Cleanout tools and related methods of operation. At least some of the example embodiments are cleanout tools including a tool body that defines an internal annular channel, a joiner coupled to the tool body, a sleeve telescoped within the joiner and tool body, and a ball disposed within the annular channel. The ball held within the annular channel by the sleeve, and the ball configured to move along the annular channel under force of fluid pumped into the cleanout tool. The ball creates a pulsing of fluid streams exiting the tool body. Moreover, in some example systems the fluid streams created by the tool body intersect the inside diameter of a casing at non-perpendicular angles.

Use of methyl glycine diacetic acid (MGDA) as additive in processes for recovering crude oil and/or gas from subterranean formations, wherein the MGDA is a mixture of L- and D-enantiomers of MGDA or salts thereof, said mixture containing an excess of the respective L-isomer, and the enantiomeric excess (ee) of the L-isomer is in the range of from 10% to 75% Preferably, the process is a processes of acidizing subterranean formations.

Use of methyl glycine diacetic acid (MGDA) as additive in processes for recovering crude oil and/or gas from subterranean formations, wherein the MGDA is a mixture of L- and D-enantiomers of MGDA or salts thereof, said mixture containing an excess of the respective L-isomer, and the enantiomeric excess (ee) of the L-isomer is in the range of from 10% to 75% Preferably, the process is a processes of acidizing subterranean formations.

The invention relates to a method of conducting a perf wash cement (“P/W/C”) abandonment job in an offshore oil or gas well annulus, in particular the washing or cementing operation using a rotating head with nozzles dispensing wash fluid or cement at pressure. A new design of bottom hole assembly is proposed in which the cementing tool has a relatively large diameter in order to optimize pressure whilst the wash tool has a relatively small diameter. The wash process, for a number of reasons, appears to be less sensitive to tool diameter and making the wash tool smaller reduces the overall risk of stuck pipe.

The invention relates to a method of conducting a perf wash cement (“P/W/C”) abandonment job in an offshore oil or gas well annulus, in particular the washing or cementing operation using a rotating head with nozzles dispensing wash fluid or cement at pressure. A new design of bottom hole assembly is proposed in which the cementing tool has a relatively large diameter in order to optimize pressure whilst the wash tool has a relatively small diameter. The wash process, for a number of reasons, appears to be less sensitive to tool diameter and making the wash tool smaller reduces the overall risk of stuck pipe.

An oilwell treatment composition comprising (i) a solubilizing agent wherein the solubilizing agent comprises a saturated compound of the formula:

H—(OC.sub.aH.sub.2a).sub.x(OC.sub.bH.sub.2b).sub.y—OC.sub.cH.sub.2c+1

where a and b are each independently 1, 3, or 4; c is 1, 2 or 3; x and y each independently, are numbers ranging from 1 to 5; (ii) a solid acid precursor and (iii) an aqueous fluid wherein the mass ratio of the solubilizing agent to the aqueous solution is within the range of about 1:3 to about 1:5 and the mass ratio of the solubilizing agent to the solid acid precursor is within the range of about 3:1 to about 2:1.

An oilwell treatment composition comprising (i) a solubilizing agent wherein the solubilizing agent comprises a saturated compound of the formula:

H—(OC.sub.aH.sub.2a).sub.x(OC.sub.bH.sub.2b).sub.y—OC.sub.cH.sub.2c+1

where a and b are each independently 1, 3, or 4; c is 1, 2 or 3; x and y each independently, are numbers ranging from 1 to 5; (ii) a solid acid precursor and (iii) an aqueous fluid wherein the mass ratio of the solubilizing agent to the aqueous solution is within the range of about 1:3 to about 1:5 and the mass ratio of the solubilizing agent to the solid acid precursor is within the range of about 3:1 to about 2:1.

A debris barrier for protecting a hydrocarbon reservoir in a downhole well environment includes a filter securely positioned within a production tubing section of the downhole well environment. The production tubing section is couple-able with an isolation valve downstream of the isolation valve. The production tubing section includes a first set of members securely positioned along a first circumferential surface of the production tubing section and a second set of members securely positioned along a second circumferential surface of the production tubing section, wherein the first set and the second set of members extend radially. The members can be angled in a downstream direction. The first set of members and the second set of members can be offset axially from each other. The production tubing section can comprise at least one flow hole positioned near the bristles and a debris collection chamber. The filter can be dissolvable, displaceable, and removable.

A debris barrier for protecting a hydrocarbon reservoir in a downhole well environment includes a filter securely positioned within a production tubing section of the downhole well environment. The production tubing section is couple-able with an isolation valve downstream of the isolation valve. The production tubing section includes a first set of members securely positioned along a first circumferential surface of the production tubing section and a second set of members securely positioned along a second circumferential surface of the production tubing section, wherein the first set and the second set of members extend radially. The members can be angled in a downstream direction. The first set of members and the second set of members can be offset axially from each other. The production tubing section can comprise at least one flow hole positioned near the bristles and a debris collection chamber. The filter can be dissolvable, displaceable, and removable.

Methods including applying a photo-activated catalyst to a window, directing an ultraviolet light onto the window, producing a bleach via an oxidation reaction, and breaking down organic compounds located on the window using the bleach are provided. Also provided herein are systems including an ultraviolet light source and a window having a photo-activated catalyst layer.