Detailed Drilling in Bohai Breaks Several Records in the Shale Gas Market

Detailed Drilling in Bohai Breaks Several Records in the Shale Gas Market

On October 25, there was good news from the Sichuan shale gas market: The highly difficult evaluation well, Lu216, drilled by the 70155 drilling team of Bohai Drilling Company No. 4, was successfully completed with a completion depth of 6,780 meters, a maximum vertical depth of 4,606.28 meters, and a bottom hole temperature of 168 degrees Celsius, setting a new record of the deepest vertical depth and the highest bottom hole temperature in Sichuan shale gas Luzhou block. Set a number of records for the company's shale gas construction well, the deepest casing run, and the longest one-time cementing section.

Lu216 well is a key appraisal well deployed in Luzhou block of Southwest Oil and Gas Field. The drilling purpose is to evaluate the shale gas reservoir of Longmaxi Formation in Lu201-Lu202 well area. The design depth of this well is 6758 meters, the stability of the drilled formation is poor, the formation dip Angle of the target well section is obvious, the fault is obvious, the reservoir box is thin, the hole trajectory is adjusted frequently, and the construction is difficult. In view of the construction problems, the 70155 drilling team carefully analyzed the electrical measurement data of adjacent Wells and the drilling data, carefully analyzed the lithology, formation pressure and drillability characteristics of the drilling formation, and carefully formulated the construction plan and technical instructions.

During the construction, the drilling team cooperated closely with the construction side, relied on the advantages of integrated cooperation of engineering geology, precisely determined the collapse pressure and leakage pressure window, strictly implemented the key points of horizontal section anti-stuck technology, adopted large displacement, high speed and other means to solve the problem of cuttings bed under complex geological conditions in real time, and the maximum pumping pressure of drilling construction reached 43 mpa, effectively preventing the occurrence of complex underground situations. Adhere to the 24-hour cadre system, strengthen the implementation of technical measures and process control at key nodes, and pay close attention to changes in pump pressure, torque and tension to ensure safe and smooth well completion.

At the same time, the company firmly established the awareness of "well control first response". In view of the characteristics of high formation pressure, significant drilling fluid ratio, slow mechanical drilling rate and high risk of leakage and spill in Longmaxi formation of Lu216 well, the company adopted fine pressure control operation mode to reasonably reduce drilling fluid density and effectively improve the drilling rate. Strengthen well control management, strictly implement the "three 100%" measures of well control, strengthen close cooperation with relevant parties, closely monitor downhole anomalies, and carry out blowout prevention drills under various working conditions in a timely manner. In the process of horizontal drilling, suspected overflow danger has been discovered and correctly handled many times to ensure safe construction.