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УДК 608
Деряев Аннагулы Реджепович,
Научно-исследовательский институт природного газа ГК «Туркменгаз»,
г. Ашгабат, Туркменистан
ПРОГНОЗНЫЕ ТЕХНОЛОГИЧЕСКИЕ И ТЕХНИКО-ЭКОНОМИЧЕСКИЕ ПОКАЗАТЕЛИ ВАРИАНТОВ РАЗРАБОТКИ ДЛЯ ГАЗОКОНДЕНСАТНЫХ ЗАЛЕЖЕЙ ПРИ ОСВОЕНИИ МЕТОДОМ ОДНОВРЕМЕННОЙ
РАЗДЕЛЬНОЙ ЭКСПЛУАТАЦИИ
Аннотация
В статье рассматриваeтся промысловый опыт эксплуатации двух пластов одной скважиной методом одновременной раздельной эксплуатации (ОРЭ), который указывает на его высокую эффективность. В среднем на 30% сокращаются капитальные вложения и эксплуатационные затраты в сопоставлении с затратами на бурение и эксплуатацию месторождений самостоятельными сетками на каждый пласт. Метод ОРЭ дает возможность уплотнять сетку скважин (добывающих и нагнетательных) без дополнительного метража бурения. Положительный эффект от применения технологии ОРЭ выражается в сокращении капитальных вложений на строительство скважин для каждого из эксплуатационных объектов, в сокращении эксплуатационных расходов и срока освоения многопластового месторождения, в увеличении добычи углеводородов и срока конечной нефтеотдачи с рентабельной эксплуатацией скважин.
Ключевые слова
Смета, область залежей, газоконденсатные горизонты, коэффициент конденсатоотдачи,
плотность газа, расход жидкости
Deryaev Annaguly Rejepovich
Scientific Research Institute of Natural Gas of the State Concern "Turkmengas",
Ashgabat, Turkmenistan
FORECAST TECHNOLOGICAL AND TECHNICAL AND ECONOMIC INDICATORS OF DEVELOPMENT VARIANTS FOR GAS CONDENSATE DEPOSITS DURING DEVELOPMENT BY THE METHOD OF DUAL COMPLETION
Abstract
The article discusses the field experience of operating two reservoirs with one well by the method of dual completion (DC), which indicates its high efficiency. On average, capital investments and operating costs are reduced by 30% in comparison with the costs of drilling and operating fields with independent grids for each formation. The DC method makes it possible to seal the grid of wells (producing and injection) without additional drilling footage. The positive effect of the use of DC technology is expressed in the reduction of capital investments for the construction of wells for each of the operational facilities, in the reduction of operating costs and the term of development of a multi-layer field, in the increase in hydrocarbon production and the term of final oil recovery with cost-effective operation of wells.
Keywords
Estimate, deposit area, gas condensate horizons, condensate recovery coefficient,
gas density, liquid flow rate.
Calculations of the main forecast indicators for the production of oil, gas and condensate on the productive horizons of the Korpedje field are carried out in accordance with the requirements of the guidance documents for the design of the development of oil and oil and gas fields.
This article discusses three variants for the further development of the Korpedje oil deposits. The forecast of oil production by horizons and by location as a whole has been fulfilled for the period 2011-2030.
According to the first variant, additional development of oil deposits is planned to be carried out by the existing fund of producing wells. Only on the horizon of NK-9 in block III, where a section with reserves of category Ci is allocated in the western part of the oil rim, on which there are currently no operating wells, it is recommended to drill one production well - №01.
In the second variant, it is planned to drill the eastern part of the oil deposit of the NK-7g horizon in block III.
In the eastern part of the block there is an unproductive well №52, through which a reservoir-limiting discharge 2 was carried out. However, the distance from well № 52 to productive wells No. 269,262 and 248 located to the west of it is quite large - 500 - 700m, as a result of which the position of discharge 2 cannot be considered reliably established - it can also pass significantly to the west of the position shown on the map. Therefore, this section of the deposit was not covered by drilling when drilling the main grid of wells.
It is recommended to drill 5 production wells in this zone - №02...06. The issuance of well points for construction must be carried out on the principle of "from the known to the unknown" - from west to east.
In the northern part of block I of the NK-7g horizon in the western part of the oil rim, according to the data of testing and operation of well №53 (currently inactive), oil reserves of category Q have been identified. Two priority production wells are recommended for laying here - №№ 07 and 08 [1].
Thus, according to the second variant, it is proposed to drill 8 new oil wells. The project wells recommended for drilling have been assigned conditional numbers starting with "O" (№№ 01, 02, etc.).
In the third variant of the further development of the oil deposits of the Korpedje field, exploration, transfer to category Ci and commissioning of the C2 oil reserves available at the field are envisaged.
According to long-term actual data of exploration of the lower red-colored deposits of Southwestern Turkmenistan, the coefficient of confirmed oil reserves when transferring them from category C2 to category C1 is on average 0.5.
The average efficiency of exploration for oil deposits in Southwestern Turkmenistan in recent years is determined by the increase in reserves of Ci. With this in mind, the commissioning of four productive exploration wells has been accepted. Drilling of five production wells is planned for the introduction of incremental reserves into development. Exploration drilling is scheduled to begin in 2015. Since the field is equipped for oil production, it is planned to put wells into operation from the same year. Taking into account the capabilities of drilling companies, drilling of incremental reserves ends in 2019.
The calculated parameters for oil reserves transferred from the C2 category are accepted at the level of the average for the field [2].
The indicators of exploitation of the developed deposits with reserves of category C1 according to the third variant are the same as for the first variant.
The indicators of production drilling for the variants of additional development of oil deposits are shown in the table below.
Table
Indicators of production drilling by variants for further development of oil deposits
Indicators I variant II variant III variant
Commissioning of new wells 1 8 10
Average depth of new wells, m 4200 3675 4033
Metric area of production drilling, thousand meters 4,2 29,4 24,2
The metric area of exploration drilling according to the III variant is 16 thousand meters. Four wells with an average depth of 4000m are planned for drilling.
The calculations take into account the actual dynamics of changes in the main indicators of the development of operational facilities over the past period and its projected change for the future and the commissioning of new production wells recommended for drilling. When calculating oil production by development facilities (by horizons), the transfer of wells to the overlying horizons is also taken into account. The initial flow rates of the wells put into operation are estimated taking into account the depletion of block reserves and the current state of the working wells [3, 4].
In those areas of the field where the boundaries of the deposits of oil and gas-saturated horizons overlap in terms, calculations of oil and gas production along the horizons provide for the production of well returns to the overlying horizons after the development of the operated object or for technical reasons. The experience of the development of multi-layer deposits in Western Turkmenistan shows that due to the influence of a large number of various factors, reliable forecasting of the timing of the retirement of wells from operation for a long period is very difficult. In this regard, the timing of the disposal of wells from the operational fund and the transfer of wells to the overlying horizons are estimated approximately.
In the summary calculations for the development variants for the field as a whole, the transfer of wells to other horizons is not shown, because wells transferred to other horizons remain in the operational fund of the wells of the field. The time required for the production of return operations is taken into account in the coefficient of operation of transferred wells taken into account in the calculations.
The oil deposits of the field are characterized by very complex drainage regimes, which significantly affects the dynamics of the gas factor. Therefore, the determination of the dynamics of the gas factor was carried out taking into account the experience of developing the lower red-colored horizons of other deposits.
In accordance with the accepted development variant of the Korpedje oil and gas condensate field, the transfer of most wells to gas lift is envisaged for the future, which requires a fundamental solution to the problem of providing gas lift wells with a working agent and, accordingly, the development of recommendations for the design of gas lift complexes.
At the current stage of development, the analysis of technical and technological parameters of the operation of the fund of existing gas lift wells is the basis for the fundamental choice of the field development variant with the expansion of the gas lift complex.
According to the current data, the technical and operational characteristics of the background of the existing gas lift wells at the Korpedje field lead to the following conclusions:
Gas lift wells are equipped with elevators with a diameter of 73 mm, lowered to filter marks.
The main number of wells should be classified as low-flow (according to the criteria of the gas lift method of operation).
The ratio of liquid and oil flow rates indicates the presence of emulsions of increased viscosity (taking into account the fact that the extracted oil is highly paraffinic).
There are high (1,6-2,5 MPa) buffer pressures at the wells, which with the installed regime fittings on the buffers of wells with a diameter of 16-25 mm, which indicates high hydraulic resistances during the movement of the gas-liquid mixture in the collection system of high-paraffin oil, including the pressure drop in the regime fittings of wells with a large gas factor).
We note that the magnitude of the total gas factor and, accordingly, the required specific flow rate of the working agent supplied to the well depends on a set of factors, including, in particular, the depth of gas input into the tubing column chosen during the design of the elevator (immersion under the dynamic level).
The choice of the gas input system into the elevator (starting valves, working valves, starting holes)
made during the design of gas lift wells can lead to significant deviations in the technological parameters of the working well from the option of single-point gas input under the lift shoe, which is usually taken as the basis of standard calculations.
Such a significant discrepancy is observed for the wells of the Korpedje field, where starting holes ("Punchers") are used. At the same time, it is difficult to calculate the required pressure of the working agent.
Taking into account the use of the working agent of the gas lift up to 8,0 MPa at average depths of gas input into the elevator and the need to deepen the points of gas input in the future during the development of deposits, the pressure of the working agent should be selected in the range of 9,0-10,0 MPa.
Taking into account the presence of a compression line for associated gas from an inlet pressure of 0,3 MPa to 7,5 MPa, which has a throughput capacity of 1 billion m3, it should be considered expedient to continue using a compressor-free gas lift scheme with utilization (compression on the CS) of associated gas, which is a mixture of petroleum gas and a working agent. At the same time, it is proposed to compress natural gas extracted from gas condensate wells with a wellhead pressure of 4,5-5,0 MPa to the required pressure of 9,0-10,0 MPa using booster compressor stations of block type, for example, BCS 28NM/1 with a capacity of 1,1 MW, with a capacity of 500 m /day. The experience of operating these compressor stations is available at the Goturdepe and Barsagelmez fields.
The amount of gas supplied for the gas lift is determined based on the average specific consumption of the working agent, determined by the formula:
where is Rtot - the total specific flow rate required for lifting the liquid by gas lift (Rtot = 500m3 /m3, );
Gf - is a reservoir (borehole) gas factor.
Three variants for the development of gas deposits of the Korpedje field are considered.
The first variant is basic. Development is provided by the existing well fund.
In the second variant, drilling of 20 new producing gas wells with a total area of 69 thousand meters is recommended for the horizons NK-9, NK-8, NK-7d, NK-7g and NK-76 in 2012-2018.
In the third variant, it is recommended to refrain from drilling five new wells on the horizons of NK-76 and NK-7g by opening these horizons with the use of DC in wells projected on the underlying horizons. Thus, according to the third variant, 15 new production gas wells with a total area of 53 thousand meters are recommended for drilling. The commissioning of wells from drilling has been planned since 2012 - 2 wells: in 2013 - 3 wells; in 2014 - 2 wells, in 2015 - 3 wells, in 2016 - 2 wells, in 2017 - 2 wells and in 2018 - 1 well.
In all variants for wells of the existing fund, it is planned, after working off the exploited horizon, the production of well returns to the overlying horizons. Gas deposits, the development of which involves the use of DC, for each pair of horizons are located in tectonic blocks of the same name and have a similar relationship with the legal area, and, consequently, similar drainage regimes. This is a good condition for ensuring approximately the same rate of fall of reservoir and wellhead pressures over a long period. It is also recommended to continue the operation of wells with DC equipment and wells with downhole gas lift currently operating.
The determination of the parameters of the operation of gas wells and the forecast of the indicators of the development of gas condensate deposits are carried out on the basis of reserves of gas condensate horizons and areas for which the presence of oil rims has not been established. When determining the initial recoverable gas reserves, the expected final gas recovery coefficient of 0,85 was adopted.
Based on the analysis of field data using the available actual data on reservoir pressure measurements for horizons, dependences of reservoir pressure changes on accumulated gas extraction were constructed in a dimensionless form. When it was taken into account that for the gas condensate deposits of Korpedje, as well as other deposits in the region, during the development process, an increasing share of participation in
Rtot - г
the drainage regime of the pressure of marginal and plantar waters is manifested over time.
Each of the horizons under consideration is an independent operational object with its own design grid of wells. Therefore, the use of DC technology will significantly reduce the number of wells for drilling, and, consequently, the material and technical costs associated with drilling the field as a whole. Literature
1. Сандахчиев И.С., Атамамедов Е. Проект пробной эксплуатации Корпе-джинской группы месторождений //Отчет// 85.4315.86, ТуркменНИ- ПИнефть. - Небит-Даг, 1986 - С. 37.
2. Сандахчиев И.С. Проект пробной эксплуатации нефтяных залежей месторождения Корпедже //Отчет// 21/88, ТуркменНИПИнефть. - Небит-Даг, 1988-С. 95.
3. Прокудин А.В. Результаты внедрения оборудования ОРЭ на месторождениях ООО Лукойл - Западная Сибирь / Прокудин А.В. // Инженерная практика. - 2013. № 2. стр. 42-44.
4. Разработка и результаты испытаний оборудования для одновременно-раздельной эксплуатации скважин с установками электроцентробежных насосов/ Валеев М.Д., Газаров А.Г., Масенкин В.А. [и др.] // Нефтяное хозяйство. -2008. -№2. стр. 86-88.
© Деряев А.Р., 2022
УДК 608
Деряев Аннагулы Реджепович,
Научно-исследовательский институт природного газа ГК «Туркменгаз»,
г. Ашгабат, Туркменистан
АНАЛИЗ СУЩЕСТВУЮЩИХ СХЕМ УСТАНОВОК ДЛЯ ОДНОВРЕМЕННО-РАЗДЕЛЬНОЙ ЭКСПЛУАТАЦИИ ПЛАСТОВ
Аннотация
Обязательные требования ко всем схемам одновременно-раздельной эксплуатации -возможность раздельного освоения и пуска в эксплуатацию каждого пласта, замера дебитов нефти каждого пласта в отдельности, а также раздельного замера каждого пласта на обводненность, газосодержание и исследование каждого пласта на приток нефти и газа.
Ключевые слова
Расширенный ствол, пакер, мандрель, подъемный агрегат, извлекаемый забойный отсекатель,
центрабежный насос, двухлифтовая установка.
Deryaev Annaguly Rejepovich
Scientific Research Institute of Natural Gas of the State Concern "Turkmengas",
Ashgabat, Turkmenistan
ANALYSIS OF EXISTING INSTALLATION SCHEMES FOR DUAL COMPLETION OF LAYERS
Abstract
Mandatory requirements for all schemes of dual completion (DC) are the possibility of separate
