Monitoring Injection Pressure Data to Predict Performance of Acid Fracturing Jobs in Horizontal Wells

Abstract

Evaluating the success of an acid fracturing job using injection pressure data is a valuable tool to diagnose the success of the treatment. In this work, a new strategy of analyzing the performance of acid fracturing jobs is presented. The strategy includes analyzing different plots of injection pressure data simultaneously to understand the progress of the job and identify some fracture parameters.

The new strategy can evaluate four main aspects of an acid treatment: the propagation and evolution of the fracture, the general shape of the fracture, fracture area and the type of treatment undergoing either etching or matrix acidizing. Combining different studies to analyze the trends of Δp on log-log plot to make conclusions is one of the main scopes of the study. A new approach in this work is applied to predict the area of fracture by adjusting the transient dual porosity solutions used for production data to accommodate the conditions of acid fracturing. The new technique allows use of modified models to interpret bilinear flow regimes and determine the fracture area.

This strategy has been applied to three horizontal fractured wells. The proposed technique was used to understand the fracture status at different stages during the treatment. The fracture area was calculated at different periods, showing the signature of bilinear flow with a quarter slope on the log-log plot of Δp vs. time. Calculated fracture area was compared to the one obtained from production data, and the results showed similarity.

The novelty of the new strategy is that it evaluates the performance of acid fracturing jobs without the need of either mechanical properties of the rock or production data. In addition, this strategy can be adapted for hydraulic fracturing treatments.