A New Technique for the Evaluation of Acid Additive Packages

Abstract

The expanded use of sandstone matrix acidizing techniques may have been the most significant trend of the turbulent 1980's. Gulf Coast operators have found that remedial acid treatments cost a fraction of that required for a comparable offshore completion. Improved design and application techniques now provide economic success rates greater than 80% with most treatments paying out in less than 30 days. However, one area that continues to frustrate designers of acid treatments is the unpredictability of crude oil reservoirs. Current testing procedures are inadequate, failing to accurately replicate the interaction between the treating fluid and acid sensitive crudes. Reliance on these procedures can produce catastrophic facility upsets, downhole emulsion blocks, reduced damage removal efficiency or result in a marginal treatment response. A new simplified laboratory testing procedure was developed which more accurately simulates treatment effects under reservoir conditions. This laboratory test demonstrates the need for less reliance on surfactant non-emulsifiers and an expanded use of mutual solvents. Field data confirms more accurate prediction of add compatibility. In addition, acid treatments designed utilizing this laboratory procedure showed greater initial production response and maintained the incremental increase for a much longer time. Design guidelines are presented which address concerns of mutual solvent/corrosion inhibitor incompatibility, high temperature applications and treating volume requirements.

Influence of Oilfield Chemicals on the Surface Tension of Stimulating Fluids

“…They are also used to prevent the formation of acid-in-oil sludges and emulsions. 17 The mutual solvent examined in the present study was EGMBE and had an assay of nearly 100 wt%. EGMBE is commonly added to acid formulations at 5 to 15 vol%.…”

Eliminate Formation Damage Caused By High Density Completion Fluid - Crude Oil Emulsion

“…This filtration procedure was designed to simulate the stripping of surfactant as the brine penetrates the formation (2,3,4) . The sand pack was composed of 20 grams of sand and clay (80 weight percent of 100-mesh quartz sand, 10 weight percent API bentonite and 10 weight percent fine silica flour).…”

New Environmentally Friendly Surfactant Enhances Well Cleanup

“…In an attempt to improve on the methods of API RP 42, Houchin et al 6 devised yet another modification to the packed column tests. A pack consisting of 100-mesh sand (80 wt%), Wyoming bentonite (10 wt%), and silica flour (10 wt%) was proposed.…”