Application of geomechanics modeling in the study of fluid loss mechanism of fractured reservoirs in Bohai Bay, China

Abstract

Drilling fluid loss in fractured formations is still an engineering problem to be solved. This work establishes an analysis method for fluid loss in fractured formation based on geomechanics modeling. The method is applied in the Bohai B oilfield in Bohai Bay, China. Three-dimensional fracture intensity and lost circulation pressure of the reservoir are established. Meanwhile, the influence of fracture dip angle and fracture width on fluid loss and the performance of onsite lost circulation materials are investigated. The results show that the reservoir of Bohai B oilfield has extensively developed fractures and the safety mud density window is very narrow in the fracture-development areas. The areas with fracture development are strongly correlated to the zones of high fluid loss risk. In addition to fracture size, the magnitude of fluid loss is also closely related to the dip angle of the fractures, and a higher fracture dip aggravates fluid loss. The proposed method can effectively characterize the development of fractures, evaluate the impact of fracture characteristics on fluid loss, and identify locations with a high risk of fluid loss.