Screened well drainage pipe structure with sealed, variable length labyrinth inlet flow control apparatus

Production fluid drainage apparatus for a subterranean well, comprising:

• a base pipe having a sidewall inlet opening therein;
• a tubular structure coaxially circumscribing the base pipe and forming therewith an annular fluid flow passage communicating with the interior of the base pipe through the sidewall inlet opening, the tubular structure having a fluid filtering section axially offset from the sidewall inlet opening and through which well fluid may flow into the annular fluid flow passage;
• and
• an adjustable fluid flow control structure operative to selectively vary well fluid inflow through the fluid filtering section into the base pipe and including (1) an annular flow control member coaxially circumscribing the base pipe and interposed in the fluid flow passage between the sidewall inlet opening and the fluid filtering section, the flow control member having an inner side surface and further having a selectively variable length flow passage for permitting well fluid to axially traverse the flow control member, and (2) an adhesive type resilient sealant material interposed and forming an annular resilient seal between the flow control member and the base pipe.

Production fluid drainage apparatus for a subterranean well, comprising:

• a base pipe having a sidewall inlet opening therein;
• a tubular structure coaxially circumscribing the base pipe and forming therewith an annular fluid flow passage communicating with the interior of the base pipe through the sidewall inlet opening, the tubular structure having a fluid filtering section axially offset from the sidewall inlet opening and through which well fluid may flow into the annular fluid flow passage;
• and
• an adjustable fluid flow control structure operative to selectively vary well fluid inflow through the fluid filtering section into the base pipe and including:
• an annular flow control member coaxially circumscribing the base pipe and interposed in the fluid flow passage between the sidewall inlet opening and the fluid filtering section, the flow control member having an outer side surface into which a labyrinth flow passage, through which pressurized well fluid may axially traverse the flow control member, is recessed, the labyrinth flow passage having a plurality of outlet portions spaced apart along its length which may be selectively blocked to correspondingly vary the fluid flow length of the labyrinth flow passage,
• a spaced series of plug openings extending through the tubular structure in overlying alignment with the labyrinth flow passage outlet portions, and
• a series of first plug structures operative to sealingly block selected ones of the labyrinth flow passage outlet portions, each first plug structure having (1) a resilient portion with a first section positionable in one of the labyrinth flow passage outlet portion, and a second section positionable in the overlying plug opening, and (2) a rigid portion securable in the overlying plug opening in forcible engagement with the second resilient section in a manner deforming the resilient portion into a sealingly blocking relationship with its associated plug opening and labyrinth flow passage outlet portion.

Production fluid drainage apparatus for a subterranean well, comprising:

• a base pipe having a sidewall inlet opening therein;
• a tubular structure coaxially circumscribing the base pipe and forming therewith an annular fluid flow passage communicating with the interior of the base pipe through the sidewall inlet opening, the tubular structure having a fluid filtering section axially offset from the sidewall inlet opening and through which well fluid may flow into the annular fluid flow passage, and an axially outer end portion forming between itself and the base pipe an annular gap disposed axially outwardly of the base pipe sidewall inlet opening and through which the annular fluid flow passage outwardly opens;
• an adjustable fluid flow control structure operative to selectively vary well fluid inflow through the fluid filtering section into the base pipe and including a flow control member coaxially interposed in the fluid flow passage between the sidewall inlet opening and the fluid filtering section;
• and
• seal apparatus disposed axially outwardly of the base pipe sidewall opening and being operative to essentially prevent pressurized well fluid from entering the annular fluid flow passage through the annular gap, the seal apparatus including:
• an annular interior side surface recess disposed axially inwardly of the annular gap and defining a radial enlargement thereof, and
• a quantity of an adhesive type resilient sealant material filling the interior side surface recess and extending therefrom into the annular gap.

A method of constructing a drainage pipe section for a subterranean well, the method comprising the steps of:

• providing a base pipe having a sidewall fluid inlet opening therein;
• coaxially positioning a tubular structure around the base pipe to form therebetween an annular passage that communicates with the interior of the base pipe through its sidewall fluid inlet opening;
• coaxially positioning an annular flow control member in the annular passage in an axially offset relationship with the sidewall fluid inlet opening, the positioned tubular structure and flow control member being relatively configured in a manner creating an annular gap therebetween;
• forming a circumferentially spaced series of radially extending holes inwardly through the tubular structure and the flow control member into the annular gap;
• and
• injecting an adhesive type resilient sealant material inwardly through the holes into the annular gap in a manner forming therein a continuous annular resilient seal structure radially extending between facing surface portions of the base pipe and flow control member.

A method of constructing a drainage pipe section for a subterranean well, the method comprising the steps of:

• providing a base pipe having a sidewall fluid inlet opening therein;
• coaxially positioning a tubular structure around the base pipe to form therebetween an annular passage that communicates with the interior of the base pipe through its sidewall fluid inlet opening, the positioned tubular structure having an axially outer end portion disposed axially outwardly of the sidewall fluid inlet opening and forming an annular gap between itself a facing portion of the base pipe;
• coaxially positioning an annular flow control member in the annular passage in an axially inwardly offset relationship with the sidewall fluid inlet opening;
• and
• forming an essentially fluid tight seal between the axially outer end portion of the tubular structure and the facing portion of the base pipe by (1) forming in the axially outer end portion of the tubular structure an annular interior side surface recess which is positioned axially inwardly of and defines a radial enlargement of the annular gap, (2) forming an injection opening in the tubular structure that extends into the annular interior side surface recess, and (3) forcing an adhesive type sealant material inwardly through the injection opening in a manner causing the sealant material to fill the annular interior side surface recess and flow into and fill at least a portion of the annular gap.