BACKGROUND

Long horizontal wells are commonly drilled in the oil and gas industry to ensure maximum contact with a hydrocarbon bearing reservoir. Some of these wells are fitted with artificial lift systems to facilitate fluid production. However, long horizontal wells are susceptible to slugging flows, which in turn is detrimental to performance of the artificial lift system and subsequently affects the economic bottom line for the operator. Effective control of these slugging flows is therefore essential and beneficial for efficient production operations.

One of the current commercial systems used to control slugging flows downhole, separate fluids and solids downhole, and produce fluids to the surface is the Horizontal Enhanced Artificial Lift (HEAL) system, which is described, for example, in U.S. Patent Application No. 2018/0100384 (Saponja et al.). In the HEAL system, solids, liquid, and gas flow from a horizontal section of the well into a sized regulating tubing, which conditions the flow to ensure there is no slugging flow. At the end of the regulating tubing, a vortex separator separates the solids, liquid, and gas. The gas flows up an annulus between a pump and a casing to the surface, whereas the liquid and solids flow downwards by gravity. The liquid reverses direction around a corner and flows upwards towards the pump, while the solids continue their downward flow, where they accumulate at the HEAL seal within a solids sump.

The solids sump of the HEAL system is part of the casing in the well. Over time, solids accumulate in the sump, and the level of the solids rises to the turning corner where the liquid is separated from the solids. When this occurs, liquid supply is cut off from the pump. In other words, the pump can run dry or is starved of liquids. In addition, solids can be sucked into the inlet of the pump. Either or a combination of these events will result in a premature failure of the artificial lift system. In a more advanced case, even if the pump is shut in to prevent liquid starvation and solids ingestion, solids can also accumulate up to the discharge of the vortex separator. When this occurs, gas production stops, and the entire system is no longer operative.

SUMMARY

In one aspect of the disclosure, a system for handling solids downhole includes a receptacle disposed in a wellbore. The receptacle has a top end, a closed bottom end, and a chamber between the top end and the closed bottom end. The receptacle is positioned to form a first annulus between the receptacle and the wellbore. The system includes a first tubing disposed in the wellbore and positioned to form a second annulus between the first tubing and the receptacle. The second annulus is fluidly connected to the chamber. The system includes a second tubing disposed in the wellbore and positioned to form a third annulus between the second tubing and the wellbore. The third annulus is fluidly connected to the first annulus, and the second tubing is fluidly connected to the first tubing. The system includes a first separation region formed at an end of the first annulus to separate a fluid stream carrying solids into a first separated stream that is reversed in direction into the second annulus and a second separated stream that continues to move in an uphole direction into the third annulus. The system includes a second separation region formed at an end of the first tubing to separate the first separated stream into a third separated stream that is reversed in direction into the first tubing and a fourth separated stream that continues to move in a downhole direction into the chamber.

The first separated stream may include a liquid component of the fluid stream and the solids, and the second separated stream may include a gas component of the fluid stream. The first tubing may extend into the chamber. The first separation region may be located proximate the top end of the receptacle. The second separation region may be located proximate a bottom end of the first tubing inside the chamber. The receptacle may be physically coupled to the first tubing, which may be physically coupled to the second tubing. The second tubing may be a production tubing. The system may include an artificial lift system disposed along the second tubing and operable to lift the third separated stream received in the first tubing up the second tubing.

The receptacle may include at least one port that is fluidly connected to the second annulus. The system may include an inlet check valve positioned in the at least one inlet port to control flow into the second annulus. The inlet check valve may be responsive to a pressure of the fluid stream. The receptacle may include at least one outlet port that is fluidly connected to the chamber. The system may include an outlet check valve positioned to control flow out of the at least one outlet port. The outlet check valve may be responsive to a fluid pressure inside the chamber. The system may include an artificial system disposed along the second tubing. The artificial lift system may be operable in a first mode to lift the third separated stream received in the first tubing up the second tubing and in a second mode to increase the fluid pressure within the chamber to at least a threshold pressure at which the outlet check valve opens.

In another aspect of the disclosure, an apparatus for handling solids includes a receptacle having a top end, a closed bottom end, and a chamber. The top end has at least one inlet port and a central bore. A first tubing is inserted into the chamber through the central bore. A second tubing is physically and fluidly connected to the first tubing. An artificial lift system is disposed along the second tubing.

The receptacle may include at least one outlet port that is fluidly connected to the chamber. The apparatus may include an inlet check valve positioned to control flow through the at least one inlet port and an outlet check valve positioned to control flow through the at least one outlet port. The artificial lift system may be operable to pump fluid in a first direction in one mode and in a second direction that is opposed to the first direction in a second mode.

In yet another aspect of the disclosure, a method for handling solids downhole includes disposing a tubing in a wellbore. The method includes disposing a receptacle in the wellbore and proximate a bottom end of the tubing. The method includes receiving a reservoir fluid stream carrying solids in a first annulus formed between the receptacle and the wellbore from a producing zone of the wellbore. The method includes separating the reservoir fluid stream into a first separated stream and a second separated stream at a first separation region formed at an end of the first annulus. The first separated stream is reversed in direction into a second annulus formed between the tubing and receptacle. The second separated stream is directed in an uphole direction into a third annulus formed between the tubing and the wellbore. The first separated stream is separated into a third separated stream and a fourth separated stream at a second separation region formed at an end of the second annulus. The third separated stream is reversed in direction into the tubing. The fourth separated stream is directed in a downhole direction into a chamber of the receptacle.

The method may include lifting the third separated stream received in the tubing to a surface location. The method may include retrieving the tubing and receptacle to a surface location and emptying the chamber. The method may include conditioning the reservoir fluid stream to prevent slugging prior to separating the reservoir fluid stream.

The act of reversing the first separated stream in direction into the second annulus formed between the tubing and the receptacle may include directing the first separated stream into the second annulus through at least one inlet check valve positioned at an inlet of the second annulus. The method may include flushing out the chamber through one or more outlet ports formed in the receptacle by increasing a fluid pressure within the chamber to open at least one check valve positioned to control flow out of the one or more outlet ports. The act of increasing the fluid pressure within the chamber may include operating an artificial lift system disposed along the tubing to pump fluid into the chamber.

The act of separating the reservoir fluid stream into the first separated stream and the second separated stream at the first separation region may include separating out a liquid component of the reservoir fluid stream and the solids as the first separated stream and separating out a gas component of the reservoir fluid stream as the second separated stream. The act of separating the first separated stream into the third separated stream and the fourth separated stream at the second separation region may include separating out the liquid component carried by the first separated stream as the third separated stream and separating out the solids carried by the first separated stream as the fourth separated stream.

The foregoing general description and the following detailed description are exemplary of the invention and are intended to provide an overview or framework for understanding the nature of the invention as it is claimed. The accompanying drawings are included to provide further understanding of the invention and are incorporated in and constitute a part of the specification. The drawings illustrate various embodiments of the invention and together with the description serve to explain the principles and operation of the invention.

