The science of artificial lift has evolved dramatically, driven by operational challenges ranging from high-pressure/high temperature deepwater oil reservoirs to liquids loading in natural gas wells producing below the critical rates and pressures needed to keep wellbores unloaded.
Arguably the biggest step changes in artificial lift technology, however, are being driven by the proliferation of horizontal wells in onshore resource plays, with their characteristic multiphase flow regimes and steep decline curves, according to Lloyd Heinze, a professor of petroleum engineering at Texas Tech University and executive director of the Southwestern Petroleum Short Course.
While more than 95 percent of all U.S. oil wells require some form of artificial lift (as do increasing numbers of gas wells), Heinze says future advances will revolve around two key challenges:
- Lifting the full liquid contents of long horizontal well sections as operators continue to extend lateral lengths; and
- Separating water down hole so that it does not have to be lifted to surface and then either disposed of or treated and recycled.
Regardless of the type of artificial lift technology, Bobby Mason, president of SPOC Automation, says oil and gas companies should look to automation and control systems to help keep equipment running as efficiently as possible, lower lifting costs, save energy, and ultimately, ensure that wells are generating revenue.
A key element in any artificial lift control and automated production operation is the variable frequency drive (VFD) that controls pump speeds and run times. According to Mason, three key attributes are guiding operators’ deployment of VFDs: ease of use, energy efficiency, and reliable communications capability.
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