Application of acidizing in bi-lateral horizontal well in carbonate reservoir

In order to increase single well control area, producing degree and production of single well, a pilot test of bi-lateral horizontal well acidizing was conduced in K oilfield, Kazakhstan. First, clean self-diverting-acid system was chosen as the main acid, which has self-diverting and little formation pollution, based on the characteristics of the reservoir, lithology and physical properties of this oilfield. Besides, nitrogen and liquid nitrogen were used to temporarily block high permeability layers and make the acidizing more uniform. They can also accelerate flowing back velocity of residual acid. Treating pressure, pumping rate, and coiled tubing drawback velocity were optimized. The analysis after acidizing shows that acidizing worked in plugging removal and productivity restoration in both branches, and the production of single branch equals to its neighbour well separately. This means that bi-lateral horizontal well acidizing can get good application effect in this oilfield.