Publications

Tight oil reservoir becomes a new challenge and generates new opportunity in the brownfield areas. The main reservoir properties have to be refined prior to field development planning. It can be obtained through several well testing methods such as Pressure Build Up (PBU) test, Pressure drawdown (PDD) test, Leak Off Test (LOT) for injection well and others. While there is no production rate or very low production rate as usually occurred in tight oil reservoir, PBU and PDD test cannot be applied. Leak off test can be an alternative method to measure the reservoir properties by injecting an amount of fluid to the well at constant rate and then shut in to let the pressure in transient condition in the wellbore. This paper presents comparison between LOT and PBU test result. LOT is conducted along with the pre-fracturing treatment before main hydraulic fracturing. LOT yields breakdown and fracture closure pressure and if a pseudo-radial flow regime achieved, reservoir matrix permeability and initial reservoir pressure can be determined. Meanwhile, PBU test is applied after hydraulic fracturing stimulation at the same well. As typical PBU test, reservoir matrix permeability, initial reservoir pressure and skin factor can be observed. The skin factor is the combination product of fracture and well geometry. Both two methods show a consistent result in reservoir properties. The difference between PBU test LOT result, especially in reservoir matrix permeability and initial reservoir pressure, is less than 10%. LOT prior to fracturing treatment is concluded as a reliable method in determining the key reservoir properties and could eliminate oil deferment as occurred in PBU test after hydraulic fracturing. It also becomes an accurate reference in reservoir static modeling and history matching in dynamic modeling. As the result, field development strategy is more convenient to maximize field oil recovery.