Pore Pressure Prediction in Deep Complex Formations Based on Well-Seismic Combination

Abstract

ABSTRACT: With the development of oil and gas drilling technology, oil and gas exploration and development have moved towards deep to ultra-deep layers. Due to its deep burial depth, deep formations face various challenges such as high temperature, high pressure, and high stress. The prediction of formation pore pressure is a core factor of drilling design optimization and risk prevention. In order to improve the prediction accuracy on the basis of existing pre-drilling formation pore pressure prediction methods, the logging data and actual drilling data of the drilled wells were combined with the seismic data. In this paper, a set of high accuracy pore pressure prediction method based on well-seismic combination are formed by using the interval-controlled interval velocity modeling method and the well-controlled interval velocity correction method. The method is applied to a deep well in Tarim Basin. This well was designed to exceed a depth of 8,000 meters. The predicted pore pressure coefficient of the well is between 1.04 and 1.22 g/cm3. The measured pore pressure coefficient after drilling was between 1.07 and 1.22 g/cm3. Actual analysis has demonstrated the accuracy and reliability of pore pressure prediction, providing support for pre-drilling pressure forecasts. 1. INTRODUCTION In recent years, with the acceleration of China's exploration and development of deep oil and gas resources, the demand for ultra-deep well drilling technology has become increasingly urgent, and higher requirements have been put forward for ultra-deep well drilling technology. However, the engineering geological conditions of ultra-deep formations are extremely complex, and the design of wellbore structures under multiple pressure systems is difficult, which also poses great challenges to efficient and safe drilling. Therefore, for ultra-deep and complex formations, solving the problem of accurate prediction of formation pore pressure under complex geological conditions has great practical significance for oil and gas drilling. At the same time, it also provides strong technical support for the exploration and development of ultra-deep oil and gas resources.