Abstract
Injection wells have an important role in the upstream oil and gas industry not only as injection of produced water but also as a secondary option in creating opportunities to increase oil and gas production. For old fields, the reliability of injection wells is very important in maintaining production stability and can even create opportunities to increase production by grossing up existing wells and adding new wells. The objective of this paper is to show an alternative corrective treatment for injection wells that is more efficient and low cost using the concept of the ventury effect. LSA-175 is an injection well that has a decrease in rate of 800-1000 bbl/day due to plugging and occurs frequently enough to require repeated treatment but is always hampered due to poor access road conditions and high cost.
To overcome plugging in injection wells, we made an Autosuction Chemical Pump (ASCP)" tool, which is a modified pipe through the ventury concept. This tool is designed to have a length of 50 cm consisting of throat, nozzle and diffuser which are configured to form a series to produce a vacuum effect. ASCP is made using stainless steel (SS) 316 material so that it is resistant to chemical acids, has a thickness that can withstand pressure >1500 psig, installation is simple and movable. ASCP was installed in the flowline by adding by pass flow to the LSA-175 injection well, then corrective treatment was carried out by injecting 15% HCl through the ASCP which resulted in a vacuum effect when fluid flow entered the ASCP. When the fluid enters the ASCP it produces delta pressure which causes a vacuum effect then the water produced with 15% HCl enters the well with a mixture of 8 - 10% as well plugging treatment media. After 20 bbl of 15% HCl treatment, LSA-175 show in increase in rate of 700 bbl/day and the wellhead pressure decreased by 30 Psig. The delta pressure that occurs is 200 psig to produce a vacuum effect.
Corrective treatment using ASCP is suitable for remote fields, if there is bad road access, the installation is simple and does not require heavy equipment. Chemical acid can be carried in a double cabin car using a 1000 liter IBC tank.
