Development, Testing and Field Application of a Novel Combination Foamer-Iron Sulfide Scale Inhibitor-Corrosion Inhibitor in East Texas

摘要

Production in East Texas has a long and rich history in both liquid and gas plays. This paper concerns wet gas production in the Fairfield, TX area and a unique challenge that was overcome by a collaboration between operator and service company. The application in question spans many wells in the Central and East Texas area where a common challenge was production of gas with associated corrosive fluids that led to significant deposition of iron sulfide scale in the production tubing. This paper details the unique challenge of creating a single chemistry that not only can successfully deliquify the wells when pumped on a continuous basis but also one that can reduce the corrosion and prevent the build-up of carbonate scales and most importantly iron sulfide scale in the production tubing. Development work presented includes laboratory and field foamer testing, iron sulfide scale testing, and autoclave corrosion testing. This was made all the more challenging due to the high downhole temperatures of 300°F with a pressure of 1,000 psi and a mixed sweet / sour gas with a composition of 2.2mol% CO2 and 0.75mol% H2S. Testing showed that application of these products up to 6,000 ppm was able to stabilize gas production, reduce the corrosion to acceptable levels and prevent the deposition of iron sulfide scale in static and dynamic tests. Extensive detail is provided on the field trials and the monitoring regimen that was put in place to monitor all functionalities provided by this chemistry. As this was across a whole host of different well types, significant data was generated and a wealth of information and lessons learned for the industry can be extracted from it. The paper concludes with the overall lessons learned and summary of the validity of this technology and how it could potentially be a game changer for the industry at large in East Texas where gas well deliquification combined with corrosion and scale formation is a shared challenge.