scholarly journals Generalization of the basic research on the increase of recovery factors in water-drive gas-condensate reservoirs

Author(s):  
S. V. Matkivskyi ◽  
O. R. Kondrat

The problem of monitoring and preventing deposit inundation is becoming increasingly important in Ukraine. The solution to this problem is one of the ways to ensure the energy independence of the state. The operation of producing wells is complicated by the accumulation of liquid at the bottom. Subsequently, it leads to premature shutdown of the wells. Inundation determines the need to isolate the influx of formation water. Considering the significant residual reserves of gas trapped in water, it is important to improve existing technologies and to develop new ones for the development of depleted fields under the conditions of dynamic water drive in order to ensure maximum hydrocarbon recovery rates. This paper summarizes domestic and foreign field development technologies under water pressure conditions and analyzes the main disadvantages and advantages of the existing methods of stimulating hydrocarbon inflows in waterlogged gas and gas condensate wells. The main factors that determine the causes and nature of flooding of productive formations and ways to prevent them are analyzed. Based on the results of the analysis of laboratory and experimental studies, the behavior of gas trapped by brine water has been established.But the issue of determining the localization of residual reserves has not been studied sufficiently. Considering the above mentioned ideas, the author asserts the necessity to and to use geological and technological models constantly. It ensures better extraction of the residual gas from depleted fields under the condition of intensive advance of reservoir water into productive formations. In the case of adapting the three-dimensional model to the actual data of the production history and the simulation of  the exact breakthrough of produced water in production wells, there comes the possible to determine the most promising zones and sections of the field, the reservoirs of which are characterized by the best filtration-capacitive properties and significant gas reserves. The use of a constantly operating geological and technological model of the field will make it possible to develop ways of extracting the residual gas reserves trapped in produced water, to improve existing production technologies and to ensure maximum recovery factors.

2021 ◽  
Author(s):  
Pavel Dmitrievich Gladkov ◽  
Anastasiia Vladimirovna Zheltikova

Abstract As is known, fractured reservoirs compared to conventional reservoirs have such features as complex pore volume structure, high heterogeneity of the porosity and permeability properties etc. Apart from this, the productivity of a specific well is defined above all by the number of natural fractures penetrated by the wellbore and their properties. Development of fractured reservoirs is associated with a number of issues, one of which is related to uneven and accelerated water flooding due to water breakthrough through fractures to the wellbores, for this reason it becomes difficult to forecast the well performance. Under conditions of lack of information on the reservoir structure and aquifer activity, the 3D digital models of the field generated using the hydrodynamic simulators may feature insufficient predictive capability. However, forecasting of breakthroughs is important in terms of generating reliable HC and water production profiles and decision-making on reservoir management and field facilities for produced water treatment. Identification of possible sources of water flooding and planning of individual parameters of production well operation for the purpose of extending the water-free operation period play significant role in the development of these reservoirs. The purpose of this study is to describe the results of the hydrochemical monitoring to forecast the water flooding of the wells that penetrated a fractured reservoir on the example of a gas condensate field in Bolivia. The study contains data on the field development status and associated difficulties and uncertainties. The initial data were results of monthly analyses of the produced water and the water-gas ratio dynamics that were analyzed and compared to the data on the analogue fields. The data analysis demonstrated that first signs of water flooding for the wells of the field under study may be diagnosed through the monitoring of the produced water mineralization - the water-gas ratio (WGR) increase is preceded by the mineralization increase that may be observed approximately a month earlier. However, the data on the analogue fields shows that this period may be longer – from few months to two years. Thus, the hydrochemical method within integrated monitoring of development of a field with a fractured reservoir could be one of the efficient methods to timely adjust the well operation parameters and may extend the water-free period of its operation.


2020 ◽  
Vol 43 (3) ◽  
pp. 350-363
Author(s):  
L. A. Rapatskaya

The study aims to analyze the relationship between the redetermination of the complexity of the geological structure of the Verkhnechonsky oil and gas condensate field and the schedule adjustment of the field development plans. The paper uses the data on the exploration and production wells obtained from the pilot operation of JSC Verkhnechonskneftegaz, the geophysical work results, and the research materials publicly available in the press. The geological structure of the Verhnechonskoye oil and gas condensate field is unique in its complexity. This is due to the following factors: a combination of tectonic disturbances accompanied by the intrusion of traps; high mineralization of the reservoir water; sharp variability of the filtration and reservoir properties of the producing horizons by area and section due to the unevenness of the lithological composition of the reservoirs, their salinization and complete pinch-out. The development system of any field should take into account the peculiarities of the field’s tectonic and lithological-facies structure, and meet specific technical and economic requirements for drilling and operating wells. The complexity of the field structure requires a thorough selection of a development system that inevitably changes as the features of the field structure are studied, e.g. vertical drilling suggested at the initial stage of the filed development was shortly after replaced with inclined-horizontal drilling with the calculation of two options. Within the pilot operation project of the Verkhnechonsky field, JSC Verkhnechonskneftegaz has developed two variants of uniform grids of directional and horizontal wells with pattern flooding for the most explored deposits of the Verkhnechonsky horizon of blocks I and II. Because of the intensive processes of the reservoirs’ secondary salinization, the flooding method required a study of the reservoir water composition. However, the proposed drilling plan using a downhole engine and gamma-ray logging could not ensure the wellbores ducting through the most productive sections of the horizon, therefore, the flow rates of some directional and horizontal wells were not high enough. To increase the drilling efficiency, the specialists of the Drilling Department (JSC Verhnechonskneftegaz), together with the Department of Geology and Field Development (Schlumberger Ltd.), proposed a new methodology that increases the drilling efficiency by using a rotary-controlled system, logging-while-drilling, and geosteering. Thus, the development system of the Verkhnechonsky oils and gas condensate field was changing in the process of specifying the field’s geological structure, anisotropy reservoir properties, and the thickness of the producing horizons in size and cut, their salinization and pinch-out, and the composition of the reservoir waters.


2021 ◽  
Vol 280 ◽  
pp. 07011
Author(s):  
Viktoriia Dmytrenko ◽  
Ivan Zezekalо ◽  
Yuriy Vynnykov ◽  
Nikolay Hristov ◽  
Gergana Meracheva

The work is devoted to the problem of increasing gas condensate production in gas condensate fields. It was found that ammonium carbonate salts, in the absence of calcium chloride type waters, interact with carbonate rocks, increase the permeability of reservoirs. Solutions of ammonium carbonate salts when interacting with formation water of the calcium chloride type form chemically precipitated chalk in the pore space, while the permeability of carbonate rocks decreases. A set of experimental studies was carried out to study the displacing and washing properties of ammonium carbonate salts. It was found that ammonium carbonate salts have high displacing properties, the displacement ratio of kerosene by NH4HCO3 solution is 0.75-0.80, while reservoir water – 0.55-0.58. According to the results of laboratory studies of the displacing and washing characteristics of ammonium carbonate salts, conclusions were made about the effect of bicarbonate solution (ammonium carbonate salts) on the production characteristics of a well in reservoir conditions at temperatures of 80-100 °C and above. Industrial tests of ammonium carbonate salts showed an increase in gas flow by 30-50% at wells № 23 of Opishnia, № 115 of Mashivka, № 3 of Tymofiivka gas condensate fields. The effect of formation treatment with ammonium carbonate salts is achieved due to clearing of well bottom zone and increasing the formation permeability. At wells № 56, 108 of Yablunivka and № 58 of Tymofiivka gas condensate fields, an increase in the condensate ratio was observed by 22-35%. The effectiveness of this treatment is associated with the simultaneous bottomhole zone cleaning from asphalt-resinous contaminants and permeability increase, as well as with the hydrophilization of the pore space and mobility increase of condensate precipitated as a result of carbon dioxide effect, which was rejected as a result of decomposition of ammonium carbonate. Thus, experimental and industrial tests in Opishnia, Mashivka, Tymofiivka, Yablunivka gas condensate fields of Poltava region confirmed the effectiveness of using ammonium carbonate to increase hydrocarbon production. The prospect of further research is aimed at developing a technology for increasing the production of liquid hydrocarbons by using ammonium carbonate salts.


Author(s):  
R.R. Haliulin ◽  
◽  
S.N. Zakirov ◽  
A.H. Kha ◽  
N.E. Vedernikov ◽  
...  

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Bing Han ◽  
Bin Tong ◽  
Jinkai Yan ◽  
Chunrong Yin ◽  
Liang Chen ◽  
...  

Reservoir landslide is a type of commonly seen geological hazards in reservoir area and could potentially cause significant risk to the routine operation of reservoir and hydropower station. It has been accepted that reservoir landslides are mainly induced by periodic variations of reservoir water level during the impoundment and drawdown process. In this study, to better understand the deformation characters and controlling factors of the reservoir landslide, a multiparameter-based monitoring program was conducted on a reservoir landslide—the Hongyanzi landslide located in Pubugou reservoir area in the southwest of China. The results indicated that significant deformation occurred to the landslide during the drawdown period; otherwise, the landslide remained stable. The major reason of reservoir landslide deformation is the generation of seepage water pressure caused by the rapidly growing water level difference inside and outside of the slope. The influences of precipitation and earthquake on the slope deformation of the Hongyanzi landslide were insignificant.


2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Andreas Pollreisz ◽  
Ursula Schmidt-Erfurth

Cataract in diabetic patients is a major cause of blindness in developed and developing countries. The pathogenesis of diabetic cataract development is still not fully understood. Recent basic research studies have emphasized the role of the polyol pathway in the initiation of the disease process. Population-based studies have greatly increased our knowledge concerning the association between diabetes and cataract formation and have defined risk factors for the development of cataract. Diabetic patients also have a higher risk of complications after phacoemulsification cataract surgery compared to nondiabetics. Aldose-reductase inhibitors and antioxidants have been proven beneficial in the prevention or treatment of this sightthreatening condition in in vitro and in vivo experimental studies. This paper provides an overview of the pathogenesis of diabetic cataract, clinical studies investigating the association between diabetes and cataract development, and current treatment of cataract in diabetics.


2021 ◽  
Author(s):  
Khidir Mansum Ibragimov ◽  
Nahide Ismat Huseinova ◽  
Aliabas Alipasha Gadzhiev

Abstract For controlling the oil field development proposed an economically efficient express calculation and visualization method of the hydrodynamic parameters current values distribution in the productive formation. The presented report shows the results of applying this technique for determining the injected water propagation direction into the productive formation (X horizon) at the «Neft Dashlary» field. Based on the calculated results, the current distribution of the injected water was visualized in the selected section of the formation. High accuracy of the calculation was confirmed by comparing obtained results with the results of a simultaneous tracer study conducted in the field conditions. During tracer studies it was tested a new tracer material, more effective than its analogs. According to laboratory and experimental studies, the addition of 0.003% of this indicator substance to the volume of injected water is the optimal amount for its recognition in the well's product. At the allocated area of the "Neft Dashlari" field, the benefits from the use of the calculation method amounted to 62.9 thousand manats. Based on the obtained satisfying results of the new method for calculating hydrodynamic parameters and the use of a tracer indicator application at the «Neft Dashlary» oilfield, it is recommended to apply these developments in other oil and gas fields for mass diagnostic of the reservoir fluid distribution in a selected area of productive formations.


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