Artificial Lift

Sucker rods are subjected to cyclic stress which leads to fatigue failure. It is well known that the shot peen process increases the fatigue life on metal parts. Although several manufacturers implemented shot peening in the sucker rod manufacturing for years, optimal parameters that yield a dramatic increase in fatigue life require extensive studies on both input parameters and comparative fatigue testing.

With the increase in horizontal completions and multi-stage sand fracturing, sand problems and the detrimental affect that arises from excess sand production have increased significantly over recent years. The simple fact remains that although both ESP and rod pumps can handle some amounts of sand, they are both liquid pumps and excessive sand production reduces system efficiency and shortens the effective life span of the pumps. This has resulted in higher maintenance costs and reduces run times which are costly to producers.

Workover operations effectively probe the wellbore using the rods or tubing. Friction encountered as the rods or tubing pass through the wellbore can be measured at surface. By applying wave equation methods to eliminate surface dynamics, a measure of friction acting along the remaining rods can be quantified. Because the workover process methodically removes rods, a map of friction through the wellbore can be obtained. The act of pulling rods is virtually identical to a deep rod part, and each pull of the rods eliminates friction previously acting below the remaining rods.

A process for modeling multivariate Electric Submersible Pump data in a central host system is proposed in to support managing fields by exception by using artificial intelligence models to identify failure modes and operating conditions. The AI model enables operators to immediately identify failure modes and operational conditions, as it is continuously analyzing, facilitating quicker decision making. It also increases the number of wells an operator can effectively manage, and can be used as an educational tool, empowering users to interpret complex ESP trends.

Field case studies for Harbison-Fischer’s latest enhanced Back Pressure Regulator (BPR) has increased production for multiple operators in the Permian Basin. Back pressure regulators have operated successfully under rod lift conditions in wells that include intermittent flow, low fluid production, and a wide range of gas production. But when tested in wells with Electrical Submersible Pumps (ESP), constant production rates between 2,000 and 3,000 BPD, and large amounts of sand, it caused accelerated wear that resulted in costly cleaning jobs and unsafe working conditions at the wellsite.

Major operators in North America performed field case studies for a new coated plunger. During this time pump repair data was collected from Harbison-Fischer’s pump tracker system, while the field operator captured well conditions and parameters through their well tracker system. A total of 28 wells known for premature spray metal plunger failures, due to severe abrasive wear created by high solids concentration have run the new coated plunger since January of 2018.

In the past 10 years, drilling methods have drastically reduced the time it takes to drill wells. This is especially true in today’s unconventional shale market where 20,000 ft wells are being drilled in under 14 days. This increase in drilling rates along with increasing depths and deviations has presented many challenges for the conventional rod lift system, which was designed to last for ten years but are now having issues within the first twenty-four months resulting in substantial increases in workover costs.

In principle, no well is perfectly vertical since deviations in the drilling process are inevitable. Moreover, the number of intentionally deviated wells has steadily increased over the years. Complex three-dimensional borehole trajectories give rise to a number of physical phenomena that are usually negligible when the borehole is intended to be drilled as vertical. Those include three-dimensional vibrations of the rod string and mechanical (or Coulomb) friction between the rods/couplings and the tubing. Also, the impact of gravity becomes more subtle.

Two widely used methods of artificial lift are Electrical Submersible Pumps (ESP) and Sucker Rod Pumps (SRP. Each of these methods frequently require methods to avoid or handle gas for successful operations. Presented here are discussions of methods of gas separation for each method and graphical techniques for prediction of the gas separator performance that will allow the user to better select a workable gas separator system and predict maximum well drawdown with the selected method of lift. 
 

Surface coatings are commonly used in many industries including oil and gas with the aim of hardening the part surfaces to improve wear resistance without compromising the corrosion resistance. Sucker rod pumps employ several parts with coated surfaces as well, including the pump barrels. Both standardized surface modifications and specialty applications for pump barrels are readily available in the market for different well conditions, including extreme well solids and H2S or CO2 service.