Case Studies

Oil and Gas Fields and Potable Water Supplies

The Issue: Well damage due to bio-fouling, polymers, or sulfidic matricies.

The Solution: Sabre's Chlorine Dioxide ClO2 Generator

Background

Chlorine dioxide is a powerful oxidant and microbiocide that has been used for drinking water disinfection and as an Oilfield injection water microbial control agent. Because chlorine dioxide exhibits the capability to break cell walls (cell lysis) and cleave natural and synthetic polymers its use was considered as a well stimulation additive.

Chlorine Dioxide Application Considerations

The first trials for chlorine dioxide use as a well stimulant were done on potable water wells. The second trials use in Oilfield application.

Chlorine Dioxide Treatment Approach

To date Sabre has performed over 700 well stimulation's in the Oilfield using chlorine dioxide. In situations where the well damage is due to bio-fouling, polymers, or sulfidic matrices, chlorine dioxide use has been very successful.

Results

Data was complied from long term results on Diklor for the treatment of producing wells. These results are from 7 wells treated in a West Texas producing field. All seven of the wells were selected on a basis of either having shown a decline in production over the past year (Stim), evidence of microbiological activity (MIC), or presence of iron sulfide (FeS). The "Job Cost" is the total cost for treatment of the well including transport and pumping charges. Table 1 details the results of the treatment of these wells based upon 120 days before and after treatment comparison.

Well #	Days Problem	BOPD Date	Change	Job Return	Net Cost	Return	%ROI
1	FeS	120	9.0	$19,440	$1,829	$17,611	963%
2	MIC	120	12	$25,920	$2,120	$23,800	1123%
3	Stim	120	7.0	$15,120	$3,213	$11,907	371%
4	MIC	120	0	$2,160	$1,972	$(1,972)	-100%
5	Stim	120	6	$12,960	$3,133	$9,827	314%
6	Stim	120	1	$2,160	$3,375	$(1,215)	-36%
7	Stim	120	2	$4,320	$3,413	$907	27%
			Total:	$82,080	$19,055	$61,153	321%

Table 2 depicts the most recent data we have, which in some cases extends to 270 days. For the purposes of putting together this information, all data points were included, with no throw outs taken for days when there was no pump operation. For each of the wells there were at least 30 data points.

Well #	Days Problem	BOPD Date	Change	Job Return	Net Cost	Return	%ROI
1	FeS	120	9.0	$19,440	$1,829	$17,611	963%
2	MIC	270	4.9	$23,814	$2,120	$21,694	1023%
3	Stim	180	10.6	$34,344	$3,213	$31,131	969%
4	MIC	180	0	$-	$1,972	$(1,972)	-100%
5	Stim	10	4.5	$12,150	$3,133	$9,017	288%
6	Stim	150	6.7	$18,090	$3,375	$14,715	436%
7	Stim	180	4.3	$13,932	$3,413	$10,519	308%
			Total:	$121,770	$19,055	$102,715	539%

The Science of Success

It can be noted that the performance on some of the wells improved over the longer periods. We believe that this was due to better fluid levels and water pump off over the longer period. Well #4 shows evidence of other problems relating to pump operation or flood pattern.

Follow Up

Overall, we have had a success on six out of seven wells treated to date, with an excellent return on investment to the producer. We are presently reviewing this information with the producer to secure a larger package of wells to further develop this technology.