High-Rate High Volume a Novel Technique for Uniform Matrix Stimulation of Naturally Fractured Low-Pressure Reservoirs

Abstract

Abstract Matrix stimulation techniques are primarily employed to eliminate the near-wellbore skin. In reservoirs with high permeability and natural fractures, achieving a uniform distribution of treatment fluid poses a significant challenge. The use of chemical diverters is not always effective and often leads to fluid losses in zones with high permeability with little to no impact on the production parameters. Therefore, it is necessary to investigate additional parameters and conduct a detailed analysis of past job executions, procedures, and results. Implementing modifications in procedures, stages, and treatment design based on this analysis can enhance the success rate. A highly effective method for uniformly stimulating the reservoir is a high-rate, high-volume job. By combining a high flow rate with chemical diverters, the high permeability zone is bottlenecked, diverting the flow to the low permeable zone, and ensuring uniform distribution of the treatment fluid. The flow rate is determined based on injectivity tests and maximum pressure limitations, while the volume of the treatment fluid is selected based on the pay zone interval and formation porosity. This stimulation technique is particularly advantageous in low-pressure reservoirs with naturally high-conductivity fractures where losses are very common. The aforementioned technique has been employed in various wells located in the North and South regions of Pakistan, resulting in significant improvements in almost all cases. For instance, in one case study, it led to a production gain of 03 million standard cubic feet per day (MMSCFD), while another case observed a 2,000-barrel per day increase in oil production. This paper describes the modifications implemented in acid placement procedures that ultimately improve the productivity of stimulated wells. It will cover the below: Various methods of acid placement with their pros and cons. A comparative analysis of conventional acid placement methods vs. adopted methodology. Laboratory analysis illustrating solubility and compatibility of the proposed treatment fluid. Simulations results of adopted methodology along with the execution. A comparison of Post Job Parameters using conventional vs. implemented techniques.