Exploration Of Gas Fields Research Articles

Facies associations dispersion via rule-based simulation with genetic algorithm and kriging: A methodology conditioned by seismic facies

Rule-based simulation of facies is a valuable tool in oil and gas field exploration. The manuscript presents a hybrid methodology for simulating facies associations, using paleobathymetry as the main data and seismic facies as the secondary. A dispersion model of facies, which is based on paleobathymetry and wave energy is proposed, and the parameters of this dispersion are optimized via genetic algorithm, using seismic facies. The relationship between seismic facies e facies associations is quantified in order to construct a fitness function used in genetic algorithm to select good parameters for the dispersion model. In order to refine the model generated by the genetic algorithm, we use indicator kriging to adjust the simulation to the available well data. The methodology was applied to data from the Sapinhoa field-Brazil, focusing on three ages, 113 Ma, 114 Ma, and 115 Ma. The results obtained demonstrate that the simulated facies association maps largely respect the geometries observed in the seismic facies, and at the same time, honor the data from wells along the simulated area. The results demonstrate that the simulated facies association maps largely respect the geometries observed in the seismic facies while honoring well data across the simulated area. This approach addresses the inherent uncertainties and biases in traditional facies modeling, providing a more reliable and automated method for calibrating facies intervals.

Review on the Study of Microscopic Pore Structure and Seepage Characteristics

Pore structure, as the focus of researchers, is also one of the main contents of reservoir geological research, and the characteristics of percolation depend on the micro-pore structure of the reservoir. The study of the characteristics of fluid percolation in the reservoir plays an important role in formulating a reasonable oil and gas exploitation scheme. Understanding the micro pore structure of the reservoir, analyzing the pore throat structure inside the oil and gas reservoir, and systematically studying the micro seepage characteristics of the reservoir have far-reaching influence and great significance for the exploration and development of oil and gas fields.

A Review of Research on Improving Wear Resistance of Titanium Alloys

Titanium alloy is widely used as oil drill pipe material because of its light weight, high strength, good toughness, corrosion resistance, fatigue resistance, and good process performance. However, due to its low hardness, poor wear resistance, serious oxidation at high temperature (700 °C), and difficulty in lubrication, in oil and gas field exploration and development drilling, especially in deep wells, high displacement wells, horizontal wells, and highly deviated wells, wear and tear are prone to occur. The application and development of titanium alloys are greatly limited. This paper introduces the research status of the common surface modification technologies of titanium alloys, such as laser cladding, magnetron sputtering, plasma spraying, micro arc oxidation, etc. It points out the improvement effect of various modification technologies on the wear resistance and high-temperature oxidation resistance of titanium alloys and discusses the advantages and disadvantages of various modification technologies. A proposed method for enhancing the wear resistance and high-temperature oxidation resistance of titanium alloys was finally introduced, and its potential for future development was investigated.

Main controlling factors and exploration enlightenment of aluminous rock series gas reservoirs in Ordos Basin, NW China

Based on the data of outcrop, core, logging, gas testing, and experiments, the natural gas accumulation and aluminous rock mineralization integrated research was adopted to analyze the controlling factors of aluminous rock series effective reservoirs in the Ordos Basin, NW China, as well as the configuration of coal-measure source rocks and aluminous rock series reservoirs. A natural gas accumulation model was constructed to evaluate the gas exploration potential of aluminous rock series under coal seam in the basin. The effective reservoirs of aluminous rock series in the Ordos Basin are composed of honeycomb-shaped bauxites with porous residual pisolitic and detrital structures, with the diasporite content of greater than 80% and dissolved pores as the main storage space. The bauxite reservoirs are formed under a model that planation controls the material supply, karst paleogeomorphology controls diagenesis, and land surface leaching improves reservoir quality. The hot humid climate and sea level changes in the Late Carboniferous–Early Permian dominated the development of a typical coal-aluminum-iron three-stage stratigraphic structure. The natural gas generated by the extensive hydrocarbon generation of coal-measure source rocks was accumulated in aluminous rock series under the coal seam, indicating a model of hydrocarbon accumulation under the source. During the Upper Carboniferous–Lower Permian, the relatively low-lying area on the edge of an ancient land or island in the North China landmass was developed. The gas reservoirs of aluminous rock series, which are clustered at multiple points in lenticular shape, are important new natural gas exploration fields with great potential in the Upper Paleozoic of North China Craton.

Characteristics of carbon isotopic composition of alkane gas in large gas fields in China

Exploration and development of large gas fields is an important way for a country to rapidly develop its natural gas industry. From 1991 to 2020, China discovered 68 new large gas fields, boosting its annual gas output to 1 925×108 m3 in 2020, making it the fourth largest gas-producing country in the world. Based on 1696 molecular components and carbon isotopic composition data of alkane gas in 70 large gas fields in China, the characteristics of carbon isotopic composition of alkane gas in large gas fields in China were obtained. The lightest and average values of δ13C1, δ13C2, δ13C3 and δ13C4 become heavier with increasing carbon number, while the heaviest values of δ13C1, δ13C2, δ13C3 and δ13C4 become lighter with increasing carbon number. The δ13C1 values of large gas fields in China range from −71.2‰ to −11.4‰ (specifically, from −71.2‰ to −56.4‰ for bacterial gas, from −54.4‰ to −21.6‰ for oil-related gas, from −49.3‰ to −18.9‰ for coal-derived gas, and from −35.6‰ to −11.4‰ for abiogenic gas). Based on these data, the δ13C1 chart of large gas fields in China was plotted. Moreover, the δ13C1 values of natural gas in China range from −107.1‰ to −8.9‰, specifically, from −107.1‰ to −55.1‰ for bacterial gas, from −54.4‰ to −21.6‰ for oil-related gas, from −49.3‰ to −13.3‰ for coal-derived gas, and from −36.2‰ to −8.9‰ for abiogenic gas. Based on these data, the δ13C1 chart of natural gas in China was plotted.

A mechanistic mathematical model for the treatment of synthetic oil-field wastewater (produced water) by electrocoagulation process using aluminium electrodes.

Produced water (PW) is the largest by-product that comes out of the oil wells during oil and gas (O&G) field exploration. PW contains high-salt concentration along with other organic and inorganic components; therefore, PW must be treated before disposal. Electrocoagulation (EC) is an effective treatment method to remove pollutants from PW which has been the focus of many experimental studies; however, a mathematical model specifically for PW treatment by EC has not been developed yet. In this work, a comprehensive mathematical model has been developed to elucidate the role of EC operating parameters on the PW treatment performance and determine the mechanism for COD (Chemical Oxygen Demand) removal. The present model considers and identifies the dominant Al-hydroxy complex species and their contribution to the COD removal from synthetic PW samples by estimating their rate constants and comparing their magnitudes and investigates multi-scale modelling of the EC reactor. The influence of working parameters such as current density, initial pH, interelectrode distance, mixing speed and solution volume of PW on Al coagulant production and COD removal was investigated and modelled. The study estimates the rate constants of the reactions taking place for COD removal by EC process and by comparing their magnitudes identifies the dominant reactions and coagulant species involved in the process. The mathematical model prediction of COD removal fits well with the experimental data at 10mAcm-2, 15mAcm-2 and 20mAcm-2 current density with R2 value of 0.96, 0.97 and 0.92, respectively and for dissolved Al concentration R2 value of 0.96, 0.99, and 0.97, respectively. The simulated results reproduced a good fit at initial pH of 6.1, 7.3 and 8.6 with R2 value of 0.92, 0.96 and 0.98, respectively for COD removal. The mathematical model and the experimental results showed the role of dominant Al-hydroxy complex species such as , , , and in controlling the COD removal process. Under different operating conditions considered in the study, the model also predicted the COD removal performance of the EC reactors at different reactor volumes with R2 value of 0.96 for higher solution volume and larger reactor. The model presented and rate constants determined in the study will provide a theoretical basis for designing, scaling up and operating the EC reactor for oil-field PW treatment.

MODELING of Water Saturation in Shallow Sandstone Oilfield

3D geological modeling technology has achieved visualization of underground reservoirs in oil and gas fields, and has been widely applied in oil and gas field development. 3D geological modeling includes structural modeling and attribute modeling, and strata and faults can be completed based on data from oil and gas field exploration and development. The porosity and permeability in the geological attribute model can be established based on logging interpretation conclusions and other relevant data, The establishment of a saturation model has always been a difficulty in 3D geological modelling. As the water saturation, is different from porosity and permeability of an oil field. Saturation is distributed under the control of factors such as gravity and capillary force, and cannot be established through spatial simulation interpolation. Instead, the influence of factors such as gravity and capillary force should be considered. This article takes the shallow sandstone M oilfield in Kazakhstan as an example, and establishes the J function of the oilfield by combining the capillary pressure experiment of the core well, in order to establish an oilfield saturation model.

Sequence Stratigraphic Analysis of the Volcanic Rock–Evaporite–Clastic Rock Symbiotic Zone in the Fourth Member of the Shahejie Formation in the South of Laizhou Bay

Laizhou Bay Sag is a typical continental rift lake basin, which is affected by strike–slip activity, salt rock activity, volcanic activity, and paleoclimate change in the Tanlu fault zone, where three major lithologies—volcanic rock, clastic rock, and evaporite—mainly develop. In order to determine the sequence correspondence between the different lithologies in the study area based on drilling, logging data, and seismic data, it is determined that the fourth member of the Shahejie Formation in the southern Laizhou Bay mainly develops three types of sequences: clastic rock type sequences, salt lake type sequences, and volcanic rock/clastic rock type sequences. Two second-order sequence boundaries (SBs3L, SBs4L) and one third-order sequence boundary (SBs4U) were identified, and the principle of three divisions of system tracts (LST, TST, HST) and sedimentary processes in different types of sequences were determined by analyzing the stacking patterns of different sequences. Compared with the previous research results, this study provides a more detailed analysis of the sequence boundary definition of different blocks and different lithologic strata, and it improves the previous general sequence stratigraphic division method. Based on the study of distinct types of sequences, a unified stratigraphic framework is established in the whole zone, and the stratum thickness distribution of the fourth member of Shahejie Formation is smaller in the southwest and larger in the northeast. The study area is generally filled with pyroclastic rocks–evaporite–clastic rocks, changing from fan delta–saline lake filling to braided river delta–freshwater lake–fan delta filling from bottom to top. A sequence stratigraphic model for the comparison of steep slope–gentle slope differences is established to provide guidance for future oil and gas field exploration and development.

Анализ фильтрационного процесса в угольном пласте, отрабатываемом длинными столбами по простиранию

The underground coal field mining is inevitably associated with coal oxidation process accompanied with the thermal energy emission and the formation of coal self-heating spots. The self-heating spots can emerge in both coal dust accumulations deposited in the excavations and in the excavated coal seams. It is known that self-heating is caused by both chemical processes accompanied with heat emission and physical processes, primarily the filtration of gas-air mixtures through porous and fractured layers of rocks and coal seams. Although the filtration processes accompanying oil and gas field exploration have been thoroughly studied, similar processes accompanying coal mining have been studied less. The article focuses on the mathematic problem concerning the filtration process in the coal seam when excavated by long pillars. In this system, both fresh airflows and worked out flows move in opposite directions and under different pressures along the mine roadway and the ventilation opening. This causes so-called air suctions due to air infiltration through the coal seam. In theory, this problem has not been solved yet and thus is considered urgent. Based on the classic filtration theories and assumptions regarding the coal seam isotropy and homogeneity, the one-dimensional initial value problem describing the non-stationary air filtration process through the coal seam was formulated. The solution provided explicit formulas to determine the pressure and rate of air-gas mixture filtration and identified several regularities of the filtration process in the coal seam. Particularly, it was established that the filtration rate increases significantly in the direction towards the ventilation opening, especially at the initial stages of filtration. In process of time, however, the filtration rate aligns and after 5 days, the rate difference is not so significant.

ANALYSIS OF THE EFFECTIVENESS OF STIMULATION METHODS AT THE TRIZ FACILITY — PREOBRAZHENSK PETROLEUM PRODUCT HORIZON, EASTERN SIBERIA

The history of prospecting and exploration of oil and gas fields within the Nepsko-Botuoba Anteklisa (NBA) and the eponymous oil and gas region (OGR) of the Leno-Tunguska Oil and Gas Province of the Siberian Platform dates back more than half a century. The base object of exploration for a long time remained the terrigenous deposits of the Venda reservoir. A number of large, medium and small hydrocarbon deposits are associated with them. The beginning of a systematic study of the northern regions of the Irkutsk region was the receipt of oil inflow from the Markov reference well in 1962. In 1971, the Yaraktinskoye gas condensate field was discovered north of Markovsky. In 1970, a parametric well was drilled within the Preobrazhensky uplift, which made it possible to identify a productive carbonate horizon (Zone B12), from which a gas inflow was obtained after hydrochloric acid treatment. Further continuation of the complex of geophysical studies east and south of Preobrazhenskaya Square made it possible to identify a number of positive structural forms. In the Chonsky zone, several local complications were identified — Chonsky, Molchalunsky and Verkhnechonsky structural noses, recommended for setting up area studies of MOU. The Preobrazhensky horizon (Zone B12) ranks second among the pay zones in terms of potential in-place reserves. It is the extremely low filtrationcapacitive properties of the natural reservoir and the harsh thermobaric conditions at the pressure of oil saturation with gas close to the initial reservoir pressure that is the basis for classifying these reserves as hard to recover (RHR).This article discusses the methodological features of drilling and completion of oil producing wells with a horizontal end of a long length, ascending inclined boreholes, multi-hole horizontal wells (MHW), conducting MHW, large-volume MKO and KGRP in the carbonate natural reservoir of the Preobrazhensky productive horizon (B12) of one of the fields of the Nepsky arch in the north of the Irkutsk region. The oil reserves of this tank are classified as difficult to recover (RHR). Research and search for new approaches to the development of the TRiZ facilities of the Preobrazhensky carbonate horizon in this field is today the most important task. The main results of the testing of the complex of geological and technological measures (GTM) are summarized, including a new effective technology for conducting multi-stage hydraulic fracturing, which is planned for use in the further full-scale development of the oil reservoir.

Machine Learning-Based Qualitative Identification of Four-Phase Fluid in Reservoir.

The identification of fluid types has always been the focus of oil and gas field exploration and development research. At this stage, a large amount of CO2 has been found in many basins during exploration and development, which greatly affects the accuracy of reservoir understanding and evaluation, so it is very important to accurately identify the fluid type of the CO2-bearing reservoirs. However, methods utilizing multiple logging data are greatly affected by physical changes in the formation, resulting in methods that are only applicable to the area and layer under study, are poorly generalized, and require multiple instruments and experimental support. Existing nuclear logging methods that primarily utilize logging curve stacking and intersection map methods fail to take full advantage of logging. In this study, taking advantage of the fact that the neutron gamma technique of nuclear logging measurement can provide multiparameter information with the characteristics of machine learning to deal with multidimensional data, comparing the classification results of different ware learning methods under different classification strategies and selecting a method of identifying fluids in logging while drilling was based on the idea of dichotomy and the use of the support vector machine as a meta-model. This solved the problem of identifying fluids in the CO2-bearing reservoirs, providing new ideas for the design and fabrication of logging instruments. These instruments can assist with the exploration and development of oil and gas fields and has a broad application prospect in CO2-EOR and CCUS.

Современные подходы к реализации проектов по бурению скважин различной классификации на разных стадиях геолого-разведочных работ

The problem of obsolescence and irrelevance of the standard classification of drilling wells for the intended purpose and a new interpretation of this classification within the framework of modern reality are considered. It is noted that the search for new ways to obtain information during geological exploration leads to the understanding that drilling some types of wells is already completely impractical. In the current situation, projects should be implemented that, on the one hand, will ensure the solution of the set geological tasks, on the other hand, minimize the costs of drilling wells, reduce industrial and environmental risks, with the unconditional receipt of the entire set of required geological information. The complex of works applied in the waters of the inland seas, for the purpose of prospecting, exploration and development of oil and gas fields, can become an example of rational money savings and the efficiency of geological data collection. Currently, the share of large structural deposits of simple structure is completely insignificant, and there are practically no promising oil and gas-bearing areas on land. Current realities are such that geological exploration works penetrate deep horizons of the Earth's crust with a complex geological structure and cover oil and gas-bearing regions located in remote and remote parts of the land. The complex implemented at sea may well be applicable for such sites and will successfully compensate for anachronistic drilling methods.

Prospects for the gas and condensate production from the South Hrabyne zone of the Precarpathian foredeep

The main problems of prospecting and exploration of gas and gas condensate fields in the lithological and stratigraphic strata of the southwestern and central parts of the Bilche-Volytsia zone are due to the complex tectonic and lithological and stratigraphic conditions for the hydrocarbon deposits formation. The objective factors include the complex geological structure of reservoir rocks due to tectonic disturbances in the process of trap formation, the presence of various types of voids and clay material, as well as flooding of productive formations at the final stage of development. In addition, it is necessary to note the decrease in the information content and efficiency of both ground and borehole electrical exploration. At the same time, lithotypes with a complex petrographic and petrophysical thin layer structure of the rock matrix are observed in the Neogene deposits. Thus, in order to increase the information content of the results of geophysical well surveys (GWS) and the efficiency of hydrocarbon prospecting, it is necessary to form an optimal set of the latest geophysical methods, in particular: high-frequency induction logging with isoparametric sounding (HFILIS), nuclear magnetic logging (NML), as well as acoustic and radioactive studies. The introduction of this type of innovation will increase the information content of geological and geophysical studies. The main basis of this approach is the petrographic and petrophysical base for specific territories and prospecting areas. In view of the foregoing, we identified gas-saturated reservoir rocks, established the structure of their seal rocks, as well as determined the effective thicknesses of rocks and developed correlation schemes for their distribution within the Sarmatian, Badenian, and Helvetian deposits.

Wide azimuth seismic data processing technology and application: a case study of tight gas reservoirs in western China

As the difficulty of oil and gas field exploration and development increases both domestically and internationally, onshore exploration targets have gradually shifted from the shallow to the deep and from conventional oil and gas reservoirs to unconventional ones. Particularly in the exploration and development of unconventional oil and gas horizontal wells, there is an increasing demand for higher precision and quality of seismic data to better identify formation lithology, rock fractures, and improve the characterization of reservoirs, reservoir positioning, and connectivity. Wide-azimuth seismic exploration possesses significant technical advantages in addressing exploration challenges such as lithologic exploration, small fault imaging, and detailed characterization of oil and gas reservoirs. Wide azimuth seismic data reduces blind spots in seismic acquisition and improves the imaging accuracy of small faults. Notably, there exist distinct anisotropic characteristics in fault areas and fractured reservoirs. Wide azimuth seismic data is particularly advantageous for studying amplitude variation with variations in amplitude with offset (AVO), incident angle (AVA), or azimuth (AVAZ), as well as velocity with azimuth (VVA). These variations aid in identifying faults, fractures, and changes in formation lithology. As the focus of oil and gas exploration gradually shifts to complex lithological reservoirs and unconventional oil and gas reservoirs, narrow azimuth seismic exploration has been gradually replaced by wide azimuth exploration. However, as observation azimuth increases, challenges related to velocity variations with azimuth, azimuth-related traveltime differences, and azimuth-related anisotropy arise. Based on wide-azimuth seismic data from tight gas reservoirs in western China, this study conducted wide-azimuth anisotropic velocity analysis, OVT domain data regularization processing, OVT domain prestack time/depth migration, and horizontally transverse isotropy (HTI) azimuth anisotropy correction techniques. After applying specialized processing to the wide-azimuth seismic data, significant improvements were observed in the S/N and resolution of the target layer. The delineation of fractures related to hydrocarbon sources also became more distinct. These advancements not only provided high-quality results for high-fidelity, high-resolution imaging of tight gas reservoirs but also provided azimuth volume corresponding to fast and slow wave velocities for seismic data interpretation, facilitating velocity variation with azimuth (VVAZ) fracture detection and AVO analysis research.

Drilling Parameters Multi-Objective Optimization Method Based on PSO-Bi-LSTM

The increasing exploration and development of complex oil and gas fields pose challenges to drilling efficiency and safety due to the presence of formations with varying hardness, abrasiveness, and rigidity. Consequently, there is a growing demand for drilling parameter optimization and speed-up technologies. However, existing models based on expert experience can only achieve single-objective optimization with limited accuracy, making real-time adaptation to changing drilling conditions and formation environments challenging. The emergence of artificial intelligence provides a new approach for optimizing drilling parameters. In this study, we introduce the Bi-directional Long Short-Term Memory (Bi-LSTM) deep learning algorithm with the attention mechanism to predict the rate of penetration (ROP). This algorithm improves the ROP prediction accuracy to 98.33%, ensuring reliable subsequent optimization results. Additionally, we propose a coupling optimization algorithm that combines Bi-LSTM with the particle swarm optimization algorithm (PSO) to enhance drilling efficiency through parameter optimization. Our approach aims to maximize drilling footage while maintaining the highest ROP. The optimal solutions obtained are verified through multi-parameter cloud image analysis, yielding consistent results. The application of our approach demonstrates an 81% increase in drilling speed and a 28% reduction in drill bit energy losses. Moreover, the real-time optimization results effectively guide field operations.

Some Possibilities of Increasing the Completeness of Oil and Gas Recovery

The purpose of this work is to focus the attention of specialists in the field of development and exploration of oil and gas fields on the possibilities of increasing the completeness of oil and gas recovery by taking into account natural phenomena that occur in pools, using existing methods development. Failure to take into account these natural phenomena causes low completeness of oil and gas recovery, as well as unjustified costs in the development of pools. As a result of 60 years of research by a large group of specialists in various fields of knowledge, the presence of a number of natural phenomena in oil and gas pools was established, and taking into account them, the completeness of gas, condensate and oil recovery from a number of pools was increased. The following main natural phenomena have been identified: 1. Multi-scale block structure of all pools and the absence of hydrodynamic connection between different parts of each pool within the framework of Darcy’s law. 2. Changes in the filtration properties of the pool during development. 3. Influence of fractionation of hydrocarbons in pools on the properties of produced and residual oil during water flooding in sediments with different reservoir properties. The following proposals are substantiated: • Additions to the complex of exploration works; • Some ways to increase the completeness of oil and gas recovery; • The results of the industrial use of a comprehensive study of conventional and unconventional oil and gas pools.

Application of a new innovative technique in studying, searching and exploration of oil and gas fields on the example of the Karakum areas

Application of a new innovative technique in studying, searching and exploration of oil and gas fields on the example of the Karakum areas

Нефтегазовая отрасль Чеченской Республики: история и современность (к 130-летию промышленной добычи нефти)

This article is devoted to the period of intensive development of oil production in the Grozny region, which is one of the oldest oil and gas regions in Russia. The issues of the formation, repeated reorganizations of “Grozneft” are highlighted, its role as a city-forming industry, in particular, in the development of the city of Grozny, in solving social and housing issues of oil workers in the difficult years of 1920-1930 is noted, construction of brick houses for oil workers in the Staropromyslovsky district of Grozny, creation of conditions for rest and treatment, etc. It was noted about the gradual improvement of methods for drilling and oil production, the introduction of more efficient methods and techniques for prospecting and exploration of oil and gas fields, which made it possible to develop deep-lying chalk horizons.

Research on the Construction Method of a Training Image Library Based on cDCGAN

There is a close relationship between the size and property of a reservoir and the production and capacity. Therefore, in the process of oil and gas field exploration and development, it is of great importance to study the macro distribution of oil–gas reservoirs, the inner structure, the distribution of reservoir parameters, and the dynamic variation of reservoir characteristics. A reservoir model is an important bridge between first-hand geologic data and other results such as ground stress models and fracture models, and the quality of the model can influence the evaluation of the sweet spots, the deployment of a horizontal well, and the optimization of the well network. Reservoir facies modeling and physical parameter modeling are the key points in reservoir characterization and modeling. Deep learning, as an artificial intelligence method, has been shown to be a powerful tool in many fields, such as data fusion, feature extraction, pattern recognition, and nonlinear fitting. Thus, deep learning can be used to characterize the reservoir features in 3D space. In recent years, there have been increasing attempts to apply deep learning in the oil and gas industry, and many scholars have made attempts in logging interpretation, seismic processing and interpretation, geological modeling, and petroleum engineering. Traditional training image construction methods have drawbacks such as low construction efficiency and limited types of sedimentary facies. For this purpose, some of the problems of the current reservoir facies modeling are solved in this paper. This study constructs a method that can quickly generate multiple types of sedimentary facies training images based on deep learning. Based on the features and merits of all kinds of deep learning methods, this paper makes some improvements and optimizations to the conventional reservoir facies modeling. The main outcomes of this thesis are as follows: (a) the construction of a training image library for reservoir facies modeling is realized. (b) the concept model of the typical sedimentary facies domain is used as a key constraint in the training image library. In order to construct a conditional convolutional adversarial network model, One-Hot and Distributed Representation is used to label the dataset. (c) The method is verified and tested with typical sedimentary facies types such as fluvial and delta. The results show that this method can generate six kinds of non-homogeneous and homogeneous training images that are almost identical to the target sedimentary facies in terms of generation quality. In terms of generating result formats, compared to the cDCGAN training image generation method, traditional methods took 31.5 and 9 times longer. In terms of generating result formats, cDCGAN can generate more formats than traditional methods. Furthermore, the method can store and rapidly generate the training image library of the typical sedimentary facies model of various types and styles in terms of generation efficiency.

Acid-Soluble Drilling Fluid in the Northern Carbonate Reservoir of the Yishan Slope in the Ordos Basin

The carbonate reservoir in the northern Yishan slope of the Ordos Basin presents significant challenges to gas field exploration and development. With its low pressure, limited porosity, low permeability, and abundance of micro-fractures, the reservoir is resistant to acid dissolution. Once solid particles block these fractures during drilling and completion, serious reservoir damage ensues. To address these obstacles, we engineered an acid-soluble, solid-free drilling fluid system in the lab. This involved incorporating sodium carboxymethyl cellulose, heat-resistant starch, fungicides, and lubricants. Contrasted with the commonly used potassium ammonium based drilling fluid system, our innovative solution showed notable improvements. Specifically, the density decreased by 0.04 to 0.06 g/cm3, and the solid content decreased by 4.0% to 6.50%, while the acid-soluble rate surged from 8.50% to 95.45%. In addition, the reservoir permeability recovery value saw an increase from 51.50% to 95.88%. In practical field application, we employed this novel drilling fluid system in ten horizontal wells. Following acid fracturing and reconstruction, these wells registered a 75.94% increase in gas production compared to nearby wells. Our findings demonstrate that the proposed system effectively mitigates the incursion of solid-phase particles into the reservoir while enhancing acidification during acid fracturing. This results in the swift removal of plugging, restoration of formation permeability, and improved well production. Our research thus introduces a drilling and completion fluid system of high efficiency with superior reservoir protection performance, potentially offering substantial benefits to the development of carbonate rock salt gas reservoirs.