Preliminary Study of Influence Factors and Estimation Model of the Enhanced Gas Recovery Stimulated by Carbon Dioxide Utilization in Shale

Abstract

Carbon dioxide (CO 2 ) injection into shale enables enhanced gas recovery (EGR) associated with geological CO 2 sequestration. Although primary research has been conducted on the CO 2 -based EGR technique in shale, the factors that influence the EGR efficiency remain unclear and need to be examined. This study presents a novel nuclear magnetic resonance (NMR)-based methodology to measure the EGR efficiency caused by CO 2 injection into shale samples with various properties. Accordingly, the effects of shale properties on the CO 2 -based EGR efficiency were revealed, and a calculation model for estimating the EGR efficiency was established. The results indicated that CO 2 injection enables significant production enhancement of shale gas, with the EGR efficiency averaging 23.54% and ranging from 16.22 to 34.34%, thus indicating that the EGR efficiency varies with the shale properties. The results also indicated that a higher CO 2 -based EGR efficiency, while adhering to a higher CO 2 -sequestration capacity, usually occurs in shales with a higher content of total organic carbon, higher methane-adsorption capacity, lower permeability, and lower clay mineral content. Moreover, an estimation model is developed to forecast the CO 2 -based EGR efficiency according to the shale properties. In general, these far-reaching results are of significance for predicting the benefit of CO 2 utilization in different shale reservoirs.

Research Status and Development Trend of Self-Compacting Concrete technology

“…At present, there are many methods to test the rheological properties of concrete at home and abroad. The commonly used methods are slump and slump fluidity methods, that is, to test the slump height and diffusion diameter of concrete mixture, and to test the outflow time of slump cone [38][39] . However, this method can not reflect the actual application of concrete, such as steel bar permeability and concrete filling.…”

Controlling Mechanism of Rock Burst by CO2 Fracturing Blasting Based on Rock Burst System

“…If the structure and energy characteristics of coal and rock mass can be predicted and preventive measures can be taken according to the predicted results, the prevention level of rock burst will be improved and the cost of risk relief will be reduced. e gestation and generation of rock burst can be affected by the stress concentration degree and energy storage size of the regional coal-rock mass structure system, and the coal-rock mass system should have a certain scale range [24,25]. In order to study the structure system and energy characteristics of rock mass under rock burst, a rock burst system based on the tectonic stress field is established.…”

Pore Structure Petrophysical Characterization of the Upper Cretaceous Oil Shale from the Songliao Basin (NE China) Using Low-Field NMR

“…Due to the ultrafine grained microfabric and microlevel heterogeneity of shale, the conventional methods above are defective and unable to examine the entire pore network [16]. In order to remedy this defect, low-field NMR technique, as a time-consuming, convenient, and nondestructive method, gradually enters the mainstream for measuring the pore structure by quantifying the interactions of protons and the porous media [17,18]. In this study, low-field NMR methodology is introduced to describe the pore structure of the UCQ and UCN shales, which is beneficial for the shale oil industry in the Songliao basin, especially for the resource estimation and reservoir evaluation.…”