Research And Design Of Real - Time Monitoring And Diagnosis System For Coalbed Methane Horizontal Well Shaft Wall Collapse

Coalbed methane (CBM) horizontal drilling technology is one of the primary means for enhancing single well production of coalbed methane. Compared with conventional hydrocarbon reservoirs, coal seams because of its special geological structure is likely to lead to hole collapse that in severe cases can even result in sticking, drilling tools sloughing and other derivative accidents during the drilling operations, which increases the difficulty in exploration and development of coalbed methane. Therefore, hole collapse is the key issue to be addressed for CBM horizontal drilling. Currently, the most common monitoring measure on hole collapse is mainly achieved by comprehensively analyzing the logging data collected by underground measurement instruments timely. However, since CBM development belongs to low-cost development and hole collapse in CBM wells is inevitable, the use of underground instruments has certain limitations.As a result, this paper proposes a set of CBM horizontal well hole collapse real-time monitoring techniques based on ground survey data, and has obtained the following results:1.The hole collapse real-time monitoring and diagnosis system which is suitable for CBM horizontal drilling is developed in this paper. The system based on ground instruments and auxiliary data acquisition system realizes collection, transmission and integration of real-time data, and completes real-time monitoring and diagnosis on hole collapse during the drilling process. It effectively improves the success rate of CBM horizontal drilling, reduces the occurrence of derivative accidents caused by hole collapse, and has field application ability;.2.Through the research on the occurrence mechanism of hole collapse, the characterized phenomenon and law of hole collapse are summarized; on the basis of the study on real-time monitoring and diagnosis methods of hole collapse in CBM horizontal wells, the monitoring parameters of hole collapse are determined, and the evaluation and analysis of the monitoring parameters is completed;3.According to the selected monitoring parameters, a hole collapse monitoring and diagnosis scheme which is suitable for CBM horizontal drilling is put forward:and combined with support vector regression algorithm, the hole collapse real-time monitoring and diagnosis model is established, so as to improve the veracity and reliability of monitoring and diagnosis system;4.Based on WITS data collection and transmission protocol, the ancillary data acquisition system is designed and developed, provides data support to the hole collapse real-time monitoring and diagnosis system;5.On the basis of the established hole collapse diagnosis model, the overall architecture and software system of the hole collapse real-time monitoring and diagnosis system are designed and developed, and the test results of instance data of XX block X well show that the monitoring and diagnosis results on the hole collapse interval are in good agreement with actual situation. As a result, the system can meet the requirements of field application, and has a good application prospect.The CBM horizontal well hole collapse real-time monitoring and diagnosis system designed and developed in this paper is of high practical value that takes full advantage of existing ancillary equipment, meets the low-cost requirements of coalbed methane development in China while achieves good real-time monitoring and diagnosis on hole collapse.