Research And Application Of Rapid Monitoring Technology For Horizontal Well Guidance Of Coalbed Methane

The rapid geosteering monitoring technology for coalbed methane horizontal well is an important technology to ensure the effect of geosteering in the process of drilling coalbed methane horizontal wells.It is an important mean to improve the drilling rate and guide the drill bit drilling smoothly in the coal seam.The combination of Logging While Drilling(LWD)tools and interpretation software systems nowadays is widely used to realize rapid geosteering monitoring,but the expense of the method is high,which doesn't accord with the low cost exploration principle of domestic coalbed methane horizontal well.The downhole measurement method has blind spot.The rate of penetration is so fast when drills in the coal seam that it takes a very short time to drill through the blind spot.This period of time is far less than the time when the underground data transmits to the ground,so it is very likely that drill bit drills out of the coal seam before the software system responses.Therefore,a technical mean for rapid geosteering monitoring for coalbed methane horizontal well drilling based on the ground measurement data is proposed in this paper.the present stratum is judged by the lithology at the drill bit position indirectly recognized through the ground measurement,which meets the requirement of low cost and high speed at the same time for the coalbed methane horizontal well in rapid geosteering monitoring.The following results are obtained through the research:1.The rapid geosteering monitoring system which is suitable for coalbed methane horizontal well drilling and based on ground measurement data is designed and developed in this paper.The system based on the ground instruments and data acquisition technology realizes data collection and analysis real-time.Through the monitoring of ground data,the system can identify the present lithology and realize the rapid geosteering monitoring,which effectively improve the drilling rate;2.Through the research on the drilling technology and steering drilling technology of coalbed methane horizontal well,the advantages and disadvantages of the two kinds of guidance monitoring methods separately based on downhole measurement data and ground measurement data are compared and analyzed.Concluding that the steering monitoring based on the ground measurement data is more suitable for the coalbed methane horizontal wells.Determining how to realize the rapid geosteering monitoring of coalbed methane drilling through ground measurement method,so as to effectively meet the needs of low cost development for coalbed methane drilling;3.According to the analysis of the theory on mechanical specific energy and rock specific energy,the mechanical specific energy and rock specific energy model are established,and the mechanical specific energy and rock specific energy are obtained by using the ground measurement data,which layed the theory foundation for the multi-source fusion model;4.Based on the study of drilling engineering parameters,the parameters which can best reflect the performance of the formation are selected and used as the system monitoring parameters,including the following parameters:weight of bit(WOB),drill time,torque,rotary per minute(RPM),mechanical specific energy and rock specific energy.The gray correlative clustering algorithm is used to establish the multi-source information fusion recognition model.The model is simulated and analyzed using data collected at the wellsite and effectively examined the correctness of the model,which provide the theoretical basis for exploration of rapid geosteering monitoring system for the coalbed methane horizontal wells.5.On the basis of rapid geosteering monitoring technology and the gray relational recognition model,the technical design of the rapid monitoring system of the coalbed methane horizontal well is completed,and the matching of the hardware and equipment of the system is completed.Based on the data requirement analysis of the software system,the supporting database is established,which provided the data support for the rapid monitoring of coalbed methane horizontal well;6.Based on the established multi-source fusion model and matching database,the software architecture design of the rapid geosteering monitoring system of coalbed methane horizontal well and the development of the functional modules of the software system are completed.The field application are carried out at the two wells in the Qinshui Basin.The results shows that the system is stable in the field.According to the collected ground data,the lithology of the strata is quickly identified and the geosteering condition is monitored quickly.It meets the requirement of rapid monitoring and analysis of geosteering for the coalbed methane horizontal well drilling site.The rapid geosteering monitoring system of coalbed methane horizontal well designed and explored in this paper gives full play to its advantages in rapid monitoring based on the ground measurement data,which really reflects the rapidity and realizes the rapid monitoring on the basis of meeting the low-cost development of coalbed methane horizontal wells,the method has a high value of application.