Abstract:
Currently,there are some problems in the China CBM industry,such as “low success rate of well con-struction”,“less than half production qualified to designed capacity”,and “little percentage of reserve discovery to total gas-in-place”.Due to these poor performances,the growth of annual CBM production in China has come to a standstill for years.Analysis of what contributes to this situation shows three attributions,i.e.“lack of theoretical guidance on stress-gas development”,“inappropriate industrial requirements leading to ineffective E&P activities”,and “poorly-performed incentive regulations neglecting the growth of service capability and innovations”.Based on the characteristics of China CBM resources,a “4-element geology model” comprised of “coal-water-rock-gas”,is built according to the “3-fields”(pressure+stress+temperature) which play the most important role for CBM reserverization in geology process.By identifying the major routes of such dynamic processes,an engineering model of “dual-cycle” of pressure and stress release is established to put the four types of CBM reserves in the four quadrants of a pressure-stress coordinate system.Matches of engineering design with the most suitable technologies are advised interpreting how gas is deconstructed from the “soluids (solid+fluid)” complexity of 4-elements,according to which axis of the coordinate system dominating the reservoir occurrence.In regards to the non-technical aspects of E&P onsite organizations,it is pointed out that seeking an unduly low-cost of well construction instead of pursuing best well-performances in terms of cost-output is one of the most destructive habits adversely affecting the industry.The regulation issued by the government,requiring strict stage by stage authorization from exploration to development,takes the second responsibility to both poor reserve registry quality and bad well deliverability.An approach of “progressive exploration and development” is strongly recommended.Finally,an all calibre retrospection is to check what the governmental incentives issued in the past 30 years work best to boost the industry.It is found that there are two major issues heavily restricting the extension of the industry chain.The one is the low frequency of mining right trading deteriorated by poor data shares,the other is incentives never apply to the service portion of the industry chain,which leads to almost no technical invention to meet some case-specific reservoir development requirements.A strategy of restructuring incentive package and encouraging mining right trading are accordingly suggested.