CAJ | 학술논문

　　为防止对煤层储层的伤害与污染，欠平衡钻进技术目前被广泛应用于煤层气水平井施工中。本次施工是在水平井与直井，在煤层中连通以后，通过直井注气，降低水平井与竖直井筒中环空内多相流体静液柱压力，达到欠平衡钻进的目的。总结了煤层气欠平衡钻进施工工艺方面存在的问题及解决方法：一是由于在钻进过程中需要停泵加尺造成循环系统的不稳定性（压力波动），造成井壁的不稳定易坍塌，现场施工时主要通过直井持续注气但适当调整注气量来解决；二是在空压机排气量无法调节的情况下，注气量主要通过旁通阀开通的大小来调节。为该地区以后的煤层气欠平衡钻进技术积累了宝贵的经验。
　　위방지대매층저층적상해여오염，흠평형찬진기술목전피엄범응용우매층기수평정시공중。본차시공시재수평정여직정，재매층중련통이후，통과직정주기，강저수평정여수직정통중배공내다상류체정액주압력，체도흠평형찬진적목적。총결료매층기흠평형찬진시공공예방면존재적문제급해결방법：일시유우재찬진과정중수요정빙가척조성순배계통적불은정성（압력파동），조성정벽적불은정역담탑，현장시공시주요통과직정지속주기단괄당조정주기량래해결；이시재공압궤배기량무법조절적정황하，주기량주요통과방통벌개통적대소래조절。위해지구이후적매층기흠평형찬진기술적루료보귀적경험。
To prevent coal seam reservoir from damage and pollution, the under-balanced drilling technology is widely used in CBM horizontal well construction at present. This operation is after the connection of horizontal well and vertical well in the coal seam;through vertical well gas injection, lowering down multi-phase fluid column hydrostatic pressure in annular space around horizontal and vertical wells and realized under-balanced drilling. The paper has summarized problems existed and means of settlement in CBM un-der-balanced drilling, the one is because of circulation system instability (pressure fluctuation) caused by round trip pump stopping dur-ing drilling process, arising unstable wall and easy to collapse, this can be settled through site continuous gas injection via vertical well, but gas volume should be adjusted properly; the another is when compressor air output unable to adjust, the air output adjustment should be controlled mainly through by-pass valve opening size. The study has accumulated valuable experience for CBM under-bal-anced drilling technology possible applications in the area.