Enhanced Oil Recovery (EOR) methods are on the rise and Petroleum Development Oman (PDO) has successfully embarked on several projects including thermal recovery. Thermal EOR operations require rapid response and adaptation to the dynamic thermal conditions inherent within the reservoir. The challenges associated with Cyclic Steam Stimulation (CSS) necessitated a creative solution to maximize recovery and improve well management. A fit for purpose algorithm was developed to add flexibility while operating the well in combination with the Variable Speed Drive (VSD). An automation algorithm was developed to optimize oil recovery and accelerate peak oil throughout the CSS production cycle. This algorithm maximized inflow potential by creating a low fluid level above the pump and maintaining near pumped-off conditions. The project was named Beam Lift Auto Delivery Evolution (BLADE). Live control of the pumping unit provides equipment safe guarding while ensuring continuous operation within the defined envelope. This is achieved by applying real time assessment of pump fillage and temperature conditions. This approach optimized production while maintaining adequate fillage, thereby increasing operations efficiency and prolonging pump life. Within a thermal environment, enhanced automation provides the additional advantage of steam break through mitigation. The mitigation improves pump efficiency and prevents pump gas lock. This algorithm provided a unique advantage within this thermal operation by adapting to varying viscosities impacting inflow throughout the production phase. Thermal CSS requires continuous monitoring and rapid reaction time to adapt to the dynamic conditions inherent to the CSS operation. The BLADE project has demonstrated that utilization of carefully designed logic in conjunction with robust field steaming strategy, not only improved field recovery but also significantly reduced manpower demand by 20% and decreased the total EOR cost.

The "A" East Haradh formation contains a 200 m thick oil column of highly viscous oil, with viscosity ranging from 200 to 400,000 cp. Due to the high viscosity, first production was considered only possible using thermal EOR techniques, starting with Cyclic Steam Stimulation (CSS). The field has now been in operation for more than two years, with a number of wells already into a third CSS cycle. This paper will focus on the key learnings derived during this initial operations phase of CSS in "A" East Field including, amongst others, key trial results on different well completions and artificial lift systems combined with new insight into the reservoir architecture. In addition, reservoir performance management is being streamlined through the development of a structured approach to the CSS planning and using dedicated visualisation. Automated Exception Based Surveillance "triggers" are currently being developed to efficiently address any deviation from the operating envelopes and further optimise the recovery from this 81 well CSS development. Based on the very encouraging performance to date, the company has already sanctioned a further 34 well CSS expansion of the current development with drilling scheduled to commence in 2016.

This paper reviews the process for artificial lift selection and highlights the creativity applied to solve operational challenges. Artificial Lift (AL) systems are an essential component of oil and gas production in which wells are not flowing naturally to surface. The typical factors in assessing AL selection in conventional fields are driven by cost, anticipated rates, operating envelopes, depth and also factors such as corrosive elements, sand expectation, anticipated failure rates and operational experience. However, in heavy oil fields, the selection is complicated by additional factors such as Steam Break Through (SBT) and extreme viscosity variation. Many challenges were encountered during the actual operation of "A" East field which required revisiting early assumptions and modifying both lift selection and operating philosophy. The "A" East reservoir has an oil viscosity range between 400 to 400,000 cp at reservoir conditions. In order to deplete the high pressure in the reservoir (~137 bar) and minimize the adverse impact on steam injection quality and efficiency, about 40% of the wells were selected to be cold produced, initially using Progressive Cavity Pumps (PCP) to handle higher viscosities. These selected cold producers would later be converted to Cyclic Steam Stimulation (CSS) using Beam Pumps (BP). Cold production helped to lower the reservoir pressure. The remaining of the field operated with BP using down hole Steam By Pass Pumps (SBPP). The SBPP approach was adopted to minimize conversion time between injector and producer in CSS cycles. Challenges operating the SBPP pumps led to abandoning this approach, however, the insert pump concept continued. There were notable challenges operating the insert pumps as well mostly at the flanks after several steam cycles and various efforts which required a re-evaluation of AL systems available. Metal to Metal Progressive Cavity Pump (M2MPCP) was introduced to mitigate some extreme viscosities encountered in the flanks and reaching viscosities above 15000 cp at 60 C° (see figure 1). There were some operating challenges related to slow optimization and reaction times were mitigated by the introduction of automation using an algorithm-driven approach. Other challenges were related to BP start-ups in thick oil and other pump struggles with gas locking due to SBT. These challenges required adaptations and modifications such as slow start after interventions until heated fluids arrive to the wellbore. In other cases, production choke backs allowing for single phase flow through the pump. Conversion methods between cycles was accelerated by the introduction of stripping tool. Optimization efforts were also challenging and slow and demanded higher than expected manpower, this challenge was addressed by utilizing automation and algorithms which made a significant difference. The selection of a suitable AL system needs to take into consideration the overall requirements at the different developmental stages. Standardization of equipment has advantages such as accumulated experience and reduction of maintenance costs however, there should be some flexibility and variation in Lift system options to address unforeseen operational challenges. This flexibility has allowed maximization of field production potential and has the added benefit of increasing the operating team’s exposure to various lift systems.