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.
This Month's Technical Papers
New Methods and Workflows Boost Effectiveness of Multizone Stimulation
Optimization of Limited-Entry Matrix Acid Stimulations in the Danish Central Graben
A New Strategy Explores Tight Oil/Gas Reservoirs: Fit-for-Purpose Acid Fracturing
Recommended Additional Reading
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.
Gerald R. Coulter, SPE, is a consulting petroleum engineer and president of Coulter Energy International. He is involved in consulting and technology transfer with respect to well-completion, formation-damage, and well-stimulation technology. Coulter’s industry experience includes work with Sun Oil/Oryx Energy Company, Halliburton, and Conoco. He has authored numerous technical papers and holds several patents. Coulter has been chairman of and served on numerous SPE committees. He is a past SPE Distinguished Lecturer and currently serves on the JPT Editorial Committee. Coulter holds a BS degree in geology and a BA degree in chemistry from Oklahoma State University and an MS degree in petroleum engineering from the University of Oklahoma.