Integrated approach to optimizing wells with srp

26.12.2018

Источник: Журнал «PROнефть»

Комплексный подход к оптимизации работы установок скважинных штанговых насосов

UDC 621.651/.69 

B. Martinovic, S. Stuchny, M. Repac
NTC NIS – NafTagaS d.o.o., Novi Sad
G. Andjusic, N. Stevanovic
NIS a.d., Novi Sad

E-mail: bojan.martinovic@nis.eu

Keywords: аrtificial lift, sucker rod pump (SRP), optimization

Б. Мартинович, С. Штучни, М. Репац
NTC NIS – NafTagaS d.o.o., Novi Sad
Г. Анджушич, Н. Стеванович
NIS a.d., Novi Sad

В статье рассмотрена проблематика механизированного способа эксплуатации установок скважинных штанговых насосов (УСШН), методы их оптимизации, повышение эксплуатационного ресурса и экономический эффект при добыче нефти. Особое внимание было уделено оптимизации УСШН с целью снижения и удержания на низком уровне стоимости механизированного подъема жидкости на поверхность. Описаны шаги по оптимизации процесса добычи и разработаны рабочие алгоритмы для каждого из шагов. Кроме того, анализ экономической эффективности подтверждает целесообразность и достижение положительного эффекта от проведенных мероприятий.

Ключевые слова: механизированный способ эксплуатации, установка скважинных штанговых насосов (УСШН), методология, оптимизация

DOI: 10.24887/2587-7399-2018-4-64-66

INtRODUCtION

In NIS oil company 710 oil wells represent active oil wells stock, out of which 638 oil wells are involved in artificial-lift well operation. an increase in producing well stock brings about more complicated well operation, which ought to be stamped out both by new technologies implementation and by optimisations of current processes. Reducing expenses of artificial-lift well operation is the priority within the project of optimisation of current processes.
Solving this task requires a synergy of novel scientific and technological knowledge, software solutions and gained experience to reach the objective of putting in place specific measures that would result in the reduced expenses of artificial lift production technique.

Out of total stock of wells outfitted with artificial lift ESP pump-outfitted wells (245 wells) were singled out and those outfitted with SRP pump (345 wells) as a group of wells, which may be optimised. We divided our approach into 4 stages, applying certain methodology for each stage and at the end of each stage we calculated economic effect.

StAGE 1: POSSIBIlIty Of tRANSItION fROM ESP tO SRP

Economic calculations have demonstrated that lifting one ton of crude oil is least cost-effective with ESP production method and most cost-effective with sucker rod pump, so our principal task was to determine wells that would be the candidates for transition from ESP to SRP, while keeping the same level of efficiency in the entire system. With a view to achieve this, we have developed an algorithm providing a solution precisely determining candidate-wells [1]. 

We applied this algorithm to the entire ESP wells stock to identify wells that might be the candidates for transition and defined our entire stock of wells, which are capable to operate with SRP. furthermore, this stage produced action plan to improve operational efficiency proving and confirming economic effect.

 

StAGE 2: SRP SUBSURfACE EqUIPMENt OPtIMISAtION

Once we defined our well stock (fig. 1), the first step towards optimisation was to create a virtual wells’ mathematical models [2], which would be identical with the situation on the field.

fig. 1. Candidate wells to change from ESP to SRP

These models gave us the freedom of changing parameters, equpiment and so on in virtual world and to monitor its impact on the system. The examination identified that a raft of sucker rods in quite a number of wells can be optimised, and confirmed the fact that the system, in addition to economic effect, benefitted otherwise as well: possibility of deeper installing a pump for the same surface equipment as well as reduced power consumption.

StAGE 3: SRP SURfACE EqUIPMENt OPtIMISAtION

Stage 3 has been focused on surface equipment. as virtual models has already set new wells’ design, we concentrated on optimising the existing ones, where fast and efficient surface equipment optimisation is possible to bring about cost cutting. Similar to previous steps it was essential to create an algorithm (fig. 2) to simplify the selection of candidates and identify wells, which can be optimised, naturally while keeping the same level of steady system operation.

fig. 2. Algorithm for optimization of surface equipment

We applied the algorithm to all wells to unequivocally identify problematic wells and provide specific, swift and efficient measures for optimisation. We outfitted 35 wells with possibilitz of changing beam pumping unit to smaler one, hence with smaller electrical motor, we changed current equipments’ operating parameters of 18 wells and ensured a steady operation mode, while 7 wells required the installation of larger pumping unit to avoid the risk of breakdown. This stage as well is also included in action plan at increasing company’s operational efficiency, with officially proven economic effect.

StAGE 4: DEtERMINING EffICIENCy Of GAS SEPARAtOR fOR SRP

The last stage has comprised a development of a mathematical model for determining efficiency of gas separator for SRP (fig. 3).

fig. 3. Algorithm for determine efficier

Contrary to ESP pumps, whereby every producer defines efficiency of gas separator, SRP efficiency has not been defined. as almost the entire NIS’ stock of wells with SRP is also outfitted with gas separator (fig. 4), it is crucial for future implementation and analysis of operation to accurately determine its efficiency.

fig. 4. Cup type gas separator

To achieve this a mathematical model has been developed, which produced a calculated well production rate without gas separator. Difference between the production with separator and without separator represents the gas separator efficiency. With a view to make the mathematics clear-cut, we were also compelled to to test the equation. To verify the quality functioning of the equation, we had singled out 10 wells, which are not outfitted with gas separator and applied the equation to them. Deviations from production rate data reads and the production rate measured for the same wells was up to 5 %, which for us was the confirmation  of the quality functioning of the equation and that, based on the difference in production we can determine the exact efficiency of the gas separator. 

 

CONClUSION

A complex analysis resulted in an economic effect. algorithms have been developed, which may be applied in every future equpiment optimisation and selection of candidates. 

Real software mathematical models have been created to model changes in each parameter of equipment operation, thus precluding possible negative effects. 

Gas separator algorithm for determination of efficiency has been developed.

References

1. Takacs g., Sucker-rod pumping handbook—Production engineering fundamentals and long-stroke rod pumping, Oxford: Elsevier Science, 2015, 598 p.
2. Boomer P.M., Podio a.L., The beam lift handbook, Houston: PETEX, 2015, 625 p.


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