Free gas content of the rocks of the silvinite and silvinite-carnallite zones at the Upper Kama Districts

Author(s):  
S.S. Andreyko ◽  
O.V. Ivanov ◽  
T.A. Lyalina ◽  
E.A. Nesterov

The results of the mine and the laboratory studies of the free gas content of the sylvinite and sylvinite-carnallite zones of the Upper Kama districts are presented. In the process of the experimental studies, the quantitative characteristics of the free gas content were obtained for sylvinite, carnallite and rock salt layers. In the process of the laboratory studies by the gas chromatography of the natural gas samples, the component composition of the free gases was assessed. Based on the geological structure analysis and the gas content study, the assessment of the composition, the volume, the location and the intensity of the natural gases release is given. Based on the experimental studies results of the free gas content, and an analysis of the locations, the volume and the intensity of the gas emissions, the probable places of the free gases accumulation are installed. The main which are the anticlinal folds inflection the rupture and the crushing, the fractures, the tectonic disturbances, the transition of the sylvinites into the carnallite and the composition changes of the layers.

2021 ◽  
Author(s):  
Kirill Goridko ◽  
Vladimir Verbitsky ◽  
Evgeny Nikonov ◽  
Max Nikolaev

Abstract Artificial lift of oil by electric submersible pumps (ESP) is often complicated by free gas in production. Free gas content in production leads to ESP performance degradation in rate and head. Gas slip in the ESP impeller is one of the reasons of ESP performance degradation. Thus, the goal of the work is to determine the gas slip coefficient i.e. liquid holdup in the ESP impeller. It is known that a gas-liquid mixture (GLM) flow characterized by a slippage effect. Gas slippage relative to the liquid determines the GLM structure (bubble, dispersed-bubble, slug, stratified or annular), as well as the difference between the GLM densities calculated by liquid holdup or liquid volume content. Special stand was designed and created to determine the liquid holdup at the Department of Oil Fields Development and Operation of Gubkin University. Liquid holdup in the impeller of the ESP was measured by the method of cutting off the flow. This paper shows the results of experimental studies of liquid holdup and gas slip velocity in the ESP impeller (ESP5-50) at a rotational speed n = 2997 rpm, at an absolute intake pressure Pin = 0.4 MPa. The dependence of the liquid holdup on liquid volume content (i.e. the dependence of the gas void fraction on gas volume fraction) was determined for the model GLM "water-air", "water-surfactant-air" with different foaming capacity. The degradation of the ESP characteristics, boundaries of surging and gas locking limits are determined taking into account liquid holdup. The dependence of gas holdup was experimentally obtained over the entire range of ESP operation (from 0.5∙Qopt to Qmax). A comparison of the obtained correlation with existing models is presented too. A new correlation for predicting liquid holdup in the ESP impeller for the low-rate wells operation is obtained. A new approach to determining the liquid holdup and consequently gas slip velocity in the ESP impeller is proposed.


2021 ◽  
Author(s):  
Kirill Alexandrovich Goridko ◽  
Rinat Alfredovich Khabibullin ◽  
Vladimir Sergeevich Verbitsky ◽  
Arturas Rimo Shabonas ◽  
Guzel Kazakbaeva

Abstract One of the most common complications in the operation of wells with electric submersible pumps (ESP) is the presence of free gas in the produced well product. The work considers a model of ESP operation taking into account a large share of free gas in the flow obtained on the basis of bench tests and its applicability for analyzing the operation of real producing wells equipped with ESPs. Tests of ESP5-50 (118 radial stages) with model gas-liquid mixtures in a wide range of inlet gas volume-flow rate (0-60%), inlet pressure (0.6-2.1 MPa), shaft speed (2400-3600 rpm) with simultaneous pressure measurement along the pump length and direct measuring of power at the shaft by means of motor weights were performed at the oilfield development and operation department. Mathematical model is obtained by means of regression analysis of experimentally received characteristics of ESPs on gas liquid mixtures; a simple engineering method of calculating the degradation of ESPs characteristics by flow, head and power is suggested. The experience of building similar models described in the literature was taken into account. Experimental studies and creation of a mathematical model of ESP were carried out during Kirill Goridko's PhD thesis. As a result of the research we obtained the degradation dependencies of the pump's delivery and the head of ESP while pumping mixtures of different foam capacity, which simulate the pump operation in low and high watercut wells. The patterns of delivery and head coefficients depending on the zone (left, optimum, right) of ESP characteristic are revealed. The degradation of ESP power during pumping gas liquid mixture is clarified, which allows to calculate more accurately the specific energy consumption of well products lifting. The developed method of recalculation of the pressure and power characteristics of ESPs is implemented in the form of calculation modules designed for engineering calculations in oil production. The proposed tool has been tested on the data of the Western Siberia fields while analyzing the operation of wells with high gas content in the produced product. Calculation modules have been made publicly available. A new simple engineering method was developed to account for the degradation of the pressure and flow and power characteristics of ESPs for low- and medium-rate wells based on a large number of benchmark studies. Оbtained degradation dependences are programmed in the form of calculation modules, which allows to analyze the operation of a large number of wells on the basis of their technological mode, as well as to propose optimization measures to change the ESP operation at a higher level.


2021 ◽  
Vol 23 ◽  
pp. 346-355
Author(s):  
Anatoliy Pavlenko

This work was performed to improve the storage and transportation technology of gas hydrates in nonequilibrium conditions. At atmospheric pressure and positive ambient temperature, they gradually dissociate into gas and water. Simulation of the gas hydrate dissociation will determine optimal conditions for their transportation and storage, as well as minimize gas loss. Thermodynamic parameters of adiabatic processes of forced preservation of pre-cooled gas hydrate blocks with ice layer were determined theoretically and experimentally. Physical and mathematical models of these processes were proposed. The scientific novelty is in establishing quantitative characteristics that describe the gas hydrates thermophysical parameters thermophysical characteristics influence on the heat transfer processes intensity on the interphase surface under conditions of gas hydrates dissociation. Based on the results of experimental studies, approximation dependences for determining the temperature in the depths of a dissociating gas hydrate array have been obtained. Gas hydrates dissociation mathematical model is presented.


Author(s):  
С.А. Мамаев ◽  
А.Р. Юсупов ◽  
А.С. Мамаев ◽  
З.А. Юсупов

В данной статье даны особенности геологического строения района газопроявления «Цущар» в Кулинском районе на отложениях среднеюрского возраста, предлагается геолого-структурная схема возможного формирования залежи нефти и газа. Незначительные проявления газоносности, связанные обычно с минеральными источниками и подчиненные мощной толще юрских сланцев, развитых на значительных площадях нагорного Дагестана, начали обращать на себя внимание с 1931 г., в связи с поисками месторождений легких редких газов. Анализы газов показывают повышенное содержание легких редких газов в целом ряде месторождений нагорного Дагестана. Кроме группы месторождений Южного Дагестана известен пока только один выход горючего газа в Центральном Дагестане – Кулинском районе. На него указывает в своем рукописном отчете Дагестанскому Совнархозу геолог Н. М. Леднев. Этот выход подчинен юрским сланцам, связан с нарушениями неотектонического характера, образованными в результате сейсмической активизации региона. Цель исследования. Целью наших исследований является обоснование перспектив газоносности Горного Дагестана. На изучаемой территории отмечается наличие неправильных куполовидных складок с неожиданными направлениями их осей, пересекающими основное направление складчатости, частичными местными уклонениями в залегании пластов. Методы исследования. Основными методами исследования при изучении перспектив газоносности Горного Дагестана являлись геолого-структурный, стратиграфический, морфологический, тектонический и дешифрирование аэрофотоснимков. Результаты исследования. По сравнению с Предгорным Дагестаном и Прикумским районом, Горный Дагестан был подвержен более интенсивным геотектоническим движениям, неоднократно подвергался складчатости, испытал инверсию, со значительно большей амплитудой, что привело к усиленной денудации, развитию трещиноватости и разрывов, метаморфизму пород и органических образований. Все это отрицательно влияло на сохранение нефти и газа. Можно предполагать, что многие залежи, сформировавшиеся при прохождении продуцирующими толщами главной фазы нефтеобразования, были разрушены в периоды активизации тектонической деятельности на рубеже юры и мела, мела и палеогена. В дальнейшем шла генерация, преимущественно, газообразных углеводородов, которые при особенно благоприятных условиях могли сохраниться до настоящего времени. По результатам исследований можно утверждать, что газовое проявление Цущар могло проявиться в 1622, 1652 гг. в результате сильных землетрясений, эпицентр которых располагался в пределахисследуемого района This article describes the features of the geological structure of the Tsushar gas show area in the Kulinsky region on the Middle Jurassic deposits, and proposes a geological-structural diagram of the possible formation of oil and gas deposits. Minor manifestations of gas content, usually associated with mineral springs and subordinate to a thick stratum of Jurassic shales, developed over large areas of highland Dagestan, began to attract attention from 1931, in connection with the search for deposits of light rare gases. Gas analyzes show an increased content of light rare gases in a number of fields in highland Dagestan. In addition to the group of fields in Southern Dagestan, only one outlet of combustible gas in Central Dagestan is known – the Kulinsky region. It is pointed out in his handwritten report to the Dagestan Economic Council by the geologist N. M. Lednev. This outlet is subordinate to the Jurassic shale and is associated with neotectonic disturbances formed as a result of seismic activation of the region. Aim. The purpose of our research is to substantiate the prospects for gas content in Gorny Dagestan. In the study area, there are irregular dome-shaped folds with unexpected directions of their axes crossing the main direction of folding, partial local deviations in bedding. Methods. The main research methods in the study of the prospects for the gas content of Mountainous Dagestan were geological-structural, stratigraphic, morphological, tectonic and additional aerial photographs. Research results. Compared to Piedmont Dagestan and Prikumskiy region, Gorny Dagestan was subject to more intense geotectonic movements, repeatedly underwent folding, experienced inversion, with a much higher amplitude, which led to increased denudation, the development of fracturing and fractures, metamorphism of rocks and organic formations. All of this negatively affected the conservation of oil and gas. It can be assumed that many deposits, formed during the passage of the producing strata of the main phase of oil formation, were destroyed during periods of intensified tectonic activity at the boundary between the Jurassic and Cretaceous, Cretaceous and Paleogene. In the future, there was the generation of mainly gaseous hydrocarbons, which, under especially favorable conditions, could persist to the present day. According to the research results, it can be argued that the gas manifestation of Tsushar could have manifested itself in 1622, 1652. as a result of strong earthquakes, the epicenter, which was located within the study area


2021 ◽  
Vol 43 (3) ◽  
pp. 123-134
Author(s):  
T. R. Akhmedov ◽  
T. Kh. Niyazov

The article is devoted to the elucidation of the nature of the wave field recorded below the supporting-dominant seismic horizon «P» in the Middle Kura depression of Azerbaijan. A brief overview of the work carried out here is given; it is indicated that some geologists and geophysicists of our country, in our opinion, mistakenly assume that the observed wave field below the specified horizon is formed mainly by multiple reflections. Since the introduction of the common depth point method into the practice of seismic exploration, individual areas of the Middle Kura depression in Azerbaijan, including the Yevlakh-Agjabedi trough, have been repeatedly studied with varying degrees of frequency tracking. On the basis of this, a fairly large number of promising structures have been identified and mapped. But the structure of the Mesozoic, in particular the deposits of the Upper Cretaceous, still remains insufficiently studied. The study of the geological structure of the Mesozoic sediments, which are considered promising in terms of oil and gas content, is an urgent geological task; exploration work was carried out in the studied areas of the Middle Kura depression using a complex of geophysical methods at the modern technical and methodological level and new results were obtained. The constructed seismic sections show a dynamically pronounced and well-traceable seismic horizon corresponding to the Mesozoic surface and located deeper than it, relatively weak, short, discontinuous reflective boundaries that characterize the structure within the Mesozoic deposits. The studies carried out on the basis of modeling and velocity analysis made it possible to prove that the wave field in the time interval corresponding to the Mesozoic deposits owes its origin to intermittent single reflections from volcanic-carbonate deposits of the Upper Cretaceous age.


1984 ◽  
Vol 24 (01) ◽  
pp. 38-48 ◽  
Author(s):  
Surendra P. Gupta

Abstract The performance of the micellar/polymer flood conducted in the Sloss reservoir did not follow predictions by a streamtube model. The model assumed that micellar flood displaces oil and water in a piston-type miscible manner with a final oil saturation of 5 % PV, and sulfonate retention based on short-term laboratory adsorption tests. This paper, in conjunction with a complementary paper,1 describes process mechanisms needed to model the flood performance. The results of laboratory studies show higher sulfonate retention caused by ion-exchange effects, which result in partitioning of sulfonate into the oil phase and higher adsorption caused by long contact times. Long-term aging of the Sloss micellar fluid at the high reservoir temperature (93.3°C [200°F]) does not reduce oil recovery. The results of laboratory studies also show that the final oil saturation after micellar flooding is capillary-number dependent. A higher final oil saturation can be the result of reduced injectivity /productivity, increased interfacial tension (1FT), and/or decreased viscosity. This paper demonstrates that ion exchange, hardness, and sulfonate partitioning can significantly affect micellar-flood performance. The paper presents an experimental plan that provides information for optimizing the design of micellar/polymer floods. This plan, when applied to a specific flood, allows an investigator to examine effects of adsorption, ion exchange, hardness, and partitioning on flood performance. Specifically, phase studies and sulfonate requirements must encompass effects of in-situ-generated calcium ions as a result of sodium/calcium ion exchange. Sulfonate itself can increase the calcium content of the fluids because of a calcium/micelle association. High calcium concentrations can increase sulfonate requirements. Sulfonate adsorption requirements for micellar flood design are sensitive to the experimental procedures employed. The paper outlines improved procedures encompassing ion exchange and time effects and demonstrates that a favorable ion-exchange process can be used to reduce adsorption requirements. Introduction Interpretation of micellar-flooding pilots is essential to the development of a predictive model for commercial demonstration and fieldwide micellar floods. To interpret field micellar-flood performance, process variables (e.g., compositional effects) must be separated from field variables (e.g., reservoir description and operational difficulties), and the process mechanisms must be identified. This paper describes experimental procedures for use by industry to identify effects of composition changes during micellar flooding. The paper describes application of these procedures to determine the effects of composition changes on the displacement mechanisms of the micellar/polymer fluids injected in the Sloss field, Kimball County, NE.2 The results enhanced our mechanistic understanding of the micellar-flooding process. This understanding is required for interpretation of pilot performance. This paper discusses the first portion of the mechanism studies for the micellar/polymer system used in the Sloss reservoir. Results of the second portion of the mechanism research were published in 1982.1 A separate paper discussed results of the Sloss pilot posttest evaluation well.3 Pilot Performance The streamtube model with classical miscible-immiscible displacements was used to obtain preflood predictions.1 This model assumed sulfonate retention (by adsorption) of 3.42 kg active Mahogany AA sulfonate/m3 contacted PV [1.20 lbm/bbl PV], a final oil saturation of 5 % PV in the micellar swept zone, and mobility control. The preflood predictions and pilot performance were in excellent agreement during the early stages of the project.2 However, the observed performance later deviated from the preflood predicted performance.2,4 Postflood predictions by the same model more closely matched total pilot performance by assuming an increased sulfonate retention and a higher final oil saturation. Process Mechanism Studies Detailed laboratory studies were initiated to enhance our mechanistic understanding of the process. These studies needed for interpretation of the pilot performance included:phase behavior,compositional effects on oil displacement,propagation of the oil and micellar banks,ion-exchange behavior,sulfonate retention,time effects on sulfonate adsorption, andeffect of micellar fluid aging on oil recovery.


Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6003
Author(s):  
Ming Li ◽  
Bo Jiang ◽  
Qi Miao ◽  
Geoff Wang ◽  
Zhenjiang You ◽  
...  

Multi-phase tectonic movements and complex geological structures limit the exploration and hotspot prediction of coalbed methane (CBM) in structurally complex areas. This scientific problem is still not fully understood, particularly in the Bumu region, Southwest China. The present paper analyses the occurrence characteristics and distribution of CBM based on the comprehensive analysis of CBM data. In combination with the analysis of the regional tectonics setting, geological structure features and tectonic evolution. The control action of multi-phase tectonic movements on CBM occurrence are further discussed. Results show that the Indosinian local deformation, Yanshanian intense deformation, and Himalayan secondary derived deformation formed the current tectonic framework of Enhong synclinorium. The intense tectonic compression and dextral shear action in the Yanshanian and Himalayan movements caused the complex geological structures in Bumu region, composed of the Enhong syncline, associated reverse faults and late derived normal fault. The CBM distribution is complex, which has the central and western NNE-trending high gas content zones along the syncline hinge zone and the reverse faults. The geological structure controls on CBM enrichment are definite and important. Based on geological structure features and responses of gas content, methane concentration, and gas content gradient, the gas controlling patterns of geological structure are determined and can be classified into five types: the reverse fault sealing, syncline sealing, monoclinal enrichment, normal fault dispersion, and buried floor fault dispersion types. The structural compression above the neutral surface plays an important role in the syncline sealing process, which is indicated by an increase in gas content gradient. The EW-trending tectonic intense compression and dextral shear action in the Himalayan movement avoided the negative inversion of NNE-trending Yanshanian compressive structure and its destruction of CBM reservoir. However, the chronic uplift and derived normal fault during Himalayan period caused the constant dissipation of CBM.


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