Performance Prediction and Heating Parameter Optimization of Organic-Rich Shale In Situ Conversion Based on Numerical Simulation and Artificial Intelligence Algorithms

Abstract

In situ conversion technology is a green and effective way to realize the development of organic-rich shale. Supercritical CO 2 can be used as a good heating medium for shale in situ conversion. Numerical simulation is an important means to explore the shale in situ conversion process, but it requires a lot of time and computational cost for in situ conversion simulation under different working conditions. Therefore, a computational framework for rapid prediction of shale in situ conversion development performance and heating parameter optimization is proposed by coupling artificial neural network (ANN) and particle swarm optimization (PSO). The results indicated that kerogen pyrolysis and hydrocarbon product release mainly occurred within 2 years of shale in situ conversion. The production curves of pyrolysis hydrocarbon obviously slowed after in situ conversion for 2 years. The database was constructed by a large number of in situ conversion simulations, and Pearson correlation analysis and the random forest method were adopted to obtain seven main controlling factors affecting reservoir temperature and hydrocarbon production. The determination coefficient of the obtained ANN-based prediction models is higher than 97%, and the mean square error (MSE) is lower than 0.3%. The basic reservoir case can choose to inject 350−450 °C supercritical CO 2 (Sc-CO 2 ) fluid with a rate of 600 m 3 /day to obtain a more promising development effect. The heating parameter optimization for three typical reservoir cases using PSO was performed, and reasonable injection temperature and injection rate were obtained. It realized accurate development prediction and rapid heating parameter optimization, which helps the effective application of shale in situ conversion development design.

Numerical Simulation Study of the Operating Characteristics of Attached-Wall Bistable Jet Elements

“…A jet assembly is an automated fluidic assembly that operates in a fluid medium and does not contain mechanically moving components. − Jet assemblies are widely used in hydraulic engineering, aircraft, petrochemical industry, metrology, medical devices, microelectronics, and other fields. − Attached-wall jet assembly is the most commonly used jet assembly, − which mainly utilizes the attached-wall effect and entrainment effect of the jet to achieve various functions. − Drillers introduced the attached bistable jet assembly as the control structure of the impactor into the design of the impactor and invented the jet impactor. − When the jet impactor operates, drilling fluid enters through the nozzle of the jet assembly and is wall-attached and repetitively switched within the assembly. − The output fluid flows into a piston cylinder attached to the underside of the component, which then drives a piston and a hammer attached to the piston up and down. − …”

Study on the Inner Mechanisms of Gas Transport in Matrix for Shale Gas Recovery with In Situ Heating Technology

“…Considering its high compactness, in order to improve the productivity of shale gas, in situ heating technology has gradually been applied to increase shale gas production in addition to hydraulic fracturing technology. The study of gas transport in heated shale matrix could help to clarify the permeability increment of heated shale matrix and its impact on gas productivity improvement, providing valuable data for the effective combination of in situ heating technology and supporting technologies [1,2].…”