The need for better understanding of sucker rod pumping process is heavily required. Many problems are still under investigation such as determination of the fluid level from surface, selection of the optimum pump size and the required pump setting depth to maximize the pumping rate in a particular well. The main purposes of this study are to investigate effects of fluid level over pump, pump size, and pump setting depth on the sucker rod performance. These goals are achieved using the Artificial Sucker Rod Pump (ASRP) design simulator with actual field data.
The results show that applying good fluid level from the surface and increasing the plunger stroke consequently increase the resultant pumping flow rate. Furthermore, good fluid level yields high pump intake pressure and results in a good pump fillage, which increases the pump efficiency. In addition, the analysis of the effect of pump size on rod stress shows that the increase of pump size increases the rod stress and increases the pump flow rate. Therefore, the plunger size must be selected according to both the required flow rate and the allowable sucker rod stress. With respect to the effect of the pump setting depth on the performance of the sucker rod pump, the increase of the pump setting depth reduces the pump flow rate and increases the rod stress. Actual Egyptian field data is used for the purpose of achieving this simulation investigation of the above-mention effects.
The energy crisis confronting the world now has made the optimum selection and operating of the oil field production equipment to be a must. This is certainly very true of oil field pumping units, especially for the developed/depleted wells. It is imperative to size the pumping unit according to the well conditions as accurate as possible. In the mean time, it is equally important to operate the pumping unit within its optimum rate to avoid the costly downtime due to breakdown. This means obtaining a better understanding of the important factors affecting the pump performance such as the influence of the fluid level from surface, the effect of pump size and pump setting depth on both the pump flow rate and the rod stress of the sucker rod as an artificial lift method.
The purpose of the artificial lift is to maintain a reduced bottom-hole pressure so that the producing formation can provide the desired flow rate of reservoir fluids. There are many artificial lift systems 1–6 currently applicable in the petroleum industry. These systems include:
Sucker rod pumping (Beam pumping),
Electrical submersible pumping,
Hydraulic (Piston and Jet) pumping,
Plunger (Free-piston) lift, and
other methods such as: Ball-pump and Gas-actuated pump.
The beam pumping system 3 is the most popular artificial lift system all over the world. The sucker rod pumping system 1,3,5,6 consists mainly of five parts including (1) The subsurface sucker rod-driven pump, (2) The sucker rod string, (3) The surface pumping equipment, (4) The power transmission unit, and (5) The prime mover. The pump 1 consists simply of a working barrel (or linear) suspended on the tubing; the plunger is moved up and down inside this barrel by the sucker rod string. At the surface, the unit and prime mover provide the oscillating motion to the sucker rod string and then to the subsurface pump. Sucker rods are available in different sizes including the following standard sizes 5/8, 3/4, 7/8, 1.0, and 17/8/ in diameter. Two valves are installed at the bottom of the working barrel. These valves are (a) standing valve (SV): it is a stationary ball-and-seat valve, and (b) travelling valve (TV): it is located in the plunger.