Method and device for testing rock drillability of deep well drilling and extra-deep well drilling

Abstract

The invention discloses a method and device for testing rock drillability of deep well drilling and extra-deep well drilling. The device comprises a machine frame (1), a high temperature and high pressure loading mechanism and a micro drill bit rock breaking drilling depth measurement mechanism, wherein the high temperature and high pressure loading mechanism and the micro drill bit rock breaking drilling depth measurement mechanism are arranged on the machine frame (1). The device exerts confining pressure, pore pressure and fluid column pressure on rock samples in cavities in three axes, overburden pressure is exerted on the rock samples through a hydraulic pump, and therefore the high pressure environment of the stratum of the bottom of a well can be simulated, the relation between the drilling depth and the time is tested through a displacement sensor at the position of a micro drill bit, optimization of the drilling pressure, the rotating speed and the drilling fluid type and drilling machinery drilling speed prediction are achieved. The method and the device have the advantages that the requirements for the bottom hole temperature and the pressure can be met in the deep well drilling process and the ultra-deep well drilling process, the function of testing multiple sets of rock drillability values through a single time of experimental testing of deep well drilling is achieved, the efficiency of the single time of experimental testing is greatly improved, and experimental cost is reduced.

Description

technical field [0001] The invention relates to the technical field of rock drillability testing applied in the field of exploration and development of oil and gas fields, in particular to a deep well and ultra-deep well drilling rock drillability testing device and testing method. Background technique [0002] The concept of rock drillability was first proposed by Tillson at the Columbia University Mining Engineering Conference in 1927, which refers to the difficulty of rock being drilled by rock breaking tools under certain technical conditions. The research on rock drillability is widely used in petroleum exploration and development, mining, tunnel construction and other engineering fields. The drillability of rock is not only related to the rock's own factors such as rock mineral composition, pore development, and geological structure, but also closely related to construction parameters such as rock-breaking tool type, drilling pressure, and rotational speed. Therefore,...

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Problems solved by technology

[0003] In recent years, with the continuous development of China's oil and gas exploration and development to deep strata, deep wells and ultra-deep wells have become the mainstream of exploration and development. The characteristics of high temperature, high pressure, complex geological conditions, tight formation lithology, and poor drillability of the formation encountered by drilling have become the main technical bottlenecks restricting oil and gas exploration and development. Rock mechanical properties are significantly affected, thus seriously affecting rock drillability and drilling ROP. The compressive strength, cohesion, Poisson's ratio and elastic modulus of the rock under the conditions of formation temperature and pressure were tested. The test results showed that the mechanical properties of the rock in the deep formation changed significantly compared with the upper formation. At the same time, a 2009 article by Chongqing University The master's thesis "Experimental Research on Drillability and Rock Mechanical Properties of Deep Wellbore Rock" studied the drillability level and ROP of rock in high temperature and high pressure environment in deep formations. However, the impact of high temperature in the bottomhole temperature range on the rock drillability level is relatively small. It can be seen that the current microdrilling method for testing rock drillability without considering the bottomhole formation characteristics is no longer satisfactory for petroleum. Drilling technical requirements for medium-deep wells and ultra-deep wells in the field of natural gas exploration and development, especially the inability to effectively reveal the rock drillability characteristics in the actual drilling process of deep wells and ultra-deep wells

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