Research On Casing Punching And Drill Pipe Feeding In Radial Horizontal Well

The Radial horizontal well technology has experienced two stages of large size and non-reaming whipstock. The former needs large reaming on stratum and the usage becomes very low. The latter has a wide application range, but it’s also exists some difficult technical problems, such as the second drilling and directional difficult. Therefore, the research of ultra-short radius radial horizontal well technology which could complete the casing window and drill pipe feeding a one-time under the condition of not reaming has become a new development prospect.For non-reaming condition, the process principle which can achieve casing window with punching and drill pipe turning and feeding by using hydraulic thrust in the 51/2’’ casing is designed. After that, the article combines with the actual requirements to develop a set of whipstock prototype whose overall diameter is Φ 112 mm and length is 2.43 m. The prototype consists of punching institutions, locking mechanism, drill pipe turning and feeding institutions and so on. According to the theoretical calculation, numerical simulation and laboratory experiments show that under the effect of 40 MPa pump, the whipstock prototype can produce about 275 KN axial force. Then the axial force can convert into about 922 KN radial force in the punching institutions by the wheel’s amplification effect, and the radial force can make the punch to impact wear casing whose wall thickness is 8mm sufficiently. After that the whipstock prototype is locking, it will generate Φ16mm slide-way inside automatically. And the Φ12mm drill pipe can achieve to turn and sent in the horizontal direction with the tail piston which has been affected by 42~45MPa pump pressure.Using the finite element analysis and casing punching experiments to optimize the structure of the punch, then choosing the double conical surface and fishtail shape punch whose blade angle is 80° and auxiliary angle is 120° can meet the requirements of casing window. Choosing the "S" shape hyperbolic linear guide rail as the slide-way trajectory, and designing that the steering radius R is 90 mm, the deviator d is 2mm, and realize the pipe straightening in punch’s drill way which length is 68 mm. Using 16 Mn seamless steel pipe whose size is Φ12mm×1mm as the drill pipe. Through the feeding trial experiments, the maximum feeding distance reaches 3.1m in the laboratory and the drill pipe’s bending is minimized when the punch’s dip angle is 10°. And the drill pipe overall deformation remained below 11% after feeding.The online experiments show that it is feasible to complete the casing window and drill pipe feeding a one-time in the 51/2’’ casing with Φ12mm drill pipe.