Back to results
US 4,057,108 AGranted
Completing wells in deep reservoirs containing fluids that are hot and corrosive
AssigneeShell Oil Company
InventorLeo P. Broussard
Life of this patent
Estimating the term…
Abstract
One string of corrosion resistant tubing and a casing string which has a corrosion resistant bottom section can be connected between a wellhead and a deep, hot reservoir so that a corrosive reservoir fluid can be produced while keeping it isolated from wellbore or wellhead tubulars of conventional low alloy steel thus preventing corrosion without maintaining a downhole injection of corrosion inhibitor.
Claims10
A well completing process which comprises:
- drilling a borehole into a relatively deep, hot, highly pressurized subterranean reservoir which contains fluid which, at the reservoir conditions, is corrosive to low alloy steel;
- installing in the borehole a casing string assembly in which the bottom portion has a corrosion resistant composition capable of resisting corrosion by the reservoir fluid at the reservoir conditions, with said bottom portion being at least about 20 feet long and being arranged to extend substantially into or through the reservoir interval;
- equipping the borehole with wellhead components inclusive of a tubing string hanger capable of suspending and sealing around a tubing string extending within the casing string;
- suspending a tubing string having a composition capable of resisting corrosion by the reservoir fluid at the reservoir conditions from the tubing hanger so that the tubing string extends into the corrosion resistant portion of the casing string;
- establishing at least one path of fluid communication between the reservoir and the interiors of the tubing and casing strings;
- circulating fluids within the tubing and casing strings to the extent required to establish a hydrostatic pressure within the bore-hole, at depth of the reservoir, which is less than the fluid pressure within the reservoir;
- producing fluid from the reservoir by allowing an outflow of fluid through the top of the tubing string while injecting fluid into the top of the casing string-tubing string annulus at a rate and pressure sufficient to confine substantially all of the reservoir fluid that enters the borehole within the tubing string and the corrosion resistant portion of the casing string;
- and
- as reservoir fluid flows up through the tubing string to a point beyond the tubing hanger, mixing substantially each portion reaching that location with a corrosion inhibitor effective for substantially preventing its corroding of a low alloy steel.
6 more elements
A well completing and operating process which comprises:
- drilling a borehole into a relatively deep, hot, highly pressurized subterranean reservoir which contains fluid which at reservoir conditions is corrosive to low alloy-steel;
- installing in the borehole a casing string assembly in which the bottom portion has a corrosion resistant composition capable of resisting corrosion by the reservoir fluid at reservoir conditions, with said bottom portion being at least about 20 feet long and being arranged to extend substantially into or through the reservoir interval;
- equipping the borehole with wellhead components inclusive of a tubing string hanger capable of suspending and sealing around a tubing string extending within the casing string;
- suspending a tubing string having a composition capable of resisting corrosion by the reservoir fluid at reservoir conditions from the tubing hanger so that the tubing string extends into the corrosion resistant portion of the casing string;
- establishing at least one path of fluid communication between the reservoir and the interiors of the tubing and casing strings;
- circulating fluids within the tubing and casing strings to the extent required to establish a hydrostatic pressure within the borehole at depth of the reservoir which is less than the fluid pressure within the reservoir;
- producing fluid from the reservoir by allowing an outflow of fluid through the top of the tubing string while injecting fluid into the top of the casing string-tubing string annulus at a rate and pressure sufficient to confine substantially all of the reservoir fluid that enters the borehole within the tubing string and the corrosion resistant portion of the casing string;
- as reservoir fluid flows up through the tubing string to a point beyond the tubing hanger, mixing substantially each portion reaching that location with a corrosion inhibitor effective for substantially preventing its corroding of a low alloy steel;
- and
- subsequently circulating fluids within the tubing and casing strings to the extent required to establish a hydrostatic pressure within the tubing and casing strings which is more than the fluid pressure within the reservoir.
7 more elements
Dependencies are inferred from the claim text.