METHOD FOR CONSTRUCTION OF MULTIPLE-HOLE WELL Russian patent published in 2000 - IPC

FIELD: well construction technology. SUBSTANCE: method can be used in oil production industry. According to method, initially drilled is main bore-hole for example vertical bore-hole. Casing string is lowered into main bore-hole and is cemented there. Secured at place of expected branch line is setting spacer bush. Magnesium wedge is inserted into spacer bush. Side window is cut out in casing string. Side bore-hole is drilled through side window. Tail component is introduced into side bore-hole on string of pump-compressor pipes . Bottom part of tail component is made of metal pipe with perforated shoe-piece on its end. Installed inside metal pipe through its end is non-return valve. Also provided there is partition with through-passage and sealing unit. End of pump-compressor pipe string is introduced there at lowering of tail component. Upper part of tail component is made of easily drilled material. Installed in end part of tail component is bush with side washing windows and sealing unit for string of pump-compressor pipes. After lowering of tail component into side bore-hole, calculated amount of cement slurry is delivered through string of pump-compressor pipes. Then, string of pump-compressor pipes is raised so that its end goes out of through-passage in partition. After that, drilling fluid is delivered into string of pump-compressor pipes, and remainings of cement slurry are removed from string of pump-compressor pipes and from casing string above level of washing windows. String of pump-compressor pipes is raised. Cement plug is drilled out in main bore-hole down to magnesium wedge which is solved out by acid. Installed into spacer push is bush with wedge-like plane oriented in direction of cemented side bore-hole. Application of method improves quality of cementation of tail components in side bore-holes and in zone of joining tail components with casing string of main bore-hole of well. Also prevented are complications and emergency situations in process of construction. In addition, operation of multiple-hole well is made more convenient. EFFECT: higher efficiency. 1 dwg