Fluid control modules for use with downhole tools

An apparatus, comprising:

• a plurality of discrete modules coupled end-to-end to form at least a portion of a downhole tool having first and second flowlines each extending the collective length of the plurality of discrete modules;
• a first fluid valve disposed within a first module of the plurality of discrete modules, wherein the first module comprises first and second portions of the first flowline and first and second portions of the second flowline, wherein the first portion of the first flowline is upstream or downstream relative to the second portion of the second flowline, and wherein the first fluid valve is coupled between the first portion of the first flowline and the second portion of the second flowline;
• and
• a second fluid valve disposed within the first module and coupled between the second portion of the first flowline and the first portion of the second flowline, wherein the second portion of the first flowline is upstream or downstream relative to the first portion of the second flowline, and wherein the first and second fluid valves are controllable to cause fluid to flow between the first portion of the first flowline and the second portion of the second flowline or between the first portion of the second flowline and the second portion of the first flowline;
• wherein the first module can fluidly communicate only with an adjacent one of the plurality of modules, wherein a third one of the modules comprises a first pump, and wherein a fourth one of the modules comprises a second pump.

An apparatus for use with a drillstring, comprising:

• a plurality of discrete modules coupled end-to-end, thereby forming first and second flowlines each extending the collective length of the plurality of discrete modules, wherein each of the plurality of discrete modules comprises a body that surrounds corresponding portions of each of the first and second flowlines;
• wherein a first module of the plurality of discrete modules comprises a plurality of fluid flow valves to control a flow of fluid through and between the first and second flowlines, wherein actuating one or more of the plurality of fluid flow valves causes fluid flowing in an upstream portion of the first flowline to flow through a downstream portion of the second flowline;
• wherein the first module is not configured to:
• selectively seal off or isolate selected portions of a wellbore wall;
• fluidly couple directly to a subterranean formation;
• or
• draw a fluid sample directly from the subterranean formation;
• and
• wherein a second module of the plurality of discrete modules is configured to:
• selectively seal off or isolate a selected portion of the wellbore wall;
• fluidly couple directly to the subterranean formation;
• and
• draw a fluid sample directly from the subterranean formation, wherein a third module of the plurality of discrete modules comprises a first pump, and wherein a fourth module of the plurality of discrete modules comprises a second pump.

A method, comprising:

• forming at least a portion of a downhole tool by coupling a plurality of discrete modules end-to-end, thereby forming a first flowline and a second flowline each extending the collective length of the plurality of discrete modules, wherein the plurality of discrete modules comprises a first module and a second module;
• conveying the downhole tool within a wellbore to a subterranean formation penetrated by the wellbore;
• selectively admitting fluid from the subterranean formation into the first module of the downhole tool;
• and
• actuating a plurality of fluid valves of the second module of the downhole tool to:
• close a fluid path between first and second portions of the first flowline within the second module or close a fluid path between first and second portions of the second flowline within the second module;
• and
• open a fluid path between the first portion of the first flowline and the second portion of the second flowline within the second module or open a fluid path between the first portion of the second flowline and the second portion of the first flowline within the second module, wherein the plurality of discrete modules comprises a third module and a fourth module, wherein the third module comprises a first pump, wherein the fourth module comprises a second pump, and wherein actuating the plurality of fluid valves comprises bypassing the first pump of the third module to enable use of the second pump of the fourth module.