Rod pumping horizontal wells is more complicated and challenging than for vertical wells. For system reliability reasons, it is common for horizontal wells to have a rod pump placed in the vertical section above the wellbore’s curve, which limits drawdown. This means the pump is placed a vertical distance above the producing zone and a pressure gradient of fluid between the pump and the producing zone exists. This pressure gradient can add 200- 500 psi of back pressure to the producing zone, limiting drawdown.
Drawdown is also limited by multiphase flows emanating from the horizontal wellbore that are inconsistent and sluggy. Flow regimes and inconsistent flow slugging tendencies are different in the horizontal, curve and vertical sections of the wellbore and these sections can compound each other for a bad unmanageable slugging condition at the pump’s location. Such inconsistent flows make efficient downhole pump gas separation very challenging. Consequently, a troublesome fluid level in annulus above the pump often remains. This fluid level can add an additional 200-500 psi of back pressure to the producing zone, further limiting drawdown.
To resolve these drawdown limitations and to therefore maximize drawdown, the pump would need to be lowered down into the curve section of a horizontal well. This presents several reliability risks, including:
• reduced run life with increased wear on the pump, rods and tubing,
• increased costs for surface pumping equipment and rod string due to increase loadings,
• reduced downhole gas separation efficiency at high wellbore inclinations, and
• reduce rod pump performance with valves not opening and closing efficiently at high inclinations.
Engineering a rod pumping system to operate at high inclinations reliably around the wellbore’s curve was undertaken. Field implemented has demonstrated a high success rate for dramatically increasing production and achieving good slugging conditions, while not realizing an increase in failure frequency. Results will be reviewed and shared.

Sucker rods are an essential component for rod pumping or rod lifting of oil and gas wells, but they have been limited by the use of metals and thermoset based non-metal composites (i.e., existing fiberglass sucker rods). Steel (metal) sucker rods have been limited by a low corrosion resistance, a low strength to weight ratio (i.e., too heavy), a low fatigue endurance limit and a relatively poor environmental, social and governance (ESG) rating during its lifecycle. Composite thermoset glass fiber (fiberglass) sucker rods have been limited by a low tensile modulus of elasticity (i.e., too stretchy relative to steel), a high cost (i.e., higher cost relative to steel), and a low toughness (i.e., low tolerance to compressional loads or high impact forces). Metal end fittings have also been a costly challenge for thermoset composite rods. Composite thermoset sucker rods using carbon fibers have offered a tensile modulus of elasticity comparable to steel but have been limited primarily by a very high relative cost to steel sucker rods.
Rod lifting has been further challenged by unconventional reservoirs and associated well designs comprised of vertically deep and long horizontal wellbores, where production is commonly comprised of high gas to liquid ratios and high initial liquid rates but with associated high decline rates. Electrical submersible pumps and gas lifting artificial lifting system are commonly used during the initial high production rate phase but eventually the well is transitioned to lower operating expense (OPEX) sucker rod pumping. Being able to transition to rod pumping as early as possible and at the highest production rate possible often provides the most attractive well economics. Unfortunately, high rate deep rod pumping has been challenged by excessive failure frequencies, mostly related to sucker rod failures. It is apparent that a cost effective and high reliability solution for deep high rate rod pumping is needed.
An ideal sucker rod for resolving its current limitations and application challenges has been defined and characterized as follows:
1. High strength to weight ratio,
2. High tensile modulus,
3. High toughness and fatigue/endurance limit,
4. High corrosion tolerance,
5. Cost comparable to low carbon steel alloys (i.e., KD rod), and
6. High ESG sustainability rating being recyclable and manufactured with a relatively low carbon footprint.
A composite material was identified, and it was hypothesized that it had the potential to satisfy development of an ideal sucker rod. Unidirectional fiber reinforced thermoplastic (FRTP) composite materials have gained significant attention in recent years due to their high strength/toughness, lightweight, excellent corrosion resistance, being partially recyclable with a relatively good lifecycle ESG rating and having comparable costs to steel sucker rods. This paper focuses on the development of fiber reinforced thermoplastic (FRTP) sucker rods, highlighting their potential advantages and challenges, for rod pumping (in general) and for offering an earlier transition from ESP pumping or gas lifting to reliable deep high rate rod pumping. 
The development of fiber reinforced thermoplastic (FRTP) sucker rods involves the integration of unidirectional high-performance fibers, such as carbon or glass, into a semi-ductile thermoplastic matrix. This is vastly different from thermoset composites, which use a hard and relatively brittle epoxy matrix around the fibers. A major and unique feature of an FRTP composite rod is its remarkably high shear failure resistance as compared to a thermoset composite rod. A high shear failure resistance means the rods have compressional loading tolerance and that an entire sucker rod string could be comprised of FRTP sucker rods. The design process, prototyping/testing and recent well trials/results show promise for FRTP sucker rods. This paper explores the development of fiber-reinforced thermoplastic sucker rods as a promising alternative for overcoming the limitations of steel sucker rods and thermoset fiberglass sucker rods. Field trials will be shared and reviewed.

A sucker rod pump is an essential component for rod pumping, but it has been limited by use of machined componentry and a ball/seat valve design. Today’s deep, gassy-sluggy, foamy, solids ladened, horizontal wells commonly have high initial liquid rates that are beyond the rate capacity of sucker rod pumping, which can require use of higher operating expense ESP’s or gas lift methods. Improving the rate capacity and reliability of sucker rod pumping in such challenging environments would be highly beneficial for producers.
The sucker rod pump is one component of a complex downhole system of components for sucker rod pumping. Other components of this system include a downhole gas separator, a downhole solids separator, a tubing anchor and sucker rods. To maximize the efficiency and performance of a sucker rod pump, all these components must act together harmoniously to effectively feed the pump on demand with liquid that has been gas and solids depleted – unfortunately, achieving this has been particularly challenging. Consequently, the sucker rod pump still must contend with gas and solids.
Further, with deep high-rate sucker pumping, an acceptable reliability failure frequency has been particularly challenging. Larger and longer stroke length pumping units have improved the rate capacity of sucker rod pumping but have been limited primarily by excessive pressure loss across the pump’s standing/travelling valves, by pump gas interference and by inadequate reliability from damaging solids. Lastly, compressional loading events on the sucker rods at the commencement of each pump downstroke has also reduced system reliability.
An improved sucker rod pump was conceptualized, and design engineered for such challenging environments:
• minimal standing/travelling valve pressure loss at high pump rates and pump plunger velocities,
• solids tolerant at high concentrations of solids (from concentrated solids slugging events),
• can operate efficiently at all inclinations up to 90 degrees, and
• pressure balances the pump’s travelling valve prior to commencement of the pump’s downstroke to avoid compressional loading events and to avoid efficiency losses due to gas interference.
The Vortex Barbell SystemTM pump valves have demonstrated a step change in performance for high inclination pumping conditions. This unique valve design revealed a transformational opportunity to evolve the valve for improving a sucker rod pump at all inclinations. Three-Dimensional (3D) metal printing has gained significant attention in recent years. The ability to now print hard and tough metals has offed an opportunity to engineer and manufacture reliable sucker rod pump valves with very low-pressure losses, minimal flow turbulence and improved solids handling -- we are no longer design limited by the ball and seat design from circa 1938. A new complex shaped hydrodynamically engineered rod pump valve was developed.
A pressure balanced pump, has offered advantages for reducing the negative impacts of pump gas interference and compressional rod loading events. But this pump design can be limited by solids and can require precise pump space-outs. A hypothesis that instead of tapered top barrel section, a rifled channeled top barrel section would solve existing limitations. A rifled channel offered much greater solids tolerance and avoided the need for precise pump space-outs.
Flow loop testing and field trials have indicated promise for improvement. The design process, prototyping and flow loop testing, and well trials/results will be shared.

Understanding natural fracture systems plays a key role in tight carbonate fields where production is dependent on secondary porosity and pore connectivity. Locating geographic and stratigraphic areas with high natural fracture density and optimizing horizontal well plans to connect fractures can enhance well performance and asset value. A workflow to identify the influence of natural fractures on well performance was conducted in the stacked carbonate play in east Texas. Density, resistivity, and gamma ray logs were used to generate an index curve to identify natural fractures. In wells with image log data, a reasonable correlation was observed between the fracture zones selected by this model and the image log interpretation. The index curve was calibrated with image log interpretation, and applied in other wells without image logs. Identifying the optimal distance from the fault where fractures are still present has become the main criterion for selecting locations for horizontal wells. 

Sucker rod pumping is largely regarded as the final artificial lift method in a well’s lifecycle. Until now, the industry standard application of sucker rod pumping systems has been up to 400 barrels per day fluid production. With the industry advancing towards deeper wells and increasingly aggressive production targets, the challenge of meeting these application parameters while decreasing costs has become forefront to an operator’s requirements for profitability and in some cases, survival. To meet this need, Lufkin has established a system design comprised of a novel conventional 2560-500-320 pumping unit and fit-for-purpose rod string and pump, coupled with the ability to accurately control performance with automation. Through a comprehensive design analysis which factors in well characteristics, operational preferences, and production requirements, a system was developed to optimize production while minimizing lifting costs for operators. This approach has proven to lower or eliminate capital and operating costs for oil and gas producers by reducing the number or types of artificial lift methods, increasing fluid production, reducing failures, and lowering workover costs, as compared to other artificial lift methods or different pumping unit types. This paper will review design objectives, challenges, predictive analytics, implementation, economics, and the application results ranging from 400 to over 1000 barrels per day of fluid production achieved.