Based on the productivity equation of coalbed methane (CBM) well, considering the impact of coal reservoir reformability on gas well productivity, the main production layer optimization index in the “three-step metho...Based on the productivity equation of coalbed methane (CBM) well, considering the impact of coal reservoir reformability on gas well productivity, the main production layer optimization index in the “three-step method” of optimal combination of production layers is corrected, and then the CBM production layer potential index is introduced to evaluate favorable areas for commingled multi-coal seam production. Through analysis of the key parameters of coal reservoirs affecting the CBM productivity index, a development unit division method for areas with multi-coal seams is established, and a quantitative grading index system is proposed. On this basis, the evaluation process of CBM development favorable area is developed: the mature 3-D modeling technology is used to characterize the reservoir physical properties of multi-coal seams in full-scale;the production layer potential index of each grid is calculated, and the production layer potential index contour under single-layer or commingled multi-layer production are plotted;according to the distribution of the contour of production layer potential index, the quantitative index of CBM development unit is adopted to outline the grade I, II, III coal reservoir distribution areas, and thus to pick out the favorable development areas. The practical application in the Yuwang block of Laochang in Yunnan proved that the favorable area evaluation process proposed can effectively overcome the defects of selecting favorable development areas only relying on evaluation results of a major coal seam pay, and enhance the accuracy of the evaluation results, meeting the requirements of selecting favorable areas for multi-coal seam commingled CBM production.展开更多
Ndé Division in West-Cameroon is facing with water supply although many attempts of restoring existing SCANWATER facilities by Bangangté Municipality. In order to address the issue, we assess the exploitable...Ndé Division in West-Cameroon is facing with water supply although many attempts of restoring existing SCANWATER facilities by Bangangté Municipality. In order to address the issue, we assess the exploitable pumping flow rate of catchment aquifers and its hydraulic properties by using Jacob and Theis method, and define protection zones with Hoffman and Lillich method. It emerges that the hydraulic conductivity of aquifer is in the order of 10<sup>-4</sup> m/sec, transmissivity varies from 10<sup>-4</sup> to 10<sup>-6</sup> m<sup>2</sup>/sec. Aquifer pumping flow rate (Q) varies between 1.5 and 10.5 m<sup>3</sup>/h. In volcanic rocks, aquifer is more productive (4.5 ≤ Q ≤ 10.5 m<sup>3</sup>/h). Transfer time of pollutants to aquifer varies from 3 to 56 days depending on rock-types and groundwater slope (0.03 - 0.13 m/m). Furthermore, 113,624 m and 1123 m are radius to be implemented for a better protection of groundwater against any form of pollutant.展开更多
基金Supported by the National Natural Science Foundation of China(No.41772155)the National Science and Technology Major Project of China(No.2016ZX05044-002)the Fundamental Research Funds for the Central Universities of China(No.2015XKZD07)
文摘Based on the productivity equation of coalbed methane (CBM) well, considering the impact of coal reservoir reformability on gas well productivity, the main production layer optimization index in the “three-step method” of optimal combination of production layers is corrected, and then the CBM production layer potential index is introduced to evaluate favorable areas for commingled multi-coal seam production. Through analysis of the key parameters of coal reservoirs affecting the CBM productivity index, a development unit division method for areas with multi-coal seams is established, and a quantitative grading index system is proposed. On this basis, the evaluation process of CBM development favorable area is developed: the mature 3-D modeling technology is used to characterize the reservoir physical properties of multi-coal seams in full-scale;the production layer potential index of each grid is calculated, and the production layer potential index contour under single-layer or commingled multi-layer production are plotted;according to the distribution of the contour of production layer potential index, the quantitative index of CBM development unit is adopted to outline the grade I, II, III coal reservoir distribution areas, and thus to pick out the favorable development areas. The practical application in the Yuwang block of Laochang in Yunnan proved that the favorable area evaluation process proposed can effectively overcome the defects of selecting favorable development areas only relying on evaluation results of a major coal seam pay, and enhance the accuracy of the evaluation results, meeting the requirements of selecting favorable areas for multi-coal seam commingled CBM production.
文摘Ndé Division in West-Cameroon is facing with water supply although many attempts of restoring existing SCANWATER facilities by Bangangté Municipality. In order to address the issue, we assess the exploitable pumping flow rate of catchment aquifers and its hydraulic properties by using Jacob and Theis method, and define protection zones with Hoffman and Lillich method. It emerges that the hydraulic conductivity of aquifer is in the order of 10<sup>-4</sup> m/sec, transmissivity varies from 10<sup>-4</sup> to 10<sup>-6</sup> m<sup>2</sup>/sec. Aquifer pumping flow rate (Q) varies between 1.5 and 10.5 m<sup>3</sup>/h. In volcanic rocks, aquifer is more productive (4.5 ≤ Q ≤ 10.5 m<sup>3</sup>/h). Transfer time of pollutants to aquifer varies from 3 to 56 days depending on rock-types and groundwater slope (0.03 - 0.13 m/m). Furthermore, 113,624 m and 1123 m are radius to be implemented for a better protection of groundwater against any form of pollutant.
