A Modern Approach to Analyzing the Flowing Pressures of a Two-Phase CBM and Water Column in Producing Wellbores

Table 2

Predicted variables of flowing pressure and error in the approaches due to the relationships developed in two-phase CBM wellbores.

Well point	Average Pressure and Temperature method		Cullender & Smith methodology		The proposed methodology
	Predicted (MPa)	Error (%)	Predicted (MPa)	Error (%)	CBM column pressure (MPa)	CBM and water column pressure (10^4 Pa)	Predicted (MPa)	Error (%)
1	1.4759	−11.14	1.4657	−10.34	0.0052	0.9216	1.3778	−3.75
2	1.5397	−3.90	1.5472	−4.40	0.0284	0.3928	1.5272	−3.05
3	1.6122	−2.11	1.6021	−1.46	0.0643	0.2220	1.5993	−1.29
4	1.7433	−2.13	1.7369	−1.75	0.0639	0.2028	1.7247	−1.03
5	1.3052	4.24	1.2973	4.82	0.0321	0.1926	1.3487	1.05
6	1.8865	1.13	1.8726	1.86	0.0547	0.1061	1.9028	0.27
7	1.9321	−0.69	1.9107	0.43	0.0575	0.07770	1.9202	−0.07
8	2.1137	1.28	2.1178	1.08	0.0641	0.06662	2.1327	0.39
9	2.0462	−1.48	2.0379	−1.08	0.0616	0.04686	2.0175	−0.06
10	2.2793	−1.21	2.2838	−1.41	0.0697	0.03461	2.2613	−0.42