Abstract: A method of treating a hydrocarbon producing formation located downhole in a borehole, where the borehole has been cased and subsequently perforated, and the formation produces excessive water and an inadequate quantity of hydrocarbons through the perforations. Salt water is forced to flow down a tubing string, through the perforations, and out into the payzone. Thereafter, a spacer of fresh water follows the salt water, and thereafter a soluble alkali silicate solution flows behind the fresh water. Another spacer fluid of fresh water is forced to flow behind the silicate, followed by dilute acid. Next, the acid is displaced from the borehole and is forced out into the formation with flushing fluid, and the wellbore is then produced. The flow of the recited material through the perforations follows along the path of least resistance, which also is the flow path of the water intrusion. The salt water and silicate react with one another to form a barrier which prevents the water from invading the formation.

Abstract: A process by which vertical fracture growth is controlled downhole in a hydrocarbon producing formation through which a wellbore extends. The wellbore includes a perforated casing. Two different fluids are simultaneously forced along two separate flow paths downhole into the borehole, with the first flow path entering the uppermost perforations and the second flow path entering the lowermost perforations of the perforated casing. The first flow path conducts acid laden with relatively coarse grains of sand into the hydrocarbon producing part of the formation, while the second flow path conducts the flow of water laden with relatively fine grains of sand into the water producing part of the formation. The flow characteristics of the water/sand mixture and the acid/sand mixture causes the fine sand to drop out along the water/oil interface located between the low water and high water part of the formation.