Superior fracture-seal material using crushed date palm seeds for oil and gas well drilling operations

Abstract

Expenses for drilling represent 25% of the total oilfield exploitation cost. Drilling fluids represent 15–18% of the total cost of well petroleum drilling operations. The main drilling fluids problem is the loss into fractured and vugs. Prevention or mitigation of severe lost circulation is a main challenge while drilling in fractured formations where conventional lost circulation materials (LCM) will not cure these losses. Therefore, specialized treatment is required when drilling fractured formations.In this study, a superior LCM made from crushed date palm seeds was tested at laboratory for its ability to seal artificially fractured cores under High Temperature High Pressure (HT-HP) conditions. For this purpose, the conventional 500 ml HT-HP filter press was modified to accommodate a fractured core plug of length and diameter equal to 38.1 mm (1.5 inch) instead of the ceramic disc.Using the modified HT-HP filter press, crushed date palm seeds proved its ability to completely seal the artificially made fracture in the test core samples at overbalance pressures up to 1000 psi and temperatures up to 90 °C. The optimum mud composition was fresh water, 7% by weight bentonite, 3.5% fine crushed date palm seeds, and 3.5% coarse crushed date palm seeds in weight bases. In addition to its superior ability to seal fractured formation, the crushed date palm seeds material is cheap, locally available in commercially quantities, and environmentally friendly material.