation and superior well integrity
  • sustains stabilized production
  • reduces footprint and starts up the well faster after any plant shutdowns.

The operator requested that the Vx Spectra surface multiphase flowmeter be integrated into its drillout operation along with standard drillout equipment. The Vx Spectra flowmeter gives an output of three-phase flow rates in standard conditions through low-energy gamma radiation measurements with fluid dynamic models. By measuring from a single point in the venturi throat, the flowmeter is able to constantly determine the precise phase fractions of water, oil, gas, and solids during the job.

To determine the differential pressures during the job, Schlumberger set up two pressure sensors on the inlet and outlet of the plug catcher, both connected to the Vx Spectra flowmeter. Differential pressure acquired by the Vx Spectra flowmeter was integrated with measured proppant flowback data to identify when the solids would return to surface. Additionally, coiled tubing data was used to identify the return time for plug debris and for pumped gel sweeps. With these advanced data acquisition and evaluation processes, the well operator was able to obtain better control of the plug drillout process.

Top: Flow rates measured on a fixed surface choke at various ICV slot settings. Only the gas zone is open to flow. | Bottom: Flow rates measured on a fixed surface choke at various ICV slot settings. Both oil and gas zones are flowing commingled.
Top: Flow rates measured on a fixed surface choke at various ICV slot settings. Only the gas zone is open to flow. | Bottom: Flow rates measured on a fixed surface choke at various ICV slot settings. Both oil and gas zones are flowing commingled.
overflow image
Oil vs. gas flow rates as measured on a fixed surface choke at various ICV slot settings.

Recompleting wells with 40% increase in total field production

The dynamic response of PhaseTester equipment with Vx technology made it possible to quickly estimate well performance, even during the ICV slot changes. Well performance analysis of the multirate tests was conducted to quantify well performance and deliverability. Using PhaseTester equipment with Vx technology introduced a number of advantages for the operator, such as optimizing the oil inflow by controlling the gas inflow with an ICV and dynamically measuring the flow rates, building a choke–ICV correlation to be used as a baseline, and accurately back-allocating the surface production to two reservoirs.

The successful application of the AGL method was proven at the fullfield scale by the operator. All wells were recompleted and put back on sustained production, and total field production increased by 40%. Further, the operator required fewer well interventions and accrued significant capex savings.

Measured condensate/gas ratios (CGRs) and mole percentages (C7+) of the recombined fluid. Flow periods 3–7 are at a fixed surface choke at various ICV slot settings while flowing only the gas zone to the surface. Flow periods 8–10 are at a fixed surface choke at various ICV slot settings while flowing oil and gas zones commingled.
Measured condensate/gas ratios (CGRs) and mole percentages (C7+) of the recombined fluid. Flow periods 3–7 are at a fixed surface choke at various ICV slot settings while flowing only the gas zone to the surface. Flow periods 8–10 are at a fixed surface choke at various ICV slot settings while flowing oil and gas zones commingled.

Share This