Study on gas drilling technology and supporting technology forL-type horizontal well in Panhe Block

L-type horizontal wells have great technical advantages in the development of low-permeability coalbed methane fields.However, due to the shallow coalbed methane reservoir in the Panhe demonstration area of Qinnan basin (between 500 m and 650 m), L-type horizontal wells have the characteristics of large well inclination angle, large change rate of overall angle, long inclined shaft section with large horizontal displacement, serious pulverous coal production, high wellbore gas-liquid ratio and slight hydrogen sulfide content, which bring great difficulties to the later production and drainage.In order to give full play to the technical advantages of integrated drilling, completion and production increase of L-type horizontal wells, the countermeasure of screw pump technology with strong pulverized coal carrying capacity as the main body, supporting anti-friction, centralizing, anti-eccentric wear, underground gas-liquid separation, surface water injection and automatic control technology was put forward.Through field tests of 22 wells, effectively reduce eccentric wear, stuck pump and gas effect, eliminate the influence H2S safety, normal operation rate was 92.4%.The problem of effective drainage and production in large slant and large displacement wells is solved.Therefore, it is suggested that strong coal powder carrying capacity is a necessary condition for selecting pumps in the drainage and production process design of coalbed methane L-type horizontal wells, and the supporting technologies should be constantly improved to achieve more stable operation of the process.The study result lays a foundation for the large-scale application of L-type horizontal well technology in Qinnan coalbed methane field, and provides reference experience for the development of other coalbed methane blocks.