Patent EA-002563-B1 (EA)
Title: Method for drilling and completing a hydrocarbon production well
Inventor: LOHBECK WILHELMUS CHRISTIANUS
IPC: E21B43/10
Filed: 1998-12-28
Abstract: 1. A method for drilling and completing a hydrocarbon production well (1), the method comprising the steps of: A) drilling a section (1A) of a borehole into an underground formation (3,21,41); inserting a casing (8,24,44) into the drilled borehole section (1A) and radially expanding and securing the casing (8,24,44) within said borehole section (1A); B) lowering a drill bit through the expanded casing (8,24,44) and drilling a subsequent section (1B) of the borehole, inserting a next casing (9,25) into said subsequent section of the borehole and radially expanding and securing said next casing (9,25) within said subsequent borehole section; and C) repeating, if required, step B a number of times until the borehole has reached the vicinity of a hydrocarbon bearing formation (7), wherein at step B any subsequent casing (9,10,11) is inserted coaxially relative to the previous casing forming an overlapping zone thus providing an additional expansion of the previous casing in the process of radial expansion of a subsequent casing. 2. Th method of claim 1, wherein only the first casing (8) extends from the earth surface (2) into the borehole (1) and any subsequent casing (9,10,11) only partly overlaps a previously set casing (8,9,10). 3. The method of claim 2, wherein the length along which subsequent casing sections (8,9,10,11) overlap each other is less than 10% of the length of each casing (8,9,10,11) itself. 4. The method of claim 3, wherein along at least a substantial part of the length of the borehole from the earth surface to the vicinity of the hydrocarbon bearing formation the variation in diameter of the borehole (1) is less than 10%. 5. The method of claim 1, wherein at least two casings (24,25) that are subsequently inserted into the borehole each extend to the wellhead. 6. The method of claim 1, wherein after installing said casings (8,9,24,25,44) a production tubing is inserted into the borehole such that the production tubing (26) extends from the earth surface to the vicinity of the hydrocarbon formation; and radially expanding the tubing (25) inside the string of expanded casings (8,9,24,25,44). 7. The method of claim 1 or 6, wherein the casings (8,9,24,25,44) and optionally the tubing (26) are plastically expanded in radial direction by moving an expansion mandrel (16,45) therethrough in a longitudinal direction and are made of a formable steel grade which is subject to strain hardening without incurring any necking and ductile fracturing as a result of the expansion process and wherein an expansion mandrel (16,45) is used which has along part of its length a tapering non-metallic surface (46). 8. The method of claim 7, wherein the expansion mandrel (16,45) having a tapering non-metallic surface (46), the tubing (26) and casings (8,9,24,25,44) are made of a formable steel grade having a yield strength-tensile strength ratio which is lower than 0.8 and a yield strength of at least 275 MPa. 9. The method of claim 6, wherein the production tubing (26) and at least one of the casings (8,9,24,25,44) consists of a tubular which is inserted into the borehole by reeling the tubular from a reeling drum. 10. The method of claim 8, wherein the expansion mandrel (16,45) has a tapering ceramic surface (46) which defines a semi-top angle A which is between 15 degree  and 45 degree . 11. The method of claim 10, wherein said angle A is between 15 to 30 degree . 12. The method of claim 1, wherein at least the lowermost casing (11, 25, 26) is equipped with slots or apertures.