Performance evaluation and application of new fuzzy-ball micro bubble treatment fluid

It is easy to pollute formation using the conventional method of plug channeling when the oil well cement quality is bad. To solve the problem of formation pollution, one new oil layer diverting agent-micro bubble treatment fluid is developed. It cannot reverse rock wettability and cannot stop reservoir fluid flowing. The properties of rheology, static plugging, and dynamic pollution of micro bubble treatment fluid were evaluated. The laboratory experiment proved that the fuzzy-ball micro bubble treatment fluid has good injectability and its viscosity decrease with shear rate. Under the temperature of 120 °C, back pressure of 0.5 MPa and differential pressure of 5 MPa, the leakage of micro bubble was zero. Core permeability recovered ratio was up to 96.1 % after pollution for 48 h. The new fluid has been used on four wells in Jidong Oilfield. The results of pilot test showed that the effect of decreasing produced water and increasing oil production was very obvious. The cumulative quantity of oil was 12,435 t; the cumulative decreased quantity of water was 32,496 cubic meters and the average water cut had decreased by 17.6 %. The application effect indicates that it not only can reduce the operating risk but also has good plug channeling and layer protecting effect. After it is used on spot, the effect of increasing oil production and reducing aquifer yield is obvious, and the period of validity is longer.