Coal reservoirs have characteristically low permeability and low pressure and are highly sensitive to damage during well completion. Therefore, systematic reservoir protection measures must be taken in the process of coalbed methane exploitation. However, in some areas such as the Qinshui basin, there is a contradiction between the sidewall stability of horizontal coalbed methane (CBM) wells and the protection of coal seams, which becomes the main technical bottleneck for the efficient development of CBM. Therefore, a double-pipe double-cycle rock carrying technology based on using a clean water drilling fluid is proposed, which can be applied to multi-branch horizontal wells of CBM, improve well completion efficiency and quality, realize reservoir protection, and increase single-well production. Field tests of this technology have been completed in wells ZS1P-5H and QS12P1H with satisfactory results. For example, the QS12P1H well was drilled with one main branch, 15 branches, and 33 pulse branches. The total depth of the well is 13,270 m, and the pure coal depth is 10,288 m. A single well of 10 km footage was realized without accidents, and the daily gas output was up to 10,000 m³.

煤储层的特征在于低渗透性和低压，并且对完井过程中的破坏高度敏感。因此，在煤层气开采过程中必须采取系统的储层保护措施。但是，在沁水盆地等地区，水平煤层气井的井壁稳定性与煤层保护之间存在矛盾，成为有效开发煤层气的主要技术瓶颈。因此，提出了一种以净水钻井液为基础的双管双循环运石技术，可应用于煤层气多分支水平井，提高完井效率和质量，实现油藏保护，增加单井。井生产。ZS1P-5H和QS12P1H井已完成了该技术的现场测试，并取得了令人满意的结果。例如，QS12P1H井钻了一个主分支，15个分支和33个脉冲分支。该井的总深度为13,270 m，纯煤深度为10,288 m。实现了10公里英尺的单口井无事故，日产气量高达10,000 m³。