A plasticizer for shale gas well cementing

Abstract

The invention discloses a plasticizer for shale gas cementing. The plasticizer is prepared from, y mass percent, 10-25% of sepiolite fabric, 10-30% of expanded perlite, 2-15% of fibrous brucite, 2-20%of bagasse regeneration fiber, 15-35% of waste and old tire rubber powder, 10-20% of active silica, and 10-20% of activator. Through compounding sepiolite fabric, expanded perlite, fibrous brucite, and bagasse in different lengths, widths, grain diameters and varieties, the shortcomings of uneasy control of single fiber performance, easy thickening, easy coiling and others can be effectively avoided; the cement slurry thickness is not increased basically, and the cement slurry rheological property influence is small. Besides, the use of the bagasse and waste old tire rubber powder can lightenthe environment pressure and greatly reduce the cost of the plasticizer. The plasticizer can be applicable to the shale gas cementing and also applied to the cementing of oil and nature gas wells.

Description

technical field [0001] The invention belongs to the technical field of oil well cement additives, and in particular relates to a plasticizer suitable for cementing shale gas formations during the cementing process of oil and gas wells. Background technique [0002] With the development of shale gas in my country, the problem of shale gas cementing has become prominent. At present, horizontal wells are mainly used for shale gas development, and large-scale slick water fracturing is required before exploitation. Large-volume fracturing construction will affect the cement sheath, causing the cement sheath to break. The irregularity of long horizontal wells and boreholes also makes it difficult for the casing to be centered, resulting in uneven thickness of the cement sheath. When subjected to the impact of perforating bullets, the pressure changes greatly during the oil production process, and the stress creep in the formation, the thinner The cement sheath is prone to ruptur...

AI Technical Summary

Problems solved by technology

However, even if a single plant fiber is modified, the performance is not easy to control. The addition of fiber will affect the water loss and rheological properties of the cement slurry, and even excessive winding at the bottom of the well, increasing friction and increasing pump pressure

The latex itself is a metastable structure, the interference of the cations dissolved in the cement slurry or the formation, the high shear force mechanical agitation or the large temperature change when the slurry is mixed will destroy the stability of the latex cement and cause the latex to break. , affecting the comprehensive performance of cement slurry

The success rate of latex cement in vertical well construction is relatively high, but there are still many problems in horizontal well construction

Images