Study On Acid Fracturing Technologies In The Limestone-sandstone Reservoir Of Block Bin 105

The block Bin 105 has the characteristics of low porosity-middle porosity,super-low permeability-low permeability and complex lithology of limestone,It is mainly argillaceous cryptocrystalline limestone.the lithology of reservoir shows high content of quartz,feldspar and other clastic rocks in the high position,while in low position the content of carbonate and shale content are high,and the total shale content is high(More than 20 %),this particularity makes the pure acidification and conventional acid fracturing measures not matched,the Pertinence of liquid system is not strong,has not yet formed large-scale mining,the Reconstruction effect failed to achieve the expected target.Starting from the geological characteristics of the block Bin 105,target reservoir,this paper introduces development difficulties of block Bin 105,Acid fracturing fluid thickener,crosslinking agent,conditioning agent,corrosion inhibitor,clay stabilizer and other additives system was optimized,and the formulation system of Acid sand-carrying fracturing fluid for limestone-sandstone reservoir of block Bin 105 was formed.It has been found experimentally that the performance of the system was optimal when concentration of ground crosslinking acid thickener was 0.8%,the concentration of crosslinking agent was 0.4 %,the concentration of conditioning agent was 0.4 %,the concentration of corrosion inhibitor FL-A was 3.0 %,the concentration of ferric ion stabilizer NTS-2 was 2.0 %,the concentration of cleanup additive FL-A was 3.0%,and the concentration of clay stabilizer A-25 was 1.5 %.Through the rheological experiments of acid fracturing fluid,such as temperature resistance,shearing resistance,gel breaking property,and sand carrying ability,the apparent viscosity of acid fracturing fluid at 120? was stable at 50-70 mPa?s,Showing good sand carrying capacity,it can quickly gel breaking in 3.5h,and the viscosity of gel breaking is less than 5 mPa?s,which can meet the requirements of fast gel breaking and quick flowback.The acid rock reaction experiments of 20 % and 15 % ground crosslinking and the ground crosslinking remaining acid performance evaluation of the temperature resistance and shearing resistance of were carried out.the experimental results show that the ground crosslinking acid has good retarding and stability.At the same time,the process design of the ground cross linking acid adding sand acid fracturing and ground crosslinking acid(without sand)acid pressure was optimized.the field experiment of the ground crosslinking acid adding sand acid fracturing of the well A and the ground crosslinking acid acid fracturing(without sand)of the well B is carried out,which provides technical support for the optimization of the transformation process under different geological conditions of the block Bin 105 reservoir.