A Method for Predicting Formation Pore Pressure in Carbonate Rocks

Abstract

Abstract Formation pore pressure refers to the pressure of the pore and the fluid in it, which is an important parameter in drilling engineering, related to well depth structure design, drilling fluid preparation, and casing matching. Accurately predicting formation pore pressure helps to reduce drilling accidents and achieve safe drilling. Due to the complexity of the causes of abnormal pressure in carbonate rock formations, it is difficult to predict the formation pore pressure. Taking Block M in Qaidam Basin of Qinghai Oilfield in China as an example, this paper proposes a prediction method for formation pore pressure in carbonate rock formations based on analyzing the causes of abnormal pressure. Firstly, based on core analysis and well-log interpretation, this paper analyzes the causes of abnormal pressure in Block M; According to the causes of abnormal pressure, the Fan comprehensive interpretation method is selected as the calculation method for the formation pore pressure. The model is modified based on well-log data and experimental data, and the BP neural network is used to correct the prediction error. Based on this model, the formation pore pressure of two wells is predicted. Compared with the measured points, the error is less than 5%, which meets the engineering requirements.