Unconventional Natural Gas Production Research Articles

Modelling spatial & temporal variability of air pollution in an area of unconventional natural gas operations

Despite the growing unconventional natural gas production industry in northeastern British Columbia, Canada, few studies have explored the air quality implications on human health in nearby communities. Researchers who have worked with pregnant women in this area have found higher levels of volatile organic compounds (VOCs) in the indoor air of their homes associated with higher density and closer proximity to gas wells. To inform ongoing exposure assessments, this study develops land use regression (LUR) models to predict ambient air pollution at the homes of pregnant women by using natural gas production activities as predictor variables. Using the existing monitoring network, the models were developed for three temporal scales for 12 air pollutants. The models predicting monthly, bi-annual, and annual mean concentrations explained 23%–94%, 54%–94%, and 73%–91% of the variability in air pollutant concentrations, respectively. These models can be used to investigate associations between prenatal exposure to air pollutants associated with natural gas production and adverse health outcomes in northeastern British Columbia.

Subsidy analysis and development trend forecast of China's unconventional natural gas under the new unconventional gas subsidy policy

In June 2019, China significantly changed its unconventional natural gas subsidy policy, changing the subsidy mode from a comprehensive quota standard mode to a competitive mode, aiming to reduce its subsidy pressure and channel subsidies to specific projects that are needed to increase annual and winter electricity production. Through a brief introduction of China's cleaner energy goals and a comparative analysis of the new and old subsidy policies, the orientations and impacts of the new policy are interpreted. By comparing the changes in subsidy quota, production and price of three kinds of unconventional natural gas (shale gas, tight gas and CBM) over the past ten years, in combination with the generalized Weng model, the impact of subsidy on unconventional natural gas production is quantified. The development trend of unconventional natural gas under the new policy is forecasted on the premise that the total amount of subsidy and sales price remain unchanged.. The sensitivity of three kinds of unconventional natural gas to different subsidies is analyzed. The impact of the new policy on the change in gas production curve is illustrated after comparing the optimal production plans for typical shale gas wells under the new and old policies. The results show that shale gas and CBM may be negatively affected, while the development of tight gas may be promoted; in the future, tight gas and shale gas will dominate, while the development of CBM will be tough. The new policy will stimulate the production enterprises to adopt the plan of high initial production and high decline rate, which may lead to a reduction in total gas production and resources utilization efficiency.

Predictions on natural gas development trend in China for the next fifteen years

Domestic natural gas production serves as the foundation of China's natural gas industry layout. It is of great significance to predict the medium and long-term production trend of its natural gas industry. In comparison to the United States, the natural gas E&P in China reveals the same direction of parallel development of conventional and unconventional gas, with a more aggressive change in China. This article presents a detailed review of several challenges that China has faced in natural gas production like resource characterization, developmental technology, economic effectiveness, organization, and management. Issues about safty and Environment have also posed a challenge to the country. It also discusses the progress and future advancement of exploration, development theory, and technology. Likewise, it evaluates the potential of conventional and unconventional natural gas exploration and development. It predicts the total domestic natural gas production to be 260 × 109 m3 in 2035, with conventional natural gas production stabilizing at 135 × 109 m3. It also perceives the unconventional natural gas production to increase at 116 × 109 m3 and dissolved gas production of 9 × 109 m3, which will serve as the decision basis for energy structure adjustment and strategic layout of import pipelines and gas storage in China.

Buoyance-driven hydrocarbon accumulation depth and its implication for unconventional resource prediction

The discovery of unconventional hydrocarbon resources since the late 20th century changed geologists’ understanding of hydrocarbon migration and accumulations and provides a solution to energy shortage. In 2016, unconventional oil production in the USA accounted for 41% of the total oil production; and unconventional natural gas production in China accounted for 35% of total gas production, showing strong growth momentum of unconventional hydrocarbons explorations. Unconventional hydrocarbons generally coexist with conventional petroleum resources; they sometimes distribute in a separate system, not coexisting with a conventional system. Identification and prediction of unconventional resources and their potentials are prominent challenges for geologists. This study analyzed the results of 12,237 drilling wells in six representative petroliferous basins in China and studied the correlations and differences between conventional and unconventional hydrocarbons by comparing their geological features. Migration and accumulation of conventional hydrocarbon are caused dominantly by buoyance. We propose a concept of buoyance-driven hydrocarbon accumulation depth to describe the deepest hydrocarbon accumulation depth driven dominantly by buoyance; beyond this depth the buoyance becomes unimportant for hydrocarbon accumulation. We found that the buoyance-driven hydrocarbon accumulation depth in petroliferous basins controls the different oil/gas reservoirs distribution and resource potentials. Hydrocarbon migration and accumulations above this depth is dominated by buoyancy, forming conventional reservoirs in traps with high porosity and permeability, while hydrocarbon migration and accumulation below this depth is dominated by non-buoyancy forces (mainly refers to capillary force, hydrocarbon volume expansion force, etc.), forming unconventional reservoirs in tight layers. The buoyance-driven hydrocarbon accumulation depths in six basins in China range from 1200 m to 4200 m, which become shallower with increasing geothermal gradient, decreasing particle size of sandstone reservoir layers, or an uplift in the whole petroliferous basin. The predicted unconventional resource potential below the buoyance-driven hydrocarbon accumulation depth in six basins in China is more than 15.71 × 109 t oil equivalent, among them 4.71× 109 t reserves have been proved. Worldwide, 94% of 52,926 oil and gas reservoirs in 1186 basins are conventional reservoirs and only 6% of them are unconventional reservoirs. These 94% conventional reservoirs show promising exploration prospects in the deep area below buoyance-driven hydrocarbon accumulation depth.

Impact of unconventional natural gas development on regional water resources and market supply in China from the perspective of game analysis

This study presents a detailed framework for evaluating water resource constraint and game-based supply strategies of unconventional and conventional natural gases in China. Surface-water production pressure and groundwater-pollution risk level are used to measure the extent of water resource constraint on shale gas development. Cournot and Stackelberg game models are applied to illustrate the oligopoly mechanism between unconventional and conventional natural gas manufacturing. A subsidy multiplier model is then proposed to identify the impact of government subsidy on different game strategies. Results indicate that high amounts of estimated ultimate recovery and recycling wastewater would significantly reduce water resources consumption during shale gas development. An increased subsidy coefficient would increase the amount of unconventional natural gas but decrease the amount of conventional natural gas. However, the majority of subsidy multiplier values would be less than 1, implying an inconspicuous effect of the subsidy. Moreover, the equilibrium production of unconventional natural gas in the Cournot and Stackelberg game models would increase with the increased substitution factor m1 but decrease with the increased substitution factor m2. Conversely, the high amount of equilibrium production of conventional natural gas would increase the substitution factor m2 but reduce the substitution factor m1 within these two models.

Acoustic emission characteristics in hydraulic fracturing of stratified rocks: A laboratory study

Acoustic emission (AE) is a popular technique to monitor the process of rock failure during hydraulic fracturing for unconventional natural gas production. It contains abundant information that will be useful to study in-depth the nature of hydraulic fracturing. In this study, we focused on the AE count, energy, peak frequency, crack classification, and location recorded from four rock specimens subjected to a specific triaxial stress condition. We found the multi-frequency-response phenomenon of AE, and proposed the multi-frequency-response index to indicate the moment of the macrohydraulic crack formation. Furthermore, it was found that the power law distribution index of AE energy of non-stratified specimen was bigger than that of stratified specimens during hydraulic fracturing. The tensile crack dominated in all hydraulic fracturing tests. Our results are of significance for understanding hydraulic fracturing in stratified rocks.

Estimating Methane Emissions From Underground Coal and Natural Gas Production in Southwestern Pennsylvania

AbstractProduction of coal and natural gas is responsible for one third of anthropogenic methane (CH4) emissions in the United States. Here we examine CH4 emissions from coal and natural gas production in southwestern Pennsylvania. Using a top‐down methodology combining measurements of CH4 and ethane, we conclude that while Environmental Protection Agency inventories appear to report emissions from coal accurately, emissions from unconventional natural gas are underreported in the region by a factor of 5 (±3). However, production‐scaled CH4 emissions from unconventional gas production in the Marcellus remain small compared to other basins due to its large production per well. After normalizing emissions by energy produced, total greenhouse gas emissions from Pennsylvania unconventional natural gas production produce half the carbon footprint compared to regionally produced coal, with carbon dioxide emissions from combustion being the dominant source of greenhouse gas emissions for both sources.

Importance of Superemitter Natural Gas Well Pads in the Marcellus Shale.

A large-scale study of methane emissions from well pads was conducted in the Marcellus shale (Pennsylvania), the largest producing natural gas shale play in the United States, to better identify the prevalence and characteristics of superemitters. Roughly 2100 measurements were taken from 673 unique unconventional well pads corresponding to ∼18% of the total population of active sites and ∼32% of the total statewide unconventional natural gas production. A log-normal distribution with a geometric mean of 2.0 kg h-1 and arithmetic mean of 5.5 kg h-1 was observed, which agrees with other independent observations in this region. The geometric standard deviation (4.4 kg h-1) compared well to other studies in the region, but the top 10% of emitters observed in this study contributed 77% of the total emissions, indicating an extremely skewed distribution. The integrated proportional loss of this representative sample was equal to 0.53% with a 95% confidence interval of 0.45-0.64% of the total production of the sites, which is greater than the U.S. Environmental Protection Agency inventory estimate (0.29%), but in the lower range of other mobile observations (0.09-3.3%). These results emphasize the need for a sufficiently large sample size when characterizing emissions distributions that contain superemitters.

Fuzzy clustering analysis of hydraulic fracturing additives for environmental and human health risk mitigation

Chemical additives used in hydraulic fracturing (HF) for unconventional natural gas production can be a risk to environmental and human health (EHH). The EHH risk is affected by three factors: the chemical hazard measured, the certainty of the measured hazard, and the use frequencies of additives. Limited studies have holistically assessed the EHH risks of HF additives. This study qualitatively analyzed the EHH risks of 105 representative HF additives used in British Columbia, Canada, based on the three previously listed factors using a fuzzy clustering analysis approach. The performance of additives on these factors was converted into indices using an indexing system. The indices were grouped into seven clusters according to their relative similarities. The EHH risk of each cluster was interpreted based on the resulting indices. Results show that additives grouped in clusters 7 and 2 have relatively high EHH risks, which require special attention in HF operations. Clusters 4, 1, and 5 were identified as having moderate EHH risks, while clusters 6 and 3 are of low EHH risk concerns. Many iron control agents were classified into cluster 7, indicating that this type of additives is associated with a high EHH risk. Many friction reducers and gelling agents were classified into cluster 4 characterized by the highest hazard uncertainty. Assessment of hypothetical fracturing fluids shows that using additives grouped in clusters with a low risk could help mitigate the EHH impacts posed by HF chemicals.

MORPHOLOGY AND FRACTAL CHARACTERIZATION OF MULTISCALE PORE STRUCTURES FOR ORGANIC-RICH LACUSTRINE SHALE RESERVOIRS

Lacustrine shale gas has received considerable attention and has been playing an important role in unconventional natural gas production in China. In this study, multiple techniques, including total organic carbon (TOC) analysis, X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FE-SEM), helium pycnometry and low-pressure [Formula: see text] adsorption have been applied to characterize the pore structure of lacustrine shale of Upper Triassic Yanchang Formation from the Ordos Basin. The results show that organic matter (OM) pores are the most important type dominating the pore system, while interparticle (interP) pores, intraparticle (intraP) and microfractures are also usually observed between or within different minerals. The shapes of OM pores are less complex compared with the other two pore types based on the Image-Pro Plus software analysis. In addition, the specific surface area ranges from [Formula: see text] to [Formula: see text] and the pore volume varies between [Formula: see text] and [Formula: see text]. Two fractal dimensions [Formula: see text] and [Formula: see text] were calculated using Frenkel–Halsey–Hill (FHH) method, with [Formula: see text] varying between 2.510 and 2.632, and [Formula: see text] varying between 2.617 and 2.814. Further investigation indicates that the fractal dimensions exhibit positive correlations with TOC contents, whereas there is no definite relationship observed between fractal dimensions and clay minerals. Meanwhile, the fractal dimensions increase with the increase in specific surface area, and is negatively correlated with the pore size.

Crime and natural resource booms: evidence from unconventional natural gas production

The USA has experienced a sudden expansion of oil and natural gas production due to the combination of hydraulic fracturing and horizontal drilling. The energy extraction boom has had many localized impacts, most notably in areas with substantial shale gas reserves. This paper exploits a natural experiment in the Marcellus region to examine one channel of the so-called resource curse, the effect of resource extraction on local crime. The results show that areas experiencing a natural gas extraction boom suffer an increase in overall violent crimes, while property crimes remain similar to non-boom areas. Furthermore, the violent crime increase appears to be driven primarily by increases in aggravated and sexual assaults.

Hazard assessment of hydraulic fracturing chemicals using an indexing method

The rapid expansion of unconventional natural gas production has triggered considerable public concerns, particularly regarding environmental and human health (EHH) risks posed by various chemical additives used in hydraulic fracturing (HF) operations. There is a need to assess the potential EHH hazards of additives used in real-world HF operations. In this study, HF additive and fracturing fluid data was acquired, and EHH hazards were assessed using an indexing approach. The indexing system analyzed chemical toxicological data of different ingredients contained within additives and produced an aggregated EHH safety index for each additive, along with an indicator describing the completeness of the chemical toxicological data. The results show that commonly used additives are generally associated with medium-level EHH hazards. In each additive category, ingredients of high EHH concern were identified, and the high hazard designation was primarily attributed to ingredients' high aquatic toxicity and carcinogenic effects. Among all assessed additive categories, iron control agents were identified as the greatest EHH hazards. Lack of information, such as undisclosed ingredients and chemical toxicological data gaps, has resulted in different levels of assessment uncertainties. In particular, friction reducers show the highest data incompleteness with regards to EHH hazards. This study reveals the potential EHH hazards associated with chemicals used in current HF field operations and can provide decision makers with valuable information to facilitate sustainable and responsible unconventional gas production.

Quantifying methane emissions from natural gas production in north-eastern Pennsylvania

Abstract. Natural gas infrastructure releases methane (CH4), a potent greenhouse gas, into the atmosphere. The estimated emission rate associated with the production and transportation of natural gas is uncertain, hindering our understanding of its greenhouse footprint. This study presents a new application of inverse methodology for estimating regional emission rates from natural gas production and gathering facilities in north-eastern Pennsylvania. An inventory of CH4 emissions was compiled for major sources in Pennsylvania. This inventory served as input emission data for the Weather Research and Forecasting model with chemistry enabled (WRF-Chem), and atmospheric CH4 mole fraction fields were generated at 3 km resolution. Simulated atmospheric CH4 enhancements from WRF-Chem were compared to observations obtained from a 3-week flight campaign in May 2015. Modelled enhancements from sources not associated with upstream natural gas processes were assumed constant and known and therefore removed from the optimization procedure, creating a set of observed enhancements from natural gas only. Simulated emission rates from unconventional production were then adjusted to minimize the mismatch between aircraft observations and model-simulated mole fractions for 10 flights. To evaluate the method, an aircraft mass balance calculation was performed for four flights where conditions permitted its use. Using the model optimization approach, the weighted mean emission rate from unconventional natural gas production and gathering facilities in north-eastern Pennsylvania approach is found to be 0.36 % of total gas production, with a 2σ confidence interval between 0.27 and 0.45 % of production. Similarly, the mean emission estimates using the aircraft mass balance approach are calculated to be 0.40 % of regional natural gas production, with a 2σ confidence interval between 0.08 and 0.72 % of production. These emission rates as a percent of production are lower than rates found in any other basin using a top-down methodology, and may be indicative of some characteristics of the basin that make sources from the north-eastern Marcellus region unique.

Prospect and technology of unconventional gas exploration and development in China

The rapid development of natural gas lays the foundation for the unconventional gas development. In 2015, unconventional natural gas production is 44.9Bcm, accounting for 34.06% of total natural gas production. Increasing demand of natural gas provides a wide developing space for unconventional natural gas. China has deployed unconventional natural gas resource evaluation to different extent, which mainly includes tight gas, CBM and shale gas. Unconventional gas E&P in China is still in its initial stage. By 2015, 1.6 Tcm proved reserves and 36 Bcm production has made China tight gas entering a large scale and commercializing stage. CBM development is still in the initial stage of E&P, with less reserve and production, in the early stage for commercialized development. Shale gas has a significant breakthrough since its proved reserves reached to 544.1Bcm, and production reached to 4.5Bcm. At present, conventional gas develops rapidly in China. During the next 5-10 years, it will also take the dominant position in the natural gas development. Unconventional gas will play a more and more important role in the long-term development of natural gas.

Quantity of flowback and produced waters from unconventional oil and gas exploration

The management and disposal of flowback and produced waters (FP water) is one of the greatest challenges associated with unconventional oil and gas development. The development and production of unconventional natural gas and oil is projected to increase in the coming years, and a better understanding of the volume and quality of FP water is crucial for the safe management of the associated wastewater. We analyzed production data using multiple statistical methods to estimate the total FP water generated per well from six of the major unconventional oil and gas formations in the United States. The estimated median volume ranges from 1.7 to 14.3millionL (0.5 to 3.8milliongal) of FP per well over the first 5–10years of production. Using temporal volume production and water quality data, we show a rapid increase of the salinity associated with a decrease of FP production rates during the first months of unconventional oil and gas production. Based on mass-balance calculations, we estimate that only 4–8% of FP water is composed of returned hydraulic fracturing fluids, while the remaining 92–96% of FP water is derived from naturally occurring formation brines that is extracted together with oil and gas. The salinity and chemical composition of the formation brines are therefore the main limiting factors for beneficial reuse of unconventional oil and gas wastewater.

Methane Emissions from Conventional and Unconventional Natural Gas Production Sites in the Marcellus Shale Basin.

There is a need for continued assessment of methane (CH4) emissions associated with natural gas (NG) production, especially as recent advancements in horizontal drilling combined with staged hydraulic fracturing technologies have dramatically increased NG production (we refer to these wells as "unconventional" NG wells). In this study, we measured facility-level CH4 emissions rates from the NG production sector in the Marcellus region, and compared CH4 emissions between unconventional NG (UNG) well pad sites and the relatively smaller and older "conventional" NG (CvNG) sites that consist of wells drilled vertically into permeable geologic formations. A top-down tracer-flux CH4 measurement approach utilizing mobile downwind intercepts of CH4, ethane, and tracer (nitrous oxide and acetylene) plumes was performed at 18 CvNG sites (19 individual wells) and 17 UNG sites (88 individual wells). The 17 UNG sites included four sites undergoing completion flowback (FB). The mean facility-level CH4 emission rate among UNG well pad sites in routine production (18.8 kg/h (95% confidence interval (CI) on the mean of 12.0-26.8 kg/h)) was 23 times greater than the mean CH4 emissions from CvNG sites. These differences were attributed, in part, to the large size (based on number of wells and ancillary NG production equipment) and the significantly higher production rate of UNG sites. However, CvNG sites generally had much higher production-normalized CH4 emission rates (median: 11%; range: 0.35-91%) compared to UNG sites (median: 0.13%, range: 0.01-1.2%), likely resulting from a greater prevalence of avoidable process operating conditions (e.g., unresolved equipment maintenance issues). At the regional scale, we estimate that total annual CH4 emissions from 88 500 combined CvNG well pads in Pennsylvania and West Virginia (660 Gg (95% CI: 500 to 800 Gg)) exceeded that from 3390 UNG well pads by 170 Gg, reflecting the large number of CvNG wells and the comparably large fraction of CH4 lost per unit production. The new emissions data suggest that the recently instituted Pennsylvania CH4 emissions inventory substantially underestimates measured facility-level CH4 emissions by >10-40 times for five UNG sites in this study.

A devil's bargain: Rural environmental injustices and hydraulic fracturing on Pennsylvania's farms

Rural Pennsylvania, the epicenter of the Marcellus Shale region, hosts the most prolific unconventional natural gas extraction and production activity in the US. Farmers of small and midsized operations in Marcellus counties depend increasingly on incomes from booming natural gas operations, while the industry needs their land to access energy resources. These farmers thus bridge two economic sectors—unconventional natural gas production and agriculture. Related dynamics rapidly transform the social, economic, and environmental landscapes for Pennsylvania's rural communities. We ask: What, if any, are the environmental justice implications of the unconventional natural gas industry's presence in rural agricultural spaces, particularly for farmers with small and midsized operations? Presenting findings from 42 in-depth interviews, participant observation, and archival analysis, we show how farmers benefit from natural gas leases to support their agricultural livelihoods. However, they face a devil's bargain. Farmers risk entrenchment in a long-term web of natural resource dependence, increasingly unable to determine their livelihoods or land use on their own terms. Our study demonstrates how farmers' intersectoral dependence conditions procedural inequities and greater environmental risk. We show how farmers of small and midsized operations experience rural environmental injustices as they endure corporate bullying; face procedural inequities negotiating and enforcing lease terms; and increasingly contend with environmental risks associated with unconventional natural gas production.

Prospective air pollutant emissions inventory for the development and production of unconventional natural gas in the Karoo basin, South Africa

The increased use of horizontal drilling and hydraulic fracturing techniques to produce gas from unconventional deposits has led to concerns about the impacts to local and regional air quality. South Africa has the 8th largest technically recoverable shale gas reserve in the world and is in the early stages of exploration of this resource. This paper presents a prospective air pollutant emissions inventory for the development and production of unconventional natural gas in South Africa's Karoo basin. A bottom-up Monte Carlo assessment of nitrogen oxides (NOx = NO + NO2), particulate matter less than 2.5 μm in diameter (PM2.5), and non-methane volatile organic compound (NMVOC) emissions was conducted for major categories of well development and production activities. NOx emissions are estimated to be 68 tons per day (±42; standard deviation), total NMVOC emissions are 39 tons per day (±28), and PM2.5 emissions are 3.0 tons per day (±1.9). NOx and NMVOC emissions from shale gas development and production would dominate all other regional emission sources, and could be significant contributors to regional ozone and local air quality, especially considering the current lack of industrial activity in the region. Emissions of PM2.5 will contribute to local air quality, and are of a similar magnitude as typical vehicle and industrial emissions from a large South African city. This emissions inventory provides the information necessary for regulatory authorities to evaluate emissions reduction opportunities using existing technologies and to implement appropriate monitoring of shale gas-related activities.

Analysis of resource potential for China’s unconventional gas and forecast for its long-term production growth

China is vigorously promoting the development of its unconventional gas resources because natural gas is viewed as a lower-carbon energy source and because China has relatively little conventional natural gas supply. In this paper, we first evaluate how much unconventional gas might be available based on an analysis of technically recoverable resources for three types of unconventional gas resources: shale gas, coalbed methane and tight gas. We then develop three alternative scenarios of how this extraction might proceed, using the Geologic Resources Supply Demand Model. Based on our analysis, the medium scenario, which we would consider to be our best estimate, shows a resource peak of 176.1 billion cubic meters (bcm) in 2068. Depending on economic conditions and advance in extraction techniques, production could vary greatly from this. If economic conditions are adverse, unconventional natural gas production could perhaps be as low as 70.1bcm, peaking in 2021. Under the extremely optimistic assumption that all of the resources that appear to be technologically available can actually be recovered, unconventional production could amount to as much as 469.7bcm, with peak production in 2069. Even if this high scenario is achieved, China’s total gas production will only be sufficient to meet China’s lowest demand forecast. If production instead matches our best estimate, significant amounts of natural gas imports are likely to be needed.

Shale gas in China: Characteristics, challenges and prospects (I)

Abstract This paper mainly discusses the industrialization progress, “sweet spot” evaluation criterion, E&P technologies, success experiences, challenges and prospects of China's shale gas. Based on the geologic and engineering parameters of the Fuling, Changning and Weiyuan shale gas fields in the Sichuan Basin, this paper points out that China's shale gas has its particularity. The discoveries of super-giant marine shale gas fields with high evolution degree (R o =2.0%−3.5%) and ultrahigh pressure (pressure coefficient=1.3−2.1) in southern China is of important scientific significance and practical value to ancient marine shale gas exploration and development to China and even the world. It's proposed that shale gas “sweet spots” must be characterized by high gas content, excellent frackability and good economy etc. The key indicators to determine the shale gas enrichment interval and trajectory of horizontal wells include “four highs”, that is high TOC (>3.0%), high porosity (>3.0%), high gas content (>3.0 m 3 /t) and high formation pressure (pressure coefficient>1.3), and “two well-developed” (well-developed beddings and well-developed micro-fractures). It's suggested that horizontal well laneway be designed in the middle of high pressure compartment between the Upper Ordovician Wufeng Formation and Lower Silurian Longmaxi Formation. The mode of forming “artificial shale gas reservoir” by “fracturing micro-reservoir group” is proposed and the mechanisms of “closing-in after fracturing, limiting production through pressure control” are revealed. Several key technologies (such as three-dimensional seismic survey and micro-seismic monitoring of fracturing, horizontal wells, “factory-like” or industrialized production mode, etc.) were formed. Some successful experiences (such as “sweet spot” selection, horizontal well laneway control, horizontal length optimization and “factory-like” production mode, etc.) were obtained. The four main challenges to realize large-scale production of shale gas in China include uncertainty of shale gas resources, breakthroughs in key technologies and equipment of shale gas exploration and development below 3 500 m, lower cost of production, as well as water resources and environment protection. It is predicted that the recoverable resources of the Lower Paleozoic marine shale gas in southern China are approximately 8.8×10 12 m 3 , among which the recoverable resources in the Sichuan Basin are 4.5×10 12 m 3 in the favorable area of 4.0×10 4 km 2 . The productivity of (200−300)×10 8 m 3 /a is predicted to be realized by 2020 when the integrated revolution of “theory, technology, production and cost” is realized in Chinese shale gas exploration and development. It is expected in the future to be built “Southwest Daqing Oilfield (Gas Daqing)” in Sichuan Basin with conventional and unconventional natural gas production.