Huyapari Field, located in the Orinoco Oil Belt is operated by PETROPIAR, a joint venture between PDVSA and Chevron, where over 600 horizontal wells have been perforated and completed with progressive cavity pumps (PCP) as the preferred artificial lift method to produce extra heavy oil. With the objective to identify and address the main causes of failure affecting PCPs run life and performance, high repair costs as well as lost production, Root Cause Analysis (RCA) is currently being implemented, giving outstanding benefits by involving both suppliers and customers in a continuous improvement and learning experience. Between 2003 and 2011, PCP run life was 884 days on average. In 2012, this number decreased dramatically to 306 days with no changes in the reservoir characteristics besides normal depletion. Between 2012 and 2013, 74% of installed PCPs failed before reaching one year in operation, with an average run life of 162 days. Deferred production increased significantly and annual operational expenses duplicated, mostly because of PCP replacements. In response, Petropiar began in 2013 a joint effort with six manufacturers to review the process involving PCPs selection, design, simulation, transportation, storage, installation, operation, monitoring, diagnostic and pulling. To date, more than 100 pumps have been analyzed applying RCA and including: borescope inspection, destructive analysis, hardness measurement, simulation and review of operating conditions, production history, pump installation & pull out reports, wellbore geometry among others. The procedure for carrying out this RCA experience and implementing lessons learned is presented in this paper, including identification of various manufacturing quality issues for which, specific tests were put in place to evaluate key characteristics like bonding for example. Quality controls requirements were revisited and elastomers compatibility tests were included as part of the procurement process. On the other hand, new non-conventional technologies have been applied to meet challenging conditions to produce extra heavy oil with high gas production. PCP run life increased by 56% while failures on PCPs with less than 365 days run life decreased by 31% when compared with previous years.

Progressive Cavity Pumping is the preferred artificial lift method in the extra heavy crude oil field Huyapari, located in the Venezuelan Orinoco belt. Typically, PCPs operating in saturated reservoirs such as Huyapari need to cope with significant amounts of free gas, often handling more than 50% of gas void fraction (GVF) at the pump intake. This, combined with production of large amounts of sand and exposure to aggressive fluids, poses vast challenges to the durability and performance of PCP elastomers. Consequently, a proper and engineered selection of elastomer materials has critical impact on overall pump run life. This study describes a first experience in characterizing the effect of harsh fluids and solids on high acrylonitrile elastomers. Subject wells include those with high free gas and/or sand production rates, as well as those with elevated water cuts. The mechanical properties of elastomers were measured under controlled pressure and temperature conditions in order to define an optimum rotor-stator fit. Over 200 laboratory tests and several field experiments were conducted to allow for the most suitable selection of elastomer material regarding hardness and swelling behaviour. Aging tests and infrared spectroscopy were also used in these analyses to help reduce premature elastomer failures produced by hysteresis, explosive decompression and blistering. The results of the study indicate that PCP applications in wells producing high gas rates must avoid utilization of elastomers with a hardness below 65 shore A, because the increased gas permeability causes excessive swelling throughout the pump stator. In contrast, elastomers with hardness above 70-75 shore A proved to be more resistant to swelling and explosive decompression. Benefits resulting from this study include an increased pump life cycle from 306 days in-hole in 2012 to 469 days in 2016. Premature PCP failure count decreased from 275 in 2012 (59% of wells in the field) to 153 in 2017. Based on the results of this study, the authors propose new acceptance ranges for mechanical properties values (e.g. swelling performance and hardness) for PCP elastomer selection applied to extra heavy oil production in this field.