Research on Result Prediction of Coal-Bed Gas Wells Fracturing by Using Expert System

2013 ◽  
Vol 734-737 ◽  
pp. 1445-1449
Author(s):  
Chi Ai ◽  
Chao Yang Hu ◽  
Yu Wei Li ◽  
Feng Jiao Wang
Keyword(s):  
Expert System ◽  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Gas Content ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Main Method ◽  
Number Of Factors ◽  
Coal Seam Thickness ◽  
Expert Database

Hydraulic fracturing is the main method to increase the output of coal-bed methane wells, however, the hydraulic fracturing result of coal-bed methane well is usually affected by large number of factors such as the conditions of coal-bed, the conditions of coal-bed methane well, fracturing operation parameters and so on. As a result, the fracturing operation result is difficult to predict. This paper assumed coal seam thickness, the depth of coal seam, coal seam gas content and other six main factors which affect hydraulic fracturing results by analysis various factors. Membership function of the expert system was established to divide the level of each factor. The established method which applies the expert system to predict the hydraulic fracturing results of coal-bed methane wells was based on expert database. Using the established expert system to calculate 200 groups of test data and the prediction error rate is only 3.5%. The prediction results are accurate and reliable, and can provide guidance for coal-bed methane wells fracturing optimization.

Study on Well Logging Technology with Methods of Evaluating Gas Content of Coal-Bed Methane Reservoir

2014 ◽  
Vol 1003 ◽  
pp. 183-187
Author(s):  
Huai Jie Yang ◽  
He Ping Pan
Keyword(s):  
Statistical Analysis ◽  
Coal Seam ◽  
Well Logging ◽  
Langmuir Equation ◽  
Gas Content ◽  
Coal Bed ◽  
High Yield ◽  
Coal Bed Methane ◽  
Analysis Method ◽  
Statistical Analysis Method

In this study, the well logging response of CBM reservoir have been analyzed, and discussing the factors that affect the gas content of coal seam. The well logging technology has been employed in connection with log data and gas content. Take one oilfield’s well logging data for example, statistical analysis method and Langmuir equation method are selected to calculate the gas content of one coal seam, the two calculated results are basically the same, the highest value are about 26 cm3/g, is a high-yield coal seam.

Stimulating methane generation within coal seam reservoirs

2015 ◽  
Vol 55 (2) ◽  
pp. 441
Author(s):  
Nicholas Lupton ◽  
Regina Sander ◽  
Luke Connell ◽  
Michael Camilleri ◽  
Deasy Heryanto ◽  
...  
Keyword(s):  
Coal Seam ◽  
Atmospheric Pressure ◽  
Nutrient Balance ◽  
Gas Content ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Reservoir Pressure ◽  
Core Flooding ◽  
Gas Generation ◽  
Methane Generation

Methane generation by microbial activity or biogenesis is a significant source of coal bed methane (Faiz and Hendry, 2006; Strapoć et al, 2011). Being able to stimulate microbial methane generation in a coal seam reservoir has the potential to add significant value to depleted or undersaturated fields. Several laboratory studies have demonstrated that this process can be stimulated through the addition of inorganic nutrients (Jones et al, 2010; Orem et al, 2010). These studies, performed at atmospheric pressure on crushed coal, provide encouraging support for the concept of inducing in-situ biogenic methanogenesis and increasing gas-in-place in coal bed methane reservoirs. Important questions, however, remain about how laboratory results relate to what occurs in the reservoir. This extended abstract presents the results from a series of core flooding experiments conducted at reservoir pressure and temperature on intact coal core samples. Nutrient consumption is characterised by measuring the nutrient balance between the inflow and outflow waters. Gas content is measured through a helium flood at the end of the experiment, during which the pore pressure is dropped to atmospheric pressure to drive off any adsorbed gas. These experiments confirm that microbial gas generation does occur at reservoir pressure and temperature, and at high enough rates to rapidly increase gas content.

A Review of Technical Potential for Coal Production and Coal Degasification – A Conventional Source of Methane – In Nigeria

2003 ◽  
Vol 14 (1) ◽  
pp. 59-67
Author(s):  
Adepo Jepson Olumide ◽  
Ayodele Charles Oludare ◽  
Balogun Olufemi
Keyword(s):  
Coal Seam ◽  
Fossil Fuels ◽  
Underground Mining ◽  
Simple Calculation ◽  
Gas Content ◽  
Gelling Agent ◽  
Coal Bed ◽  
Natural State ◽  
Mining Operations ◽  
Inorganic Matter

Coal, a solid fuel in its natural state has been identified as one of the world's major fossil fuels. It is a compact, stratified mass of mummified plant debris interspersed with smaller amounts of inorganic matter buried in sedimentary rocks. The use of coal as an energy source can be dated back to the prehistoric times. Methane is associated with many if not all coal seams, and is the dreaded “fire damp” responsible for many pit explosions. Coal mines are designed to vent as much methane as possible. It is present in the pores of coal under pressure, released during mining operations and can be extracted through vertical well bores. This paper highlights the fact that pipeline- quality methane can be extracted economically from coal seems before and during underground mining operations. The stimulation method involves hydraulic fracturing of the coal seam by using water, sand and, a gelling agent in a staged and alternating sand/and no sand sequence. The purpose is to create new fractures in the coal seam(s). The cleating of the coal helps to determine the flow characteristics of the coal formation and is vital in the initial productivity of a coal-methane well. The simple calculation of gas-in-place is achieved by multiplying the gas content of the coal by net coal thickness, the density, and the aerial extent of the drainage. The method is claimed to be suitable for use in Nigeria and potential sites for coal bed methane extraction in Nigeria are identified.

Coal-bed methane geology of the No. 2 coal seam in Fengfeng Coalfield, North China

2019 ◽  
Vol 12 (16) ◽  
Author(s):  
Dawei Lv ◽  
Changyong Lu ◽  
Zhijie Wen ◽  
Hongzhu Song ◽  
Shuai Yin
Keyword(s):  
Coal Seam ◽  
North China ◽  
Coal Bed ◽  
Coal Bed Methane

The Studies on Gas-Bearing Characteristics of Deep Coal Seams in Yanchang Oil and Gas Province, China

2014 ◽  
Vol 962-965 ◽  
pp. 213-216
Author(s):  
Guo Ping Jiang
Keyword(s):  
Coal Seam ◽  
Layer Thickness ◽  
Oil And Gas ◽  
Single Layer ◽  
Gas Content ◽  
Coal Bed ◽  
Coal Seams ◽  
Resource Potential ◽  
Gas Bearing ◽  
Average Layer Thickness

In this paper, four general directions are described to make evaluations and their resource potential; those are coal structure and coal level, gas content of deep coalbed, the coalbed thickness and distribution and the buried depth of coalbed. Coalfields of the study area are mainly Permian and Carboniferous coal seam of Shanxi Formation coal and Benxi group 11 # coal, coal seam depth 1370-1812m. No. 3 coal-seam average layer thickness of 1.6 m, the monolayer most 2 m thick; No. 11 coal-seam in the average layer thickness of 3 m, single-layer thickness of 4.5 m. Predict the amount of coal resources of 17.3 one hundred million t. Predict coal-bed methane resources of 27.68 billion cubic reserve abundance of 104 million square / km2 in. The exploration results show that this region has good development prospects.

Important Factors to Propose High-Produced New Development Wells in CBM Project

2014 ◽  
Vol 1030-1032 ◽  
pp. 2578-2581
Author(s):  
Zhao Hui Xia ◽  
Ming Zhang ◽  
Bin Ren ◽  
Liang Chao Qu ◽  
Ze Hong Cui ◽  
...  
Keyword(s):  
Coal Seam ◽  
3D Model ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Coal Seams ◽  
Reservoir Properties ◽  
Well Design ◽  
New Development ◽  
Reservoir Type ◽  
High Production

Coal bed methane (CBM) is a kind of natural gas that generated from coal and disseminated organic matters during the stage of diagenesis and coalification, which mainly composed of methane and hosted in coal seam by free, adsorbed, and dissolved forms. Genetic, reservoir type and occurrence condition in CBM are different from traditional reservoir. And the high-produced development wells in CBM aiming to drill more coal seams with high quality therefore needs to be analyzed in the methods that are different from traditional reservoir. 3 important factors including the study on correlation and elevation depth of coal seam roof and floor in section and areal by using well-seismic ties, outcrop boundary based on coal mine data and distributions of CBM reservoir properties in 3D model are needed for high-produced development well analyze in CBM. Application in Australia CBM project shows this methodology is very successful for the development well design with high production.

The Broad Concept and Resource Calculation Method of Coalbed Methane

2014 ◽  
Vol 962-965 ◽  
pp. 185-188
Author(s):  
Wei Hou ◽  
Fang Zhang
Keyword(s):  
Coal Seam ◽  
Calculation Method ◽  
Coalbed Methane ◽  
Surrounding Rock ◽  
Gas Content ◽  
Coal Bed ◽  
Broad Concept

It has become the focus of debate about Coalbed Methane (CBM) concept whether the surrounding rock is reservoir. The gas content of surrounding rock is considerable, and it may become valuable exploration targets. In lateral, the gas content of surrounding rock is negatively related with coal bed. In vertical, the closer distance between coal seam and surrounding rock is, the higher gas content is. The broad CBM is defined as the gas that mainly originates from coal, mainly exists in the coal seam, and also widely exists in the surrounding rock. The method of volume and capacity are used to resource calculation.

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