ESP Design Procedure

Centrilift has established a nine-step procedure to design the appropriate electrical submersible pump in order to have an efficient and cost-effective performance. This article gives an overview of the ESP nine step design procedure and outlines the procedure as a manual process to illustrate the design steps. Each of the nine steps will be explained in detail in the next articles. Step 1: Basic Data Step 2: Production Capacity Step 3: Gas Calculations Step 4: Total Dynamic Head Step 5: Pump Type Step 6: Optimum Size of Components Step 7: Electric Cable Step 8: Accessory & optional Equipment Step 9: The Variable Speed Pumping System Specific examples will be […]

Once the first step “Collect basic data” is performed, we pass to the ” step 2: Production Capacity “ of the ESP Nine Step Design Procedure. It consists on predicting the well inflow performance which represents the relationship between pressure and flow rate at the well face of an individual well and it is physically defined as the well flowing bottom-hole pressure (Pwf) as a function of production rate. It describes the flow in the reservoir. Many inflow performance relationships (IPR’s) are described in the literature. In this article, we will briefly present three of the most widely used IPR’s to describe the […]

The presence of free gas in the tubing above the pump changes the fluid density, consequently reduces the required discharge pressure. Also the performance of centrifugal pumps is considerably affected by the presence of free gas in the pumped fluid. The pump starts producing lower than normal head as the produced GLR (Gas to Liquid Ratio) at the pumping conditions increases beyond a critical value. The critical value of the ratio or percentage of free gas present at the pump intake to the total volume of fluid depends on the pump impeller design (typical critical values are shown in the article “ESP: […]

The AC current is carried from the surface to the motor using either copper or aluminum cable conductors. For ESP applications, four sizes of conductors have been standardized: #1, #2, #4 and #6 AWG (AWG stands for “American Wire Gauge”). Electric Cables are available in either flat or round configurations. An electric submersible cable is mainly compounded by a cable conductor, insulation, jacket, braid & covering and armor. These cable compounds are for protection against corrosive fluids and severe environments. Cable selection involves the determination of Cable Size, Type and Length. Cable Size: The proper cable size is dependent on combined factors of […]

This article “Downhole and Surface Accessory Equipment” is the step 8 of the nine-step procedure to design an ESP with an efficient and cost-effective performance. The required downhole and surface accessory equipment are discussed and recommended practices are highlighted. Downhole Accessory Equipment: Motor Lead Extension (MLE): API RP 11S4 defines the Motor Lead Extension as a “special power cable extending from the pothead on the motor to above the end of the pump where it connects with the power cable. A low-profile cable (flat configuration) is usually needed in this area due to limited clearance between the pump housing and the well […]

Compared to conventional ESP installations with constant motor speeds, installations running at variable frequencies have several advantages. The most important benefit of a Variable Speed Submersible Pumping System is the wide flexibility of the variable frequency ESP system that permits perfect matching of the lift capacity of the ESP system and the well’s productivity. Therefore, it operates over a much broader range of capacity, head, and efficiency. NB: Variable Frequency Drive basics (also, named: Variable Speed Drive) are presented and discussed in the article “Variable Frequency Drive Basics”. Since a submersible pump motor is an induction motor, its speed is proportional to […]

As described in the previous article ESP nine step design procedure, Centrilift has established a nine-step procedure to design the appropriate electrical submersible pump. The first step of this ESP design procedure, and certainly the most important step, consists on collecting the basic data. This is the most important step because all the others design steps will depend on the basic data selected in step 1. If the basic data quality is good the design will be good and the ESP will operate at its optimum conditions. Otherwise, if the input data quality is poor the design will usually be marginal. […]

Step 1: Basic Data: As detailed in the article “Step 1: Basic data ”, step 1 of the nine step design procedure is the most important step because all the others design steps will depend on the basic data selected in this step. In this example, a high water cut well is considered. This is the simplest type of well for sizing submersible equipment. Well Profile: Vertical Well Casing: 7” 26# Tubing: 3 ½” 9,2# N80 NU Top perforation: 2003m Pump Intake depth: 1713m Fluid properties and well conditions: PVT data non-available Oil Gravity: 35 API Water Cut: 90% Water Gravity: 1,01 […]