Productivity Prediction of Coalbed Methane Wells in the Southern Junggar Basin

2013 ◽  
Vol 868 ◽  
pp. 669-672 ◽  
Author(s):  
Jin Wang ◽  
Jing Jing Fan ◽  
Xiang Hao Wang ◽  
Cheng Long Liu ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
History Matching ◽  
Influence Factors ◽  
Junggar Basin ◽  
Gas Production ◽  
Gas Content ◽  
Gas Well ◽  
Modeling Software ◽  
Coal Seam Thickness ◽  
Productivity Prediction

Based on the coal reservoirs geological feature and coalbed methane (CBM) wells production data, and taken FS-2 well in the southern Junggar Basin as examples, history matching and productivity prediction of FS-2 well were conducted by using COMET3 numerical modeling software and the influence factors sensitivity of gas well productivity in the study area were analyzed. The results suggest: FS-2 well total gas production in the eight years was 2915007 m3, and the average daily gas production reached 1209.5m3/d, the CBM well belongs to medium production well. Permeability and gas content has the most effect on the single wells production in the study area, so the influence of the fracture half-length and coal seam thickness is weakened.

A New Method to Predict Gas Production Based on Fuzzy BP Artificial Neural Network

2014 ◽  
Vol 1044-1045 ◽  
pp. 688-691
Author(s):  
Ran Zhang ◽  
Jun Zhou ◽  
Cheng Yong Li
Keyword(s):  
Neural Network ◽  
Bp Neural Network ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Gas Production ◽  
Gas Well ◽  
Well Productivity ◽  
Qualitative Factors ◽  
Productivity Prediction

BP neural network has been successfully used in the gas well productivity prediction, but as a result of neural network is sensitive to the number of input parameters, we had to ignore some factors that is less important to the gas well productivity. In addition, the existing various productivity prediction method cannot consider the influence of some important qualitative factors. This article integrated the advantages of fuzzy comprehensive evaluation and BP neural network, fuzzy comprehensive evaluation method is used to construct the BP neural network's input matrix, and BP neural network learning function is used to solve the connection weights, so as to achieve the aim of predicting gas production. This method not only can consider as many factors influence on gas well production, ut also can consider qualitative factors, so the forecast results of the new model are more realistically close to the actual production situation of reservoirs.

scholarly journals Multi-factor controls on initial gas production pressure of coalbed methane wells in Changzhi-Anze block, Central-Southern of Qinshui Basin, China

2020 ◽  
Vol 38 (1-2) ◽  
pp. 3-23 ◽  
Author(s):  
Yang Zhao ◽  
Xiaodong Zhang ◽  
Shuo Zhang ◽  
Jiaosheng Yang ◽  
Xianzhong Li ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Gas Production ◽  
Gas Content ◽  
Working Fluid ◽  
Water Yield ◽  
Burial Depth ◽  
Reservoir Pressure ◽  
Pressure Drops ◽  
Factors Affecting ◽  
Control Factors

Adsorption and desorption of coalbed methane are generally at a dynamic equilibrium state under the undisturbed coal reservoir. However, as the reservoir pressure drops to a certain value during the extraction of coalbed methane, the equilibrium state is destroyed and thus more coalbed methane desorbs and escapes from coal to wellbore. Here the corresponding bottom-hole fluid pressure is called initial gas production pressure (IGPP) in the development practice of coalbed methane wells. This paper, which has taken Changzhi-Anze block in the central-southern part of Qinshui basin as the study object, addresses the distribution characteristic and control factors of IGPP of coalbed methane wells and then explores the key factors affecting IGPP using grey correlation analysis theory. The results indicate that IGPP varies from 1.09 MPa to 6.57 MPa, showing a distribution law with high in the middle and low in the west and east of the study area, which presents a similar distribution characteristic with burial depth, thickness, coal rank, gas content, original reservoir pressure, and in-situ stress. Further, through grey correlation analysis, it concludes that the correlation degrees of control factors affecting IGPP of coalbed methane wells in the descending order are decline rate of working fluid level, water yield before gas production, reservoir pressure, coal thickness, coal rank, minimum horizontal principal stress, burial depth, and gas content. Among these factors, engineering factors, including decline rate of working fluid level and water yield before gas production, present a key controlling effect, because they can determine the smooth migration pathway directly during initial water production. And another key factor, original reservoir pressure also builds strong and positive correlation with IGPP under the interaction of other geology and reservoir factors, revealing the capability of gas desorption and the transmission of pressure drops.

Study on the composition and inter-layer correlation of coalbed methane system of Xishanyao Formation under sedimentary control, Southern Junggar Basin, NW

2020 ◽  
Author(s):  
aobo zhang ◽  
shuling Tang
Keyword(s):  
Coalbed Methane ◽  
Junggar Basin ◽  
Sedimentary Facies ◽  
Research Area ◽  
Gas Content ◽  
Sand Body ◽  
Diversion Channel ◽  
Plane Distribution ◽  
Crevasse Splay ◽  
Lacustrine Facies

<p>In order to investigate the controlling of the sedimentation environment evolution on the coalbed methane system in Xishanyao Formation on the southern margin of Junggar Basin，using drilling wells，logging wells，outcrops and other data with the assistance of fine analysis methods，such as scanning electron microscope and image granularity，the coalbed methane system was divided，and its sedimentation evolution process was researched． The research results show that sand body of five types of sedimentation microfacies，whose water and air blocking capacity is sorted as “diversion channel＜crevasse splay and beach dam＜natural levee and shore－shallow lake”，can be identified in the research area，and single－well vertical coalbed methane system was divided; during the SQ1—SQ2 period，the rise of lake level led to the expansion of the development area of lacustrine facies，as well as the weakening of the coal－accumulating process which was mainly concentrated in the TST and LST stages of SQ1，and the east－west characteristic difference regarding the coalbed development and gas content appeared and was in accordance with the plane distribution of sedimentary facies; during exploitation，the coalbed methane system should be defined according to the blocking capability of surrounding rock，appropriate exploitation methods should be selected according to the characteristics of each system，and the avoidance of vertically joint－developing sandstone aquifer and combined layer series of development should be paid attention to．</p>

Relation between coalbed permeability and in-situ stress magnitude for coalbed methane exploration in Jharia and Raniganj coalfields, India

2019 ◽  
Vol 38 (10) ◽  
pp. 800-807 ◽  
Author(s):  
Rima Chatterjee ◽  
Suman Paul ◽  
Prabir Kumar Pal
Keyword(s):  
Coalbed Methane ◽  
History Matching ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Gas Content ◽  
Major Influence ◽  
Reservoir Pressure ◽  
Horizontal Drilling ◽  
Cbm Production

India is among the top five countries in the world in terms of proven coal reserves and coal production. As such, significant potential exists for commercial recovery of coalbed methane (CBM). Two coalfields, Jharia and Raniganj, located in eastern India are currently under development for CBM. This paper describes work done to determine coal seam properties, ambient stress conditions, and effects of depletion at these coalfields that influence CBM production. Coalbed permeability is a parameter that has a major influence on CBM production. Other influences include in-situ stress direction, gas content, and the application of suitable stimulation techniques. A robust methodology is required to determine both initial coalbed permeability and its relation to in-situ horizontal stress magnitudes. Coalbed permeability at the Jharia and Raniganj coalfields was estimated from porosity and known cleat spacing. Initial permeability of major coalbeds was correlated with effective horizontal stress, yielding satisfactory to very good exponential fit using data from Raniganj and Jharia wells. Acoustic televiewer image-logging tool measurements in a single well in the Jharia coalfield were used to infer a maximum horizontal stress orientation between N25°W and N25°E. Reservoir-pressure-dependent permeability models are presented for coalbeds under uniaxial strain condition. The coalbed permeability is dominated by the existing effective horizontal stresses normal to the cleats. Two prospective coal seams from Jharia have been identified through assessment of the response of horizontal stress to the decline of CBM reservoir pressure. Coalbed permeability increases with the drawdown of reservoir pressure and is exponentially related to the change of effective horizontal stress during reservoir depletion. The results of this study are to be used for production history matching for wells in Jharia and to determine optimal horizontal drilling directions for increased CBM production.

Study on Coalbed Methane well Type Optimization of Badaowan Formation in Junggar Basin

2014 ◽  
Vol 535 ◽  
pp. 622-625
Author(s):  
Cheng Long Liu ◽  
Hui Guo ◽  
Xiang Hao Wang ◽  
Jin Wang
Keyword(s):  
Coal Seam ◽  
Coalbed Methane ◽  
Evaluation System ◽  
Horizontal Well ◽  
Evaluation Method ◽  
Junggar Basin ◽  
Fuzzy Evaluation ◽  
Ahp Method ◽  
Well Drilling ◽  
Coal Seam Thickness

This paper applies AHP method and fuzzy evaluation method to establish evaluation system of CBM well type in Junggar Basin. Conclusions are drawn as follows: weight of each factor which determines well type optimization is very different, coal seam depth is 0.402, coal seam thickness is 0.295, coal permeability is 0.163, coal seam dip is 0.14. Sikeshu area and center of the basin is not suitable for CBM ground drilling. Changji to Fukang area and Muleihasakexian to Wucaiwan area and East Wuerhe area are favorable for vertical well drilling. Jimusaer area is favorable for horizontal well drilling. Other areas in Junggar Basin need vertical and horizontal well joint drilling.

Analysis of Coalbed Methane (CBM) Enrichment and Main Controlling Factors in Southern Junggar Basin

2013 ◽  
Vol 848 ◽  
pp. 251-254
Author(s):  
Xiang Hao Wang ◽  
Yan Bin Wang ◽  
Jing Jing Fan ◽  
Jin Wang ◽  
Cheng Long Liu
Keyword(s):  
Coalbed Methane ◽  
Atmospheric Precipitation ◽  
Junggar Basin ◽  
Controlling Factors ◽  
Water Soluble ◽  
Gas Content ◽  
Runoff Water ◽  
Main Controlling Factors ◽  
Diffusion Pattern ◽  
Using Data

Using data analysis and comparative analysis, the distribution of Coalbed methane (CBM) gas content in southern Junggar were analyzed on the basis of the southern Junggar Basin coalfield geological data, and the main controlling factors of CBM accumulation were studied. The results show that, Gas content ranges from 2cm3/g to 15cm3/g, which overall is highest in central and eastern and becomes progressively smaller in trend of westward. The study area has many characteristics, such as Multi-seam, large coal seam thickness, mainly Fine-grained clastic rock, which is conducive to the enrichment of the CBM. Study area belongs to confined aquifer of low water-richness and receives the supply of atmospheric precipitation and river. In the coal seams within a certain depth formed Runoff water and the CBM diffusion pattern of desorption - diffusion - transport - water soluble gas runoff, which are not conducive to the enrichment of the CBM.

scholarly journals Productivity subarea of CBM field and its key controlling factors: A case study in the Hancheng pilot test area, southeastern Ordos Basin, China

2018 ◽  
Vol 37 (1) ◽  
pp. 102-124 ◽  
Author(s):  
Yanfei Liu ◽  
Dazhen Tang ◽  
Song Li ◽  
Hao Xu ◽  
Shu Tao ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Ordos Basin ◽  
Gas Production ◽  
Test Area ◽  
Gas Content ◽  
Pilot Test ◽  
Coal Seams ◽  
Geological Factors ◽  
Drop Rate

The Hancheng block in the southeastern Ordos Basin is one of the earliest and the most important areas for coalbed methane exploration and development in China. However, there are significant production variations in different wells or even some adjacent wells in the Hancheng block. To reveal the reasons of production differences in such a small scale, further detailed studies of coalbed methane productivity in the Hancheng pilot test area, a precursor trial area in Hancheng block with mature, well-characterized coalbed methane reservoirs and long-term production database, were conducted. The influence of nine factors (including engineering and geological factors) on gas production was analyzed. By introducing the rough set theory, which is applicable to the vague, imprecise, and incomplete information system, this paper presents a method for quantitative evaluation of the influencing factors on gas production. The results indicate that there are certain distribution characteristics of productivity in Hancheng pilot test area, which can be partitioned into four zones. The degressive order of the influencing degree of these nine factors is (i) the distance between the well and the fault, (ii) the structure curvature of the coal seams, (iii) the gas content, (iv) the critical reservoir ratio, (v) the volume of the fracturing liquids per meter, (vi) the volume of the fracturing sand per meter, (vii) the dynamic liquid level drop rate, (viii) the depth, and (ix) the thickness. Geological factors, especially the influence of fault, structural curvature of the coal seams and gas content, play a major role in controlling long-term gas production. Engineering factors (effect of fracturing and dynamic liquid level drop rate) have always been integral parts of coalbed methane development.

scholarly journals Gas Content Evaluation of Coalbed Methane Reservoir in the Fukang Area of Southern Junggar Basin, Northwest China by Multiple Geophysical Logging Methods

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1867 ◽  
Author(s):  
Xu Ge ◽  
Dameng Liu ◽  
Yidong Cai ◽  
Yingjin Wang
Keyword(s):  
Coalbed Methane ◽  
Normal Fault ◽  
Junggar Basin ◽  
Analysis Data ◽  
Northwest China ◽  
Geological Structure ◽  
Gas Content ◽  
Burial Depth ◽  
Reverse Fault ◽  
Geophysical Logging

To study the gas potential of coalbed methane (CBM) in the Fukang area, southern Junggar Basin (SJB) of North China, different methods including multiple geophysical logging, the Kim method with proximate analysis data, and Langmuir adsorption were used to evaluate the gas content. Furthermore, the geological controls on gas content were evaluated. One hundred sixteen CBM wells with geophysical logging and 20 with field-measured gas content were adopted to assess the gas content in the Fukang area of SJB, NW China. The results show that the two geophysical logging variables (DEN and CNL) were favorable for evaluating the gas content due to the perfect correlation with the measured gas content. The gas content varies from 4.22 m3/t to 16.26 m3/t, and generally increases with increasing burial depth. The gas content in coal seams along the synclinal axis is significantly higher than that along the synclinal wing in the west zone. In the east zone, the gas content of the westward is higher than that of the eastward because of the fault coating effect by reverse fault. Generally, the gas content of the SJB is in the order of syncline > surrounding reverse fault > slope of syncline > slope of anticline > central of reverse fault, if only geological structure features are considered. The favorable areas for CBM concentration appear to be a composite gas controlling result of multiple geological factors. Two typical geological scenarios with low gas content and high gas content were revealed. In the Fukang area of SJB, the low gas content is mainly due to the normal fault and roof lithology of sandstone. The most favorable area of high gas content for CBM exploration and development is in the northeast, where reversed fault, synclinal axis, mudstone roof lithology, and burial depth coincide with high gas content.

Occurrence Features of Coalbed Methane in Inclined Coal Seam of Junggar Basin, Xinjiang

2013 ◽  
Vol 868 ◽  
pp. 696-699 ◽  
Author(s):  
Cheng Long Liu ◽  
Xiang Hao Wang ◽  
Kun Liu ◽  
Jin Wang ◽  
Hui Guo ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coalbed Methane ◽  
Simple Structure ◽  
Complex Structure ◽  
Junggar Basin ◽  
Gas Content ◽  
Target Area ◽  
Huge Amount ◽  
North Xinjiang ◽  
The Relationship

Junggar Basin is located in north Xinjiang and it has a huge amount of coalbed methane resources with less exploration and mining. The most vital characteristic in junggar basin is coal dip angel and gas content varies a lot in different areas. This paper reveals the relationship between gas content and coal seam dip angel, bigger the coal seam dip angel lower the gas content. The target area of CBM exploration and mining in junggar basin is HEGSH-STH area, HEGSHX area, BSMY-JJM area,LJM area, KLMY area, HSTLG area and XZJQ area. Gas content is mainly influenced by tectonic movement in junggar basin, it is low in complex structure area and high in simple structure area. Inclination of the coal seam stands for the complexity of the structure in junggar basin, the structure is complex when the coal seam is steep, it is simple when the coal seam is flat. The result can be used as a new method for coalbed methane exploration and development in inclined coal seam areas, small coal dip area should be chosen as the high gas content target.

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