Study and Application of Starting Pressure Testing for Injection Wells

Wenmingzhai , Weicheng , and Mazhai (WMZ, WC, MZ) are mature waterflooding oilfields. The flowing contradictions are obvious because of the difference of starting pressure among the pay zones. The first is that the lower injection pressure can not start the pay zones with higher starting pressure . The second is that the aim of zonal injection can not be met under the same injection pressure . In addition, the single input profile data can not display the water absorption of all zones completely. The previous method and theory of starting pressure testing and calculation can not satisfy the requirement of the starting pressure test for multiple series formations, and the water absorption of all the zones is not clear, which resulted an unfavourable water flooding effect . This paper introduced the process theory and its oilfield application of the zonal starting pressure test technology . Based on the requirement of zonal starting pressure test, an advanced oilfield zonal starting pressure testing technology was developed. The Correlation of the test data and the formation parameters such as original formation permeability, porosity , the situation of injection and input profile data was studied. According to the analysis of correlativity of test data and formation parameters , the counter-measures were obtained . Four application examples were analyzed to show how to use the test data and how to choose the correct counter-measures. This zonal starting pressure testing technology can be widely used to improve oil recovery for mature oilfields. The zonal starting pressure testing was proved to be effective for WMZ, WC and MZ oilfields. Different methods were found to reduce the pressure difference among zones. Experience obtained through these applications is useful for planning future applications.