US 5,487,431 A · Subterranean fluid sampling systems and methods

Abstract

A subterranean sampling system of the direct push type that employes an elongated push tube in combination with hydraulic means to force the push tube down through subterranean strata includes an improved sampler unit which basically includes a sample retaining cylinder surrounding an elongated slotted tube with a pierce member at the distal end and, at the proximal end, a tube guide member plus an adapter unit by which the sampler unit is connected to the lower end of the push tube. The system enables a new fluid sampling method in which the sampler unit is manipulated by the push tube into three modes. In the first mode, the slotted tube is within the cylinder so none of its slots extend proximally of the cylinder and no ambient fluid can enter. In the second mode, the slotted tube is moved out of the cylinder so only some of its slots extend proximally of the cylinder whereby ambient fluid may enter the cylinder. In the third mode, all of slots of the slotted tube extend proximally of cylinder and no ambient fluid may again enter the cylinder. Ultimately, the sampler unit is withdrawn from the strata without again permitting any of the tube slots to extend distally of the cylinder and a valid fluid sample is recovered. The system may also be used to pump out large samples of strata water or gas and the sampler unit may be used in a reverse mode to collect samples on the top of rock layers that prevent penetration by the push tube.

Claims2

Dependent claims

In a subterranean sampling system of the direct push type comprising an elongated push tube having a tool connector lower end and hydraulic means to force said push tube downwardly through subterranean strata, an improved sampler unit connected to said lower end which comprises:

a cylinder defining a fluid sample retention space, said cylinder comprising a first end portion and a second end portion,
a pierce member defined by a pointed distal end portion and a proximal end portion in fluid tight connection with said first end portion of said cylinder,
guide means comprising a first end inlet terminus through which a central bore extends, a second end fluid tight connection with said cylinder second end portion and a longitudinal conduit extending from said central bore to said second end fluid tight connection,
an elongated tube defined by an external wall, an internal wall, a closed end part, an open end part and a longitudinal body part joining said closed end part to said open end part, said body part having a plurality of spaced apart slots extending radially through said external and internal walls,
said elongated tube being slideably received in said central bore of said guide means to prevent fluid passage between said external wall and said central bore, and
means providing a fluid tight connection between said push tube and said open end part of said elongated tube, but unconnected to said guide means or said cylinder whereby said elongated tube may first be moved partially out of said cylinder to position less than all of said plurality of spaced apart slots outside said cylinder thereby permitting and thereafter positioning all of said spaced apart slots outside said cylinder thereby preventing fluid to flow from said strata into said cylinder.

3 more elements

Dependencies are inferred from the claim text.

Subterranean fluid sampling systems and methods

Life of this patent

Subterranean fluid sampling systems and methods

Life of this patent

Abstract

Claims2