Though relatively simple, rod-actuated pumping systems are sensing some high-tech surges in control equipment.

Automating beam-pumping systems across entire fields has been a somewhat elusive goal through the years, even though bottomhole displacement-type, rod-actuated beam pumps have dominated the oil production landscape since Day One.
But the march toward automatically controlling the beam-pumping process has taken a number of advances in recent years, particularly since the burgeoning information technology boom entered the industry's upstream segment in a big way.
At one end of the spectrum, newer-generation downhole rod pumps have become more dependable and trouble-free, while at the other extreme, the efficiency and dependability of surface-mounted pump jacks also have improved. Both help producers lower production costs and optimize per-well recoveries.
But computer software now allows production engineers to match field experience with new modeling programs to help choose the right pumps for specific applications. Unlike years past, when field managers chose off-the-shelf pumps that fit the general specifications for certain well sizes, the burgeoning computer technology to which they have access today truly recognizes that no two wells are alike. Specific pumps and rods can be chosen for individual wells, and the result has been optimized production with fewer pump, rod string and tubing problems and, therefore, fewer well interventions.
Real-time monitoring, control
But the most progress in the beam-pumping universe has been in monitoring the various pumping processes and controlling them from remote locations, on the surface and down the well. Computer-based controllers are helping field workers and asset managers keep abreast of the real-time condition of entire oil fields. That's a quantum leap from days not long past, when field hands visited individual wells to conduct the time-consuming job of gauging pump and jack performance. That sometimes took weeks to accomplish for an entire field; meanwhile, problems often couldn't be detected until after damage made a service intervention necessary.
With the sophisticated hardware, software and telemetry available today, however, field operators can inspect - and control - many more wells per day. Other products, connected to each well through telemetry, allow operators to monitor and adjust pumping system parameters either at the well or from a central location.
But problems common to all rod-pumped wells occur. Field pumpers still use dynamometers to produce "cards" to reflect pump performance and identify incipient problems. However, several controller improvements are helping to better identify such problems and correct for them automatically.
One such new controller is Lufkin Automation's Sam Well Manager, which the Houston, Texas, company recently introduced. Rather than using surface dynamometer card information or prime mover power changes only, the Sam unit takes a surface card reading on every pump stroke, then uses Lufkin's patented DIAG 5.0 algorithm to calculate a downhole dynamometer card.
Lufkin officials deem this downhole card to be the industry's most accurate reading of what's happening in a beam-pumped well. It provides accurate information about pump efficiencies, intake pressure, producing pressure, tubing and pump leaks, gas interference and other downhole conditions. The DIAG 5.0 software also deals with beam-pumping systems for deviated wells, company officials said.
Controller becomes analysis tool
The information stored by the Sam unit can be accessed through a keypad and screen at the wellsite, or it can be downloaded into a laptop computer. Also, with the addition of separate data transmission and reception technology, it can be accessed via telemetry for remote operation.
After completing engineering and field testing earlier this year, Lufkin Automation is marketing Sam as an analytical tool, since it stores surface and downhole cards in memory at every pump stroke, said Andy Cordova, marketing manager. With these data, he said, producers can monitor the well for changes that might indicate a potential problem.
"For example, using data from the surface card, a controller is programmed to shut the pump off if it appears to be 'fluid pounding," said Cordova. Fluid pounding occurs when the pump strikes the top of the fluid with a less-than-full cylinder, causing damage to pump elements, connections and rods.
But if the pump is lifting a gassy fluid, for example, it could be filling properly, yet the surface card data may identify fluid pound and shut the pump off erroneously, Cordova said. If that happens, the operator's lifting cost increases due to interrupted production and the need to send a field technician out for a closer look.
In such cases, the added information from the Sam downhole card could indicate that no fluid pounding has occurred, and the well would remain on line, said Cordova.
"On the other hand, the downhole card can help confirm the onset of real problems indicated by the surface card," he said. "Producers using telemetry will find this particularly useful, since they can send a field specialist to the well before a breakdown occurs or, when it does occur, have a pulling unit dispatched immediately to minimize well downtime."
The main benefit of the Sam Well Manager is maintaining balance, Cordova said.
"You don't want your controller to allow the pump to run too long in a pumped-off state," he said. "That wastes power and causes rod, tubing and pump damage expenses. Conversely, you don't want the pump to shut off too soon, because that results in lost production costs."
Software updates for the Sam will become available from time to time, Cordova said, since an added expansion bus containing additional I/O and communications ports allows the unit to grow with the producer's requirements.
"Because it stores its software in flash memory, upgrades can be loaded into the system easily, either by hand or via telemetry," Cordova said.
Oxy orders 800 units
Even though the Sam is only now being marketed freely, Lufkin Automation already has sold a passel of them.
Occidental Petroleum Corp. purchased 800 units for installation in the Elk Hills field. The units will succeed Lufkin Automation MPC controllers at the 800 wells. Installation will be phased in during a 6-month period.
In 1998, Oxy acquired the 74-sq mile (192-sq km) field from the US government. The field, in California's San Joaquin Valley near Bakersfield, has produced more than 1 billion bbl of light oil since its discovery in 1910.
Bob Barnes, field superintendent, said the addition of the SAM Well Managers will give Oxy the ability to better control wells, due chiefly to inclusion of the downhole card for each well. (The MPC controller produces only a surface card.)
The SAM units, once installed, will be controlled from two central telemetry points, one in the eastern section of the field, the other in the western half.
"This will save money in energy efficiency and in production optimization," Barnes said, "and we believe we'll get more longevity from the pumping equipment."
Most, if not all, of the wells at Elk Hills are directional, Barnes said. The main formation being tapped is the Stevens Sand, at an average depth of about 5,500 ft (1,678 m).
Barnes said infill drilling continues in the field, and that the company could install as many as 1,200 Sam units at Elk Hills.
The "Sam" in the product name comes from Sam Gibbs, longtime technical manager at Nabla Corp., which was purchased by Lufkin Industries in 1997. Gibbs formulated the original DIAG algorithm. In 1998, Lufkin Industries also purchased Delta X Corp. and combined the two companies to form Lufkin Automation.