BACKGROUND

1. Technical Field

Embodiments relate generally to developing wells, and more particularly to drill pipes used in the oil and gas industry.

2. Description of Related Art

A well generally includes a wellbore (or “borehole”) that is drilled into the earth to provide access to a geologic formation below the earth's surface (or “subsurface formation”). The well may facilitate the extraction of natural resources, such as hydrocarbons and water, from the subsurface formation, facilitate the injection of substances into the subsurface formation, or facilitate the evaluation and monitoring of the subsurface formation. In the petroleum industry, hydrocarbon wells are often drilled to extract (or “produce”) hydrocarbons, such as oil and gas, from subsurface formations. The term “oil well” is often used to refer to a well designed to produce oil. Similarly the term “gas well” is often used to refer to a well designed to produce gas. In the case of an oil well, some natural gas is typically produced along with oil. A well producing both oil and natural gas is sometimes referred to as an “oil and gas well” or an “oil well.” The term “hydrocarbon well” is often used to describe wells that facilitate the production of hydrocarbons, including oil wells and oil and gas wells.

Creating a hydrocarbon well typically involves several stages, including a drilling stage, a completion stage and a production stage. The drilling stage normally involves drilling a wellbore into a subsurface formation that is expected to contain a concentration of hydrocarbons that can be produced. The portion of the subsurface formation expected to contain hydrocarbons is often referred to as a “hydrocarbon reservoir” or “reservoir.”

Extended reach drilling (ERD) refers to drilling directional wells in which the drilled horizontal reach (HR) attained at total depth (TD) exceeded the true vertical depth (TVD) by a factor greater than or equal to two. ERD is particularly challenging for directional drilling and requires specialized planning to execute well construction.

ERD includes deep wells with horizontal distance-to-depth, or H:V, ratios less than two. The drilling industry's ERD database classifies wells, with increasing degree of well construction complexity, into low-, medium-, extended- and very extended-reach wells. Construction complexity depends on many factors, including water depth (for offshore wells), rig capability, geologic constraints and overall TVD. For example, a vertical well with TVD greater than 7,620 m (25,000 ft) is considered an extended-reach well. Also, depending on the conditions, drilling a well in deep water or through salt may be classified as ERD even if the horizontal extent of the well is not more than twice its TVD.

SUMMARY

In ERD applications, composite drill pipes can provide advantages over other available ERD drill pipe solutions, such as aluminum drill pipes or tapered drill pipe solutions, because they are lighter in construction when compared to steel drill pipes. Composite drill pipes are typically 40-50% lighter than steel drill pipes, reduce stuck pipe issues, and increase the possible drilling reach. Dual channel drill pipes or ‘concentric’ drill pipes are also used for drilling in loss situations and ERD. Conventionally, dual channel drill pipes are manufactured using either aluminum or steel. Dual channel drill pipes have been used by either pumping air down one of the drill pipe channels and assisting the lift of mud or by using the drill string to circulate mud such that the annulus is effectively static, therefore removing equivalent circulating density (ECD) issues. ECD is the effective density exerted by a circulating fluid against the formation that takes into account the pressure drop in the annulus above the point being considered. ECD is an important parameter in avoiding kicks and losses, particularly in wells that have a narrow window between the fracture gradient and pore-pressure gradient.

Accordingly, one example embodiment is a composite drill pipe including an inner pipe having a first diameter, the inner pipe forming an inner flow channel, and an outer pipe having a second diameter greater than the first diameter. The inner pipe and the outer pipe share a common axis, and a plurality of outer flow channels are formed between the inner pipe and the outer pipe. The plurality of outer flow channels may be formed by a plurality of walls extending radially between an outer diameter of the inner pipe and an inner diameter of the outer pipe. The inner pipe, the outer pipe, or the plurality of walls may include a reinforcing fiber, which may be selected from the group consisting of glass, carbon, steel, and aramid fibers. The inner pipe, the outer pipe, or the plurality of walls may also include a matrix material, which may be selected from the group consisting of a polymer and ceramic. In one embodiment, the inner pipe, the outer pipe, and the plurality of walls are pultruded as one piece using a reinforcing fiber and a matrix material. In one embodiment, a multi-directional reinforcement is provided over an outer diameter of the outer pipe. The multi-direction reinforcement may include a reinforcing fiber, which may be selected from the group consisting of glass, carbon, steel, and aramid fibers. The composite drill pipe may also include a polymeric resin coating that at least partially or fully encapsulates the multi-directional reinforcement. In one embodiment, the inner pipe, the outer pipe, and the plurality of walls are formed using three-dimensional weaving. The composite drill pipe may also include one or more sensors embedded in the inner pipe, outer pipe, or the walls, the one or more sensors configured to collect data relating to one or more characteristics of a subsurface formation or ambient environment. It may further include a transceiver operatively coupled to the one or more sensors, the transceiver configured to send the data collected by the sensors, or receive data from above the surface.

Another example embodiment is a method of forming a composite drill pipe. The method includes pultruding a drill pipe including an inner pipe having a first diameter, an outer pipe having a second diameter greater than the first diameter, a plurality of flow channels formed between the inner pipe and the outer pipe, and providing a multi-directional reinforcement over an outer diameter of the outer pipe, wherein the multi-direction reinforcement includes a reinforcing fiber. The multi-directional reinforcement may be provided by winding a filament onto the outer diameter of the outer pipe in a plurality of directions. In one embodiment, the multi-directional reinforcement is braided, bi-axially braided, tri-axially braided, warp knitted, weft knitted, or tubular woven. The method may also include providing a polymeric resin coating that at least partially or fully encapsulates the multi-directional reinforcement.

Another example embodiment is a method for connecting a drill pipe to an end coupling. The method includes pultruding a drill pipe including an inner pipe having a first diameter, an outer pipe having a second diameter greater than the first diameter, a plurality of flow channels formed between the inner pipe and the outer pipe. The method further includes inserting the end coupling into one end of the drill pipe such that a plurality of protruding elements of the end coupling are inserted in the plurality of flow channels, thereby forming a coupling interface between the drill pipe and the end coupling. The method further includes providing a multi-directional reinforcement over an outer diameter of the outer pipe and at least a portion of the end coupling adjoining the drill pipe, thereby integrally connecting the drill pipe and the end coupling. The multi-directional reinforcement may be provided by winding a filament onto the outer diameter of the outer pipe in a plurality of directions. The method may further include providing a polymeric resin coating that at least partially or fully encapsulates the multi-directional reinforcement.

