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Quantitative prediction of shale gas sweet spots based on seismic data in Lower Silurian Longmaxi Formation, Weiyuan area, Sichuan Basin, SW China

Fig. 1. Location of the study area.

Second, data volumes with high precision of the elastic parameters were obtained from pre-stack simultaneous inversion. The horizontal distribution of key parameters for shale gas evaluation were calculated based on the results of rock physics analysis. Then, the fuzzy evaluation equation was established by fuzzy optimization method with test and

Geological characteristics, main challenges and future prospect of shale gas

Fig. 2. Distribution diagram for onshore shale gas fields in the US [3].

It includes non-marine shale gas potential, core technology and equipment for resource deep than 3500 m, complex surface “factory mode” production, human geography and other non-technical factors. (4) Process economic evaluation under the conditions of government financial subsidies. China's shale gas project FIRR is about 8.0%–9.0%. Considering the global shale

Molecular simulation of shale gas adsorption in organic-matter nanopore

Fig. 2. Configuration of CH4 and CO2 adsorbed by organic pore (burial depth 4 km). (a) Initial configuration of CH4 adsorbed (b) Initial configuration of CO2 adsorbed; (c) Initial configuration of CH4/CO2 adsorbed;

The results indicated that the adsorptions of CH4 and CO2 were physical and the optimal storage depth was 2 km; The mixed adsorption data showed the rationality of exploit shale gas by injecting CO2 to exchange CH4, and the optimal burial depth was 4 km; The relative density of CH4

Pore evolution characteristic of shale in the Longmaxi Formation, Sichuan Basin

Fig. 1. Structural characteristics of Sichuan Basin and sampling locations (modified from Liu et al. (2016)).

Through study on effect of total organic carbon (TOC), organic matter maturity (Ro), diagenesis and tectonism on shale porosity, influence of TOC on porosity could be divided into four stages: the rapid increasing stage (TOC from 0 to 2%), the slow decreasing stage (TOC from 2 to 3%), the rapid

Micron-to nano-pore characteristics in the shale of Longmaxi Formation, southeast Sichuan Basin

Fig. 2. Distribution and morphological characteristics of organic pores. (a) Abundant organic pores occurred in the band shape and were developed in irregular organic matter which was filled among mineral particles, the sample was from Well YC4 at the depth of 749.2 m;

BET specific surface area of the shale in Longmaxi Formation ranged from 3.5 to 18.1 m2/g, BJH total pore volume was from 0.00234 to 0.01338 cm3/g, DA specific surface area of micropores vaired from 1.3 to 7.3 m2/g, and DA pore volume ranged from 0.00052 to 0.00273 cm3/g. The specific

Effects of stress-dependent permeability on well performance of ultra-low permeability oil reservoir in China

Fig. 1 Permeability increment versus pore pressure or effective stress

Several analytical simulations under the conditions of constant wellbore flowing pressure were performed to quantitatively assess the impact of stress sensitivity on single well performance. It is demonstrated that despite the stress-dependent permeability can have an adverse impact on production rate and recovery volume, it may be favorable for water

Isothermal Adsorption and Desorption Properties of Marine Shales on Longmaxi Shale in South China

Figure 1. Work principles of MSB adsorption instrument.

And adsorption potential theory was used to explain the adsorption and desorption process. According to the results, the shale samples have a high level of organic carbon content with the same organic matter type II1 and high degree of maturation. The volume of adsorption increases rapidly and slows down to

Recommendations on Improving Fiscal and Taxation Policies of Shale Gas Industry in China

With the rapid development of economy and the sharp increase of population, energy consumption is increasing and fossil energy reserves are decreasing. Shale gas, as a kind of unconventional natural gas, is very rich in our country, which makes the development and utilization of natural gas enter an important field.

Therefore, this paper introduces the development situation of shale gas industry in our country and the advantages and disadvantages of the development and utilization of shale gas, and finally discusses the fiscal and taxation policy suitable for the development of shale gas industry in our country by drawing on the

Development of gas-tight threads based on API round threads and its evaluation

Fig. 2. Photos of a gas-tight thread.

It is shown that the gas sealing performance of this gas-tight thread is good, and the results of ultimate internal pressure cycling and the thermal cycling test on sealing pipe ends meet the requirements of ISO 13679. Besides, its internal pressure strength, tensile strength and collapse strength are much higher

An optimal design of network-fracture acidification for ultra-deep gas wells in the Lower Permian strata of the western Sichuan Basin

The Lower Permian reservoirs in the western Sichuan Basin are ultra-deep with high temperature, high pressure and developed natural fractures. Leakage and contamination of drilling fluid is the main factor restricting reservoir stimulation effects, so the acidification will be the solution also as the first choice to enhance the gas recovery. In view of this, an acidification design was proposed to minimize the contamination skin factor to the highest degree.

Accordingly, a skin factor calculation model for network-fracture acidification was developed. It is indicated that when the acid pumping rate is 5.0 m3/min, all natural fractures around Well S1-1 can be opened, regardless of their dip angles. Besides, the advantage of high-rate acid injection emerges gradually when the injected acid

A numerical study on horizontal hydraulic fracture

Fig. 2 Sketch of the finite element mesh

The simulated bottom-hole pressure evolution is consistent with the data measured from the field. The configurations of the fracture and porous pressure distributions in the fracture are presented and discussed. Introduction Hydraulic fracturing has been one of the most frequently implemented techniques for stimulating production of oil/gas reservoirs for several decades (Sneddon

Comparative Study and Analysis of the Development of Shale Gas between China and the USA

Figure 1. The relationship between shale gas and other types of oil and gas reservoir (revised from Schenk C. J. & Pollastro R. M., 2001 [5] ).

This paper presents the importance of the formation principle of shale gas and the energy application, and compares the progress of shale gas studies, exploitation technology as well as the study hot-points between China and the USA. Meanwhile, this paper states the difficulties and challenges with the development of shale

Fault reactivation and earthquakes with magnitudes of up to Mw4.7 induced by shale-gas hydraulic fracturing in Sichuan Basin, China

Figure 6 Numerical model for coupled thermal-hydrological-mechanical simulation of injections in horizontal wells for hydraulic fracturing.

The geologic reasons why earthquake magnitudes associated with hydraulic fracturing operations are so high in this area are discussed. Because hydraulic fracturing operations are on the rise in the Sichuan Basin, it would be beneficial for the geoscience, gas operator, regulator, and academic communities to work collectively to elucidate the

Geometric Heterogeneity of Continental Shale in the Yanchang Formation, Southern Ordos Basin, China

Figure 8 Stratified lamina with various measurements.

These measurement tools correspond to the meter scale, decimeter scale, centimeter scale, millimeter scale and ten-micrometer scale, respectively, with measured thicknesses of 2.26 m, 2.09 dm, 1.70 cm, 1.48 mm and 11.70 μm, respectively. Fractal theory was used to analyze the power exponent distribution of the lamina thickness, with a resulting fractal dimension of 1.06.

Pore structure characterization of Chang-7 tight sandstone using MICP combined with N2GA techniques and its geological control factors

Pore structure characterization of Chang-7 tight sandstone using MICP combined with N2GA techniques and its geological control factors

Abstract Understanding the pore networks of unconventional tight reservoirs such as tight sandstones and shales is crucial for extracting oil/gas from such reservoirs. Mercury injection capillary pressure (MICP) and N2 gas adsorption (N2GA) are performed to evaluate pore structure of Chang-7 tight sandstone. Thin section observation, scanning electron microscope, grain size