Title: A new approach in pressure transient analysis part I: improved diagnosis of flow regimes in oil and gas wells
Authors: Victor Torkiowei Biu; Shi-Yi Zheng
Addresses: London South Bank University, 103 Borough Rd, London SE1 0AA, UK ' London South Bank University, 103 Borough Rd, London SE1 0AA, UK
Abstract: This paper introduces the statistical method for diagnosing flow regimes for flowing and shut-in conditions. The method utilise the second differencing of pressure change and time that are stationary; then integrate the residual pressure differences using simple statistical tools such as sum of square error SSE, moving average MA and covariance of data to formulate the statistical derivative models. These models are tested with constant pressure, constant rate conditions and in well with high water production. Results from three scenarios investigated demonstrated that the statistical derivatives yielded much clearer reservoir radial flow regimes as the conventional pressure derivatives without data smoothing; therefore give more confident formation permeability estimation. It demonstrated that for high water production well, a good radial stabilisation can be identified. It also showed that in all three scenarios, the drawdown radial fingerprint can be replicated in the build-up pressure responses, hence a good match of the data.
Keywords: pressure transient analysis; PTA; drawdown and build-up test; flow regimes; derivatives; StatDev; StatExp; StattDev; StatdDev; oil wells; gas wells; constant pressure; constant rate; high water production; reservoir radial flow; permeability estimation; radial stabilisation.
International Journal of Petroleum Engineering, 2016 Vol.2 No.1, pp.38 - 59
Received: 25 Jun 2015
Accepted: 02 Apr 2016
Published online: 25 Jul 2016 *