A kind of long-acting clay stabilizer for oil well and its preparation and application

Abstract

The invention relates to a clay stabilizer for long-acting oil wells and preparation and applications thereof. The clay stabilizer is prepared by the steps of: adding epoxy chloropropane and short-chain multi-charged cation polyquaternium into a reactor in a mole ratio of 1-2:1, and simultaneously adding 5-15% by mass of a solvent and 1-5% by mass of a catalyst; stirring, heating to 30-100 DEG C, and reacting 2-6 hours so as to obtain colorless transparent liquid, namely, the clay stabilizer for long-acting oil wells. The clay stabilizer is relatively small in molecular weight and small in molecular size range, so that a situation that the clay stabilizer blocks a micropore throat of a tight reservoir can be prevented, thereby reducing the harm to the permeability of a low-permeability oil layer; a main agent of the clay stabilizer contains multiple cation points, so that the number of bonding points of the clay stabilizer molecule and the reservoir is further improved, and the anti-swelling performance is improved; the preparation process is simple, and materials are easily obtained; the clay stabilizer can endow a fracturing fluid system with a long-acting clay stabilizing performance.

Description

technical field [0001] The invention relates to the field of petroleum exploitation, in particular to a long-acting clay stabilizer suitable for oil well fracturing stimulation in tight oil reservoirs and its preparation and application. Background technique [0002] my country is rich in tight oil and gas resources, mainly distributed in Ordos, Sichuan, Songliao, Bohai Bay, Junggar and other basins. Exploration evaluation shows that only tight oil has a total resource of 11-13.5 billion tons. With the continuous improvement of exploration and development technology, especially the breakthrough of horizontal well volume fracturing technology, pilot tests of tight oil development have been carried out in Changqing Oilfield, Daqing Oilfield and Tuha Oilfield. [0003] The composition of clay minerals in tight oil reservoirs is complex, and these clay minerals are mostly composed of silicon-oxygen tetrahedrons and aluminum-oxygen octahedrons, and the interlayer surfaces are all...

AI Technical Summary

Problems solved by technology

All the above clay stabilizers can inhibit clay swelling and migration, but there are some problems: multi-charged cations need suitable pre-fluid and post-fluid in fracturing construction, which are easy to cause clogging; quaternary ammonium salt surfactants will make silicon Salt becomes oil-wetted, thereby reducing the relative permeability of hydrocarbons in rocks; polyamine clay stabilizers have a short validity period and high cost; polyquaternary ammonium relative molecular weight increases the damage to the permeability of low-permeability oil layers