INTEROFFICE MEMORANDUM

BY: DARYL CURTIS

ENGINEER

CHEVRON USA

DATE: OCTOBER 17, 1996

Stanley Filter Test

The Stanley Filter design that was used for this project is made of fiberglass, 30 feet in length. The real magic is the multi-layered filter media that is encased inside the fiberglass body. These layers of media will filter out particles that will score -.002 to -.003 plunger. Our application was designed for wells on primary production, producing 15 to 18 gravity oil. Filters for thermal applications are available also, as well as many other types for different producing environments.

Efforts and Results

1. None of the filters plugged up with sand. One filter that was pulled had 33% of the filter full of sand, after 195 day run (200% increase in run life). A sieve analysis of the sand sample showed that the particle size was uniform, however the size was slightly larger than the filter was designed for.

2. The average run life for 3 wells increased from 89 days (before the filter) to 268 days (after the filter). The remaining three wells have exceeded the average run life (before the filter installation) by 156%.

3. There has been no loss in oil production due to the addition of the filter, other than two wells that were shut in for mechanical reasons, and not filter failure. There has been an increase in production in one well after the filter and pump assembly was redesigned. Initially, a filter was run directly below the pump. During an information feedback meeting with the Stanley Filter representatives, it was recommended that a

joint of tubing be installed between the pump intake and the filter. This would allow less sand into the pump and more time for the sand to settle out into the filter. On one well, the production increased for 30 BOPD to 60 BOPD, with gross fluid increasing also. However, a second well was redesigned, with no change at all in the production.

4. In 1994, there were 29 pump related pull jobs at a total cost of $82,000. In 1995, the pump related pull jobs dropped to 7, at a total cost of $34,000.00. To date for 1996, there has been 5 pump related pull jobs, at a cost of $22,000.00. Profit per well has increased from $22,000.00 to $35,000.00 since filter installations. Total profit increase since filter installation is $79,000.00.

Conclusions / Recommendations

1. The pump repair report and the failure/pull history are the best tools for choosing appropriate filter candidates. If a well has only had one failure due to sand, then don’t install a filter. Look for consistent history of grooved plungers and barrels as a first pass. Then look at the frequency of pulls. If the well is pulled 3 or more times per year, then chances are it may be a candidate.

2. When choosing a filter, choose the largest I.D. filter possible to allow the best flow of fluid through the filter. Be aware of the O.D. of the filter and the I.D. of the casing or liner. Make sure that the filter can be drilled out without complications (due to clearance problems).

3. Even though the filter was designed to filter out a certain size of sand, it will still fill up with sand. This does not mean that the filter does not work. On the contrary, it is doing what it was designed for. It shouldn’t affect the performance of the pump until the filter is mostly full, or plugged. The function of the filter is to reduce the pump wear, not completely eliminate it.

4. The filter will not work in reservoirs that produce flour sand, or where pumps with smaller than a -.003" fit barrel and plunger are constantly worn out due to sand production.

5. There has not been any failures due to the filter not working. The Midway-Sunset South property team will continue to utilize the filter as one solution for improving the run life of sand- related pump failures.

6. The Stanley Filter will not work in every application, but it has proven its value in reducing sand related pump failures. Each time the filter is pulled, it should be inspected carefully before running back into the well. If the filter is more than 33% full, then the filter should be pulled, cleaned out reused.

7. Where there is a record of tubing movement in the well, a tubing anchor will need to re run when installing a filter, otherwise the filter may be destroyed.

8. Where possible, run a joint of tubing between the pump intake and the filter, with a joint of tubing or used filter on the bottom of the new filter. This design seems to work the best.

9. Don’t choose the worst sanding well to try a filter in. As stated above, the problem is not with sand fill, but with sand that is produced with the fluid.

10. This application has made 5 barrel oil wells very profitable to produce, especially when pull jobs have been decreased from 3 pulls per year to 1 per year.

11. Allow at least a 12 month trial period to evaluate the filters. The results will take some time before any conclusions can be drawn. This is not, and should not be, a short term project.

Stanley Filter Company
10061 E. 52nd Street
Tulsa, OK 74146