Publications

Located in West Java, the Cemara field has around 50 wells that produce from more than 7 different formations. The Conglomerate (CGL) formation, one of the most promising formations in the field, is found at depths below 8,000 ft, with bottom-hole temperatures in the range of 280 - 300 oF. This formation has a low reservoir pressure gradient, medium porosity and low to medium permeability in the range of 10-20 % and 5-20 mD, respectively. The first hydraulic fracturing treatments in Cemara field were performed in 2003, all of them using oilbased fracturing fluids. The reasons for using thiskind of fluid were because it was suspected that theformation was water-sensitive, even knowing that all the wells were drilled and completed with waterbased fluids, and also because at that time the price of diesel was low, making the oil-based fluids very cost-attractive. The rheology of the oil-based fracturing fluids at the high bottomhole temperature of these wells associated with the high friction pressures, limited the proppant concentration and the pumping rates of these treatments, resulting in non-optimum fracture geometries. Also, the actual cost of the diesel and the HSE concerns of handlingflammable fluids turned the oil-based fracturing fluids an expensive and hazardous solution. After conducting detailed laboratory testing using core samples, a high temperature water-based crosslinked fracturing fluid was optimized for the Conglomerate formation. Additionally, to avoid that excessive fracture height-growth could lead to the interception of water zones, a new design methodology where fibers are added to assist on the proppant transport was incorporated to the fluid formulation. This fiber-laden fracturing fluid has a significant reduction on the polymer loading without compromising the proppant transport properties. The production results of three wells that were hydraulicly fractured using this fiber-laden high temperature water-based fluid resulted in an increment of almost 500 bopd, boosting up the initial production by 2.5 fold increase.