scholarly journals The impact of relative permeability on type curves for coalbed methane reservoirs

2006 ◽  
Author(s):  
Sunil Lakshminarayanan
Keyword(s):  
Relative Permeability ◽  
Coalbed Methane ◽  
Type Curves ◽  
The Impact

Coalbed Methane: Current Field-Based Evaluation Methods

2011 ◽  
Vol 14 (01) ◽  
pp. 60-75 ◽  
Author(s):  
C.R.. R. Clarkson ◽  
R.M.. M. Bustin
Keyword(s):  
Relative Permeability ◽  
Coalbed Methane ◽  
Material Balance ◽  
Gas Content ◽  
Absolute Permeability ◽  
Accurate Estimation ◽  
Reservoir Properties ◽  
The Past ◽  
The Impact ◽  
Made In

Summary Coalbed methane (CBM) produced from subsurface coal deposits has been produced commercially for more than 30 years in North America, and relatively recently in Australia, China, and India. Historical challenges to predicting CBM-well performance and long-term production have included accurate estimation of gas in place (including quantification of in-situ sorbed gas storage); estimation of initial fluid saturations (in saturated reservoirs) and mobile water in place; estimation of the degree of undersaturation (undersaturated coals produce mainly water above desorption pressure); estimation of initial absolute permeability (system); selection of appropriate relative permeability curves; estimation of absolute-permeability changes as a function of depletion; prediction of produced-gas composition changes as a function of depletion; accounting for multilayer behavior; and accurate prediction of cavity or hydraulic-fracture properties. These challenges have primarily been a result of the unique reservoir properties of CBM. Much progress has been made in the past decade to evaluate fundamental properties of coal reservoirs, but obtaining accurate estimates of some basic reservoir and geomechanical properties remains challenging. The purpose of the current work is to review the state of the art in field-based techniques for CBM reservoir-property and stimulation-efficiency evaluation. Advances in production and pressure-transient analysis, gas-content determination, and material-balance methods made in the past 2 decades will be summarized. The impact of these new methods on the evaluation of key reservoir properties, such as absolute/relative permeability and gas content/gas in place, as well as completion/stimulation properties will be discussed. Recommendations on key surveillance data to assist with field-based evaluation of CBM, along with insight into practical usage of these data, will be provided.

Development of a Commercial Wireline Retrievable Coring System

1998 ◽  
Vol 1 (06) ◽  
pp. 489-495 ◽  
Author(s):  
Tommy Warren ◽  
Jim Powers ◽  
David Bode ◽  
Eric Carre ◽  
Lee Smith
Keyword(s):  
Economic Evaluation ◽  
Coalbed Methane ◽  
Technical Conference ◽  
The Core ◽  
Core Recovery ◽  
Drilling Equipment ◽  
Original Manuscript ◽  
The Impact ◽  
Conventional Drilling ◽  
Target Depth

This paper (SPE 52993) was revised for publication from paper SPE 36536, first presented at the 1996 SPE Annual Technical Conference and Exhibition, Denver, 6-9 October. Original manuscript received for review 11 October 1996. Revised manuscript received 22 September 1998. Paper peer approved 23 September 1998. Summary A Wireline retrievable coring system for use with conventional drilling equipment is described. The coring system was developed and tested for application in evaluating coalbed methane prospects where a large quantity of core is required, and it is essential that the core is processed soon after it is cut. A drill plug allows for alternation between coring and drilling without tripping the drillstring. The system is particularly advantageous for coring long intervals, multiple zones relatively close together, or when the exact target depth is unknown. The system has been used to core more than 4940 m (15,057 ft) in Poland, Germany, and France, with a combined core recovery of 94%. In addition, the impact of varying rig costs on total savings is factored into the overall economic evaluation of the system. P. 489

Unified relative permeability model and waterflooding type curves under different levels of water cut

2017 ◽  
Vol 154 ◽  
pp. 204-216 ◽  
Author(s):  
Qihong Feng ◽  
Jin Zhang ◽  
Sen Wang ◽  
Xiang Wang ◽  
Ronghao Cui ◽  
...  
Keyword(s):  
Relative Permeability ◽  
Permeability Model ◽  
Type Curves ◽  
Water Cut ◽  
Different Levels

scholarly journals Interpretation of Gas/Water Relative Permeability of Coal Using the Hybrid Bayesian-Assisted History Matching: New Insights

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 626
Author(s):  
Jiyuan Zhang ◽  
Bin Zhang ◽  
Shiqian Xu ◽  
Qihong Feng ◽  
Xianmin Zhang ◽  
...  
Keyword(s):  
Relative Permeability ◽  
Coalbed Methane ◽  
History Matching ◽  
Water Saturation ◽  
Unsteady State ◽  
Core Flooding ◽  
Rock Interaction ◽  
Interaction Mechanisms ◽  
True Value ◽  
Assisted History Matching

The relative permeability of coal to gas and water exerts a profound influence on fluid transport in coal seams in both primary and enhanced coalbed methane (ECBM) recovery processes where multiphase flow occurs. Unsteady-state core-flooding tests interpreted by the Johnson–Bossler–Naumann (JBN) method are commonly used to obtain the relative permeability of coal. However, the JBN method fails to capture multiple gas–water–coal interaction mechanisms, which inevitably results in inaccurate estimations of relative permeability. This paper proposes an improved assisted history matching framework using the Bayesian adaptive direct search (BADS) algorithm to interpret the relative permeability of coal from unsteady-state flooding test data. The validation results show that the BADS algorithm is significantly faster than previous algorithms in terms of convergence speed. The proposed method can accurately reproduce the true relative permeability curves without a presumption of the endpoint saturations given a small end-effect number of <0.56. As a comparison, the routine JBN method produces abnormal interpretation results (with the estimated connate water saturation ≈33% higher than and the endpoint water/gas relative permeability only ≈0.02 of the true value) under comparable conditions. The proposed framework is a promising computationally effective alternative to the JBN method to accurately derive relative permeability relations for gas–water–coal systems with multiple fluid–rock interaction mechanisms.

scholarly journals Gas Jet Coal-Breaking Behavior: An Elliptical Crushing Theoretical Model

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Gongda Wang ◽  
Yuanyuan Wang ◽  
Xin Yang ◽  
Xin Song
Keyword(s):  
Theoretical Model ◽  
Coalbed Methane ◽  
Clean Energy ◽  
Rock Breaking ◽  
Gas Jet ◽  
Rock Fracturing ◽  
Efficient Technology ◽  
Methane Drainage ◽  
Experimental Values ◽  
The Impact

Coalbed methane (CBM) is a source of clean energy and has been recovered in past decades all over the world. Gas dynamic disaster is the primary disaster in outburst coal, and methane drainage plays a key role in eliminating this danger. As an efficient technology, a gas jet is widely used in CBM development and methane drainage. In this work, the full impinging process of coal and rock fracturing by a supersonic gas jet was studied. To understand how jet parameters affect coal and rock fracturing results, an elliptical crushing theoretical model was proposed. In addition, a laboratory experiment was designed to examine the proposed model, and four key parameters affecting the fracturing results were studied. The results show that different from the monotonic variation of theoretical values, there is a turning point in the variation of experimental values under some parameters. Considering the influence of the depth and radius of the erosion pit, the rock-breaking effect is better when the nozzle size is 2.75 Ma. The optimal target distance is 30 mm, and the impact pressure of a gas jet should be continuously increased in order to achieve certain rock-breaking effects under the impact of the jet.

Multiphase Flow Under Heterogeneous Wettability Conditions Studied by Special Core Analysis and Pore-Scale Imaging

SPE Journal ◽  
2019 ◽  
Vol 24 (03) ◽  
pp. 1234-1247 ◽  
Author(s):  
Shuangmei Zou ◽  
Ryan T. Armstrong
Keyword(s):  
Multiphase Flow ◽  
Relative Permeability ◽  
Flow Regimes ◽  
Wettability Alteration ◽  
Core Analysis ◽  
Pore Scale ◽  
End Effect ◽  
The Impact ◽  
Capillary End Effect ◽  
Special Core Analysis

Summary Wettability is a major factor that influences multiphase flow in porous media. Numerous experimental studies have reported wettability effects on relative permeability. Laboratory determination for the impact of wettability on relative permeability continues to be a challenge because of difficulties with quantifying wettability alteration, correcting for capillary-end effect, and observing pore-scale flow regimes during core-scale experiments. Herein, we studied the impact of wettability alteration on relative permeability by integrating laboratory steady-state experiments with in-situ high-resolution imaging. We characterized wettability alteration at the core scale by conventional laboratory methods and used history matching for relative permeability determination to account for capillary-end effect. We found that because of wettability alteration from water-wet to mixed-wet conditions, oil relative permeability decreased while water relative permeability slightly increased. For the mixed-wet condition, the pore-scale data demonstrated that the interaction of viscous and capillary forces resulted in viscous-dominated flow, whereby nonwetting phase was able to flow through the smaller regions of the pore space. Overall, this study demonstrates how special-core-analysis (SCAL) techniques can be coupled with pore-scale imaging to provide further insights on pore-scale flow regimes during dynamic coreflooding experiments.

scholarly journals Fracturing curve and its corresponding gas productivity of coalbed methane wells in the Zhengzhuang block, southern Qinshui Basin, North China

2020 ◽  
Vol 38 (5) ◽  
pp. 1387-1408
Author(s):  
Yang Chen ◽  
Dameng Liu ◽  
Yidong Cai ◽  
Jingjie Yao
Keyword(s):  
Hydraulic Fracturing ◽  
Coalbed Methane ◽  
Continuous Production ◽  
Fracture Morphology ◽  
Geological Structure ◽  
In Situ Stress ◽  
Gas Production ◽  
Type Curves ◽  
Stable Type

Hydraulic fracturing has been widely used in low permeability coalbed methane reservoirs to enhance gas production. To better evaluate the hydraulic fracturing curve and its effect on gas productivity, geological and engineering data of 265 development coalbed methane wells and 14 appraisal coalbed methane wells in the Zhengzhuang block were investigated. Based on the regional geologic research and statistical analysis, the microseismic monitoring results, in-situ stress parameters, and gas productivity were synthetically evaluated. The results show that hydraulic fracturing curves can be divided into four types (descending type, stable type, wavy type, and ascending type) according to the fracturing pressure and fracture morphology, and the distributions of different type curves have direct relationship with geological structure. The vertical in-situ stress is greater than the closure stress in the Zhengzhuang block, but there is anomaly in the aggregation areas of the wavy and ascending fracturing curves, which is the main reason for the development of multi-directional propagated fractures. The fracture azimuth is consistent with the regional maximum principle in-situ stress direction (NE–NEE direction). Furthermore, the 265 fracturing curves indicate that the coalbed methane wells owned descending, and stable-type fracturing curves possibly have better fracturing effect considering the propagation pressure gradient (FP) and instantaneous shut-in pressure (PISI). Two fracturing-productivity patterns are summarized according to 61 continuous production wells with different fracturing type and their plane distribution, which indicates that the fracturing effect of different fracturing curve follows the pattern: descending type > stable type > wavy type > ascending type.

scholarly journals Analysis of hydraulic fracture behavior and well pattern optimization in anisotropic coal reservoirs

2020 ◽  
pp. 014459872096083
Author(s):  
Yulong Liu ◽  
Dazhen Tang ◽  
Hao Xu ◽  
Wei Hou ◽  
Xia Yan
Keyword(s):  
Hydraulic Fracture ◽  
Coalbed Methane ◽  
Fracture Network ◽  
Simulation Software ◽  
Natural Fracture ◽  
Hydraulic Fractures ◽  
Natural Fractures ◽  
Well Pattern ◽  
Well Pattern Optimization ◽  
The Impact

Macrolithotypes control the pore-fracture distribution heterogeneity in coal, which impacts stimulation via hydrofracturing and coalbed methane (CBM) production in the reservoir. Here, the hydraulic fracture was evaluated using the microseismic signal behavior for each macrolithotype with microfracture imaging technology, and the impact of the macrolithotype on hydraulic fracture initiation and propagation was investigated systematically. The result showed that the propagation types of hydraulic fractures are controlled by the macrolithotype. Due to the well-developed natural fracture network, the fracture in the bright coal is more likely to form the “complex fracture network”, and the “simple” case often happens in the dull coal. The hydraulic fracture differences are likely to impact the permeability pathways and the well productivity appears to vary when developing different coal macrolithtypes. Thus, considering the difference of hydraulic fracture and permeability, the CBM productivity characteristics controlled by coal petrology were simulated by numerical simulation software, and the rationality of well pattern optimization factors for each coal macrolithotype was demonstrated. The results showed the square well pattern is more suitable for dull coal and semi-dull coal with undeveloped natural fractures, while diamond and rectangular well pattern is more suitable for semi-bright coal and bright coal with more developed natural fractures and more complex fracturing fracture network; the optimum wells spacing of bright coal and semi-bright coal is 300 m and 250 m, while that of semi-dull coal and dull coal is just 200 m.

Sign in / Sign up

Export Citation Format

Share Document