Improved process and device for making aqueous wellbore treating fluids

Process for making an aqueous treatment fluid comprising water-soluble polymers for treating subterranean formations, characterized in that the process comprises, at least, the steps

• (I) diluting an aqueous polymer concentrate with an aqueous base fluid,
• (II) mixing the diluted aqueous polymer concentrate of step (I) with additional aqueous base fluid, thereby obtaining the aqueous treatment fluid for treating subterranean formations,
• wherein step (I) is carried out by means of a device comprising at least
• at least one source (1) for an aqueous base fluid,
• at least one source (4) for an aqueous polymer concentrate,
• a tube (2) for connecting the source(s) (1) with the inlet of a first pump (3), wherein the tube (2) additionally comprises an inlet (7) for adding the aqueous polymer concentrate to a stream of the aqueous base fluid,
• a second pump (6), whose inlet side is connected with the source (4) for the aqueous polymer concentrate and whose pressure side is connected with the inlet (7),
• a first pump (3), whose inlet side is connected with the tube (2), and whose outlet side is connected with a device for narrowing the cross-section (8),
• a device for narrowing the cross-section (8), whose inlet side is connected with the first pump (3), and whose outlet side is connected with an outlet (15),
• an outlet (15) for removing a diluted aqueous polymer concentrate from the device for further processing or using,
• wherein step (I) comprises at least the sub-steps
• (I-1) continuously sucking a stream of the aqueous base fluid from the at least one source (1) by means of the first pump (3),
• (I-2) continuously adding a stream of the aqueous polymer concentrate comprising 3.5 to 10 wt. % of a water-soluble polymer, relating to the total of all components of the aqueous polymer concentrate, from the at least one source (4) to the stream of the aqueous base fluid by adding the concentrate into the inlet (7), by means of the second pump (6), thereby obtaining a stream of a mixture of the aqueous base fluid and the aqueous polymer concentrate,
• (I-3) pressing the mixture obtained in (I-2) through the device for narrowing the cross-section (8) by means of the first pump (3), thereby generating a pressure difference, and
• (I-4) continuously removing a stream of the diluted aqueous polymer concentrate comprising a concentration of the water-soluble polymer in the range of 0.01 to 2 wt. %, relating to the total of all components of the diluted aqueous polymer concentrate, through the outlet (15),
• wherein the pressure difference generated when the stream of diluted aqueous polymer concentrate passes through the device for narrowing the cross-section (8) is in the range of from 6.9×105 to 1.1×106 Pa.

Device for making an aqueous treatment fluid comprising water-soluble polymers for treating subterranean formations, characterized in that the device comprises at least

• at least one source (1) for an aqueous base fluid,
• at least one source (4) for an aqueous polymer concentrate,
• a tube (2) for connecting the at least one source (1) with the inlet side of a first pump (3), wherein the tube additionally comprises an inlet (7) for adding the aqueous polymer concentrate to a stream of the aqueous base fluid,
• a second pump (6), whose inlet side is connected with the source (4) for the aqueous polymer concentrate and whose pressure side is connected with the inlet (7),
• a first pump (3), whose inlet side is connected with the tube (2), and whose outlet side is connected with a device for narrowing the cross-section (8),
• a device for narrowing the cross-section (8), whose inlet side is connected with the first pump (3), and whose outlet side is connected with an outlet (15),
• an outlet (15) for removing a diluted aqueous polymer concentrate from the device for further processing or using,
• wherein the size of the opening(s) of the device for narrowing the cross-section (8) is such that the device for narrowing the cross-section (8) generates a pressure difference in the range of 6.9×105 to 1.1×106 Pa.

Modular, relocatable device for making an aqueous treatment fluid comprising water-soluble polymers for treating subterranean formations, characterized in that the modular, relocatable device comprises at least

• a tube (2), which comprises an inlet (7) for adding an aqueous polymer concentrate to a stream of an aqueous base fluid,
• a first pump (3), whose inlet side is connected with the tube (2), and whose outlet side is connected with a device for narrowing the cross-section (8),
• a device for narrowing the cross-section (8), whose inlet side is connected with the first pump (3) and whose outlet side is connected with an outlet (15),
• an outlet (15) for removing a diluted aqueous polymer concentrate from the device for further processing or using
• the size of the opening(s) of the device for narrowing the cross-section (8) is such that the device for narrowing the cross-section (8) generates a pressure difference in the range of 6.9×105 to 1.1×106 Pa.