Intelligent identification and real-time warning method of diverse complex events in horizontal well fracturing

Current Status and Prospects of Artificial Intelligence Technology Application in Oil and Gas Field Development

“…Yang et al proposed the construction and application of a comprehensive research digital platform for oil and gas exploration and development, which greatly improves the solving efficiency of artificial intelligence recognition. In recent years, the ensemble Kalman filter (EnKF), ensemble smooth multiple data assimilation (ESMDA), random gradient approximation algorithm, Markov process, and other non gradient methods for historical fitting have been widely applied. − At the same time, breakthroughs in machine learning and deep learning have also brought new ideas to artificial intelligence recognition. − Artificial intelligence uses the EnKF method to assist in automated history fitting, − and by establishing a reservoir model, set the parameters that need to be fitted. − Based on the EnKF method combined with production performance data, reservoir parameter inversion and reservoir simulation optimization are achieved, greatly improving the fitting accuracy. − This method greatly reduces the workload of reservoir engineering personnel and simplifies the history fitting workflow. However, the upstream development of China’s petroleum industry still faces challenges…”

Characterization of Lower Paleozoic Water and Gas Distribution in Yan’an Gas Field, Ordos Basin

“…According to the nature of the basement, geological evolution history, and tectonic features, the Ordos Basin can be divided into six tectonic units: the Yimeng Uplift, the Yishan Slope, the Tianhuan ore-seeking depressions, the Jinshi Belt, the Western Marginal Fold Belt, and the Weibei Uplift. − The Yishan Slope was formed at the end of the early Bailian period. − It is the largest primary tectonic unit in the basin, 250 km wide from east to west and 400 km long from north to south. − The current tectonic feature is a large, gently dipping monocline that dips to the west, with an average dip of about 1° and a dip of less than 1°. , The Ordos Basin was uplifted as a whole at the end of the Ordovician in the Early Paleozoic and underwent hundreds of millions of years of weathering stripping and candle stripping without Silurian, Devonian, and Lower Carboniferous. , During this period, the weathering crustal solution candle stripping zones formed by exposed weathering and buried karst are of great significance for the formation of ancient weathered crustal gas reservoirs in the Lower Paleoproterozoic. − Feng et al studied the geochemical characteristics of natural gas in the Paleozoic era. Zhang et al conducted a systematic study on pore structures such as primary pores, secondary pores, and microcracks.…”

Research on the Shale Reservoir Sensitivity by Using the Mineral Analysis Method

“…Damage to oil and gas reservoirs is essentially a decrease in permeability caused by changes in the pore structure of the rock. − Diagnosis and determination of damage mechanisms need to be based on core analysis, sensitivity assessment, working fluid damage simulation experiments, and field evaluation. − Specific aspects, types, and processes of damage occurrence are revealed through comprehensive analysis. − A large number of scholars believe that the intrusion of working fluid filtrate is the main damage factor in low permeability tight gas reservoirs. − The permeability of the core matrix in such gas reservoirs is very low, and the median radius of the throat is less than 1 μm, showing high capillary force characteristics. − The initial water saturation of the reservoir is often lower than the bound water saturation, leading to easy retention of the working fluid filtrate intruding into the core and difficult to flow back, which can easily lead to a significant reduction in the gas permeability and the formation of serious water-phase trap damage. − When drilling in the reservoir section, the reservoir damage originates from drilling fluid leakage or filtration under the effect of positive differential pressure in the wellbore and capillary forces. − Intrusion into the solid phase can cause reservoir fractures and pore throat plugging, while intrusion into the liquid phase is prone to sensitivity damage and water-phase trap damage. − The depth of drilling fluid intrusion and the degree of damage increase with the increase of positive differential pressure in the wellbore and drilling time. − Among them, as an important development direction of oil and gas wells, it is crucial to study the damage factors and extent of horizontal wells. − Horizontal wells are an important means to increase the production capacity of oil and gas wells, but in many cases, the actual production capacity of horizontal wells cannot meet the expected plan. − The main fluid-sensitive minerals in shale are clay minerals. − The high content and diverse...…”

“… 15 − 18 A large number of scholars believe that the intrusion of working fluid filtrate is the main damage factor in low permeability tight gas reservoirs. 19 − 22 The permeability of the core matrix in such gas reservoirs is very low, and the median radius of the throat is less than 1 μm, showing high capillary force characteristics. 23 − 25 The initial water saturation of the reservoir is often lower than the bound water saturation, leading to easy retention of the working fluid filtrate intruding into the core and difficult to flow back, which can easily lead to a significant reduction in the gas permeability and the formation of serious water-phase trap damage.…”