Novel Quantitative Method for Estimating Breaker Filter Cake Cleaning Efficiency

Abstract

Abstract Drilling operations including drilling and completion fluids are the primary source of the reservoir rock damage. Drilling fluid filtrate accumulates around the near well-bore and decreases the reservoir rocks permeability; this can reduce the oil and natural gas flow. Drilling fluid filter cake usually consists of a biopolymer such as xanthan gums, starch along with bridging materials like sized calcium carbonate particles. Polymers are used for improving the carrying capacity of the mud, and the starch along with bridging materials to establish the mud cake on the formation and minimize leak off of the drilling fluid into the formation. Cleaning mud cake is essential for all gravel pack and open hole completion wells, it is important for stimulation operations. Cleaning mud cake maximizes the production, and injection rate by minimizing the formation damage caused by the drilling fluid filtration and deposition across the reservoir rocks while drilling operations. Extensive laboratory studies were conducted to determine the extent of formation damage that occurs while drilling the pay zone section. This paper defines novel methodology involving thermal - gravimetric analysis, to quantify the internal, external filter cake clean up efficiency. The novel lab test can quantify the cleaning efficiency of any breaker; it has several advantages over the conventional methods. This paper demonstrates the benefits and the drawbacks of some breakers (including polymer specific enzymes), aiming to select the best breaker for each well condition and reduce induced damage caused by the drill-in fluid.