ANALYSIS OF PHYSICAL CHARACTERISTICS OF PERMIAN DEEP IGNEOUS ROCKS IN THE NORTHERN TARIM BASIN AND APPLICATION OF WELL LEAKAGE

The H working area is the main production block in Ordovician formations of the Tarim Basin Oilfield. However, the lithology and velocity of the Permian igneous rocks change drastically, and the lithology changes of the igneous rocks will affect the drilling progress. Different igneous rocks have different possibilities for leakage during drilling. Therefore, it is imperative to expand research on the velocity field of Permian igneous rocks. To begin with, a petrophysical analysis was conducted on 12 rock samples from the igneous formations in this area. These samples were analyzed for physical properties, such as density, P-wave and S-wave velocity, Poisson’s ratio, Young’s modulus, and bulk modulus, under water-saturated conditions. By combining these finds with previous data from 20 igneous rock samples, we have established the relationship between P-wave and S-wave velocities, porosity, and density of the igneous rocks, providing a fundamental understanding of the velocity characteristics in this area. Subsequently, the study employed the constrained sparse pulse inversion method, specifically tailored for igneous rock, to conduct wave impedance inversion and develop a velocity model. Furthermore, utilizing the Wyllie formula and P-wave velocity–porosity formula, the rock physical data were fitted at normal temperature and atmospheric pressure to predict the porosity of the Permian igneous rocks, followed by a comparative analysis. Finally, in conjunction with seismic data and the velocity model obtained through inversion, an extensive analysis of numerous drilling failures in the Permian System was conducted. The finds were then applied to actual drilling scenarios, leading to the formulation of recommendations for drilling operations in this area.