Abstract: A method and a system for determining reservoir pressure in a wellbore during a falloff test are provided. An exemplary method includes shutting in a wellbore, measuring pressure versus time using a wellhead sensor, calculating a reservoir pressure versus time from the measured pressure, and determining if the measured pressure has dropped to zero. If the measured pressure has dropped to zero, measuring distance from the wellhead sensor to a liquid level versus time, calculating a vertical depth versus time from the distance versus time, and calculating the reservoir pressure versus time based, at least in part, on the distance and the vertical depth of the well. The method also includes creating a falloff curve from the reservoir pressure versus time and providing the falloff curve.

Abstract: A method and a system for determining reservoir pressure in a wellbore during a falloff test are provided. An exemplary method includes shutting in a wellbore, measuring pressure versus time using a wellhead sensor, calculating a reservoir pressure versus time from the measured pressure, and determining if the measured pressure has dropped to zero. If the measured pressure has dropped to zero, measuring distance from the wellhead sensor to a liquid level versus time, calculating a vertical depth versus time from the distance versus time, and calculating the reservoir pressure versus time based, at least in part, on the distance and the vertical depth of the well. The method also includes creating a falloff curve from the reservoir pressure versus time and providing the falloff curve.

Abstract: A method for extracting hydrocarbons from a carbonate reservoir in a formation, the method includes: injecting an aqueous conditioning slug having a primary reducing agent into the carbonate reservoir; injecting an aqueous main slug having an alkalinity agent and a secondary reducing agent into the carbonate reservoir to treat the carbonate reservoir and surface of the formation to reduce interfacial tension and alter wettability of the surface of the formation towards water-wet; injecting an aqueous buffering slug into the carbonate reservoir, the aqueous buffering slug having a tertiary reducing agent to treat the carbonate reservoir and surface of the formation to maintain altered wettability; wherein the primary reducing agent, secondary reducing agent, and tertiary reducing agent are inorganic sodium salts selected from the group consisting of: sodium sulfate, trisodium phosphate, sodium tetraborate, sodium iodide, and combinations of the same; and injecting a displacing fluid to drive the hydrocarbons i

Abstract: A method for extracting hydrocarbons from a carbonate reservoir in a formation, the method includes: injecting an aqueous conditioning slug having a primary reducing agent into the carbonate reservoir; injecting an aqueous main slug having an alkalinity agent and a secondary reducing agent into the carbonate reservoir to treat the carbonate reservoir and surface of the formation to reduce interfacial tension and alter wettability of the surface of the formation towards water-wet; injecting an aqueous buffering slug into the carbonate reservoir, the aqueous buffering slug having a tertiary reducing agent to treat the carbonate reservoir and surface of the formation to maintain altered wettability; wherein the primary reducing agent, secondary reducing agent, and tertiary reducing agent are inorganic sodium salts selected from the group consisting of: sodium sulfate, trisodium phosphate, sodium tetraborate, sodium iodide, and combinations of the same; and injecting a displacing fluid to drive the hydrocarbons i