High-temperature-resistant salt-resistant strong inhibitive drilling fluid system

Abstract

The invention relates to a high-temperature-resistant salt-resistant strong inhibitive drilling fluid system comprising the following materials by mass on the basis of the mass of added water of 100%: 2-7% of bentonite slurry, 0.1-0.3% of an alkaline regulator, 0.3%-2% of a shale inhibitor, 0.5-4% of a high-temperature-resistant filtrate reducer A, 0.5-4% of a heat and salt-resistant filtrate reducer B, and 1%-7% of a plugging anti sloughing agent. The invention also provides chemical structural general formula (1) of the high-temperature-resistant filtrate reducer A, and a, b, c and d are the structure unit number. The drilling fluid system has the following characteristics: the drilling fluid system can resist the high temperature reaching to 230 DEG C, before and after-aging API filter loss is less than 10mL, the drilling fluid system can resist sodium chloride until saturation, and is strong in inhibition; compared with tap water, the third time rock debris recovery improvement rate amounts to 100.54% above; and the drilling fluid system is strong in inferior soil resistance and calcium pollution resistance.

Description

technical field [0001] The invention relates to a drilling fluid system, in particular to a high-temperature and salt-resistant drilling fluid system for deep wells and ultra-deep wells. Background technique [0002] With the rapid development of the petroleum industry and the increase in the world's energy demand, the focus of petroleum exploration and development has shifted from easy to difficult, from land to ocean, and from shallow to deep formations worldwide. Drilling of deep wells and ultra-deep wells has become an important issue faced by the oil industry in my country and even in the world. During the drilling process, due to the existence of geothermal gradients and formation pressure gradients, the deeper the wellbore, the higher the temperature and pressure in the wellbore will be, and various complex formations such as salt layers, brine layers, and salt-gypsum layers encountered will be More and more, and the drilling fluid is easy to lose its original perfor...

AI Technical Summary

Problems solved by technology

In order to meet the drilling needs of deep wells, ultra-deep wells, high temperature and high salinity and other complex formations, various petroleum colleges and research institutions have successively researched and developed various high temperature and salt resistant drilling fluid systems, such as trisulfonate drilling fluid, sulfonate polymer Saturated brine drilling fluid, zwitterionic polymer salt-resistant drilling fluid, etc. These high-temperature and salt-resistant drilling fluids are mostly dispersed mud, and the outstanding problems are poor temperature resistance (temperature resistance up to 180 ℃), poor inhibition, rheology and Problems such as difficulty in coordination and unification of filtration loss

Oil-based drilling fluid has the advantages of strong temperature and salt resistance, strong inhibition, and good lubricating performance, but it also has the disadvantages of polluting the environment and high cost, and has a large safety risk

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