fluid loss control FLC 350

additive in invert emulsion drilling fluids.

Fluid loss control (FLC) and filtercake quality of a drilling fluid plays an important role in the wellbore construction process5-6 and can influence various important aspects of drilling operations, such as wellbore stability, completion process, formation damage, downhole mud losses, and differential sticking. Ultimately, FLC and filtercake quality become critical parameters for both the drilling operation and after drilling for well productivity. Different additives may be utilized in IEDF formulations in order to minimize the fluid losses to formation and to enhance the filtercake quality. These additives may be either dispersed or solublized in the oil phase. Various fluid loss additives have been developed and utilized in IEDF during drilling operation. However, the most widely used FLC additives are Gilsonite, amine-treated lignite and synthetic organo-soluble gel resin.

Of an organo amine quebracho-based fluid loss agent which is stable to 400°F. This quebracho-based fluid loss agent is compatible with synthetic-based fluids and is environmentally acceptable. The performance advantages of this product include high-temperature stability, low fluid losses, minimal to no side effects and good rheological properties. Traditionally invert emulsion drilling fluids have been used to optimize drilling performance primarily due to the high level of wellbore stability and high penetration rates seen when utilizing these fluids. Invert emulsion fluids require various additives such as emulsifiers, fluid-loss-control (FLC) agents, viscosifier etc. The list of various FLC agents traditionally used include: asphalt, polymers, Gilsonite, and amine-treated lignite. Such materials are not always compatible with the environment and do not degrade easily making it difficult to use in areas where tough environmental regulations are in place. A new environmentally acceptable FLC agent has been developed utilizing naturally occurring quebracho and fatty acid derived amines. The product is lipophilic and when used in the range of 4 to 8 lb/bbl has been found to give hightemperature, high-pressure fluid losses which are less than 6 mL; the product is stable up to a high temperature of 400°F.

Pros and Cons of Current FLC Additives:
 Gilsonite. Even though the cost of Gilsonite has increased recently, it is still one of the most economical FLC additives for invert emulsion drilling fluids. Also, Gilsonite is a very versatile FLC additive for different temperatures due to its availability in a wide melting-point range. In spite of its versatility and relatively low cost, there is the issue of potential formation damage which have prompted various papers to be written concerning formation damage and formation damage mechanisms while utilizing Gilsonite. However, formation damage by Gilsonite depends upon the type of formation drilled, fluid formulation and quality of Gilsonite. Gilsonite also has other performance-related issues – once the Gilsonite melts or dissolves, it contributes to high viscosity and gel strengths in the drilling fluid without contributing to fluid loss properties. The biggest drawback of Gilsonite is environmental concerns. It contains aromatic components and therefore cannot be used in SBM for the Gulf of Mexico where aromatic contamination is prohibited due to environmental regulations on disposal of SBM and cuttings generated during drilling operation