The Damage Experiments And Optimization Study On Yanchang Gas-field Reservoir Applied Low Concentration Guar Gum Fracturing Fluid

The Yanchang gas-field is located in the south-east of secondary structure unit of Yishan slope which is part of the upper Paleozoic of Ordos Basin.It mainly gassy formations are upper Paleozoic Shihezi formations,Benxi formations and Shanxi formations.So the advance of fracturing technology is an important measure of oilfield stimulation.While the changes of reservoir strata and different sensitivity bring different reconstruction effect and the high cost of the traditional guar gum fracturing fluid brings big pressure to the Yanchang Petroleum under the background of low oil price.The article analyses the experiment which studies the guar gum fracturing fluid with low concentration to the sensitivity of Yanchang gas-field’s reservoir.The text proposes that better fracturing fluid can improve the permeability of the reservoir and protect the reservoir from the damage of fracturing fluid.The study finds that the speed sensitivity of Shihezi Formation,Shanxi Formation and Benxi Formation are weak in general;the water sensitivity and salt sensitivity of Shanxi Formation are strong and Shihezi Formation’s are less strong.Shihezi Formation and Shanxi Formation’s acid sensitivity are moderately strong and weak acid,and the permeability of partial layers has been improved;there is only Shihezi Formation is medium to strong alkali sensitivity.On this basis,the paper further analyzes the mechanism of reservoir sensitivity,in addition to study the reservoir sensitivity affected by widespread sensitivity minerals and related to the porosity of sample.The partial minerals in tight reservoir of Shihezi Formation react with acid to sediment which clogging the throat.However there are The Shanxi Formation and Benxi Formation have cracked partly or large throat deposits that cannot accumulate.This results in good effects of acid solution on reservoir permeability.This paper puts forward the optimization suggestion in combination with the compatibility of formation water and fracturing fluid,and use different concentrations of Guar Gum fracturing fluid to make damage experiments on the core from the researched region.By comparative analysis,the concentration of guar gum is 0.35% the fracturing fluid brings the least damage to the reservoir.Compared to the conventional fracturing fluid used in the reservoir the damage was reduced by about 50%.This low-concentration fracturing fluid was applied to Zi 29 well and the test of the well is greatly improved getting great effects in the construction of the actual production process.This paper has some guiding significance for the development of Yanchang gas fields.Why It’s Innovative:1.Sensitive mineral’s rational analysis of sensitive mechanism was conducted in different reservoir sensitivity.2.The comparative damage experiments was carried out with different concentration fracturing fluid.