Acidizing Workflow for Optimized Well Performance in Zhdanov and Lam Oil Fields Offshore Caspian Sea

2021 ◽  
Author(s):  
Ruslan Kalabayev ◽  
Ekaterina Sukhova ◽  
Gadam Rovshenov ◽  
Roman Kontarev
Keyword(s):  
Experimental Data ◽  
Caspian Sea ◽  
Laboratory Testing ◽  
Efficiency Calibration ◽  
Oil Fields ◽  
Reservoir Rock ◽  
Rock Matrix ◽  
Acid Rock ◽  
Matrix Acidizing ◽  
Acid Treatments

Abstract Successful sandstone matrix stimulation treatments require addressing complex mineralogy, correctly identifying formation damage, selecting the best stimulation fluids, and placing these fluids correctly. The objective of this paper is to demonstrate a workflow considering laboratory testing, advanced software modeling including acid and diverter fluid efficiency calibration using field experimental data, field execution, and relevant case studies in two oil fields located in the Cheleken block, offshore Caspian Sea. Implementation of the workflow has led to positive results. Matrix acidizing was selected as the primary method for restoring production of the oil wells drilled into sandstone reservoirs due to the reservoir characteristics. Deep Zhdanov wells and shallower Lam wells possess ~15 and ~250 md permeability and ~90 and ~50°C static reservoir temperature, respectively. The target rock mineralogy in both fields predominantly consists of quartz, chlorite, and carbonate minerals. Fluids selection, stimulation design and job execution followed the above mentioned workflow. Treatment modeling considered calibration factors derived from field testing and incorporated several acid and diverter systems. A mix of bullhead and coiled tubing placed treatments were employed. The first step of the workflow considered characterization of the rock mineralogy and selection of the best-fit treatment fluids. Rock dissolution and X-ray diffraction (XRD) tests were run to develop the optimum formulations for the treatment conditions. Further, the results of the laboratory testing were incorporated into the advanced matrix acidizing simulator to model and optimize the treatment schedules. The recently developed matrix stimulation software incorporates geochemical, thermal, and placement simulations calibrated with experimental data. Offset well stimulation treatment pressure match was done by calibrating the acid and diverter fluid efficiency, and those calibrated values were considered for design simulations for the following acid treatments. In this paper, the term "acid efficiency" is defined as a measure of the relative rate at which the acid can penetrate when it flows in the rock matrix as a function of matrix porosity and the overall acid reactivity. The term "diverter efficiency" is defined as a measure of the viscosity developed by a given diverter when it flows in the rock matrix. Such a calibration method accounts for the actual reservoir large-scale acid-rock reaction kinetics. Finally, diagnostic tests and main acid treatments were executed that enabled achieving the desired levels of skin reduction, reservoir placement, zone coverage, and hydrocarbon production rates. Several acid stimulation operations were conducted including three cases in which a low-temperature well with carbonate damage needed repeated acidizing and two additional cases that involved wells with deep, hot, and clay-rich pay zones. Several fluid schedules were applied including foam diversion technique. The above approach uses a unique method of acid efficiency calibration using field experimental data. It requires good knowledge of reservoir rock mineralogy, porosity, and permeability profiles in the zones of interest. Pretreatment skin is calibrated using production data prior to acid efficiency calibration based on matching the actual treatment pressures. The pressure behavior observed during the following treatments closely matched the design pressures confirming applicability of the approach.

Novel Simulator for Design and Analysis of Matrix Acidizing Jobs with Fluoroboric Acid in Sandstone Reservoirs

2021 ◽  
Author(s):  
Mohammed Qamruzzaman ◽  
Mandeep Khan ◽  
Dhirendra Chandra Roy ◽  
Ravi Raman
Keyword(s):  
Reservoir Rock ◽  
Core Flooding ◽  
Pumping Rate ◽  
Matrix Acidizing ◽  
Skin Factor ◽  
Computational Fluid Dynamics Cfd ◽  
Made In ◽  
Do So ◽  
Acid Treatments

Abstract Matrix acidizing with fluoroboric acid (HBF4) has gained special attention as not only it provides deeper penetration of in – situ generated hydrofluoric acid, but also stabilizes formation fines by binding them to the pore surface. While numerous mathematical models exist in literature for design and evaluation of conventional mud acid treatments, fewer attempts have been made in developing a lab validated model that can do so for fluoroboric acid treatments. This paper presents a novel mathematical model that has been developed taking into account the chemical kinetics and equilibrium aspects of important reactions and fluid flow inside the reservoir rock. The solution to the governing equations has been obtained through tools of computational fluid dynamics (CFD). The model has been validated rigorously through use of state-of-the-art core flooding and ion chromatography setups. The resulting simulator can be used to design an optimum fluoroboric acid treatment by analysing the effects of all the important factors including reservoir temperature, formation mineralogy and job execution details like initial acid concentration, pumping rate, job volume and shut-in time post treatment. Simulation results with the developed model indicate that although penetration of fluoroboric acid is much larger compared to mud acid, its overall effect on skin factor is inferior for temperatures less than 90 °C. Stimulation in such wells should be preferred with mud acid which can be followed by fluoroboric acid for fines stabilization. For temperatures more than 120 °C, stimulation effects of fluoroboric acid become comparable to that of mud acid. Under these conditions, it can be used as an alternate fluid to mud acid to prevent issues of secondary and tertiary precipitation. It is found that major stimulation benefits with fluoroboric acid are realized during pumping and subsequent shutting of well, which is a common practice with fluoroboric acid, has relatively smaller effect on skin factor. Apart from design and evaluation of fluoroboric acid treatments, the simulator can also be used for analyzing mud acid and mud acid followed by fluoroboric acid treatments thus enabling the user to select and design the best suited treatment for a given well.

A New Method of Carbonate Matrix Stimulation Modelling and Optimisation Using Field Experimental Data for Acid Efficiency Calibration and Case Studies in Kazakhstan

2021 ◽  
Author(s):  
Ruslan Kalabayev ◽  
Dmitriy Abdrazakov ◽  
Dmitry Chuprakov
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Large Scale ◽  
Field Tests ◽  
Efficiency Calibration ◽  
Flow Profile ◽  
Matrix Acidizing ◽  
Reservoir Conditions ◽  
Scale Calibration ◽  
Carbonate Matrix

Abstract Successful carbonate matrix acidizing treatments require addressing pay rock mineralogy, produced fluid flow profile, selection of the best stimulation fluids, and correct placement of these fluids. A unique method of acid and diverter fluid efficiency calibration using field experimental data for treatment modelling and optimization has been implemented successfully in several mid-temperature reservoirs, including giant oil fields in Kazakhstan. Application of the technique led to positive results. Matrix stimulation is selected as the primary method for raising production from many carbonate reservoirs in the region because of the reservoir features. Coreflood testing conducted with candidate acid systems for selection and optimization of treatment fluid formulations and design schedules did not always lead to the desired post-stimulation skin levels, zone coverage, and production results. Hence, large-scale calibration of the acid parameters to the actual reservoir conditions was attempted. Treatment modelling in an advanced matrix acidizing software considered calibration factors derived from field tests. Thereafter, the optimized designs were implemented in the same reservoirs to improve the incremental production. Whenever possible, coreflood testing was carried out as the first step to determine the pore-volume to breakthrough parameters for the candidate acid systems. As the second step, these laboratory-derived data were used for modelling of the offset well stimulation design. Third, the actual treatment downhole pressure was matched with the simulated pressure by means of acid efficiency calibration in the matrix stimulation software. These calibrated parameters were then used for simulation of the following treatments in the same formation in attempt to model the expected reservoir placement and zone coverage more accurately and realistically to maximize the treatment effect. Post-stimulation fluid flow profile surveys have validated the optimized models and applicability of the methodology for improving incremental well productivity in the subject reservoirs. The stimulation approach uses a unique technique of acid efficiency calibration using field experimental data. It requires good knowledge of reservoir lithology and permeability and porosity profiles in the target zones. The initial skin is calibrated using pretreatment production data. Thereafter, acid efficiency is calibrated based on matching the actual stimulation job pressures.

scholarly journals Legal Status Of The Caspian Sea: History And Present

2012 ◽  
Vol 6 ◽  
Author(s):  
Ardak Kapyshev
Keyword(s):  
Caspian Sea ◽  
Legal Status ◽  
Oil Fields ◽  
Present Stage ◽  
The Caspian Sea ◽  
Interstate Relations ◽  
The Usa ◽  
History Of ◽  
The Right ◽  
Near Future

At  the  present  stage  one  of  the  unsolved   problems in  interstate relations of  Caspian bordering countries is defining international­legal status of the Caspian Sea. It is noted in the article that this problem is not a new one at all. The history of “division” of the Caspian Sea begins in the ancient age, namely in VIII century. It is underlined that the basic stumbling block  is the position of Iran on the right to use the Caspian Sea, and also occurrence of extra regional players, such as  the USA, China, etc. First of  all, it is connected with rich oil fields and other minerals, and also with convenient geopolitical and geostrategic position. The only way to worry out the international­legal delimitation of the Caspian Sea problem is a negotiating process. By now, despite of  certain disagreements on  legal status of  the Caspian Sea, five Caspian bordering countries managed to achieve certain progress, admitting the possibility of applying the principle of sectorial sectioning on the Caspian Sea.  Clear proof  of  it is the agreements on  division of ground on the northern part of Caspian Sea signed between Kazakhstan, Russia and Azerbaijan. It is important that Kazakhstan, Russia, Azerbaijan and Turkmenistan clearly stated their positions and agreed to make a compromise in their official statements. More than likely, in the near future Iran will soften its position, considering its present  situation and   strained relations with the USA. It has been alleged that the constructive  dialog  already  started; everything depends on  the mobility,  concurrency and rationality of actions of all Caspian bordering countries.

Psychometric Testing in Iran

1959 ◽  
Vol 105 (438) ◽  
pp. 93-107 ◽  
Author(s):  
Max Valentine
Keyword(s):  
Persian Gulf ◽  
Caspian Sea ◽  
Psychometric Testing ◽  
Mineral Resources ◽  
Oil Fields ◽  
The Caspian Sea ◽  
Winter Rainfall ◽  
Mountain Ranges ◽  
The People ◽  
The Persian Gulf

Geographically, Iran is for the most part a plateau at an average altitude of about a thousand metres; the terrain—the near-jungle conditions of the Caspian littoral excepted—is arid semi-desert and the typical landscape one of limestone mountain ranges between which lie flat plains. It is bordered by Iraq, Turkey, the U.S.S.R., the Caspian Sea, Afghanistan, Pakistan and the Persian Gulf. Except during spring the vegetation in most areas is sun-shrivelled on the bare treeless earth; after five months of burning heat the winter rainfall washes off the topsoil, and river-beds, dry throughout the summer, overflow with muddy torrents. Although the soil is dry and powdery there are abundant watercourses below the surface and with irrigation the land is very productive. The country has great mineral resources; apart from the oil-fields they are un-exploited due to lack of coal and road and rail communications. The people are mainly feudal villagers or nomadic tribesfolk but Tehran is a modern city of a million population and the provincial capitals are also semi-Westernized.

scholarly journals Seasonal variability and anomalies of the currents of the cyclonic gyre in the northeastern sector of Caspian sea

2019 ◽  
Vol 46 (5) ◽  
pp. 485-495
Author(s):  
A. K. Ambrosimov
Keyword(s):  
Experimental Data ◽  
Caspian Sea ◽  
Cold Water ◽  
Eastern Region ◽  
Cyclonic Gyre ◽  
Southern Slope ◽  
The South ◽  
Near Surface ◽  
The North ◽  
North Eastern

The experimental data presented in the article show that in the North-Eastern sector of the Middle Caspian sea in the area of Peschanomyssky uplift there is a disturbance of currents caused by the interaction of the cyclonic cycle with the southern slope of the uplift. As a result of this interaction, the waters of the cyclonic cycle are divided into branches – the lower and upper. The lower bottom branch is thrown by the uplift in the South-Western direction, where at the Cape of the uplift it collides with the waters flowing down the bottom of the South-Buzachinsky deflection in the South-Eastern direction, and the upper branch, consisting of near-surface and intermediate cold waters, is pushed up and passes through the uplift. As a result of the rise of cold water in the surface layer formed upwelling, which extends to the entire North-Eastern region of the sea.

scholarly journals Research in the effectiveness of acid treatments productive formations on oil fields in Western Siberia

2021 ◽  
Vol 745 (1) ◽  
pp. 012021
Author(s):  
A S Akopov ◽  
A P Yanukyan ◽  
I I Kushch ◽  
S A Kaverzin ◽  
S B Beketov
Keyword(s):  
Western Siberia ◽  
Oil Fields ◽  
Acid Treatments

REVIEW OF THE PALAEOZOIC STRATIGRAPHY AND PETROLEUM POTENTIAL OF NORTHERN SOUTH AUSTRALIA

1975 ◽  
Vol 15 (1) ◽  
pp. 45
Author(s):  
S. B. Devine ◽  
B. C. Youngs
Keyword(s):  
South Australia ◽  
Oil Fields ◽  
Reservoir Rock ◽  
Petroleum Potential ◽  
Reservoir Rocks ◽  
Block Area ◽  
Reservoir Potential ◽  
Rock Lithology ◽  
Cooper Basin

The Amadeus, Warburton, Officer, Adavale, Arckaringa, Pedirka, Cooper and Great Artesian Basins form a complex system of overlapping basins in central Australia. Cambrian rocks are widespread in the Amadeus, Warburton and possibly the Officer Basins and are marked by the major role of carbonate deposition. Gas and oil shows are known from the Amadeus and Warburton Basins. In South Australia their reservoir potential lies in shoreline clean-up of generally dirty marine sandstones and porosity-permeability associated with archaeocyathid bioherms or dolomitization of limestones.The Ordovician rocks follow the widespread distribution of the Cambrian rocks and are distinctive for thick quartzites and graptolitic shales. In South Australia, the Warburton and Officer Basins may have facies developed which are similar to the Pacoota and Stairway Sandstones, the reservoir rocks for the Amadeus Basin gas and oil fields. Large anticlinal structures have recently been suggested by S.A. Mines Department geophysical work in the Officer Basin which enhances the potential.Red beds are distinctive in the Devonian System. Deposition apparently spilt into the peri-Musgrave Block area and the Adavale Basin to Innamincka area. A thickness of over 3 000 metres of Devonian rocks was drilled in the Officer Basin which contained some reservoir rock lithology. The petroleum potential in South Australia is relatively unattractive.Some 3.4 trillion cu ft of deliverable gas reserves have been established already in the Permian sediments of the Cooper Basin which are up to 900 m thick. The Early Permian sediments of the Pedirka Basin which may be at least 500 m thick may hold similar petroleum potential.

Sign in / Sign up

Export Citation Format

Share Document