Technology Focus: Well Stimulation (June 2013)

Abstract

Technology Focus This past spring, I had the opportunity to review more than 100 SPE paper abstracts as well as numerous full papers from those abstracts. To SPE’s credit, these abstracts all represent high-quality papers, making it difficult to select those to be highlighted for this feature. The papers chosen for highlighting are those that represent some of the challenges our industry faces and solutions shown to help overcome these challenges. The nonproppant well-stimulation trend continues to be acidizing of the carbonates. What really stands out is the industry emphasis on the continued move to marginal reservoir targets (i.e., poor-quality carbonates as well as sands and shales). For this move to be successful, long-reach horizontal wells are being used. Along with the long reach comes reservoir heterogeneity and the commensurate need for zonal isolation. Or, said another way, the need is to ensure that the entire interval gets the required treatment in these low-quality reservoirs. Last year, after a similar review, it was apparent that horizontal wells and proper acid placement were priorities. The subject that seemed to prevail was distributed-temperature-sensing and distributed-acoustic-sensing diagnostics. This year, the published-literature emphasis is on methods and required equipment to achieve better acid placement. The papers chosen to be summarized are excellent resources related to this emphasis. The first paper, Improved Methods and Workflows for Multizone Stimulation, illustrates tools and workflows that have improved multizone-stimulation effectiveness. The second paper, Optimization of Limited-Entry Matrix Acid Stimulations With Laboratory Testing and Treatment Pressure Matching, is of importance because it discusses the application of acid jetting in long horizontal chalk wells but also addresses pressure drop across perforations. The paper further focuses on the elusive perforation coefficient used by many of us in the design of limited-entry zonal stimulation. And the third paper, A New Strategy To Explore Tight Oil/Gas Reservoirs—Fit-for-Purpose Acid Fracturing, demonstrates the value of a strategy to improve on the success in poor-quality reservoirs. The first additional-reading paper, Successful Application of a Fit-for-Purpose Acid Program in the Tengiz Field, demonstrates application of this approach. Recommended additional reading at OnePetro: www.onepetro.org. SPE 160804 Successful Application of a Fit-for-Purpose Acid Program in the Tengiz Field by K. Ussenbayeva, Chevron, et al. SPE 162238 Acidizing—Lessons From the Past and New Opportunities by Robert Taylor, Halliburton, et al. SPE 160762 Successful Application of Foamed-Acid Stimulation of Severely Damaged Perforations in a Horizontal Intelligent Well by W. Ruksanor, Sakhalin Energy Investment Company, et al. SPE 163384 Unique Process and Tool Provide Better Acid Stimulation and Better Production Results by Mishari Al-Saqabi, Kuwait Oil Company, et al.