Abstract One of the mayor economical impacts in a Project of artificial lift system shift is the associated cost of energy moreover the maintenance and well intervention must be considered. These variables are reflected as addition on the final artificial lift cost selected.
This study was accomplished based on experience at the Teca and Nare fields operated by Omimex Colombia where an artificial lift system shift was performed from Rod Pump (RP) into Progressive Cavity Pump (PCP), achieving significant savings in well downtime and energy consumption at the same volume of production.
The strategy to develop this project started with the identification of well candidates where steam injection was not feasible then a change on the artificial lift system was proposed to a set of wells.
Also is highlighted the importance of the operational variables in long term at the moment to choose an artificial lift system.
Introduction The heavy oil reserves have increased more than twice as conventional reserves worldwide. Heavy oil has become in an important issued to the oil industry then and a concern to its best exploitation such technical as economical methods are considered.
Traditionally heavy oil exploitation considered Rod Pump (RP) as artificial lift system, exposing occasionally well downtime as sand stickings and rod failures with poorly designs.
Nowadays thankfully to the technological development an alternative for heavy oil exploitation is presented the Progressive Cavity Pump (PCP) which offers benefits as good heavy oil and high sand contents handling and low initial investment and maintenance cost.
This paper exposes a study of the main technical and economical issues considered for the artificial lift system shift from RP into PCP in Teca and Nare fields located at the Middle Valley of Magdalena river Basin in Colombia.
Considerations for the shift system Since its initial exploitaion (early 80's) in Teca and Nare fields, Rod Pump (RD) was implemented together with cyclic steam injection as EOR to produce an oil of 12 °API and 12000 cp viscosity within heavy oil pattern.
On 1st of April of 2004 in Omimex Colombia (operator of the fields) a project of well description started and were identified a set of wells no suitables for steam injection due to conditions as high water cut, completion problems like collapsed casings, liner ruptures and high sand content at wellbore as well as low injectability factor.
A trial of PCP system on well Teca 326 started on 10th of January of 2005 with promising results on operational consitions and steady production of 50 BPD compared with the former RD.
Based on these results arose the idea to install 75 PCP systems on the set of wells with non injectable factibility.
According to the production rate 20 to 60 BPD (32 wells), 60 to 100 BPD (25 wells) and 100 to 150 BPD (18 wells) of the set of wells, three differents systems of PCP were designed with power of 10, 20 and 30 HP to cover respectively.
While installation of the new systems and period after an evaluation process and comparison, of performance and economics was done between the two systems. The results gives the following conclusions.
Technical Evaluation Technical issues evaluated were flow and viscosous fluid handling and specially energy consumption.