scholarly journals ANALYSIS OF THE INFLUENCE OF GEOLOGICAL FACTORS ON THE DEPTH OF THE FILTRATE INVADED ZONEAT THE PRIMARY DISCLOSURE OF GRANULAR RESERVOIRS ACCORDING TO THE WELL-LOGGING DATA

2020 ◽  
pp. 16-21
Author(s):  
O. Karpenko ◽  
B. Sobol ◽  
M. Myrontsov ◽  
I. Karpenko
Keyword(s):  
Oil And Gas ◽  
Well Logging ◽  
Drilling Mud ◽  
Gas Wells ◽  
Reservoir Rocks ◽  
Different Types ◽  
Geological Factors ◽  
Invaded Zone ◽  
Characteristic Features ◽  
Mud Filtrate

Possibilities of using the well-logging data for revealing the factors of the geological nature that influence the formation of invaded zone of a drilling mud filtrate at oil and gas wells drilling are considered. Electrical logging data were used with probes of different sizes and different types for adequate calculation of the relative diameter of the invaded zone. 5 wells from the gas condensate field were selected for analysis. The terrigenous section of the wells is represented by the alternation of argillites, siltstones and sandstones. Rocks reservoirs of granular type; the layers with thicknesses from 3,4 to 18,2 m were selected for analysis. The results of statistical analysis (cluster and factor analyzes) revealed 3 groups of rocks, the characteristic features of which are significantly differentfrom the invaded zone, layer thickness and porosity and gas saturation coefficients. It is established that for terrigenous sections with reservoir rocks of granular type (Serpukhovian) for one field on the example of 5 wells there is a maximum direct correlation between the value of the relative diameter of the invaded zone and the thickness of the layers. The conducted researches allow making prognostic estimations concerning the approximate distributions of diameters of an invaded zone in terrigenous cuts in case of accident-free drilling with observance of technological conditions.

scholarly journals Detection of intervals / layers in sections of the wells with anomalous areas of drilling mud filtrate contamination according to the well logging (with negative test results of horizons)

2021 ◽  
Vol 280 ◽  
pp. 09007
Author(s):  
Oleksiy Karpenko ◽  
Vasyl Sobol ◽  
Mykyta Myrontsov ◽  
Ivan Karpenko
Keyword(s):  
Gas Flow ◽  
Oil And Gas ◽  
Drilling Fluid ◽  
Well Logging ◽  
Reservoir Rock ◽  
Donets Basin ◽  
Drilling Mud ◽  
Important Conclusion ◽  
Mud Cake ◽  
Invaded Zone

The zone of infiltration of the drilling fluid filtrate into the reservoir rock creates significant difficulties for the study by logging methods and during further testing of the formation. Due to the penetration of filtrate, significant contamination of the near-wellbore zone occurs. The porosity and filtration characteristics of reservoir rocks are changing. There is a possibility of blockage by filtrate in the invaded zone of oil or gas flow from the formation to the well. As a result of the studies carried out using well logging data, it was found that the presence and distribution of a mud cake on the borehole wall opposite the reservoir is an important factor influencing the process of filtration of the drilling fluid into the layers. On the examples of the Yablunivske oil and gas and Kolomatske gas fields of the Dnieper-Donets basin, it is shown that the absence of a mud cake on the borehole walls leads to the formation of maximum, anomalous zones of filtrate invasion. The determining of the diameter of the invaded zone was carried out according to the data of electrical logging methods. In addition, the diameter of the invaded zone was calculated as a solution direct task equation for the case of direct filtration without blocking by the mud cake. Comparison of the results of determining the diameter of the invaded zone by two methods made it possible to draw certain conclusions. An important conclusion is that even partial absence of mud cake on the reservoir wall in the well leads to horizontal and vertical filtration of the drilling fluid from the well into the formation. As a result, the invaded zone may be so deep, that the gas flow rate is absent even at high values of porosity, permeability and gas saturation

Well Clean-Up Using a Combined Thermochemical/Chelating Agent Fluids

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Mohamed Mahmoud
Keyword(s):  
High Temperature ◽  
Filter Cake ◽  
Oil And Gas ◽  
Drilling Fluid ◽  
Chelating Agent ◽  
Drilling Fluids ◽  
Gas Wells ◽  
Oil And Gas Wells ◽  
Different Types ◽  
Cake Removal

The well clean-up process involves the removal of impermeable filter cake from the formation face. This process is essential to allow the formation fluids to flow from the reservoir to the wellbore. Different types of drilling fluids such as oil- and water-based drilling fluids are used to drill oil and gas wells. These drilling fluids are weighted with different weighting materials such as bentonite, calcium carbonate, and barite. The filter cake that forms on the formation face consists mainly of the drilling fluid weighting materials (around 90%), and the rest is other additives such as polymers or oil in the case of oil-base drilling fluids. The process of filter cake removal is very complicated because it involves more than one stage due to the compatibility issues of the fluids used to remove the filter cake. Different formulations were used to remove different types of filter cake, but the problem with these methods is the removal efficiency or the compatibility. In this paper, a new method was developed to remove different types of filter cakes and to clean-up oil and gas wells after drilling operations. Thermochemical fluids that consist of two inert salts when mixed together will generate very high pressure and high temperature in addition to hot water and hot nitrogen. These fluids are sodium nitrate and ammonium chloride. The filter cake was formed using barite and calcite water- and oil-based drilling fluids at high pressure and high temperature. The removal process started by injecting 500 ml of the two salts and left for different time periods from 6 to 24 h. The results of this study showed that the newly developed method of thermochemical removed the filter cake after 6 h with a removal efficiency of 89 wt% for the barite filter cake in the water-based drilling fluid. The mechanisms of removal using the combined solution of thermochemical fluid and ethylenediamine tetra-acetic acid (EDTA) chelating agent were explained by the generation of a strong pressure pulse that disturbed the filter cake and the generation of the high temperature that enhanced the barite dissolution and polymer degradation. This solution for filter cake removal works for reservoir temperatures greater than 100 °C.

Buoyant Miscible Flows in Axially Rotating Pipes: the Effects of Pipe Rotation and Viscosity

2021 ◽  
Author(s):  
Shan Lyu ◽  
Seyed Mohammad Taghavi
Keyword(s):  
Oil And Gas ◽  
Deep Understanding ◽  
Axial Rotation ◽  
Drilling Mud ◽  
Gas Wells ◽  
Two Fluids ◽  
Flow Parameters ◽  
Oil And Gas Wells ◽  
Flow Features ◽  
Primary Cementing

Abstract The primary cementing operations of oil and gas wells involve pumping a sequence of fluids into the well (initially within a circular casing and eventually within an annular region) to displace in-situ drilling mud. The fluids involved can be miscible, and they can also have different density and viscosity ratios. It is believed that a casing rotation can generally improve the displacement process, within both the circular casing and the annulus. However, there have not been a lot of laboratory studies to prove that such rotation is indeed effective for the displacement within the casing. In fact, due to the lack of knowledge, the casing axial rotation may not be still among the top recommendations to enhance the displacement occurring within the casing. This is in spite of the fact such a rotation would be feasible using various types of casing heads and special adaptors. In this work, we conduct simulations to understand the fluid mechanics behind buoyant displacement flows that occur within the casing (pipe). Our focus is to analyze the effects of the axial rotation speed of the pipe, the viscosity of the fluids and the viscosity ratio between the two fluids on the flow behaviours. Other flow parameters are also present: the fluids are miscible, and they have a density difference; the pipe inclination angle is considered to be near-horizontal (i.e. the most challenging case in terms of creating efficient displacements). We investigate important flow features, such as the behaviours of the interface between the fluids, the mixing between the fluids, the fluid front velocities, etc. Our results help develop a deep understanding of how casing rotation can be used to enhance displacement flows in the primary cementing operations of oil and gas wells.

scholarly journals Synthesis of Carboxymethyl Starch for increasing drilling mud quality in drilling oil and gas wells

2016 ◽  
Vol 43 ◽  
pp. 012071 ◽  
Author(s):  
K M Minaev ◽  
D O Martynova ◽  
A S Zakharov ◽  
R R Sagitov ◽  
A A Ber ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Drilling Mud ◽  
Gas Wells ◽  
Carboxymethyl Starch ◽  
Oil And Gas Wells

scholarly journals Investigation of Non-Linear Rheological Characteristics of Barite-Free Drilling Fluids

Fluids ◽  
2021 ◽  
Vol 6 (9) ◽  
pp. 327
Author(s):  
Ekaterina Leusheva ◽  
Nataliia Brovkina ◽  
Valentin Morenov
Keyword(s):  
Oil And Gas ◽  
Drilling Fluid ◽  
Rheological Parameters ◽  
Drilling Fluids ◽  
Drilling Mud ◽  
Gas Wells ◽  
Oil And Gas Wells ◽  
Fluid Properties ◽  
Hydrolyzed Polyacrylamide ◽  
Drilling Muds

Drilling fluids play an important role in the construction of oil and gas wells. Furthermore, drilling of oil and gas wells at offshore fields is an even more complex task that requires application of specialized drilling muds, which are non-Newtonian and complex fluids. With regard to fluid properties, it is necessary to manage the equivalent circulation density because its high values can lead to fracture in the formation, loss of circulation and wellbore instability. Thus, rheology of the used drilling mud has a significant impact on the equivalent circulation density. The aim of the present research is to develop compositions of drilling muds with a low solids load based on salts of formate acid and improve their rheological parameters for wells with a narrow drilling fluid density range. Partially hydrolyzed polyacrylamide of different molecular weights was proposed as a replacement for hydrolized polyacrylamide. The experiment was conducted on a Fann rotary viscometer. The article presents experimentally obtained data of indicators such as plastic viscosity, yield point, nonlinearity index and consistency coefficient. Experimental data were analyzed by the method of approximation. Analysis is performed in order to determine the most suitable rheological model, which describes the investigated fluids’ flow with the least error.

scholarly journals THEORETICAL AND EXPERIMENTAL STUDY OF POROPERM PROPERTIES ANISOTROPY USING ARTIFICIAL GEOMATERIALS

2021 ◽  
Vol 2 (3) ◽  
pp. 304-310
Author(s):  
Larisa A. Nazarova ◽  
Galina V. Nesterova ◽  
Leonid A. Nazarov
Keyword(s):  
Flow Characteristics ◽  
Polar Angle ◽  
Drilling Mud ◽  
Coefficient Inverse Problem ◽  
Reservoir Properties ◽  
Reservoir Rocks ◽  
Gis Data ◽  
Permeability Anisotropy ◽  
Mud Filtrate ◽  
Cylindrical Samples

The reservoir properties (reservoir properties) of reservoir rocks depend not only on the petrophysical characteristics of the formation, but also on the stresses acting in the rock mass. The redistribution of the latter during drilling causes the occurrence of permeability anisotropy in the near-wellbore zone, which affects not only the flow characteristics of the wells, but also the process of penetration of the drilling mud filtrate into the formation. This should be taken into account when building a geomechanical-electrohydrodynamic model of the near-wellbore space. The results of filtration tests of regularly inhomogeneous cylindrical samples made of artificial geomaterial are presented and a method for synthesizing the dependence of the effective permeability on the polar angle based on the solution of the coefficient inverse problem is proposed. The obtained dependencies added to the database of reservoir properties of rocks used for inversion of GIS data for quantitative assessment of reservoir properties, an example of which is presented in this article.

scholarly journals Overview of Water Shutoff Operations in Oil and Gas Wells; Chemical and Mechanical Solutions

2019 ◽  
Vol 3 (2) ◽  
pp. 51 ◽  
Author(s):  
Abdullah Taha ◽  
Mahmood Amani
Keyword(s):  
Oil And Gas ◽  
General Description ◽  
Water Production ◽  
Gas Wells ◽  
Water Shutoff ◽  
Oil And Gas Wells ◽  
Different Types ◽  
Chemical Solutions ◽  
The Common ◽  
Excessive Water

This paper provides an integrated overview of the water shutoff operations, starting from the causes to the solutions. The paper begins with explaining the benefits of eliminating excessive water production. Then, the different types of water production and their properties are explained. The paper also focuses in reviewing the disadvantages of producing unwanted water as well as the sources of it, followed by an explanation of the methodology for identifying the problem. Then, the chemical solutions for water shutoff are reviewed which are generally applied to solve the excessive unwanted water production in the reservoir or near the wellbore area. Finally, the paper illustrates the common mechanical solutions for water shutoff within the wellbore. The aim behind this paper is to provide a general description of identifying the unwanted water production sources and the common practices for water shutoff operations.

scholarly journals IMPROVEMENT OF THE TECHNIQUE AND TECHNOLOGYOF BEDS ISOLATION USING THE PROFILE EXPANDABLE CASING

2016 ◽  
pp. 34-37
Author(s):  
G. S. Abdrakhmanov ◽  
A. A. Zalyatdinov
Keyword(s):  
Oil And Gas ◽  
Fluid Loss ◽  
Drilling Mud ◽  
Gas Wells ◽  
Lost Circulation ◽  
Threaded Connections ◽  
Complex Process ◽  
Oil And Gas Wells ◽  
High Fluid ◽  
Mud Loss

Drilling of oil and gas wells is a time consuming, very complex process in which there occur all sorts of complications. The most common one is drilling mud loss. During drilling of wells the control of this fluid loss problem takes about 12 % of total time. In this case, up to 60 % of materials and time is spent on isolation of fractured-cavernous beds with high fluid loss intensity which make up only 10 % of the total number of isolated zones. The use of liners with welded and threaded connections of shaped tubes enabled to completely solve the problem of lost circulation zones isolation regardless of their thickness, the borehole caving and the fluid loss intensity.

scholarly journals PETROPHYSICAL MODELS OF TERRIGENOUS RESERVOIRS OF THE CARBONIFEROUS DEPOSITS OF THE CENTRAL PART OF THE DNIEPER-DONETS DEPRESSION

2019 ◽  
Vol 1 (178) ◽  
pp. 63-73
Author(s):  
Yulia LYSAK ◽  
Yuriy SHPOT ◽  
Andriy SHYRA ◽  
Zoriana KUCHER ◽  
Ihor KUROVETS
Keyword(s):  
Petrophysical Properties ◽  
Reservoir Properties ◽  
Lower Carboniferous ◽  
Reservoir Rocks ◽  
Geological Conditions ◽  
Geological Factors ◽  
Characteristic Features ◽  
The Given

The purpose of the work was to construct petrophysical models of reservoir rocks of different rank: typical and unified. Typical models describe connections between the parameters of individual rocks lithotypes occurring in definite geological conditions and serving as the basis for the development of petrophysical classification of reservoir rocks in the oil geology. The principle of unification provides for creation of the models structure for different reservoir lithotypes both in the geological section and in the area. We have studied petrophysical properties of reservoir rocks of Carboniferous deposits in the central part of the Dnieper-Donets depression. Petrophysical properties of rocks in conditions close to the formational ones and relations between them were studied on a number of samples formed by the core samples of different age. Main geological factors that have an influence on reservoir properties of rocks were taken into consideration. While constructing and analysing of petrophysical models we have used a probable-statistic approach with the use of the correlative-regressive analysis. Result of the work is contained in typical petrophysical models for individual areas and in unified models obtained on consolidated samples for Lower Carboniferous deposits of this region. Characteristic features in variations of petrophysical properties of reservoir rocks of Carboniferous deposits and their models have been ascertained. A conclusion has been made that multidimensional models, in which the depth of occurrence of deposits is one of the parameters that are necessary to consider while constructing petrophysical models, are the most informative for determination of petrophysical properties of the studied deposits, and the models obtained by us are known to be a petrophysical basis for quantitative interpretation of data from geophysical studies in the boreholes of the given region.

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