Comparing Fracture Stimulation Techniques

Candidate selection for acid fracturing Vs. Propped Fracturing There are no set guidelines for choosing between acid fracturing and propped fracturing. Historically, the choice often has been based on individual or collective logic. Production response is the best criterion for deciding between the two stimulation methods. Relative cost-effectiveness (value) is also a factor, as it should be. Unfortunately, despite great strides, our industry is not yet able to accurately model or predict the outcome of an acid fracturing treatment Acid fracturing lacks the higher degree of predictability associated with hydraulic fracturing with nonreactive fluids. However, knowledge of formation conditions can provide guidance for choosing the type and size of the stimulation treatment. + Candidate for propped fracturing: - Low HCl solubility (<65%-75%). - A homogeneous carbonate formation (e.g., pure limestones). - Low acid reactivity (e.g., low-temperature [<150°F] dolomites). - Very low formation permeability, thus requiring a long fracture. - Significant softening or creeping of rock under closure after contact with acid, resulting in poor retention of acid-etched fractures. + Candidate for acid fracturing: - A predominantly naturally fractured carbonate formation, potentially leading to propped fracture complications. - A heterogeneous formation, with porosity and permeability streaks that are conducive to a higher degree of differential acid etching of the fracture walls. - Good formation permeability, but with existing formation damage. - A well that will not mechanically accept proppant. In general, acid fracturing is the more conservative treatment design because proppant is not pumped. The risk of failing to complete the treatment is also much lower. There is no risk of premature screen-out, which can leave the fracturing tubing string full of proppant. Moreover, there is no risk of proppant flowback, with its troubling consequences. Another advantage of acid fracturing is that an acid frac can create conductivity to, but not within, an undesirable sandstone or shale interval. Furthermore, if effective etched conductivity can be imparted, flow turbulence in the fracture is expected to be less in an open acid fracture than in a fracture that contains proppant. Acid fracturing has to be used only where good differential etching is probable. The rock strength and closure pressure must indicate that good conductivity will remain after fracture closure. A disadvantage of acid fracturing is that controlling the leak-off rate of reactive acid in a fracture is very difficult. Without the benefit of field experience in a particular formation, prediction of etched conductivity and fracture length with a high degree of confidence is not possible. This is due to unknown leak-off characteristics. Ref, WORKOVER BEST PRACTICES, OMV Petrom #acidfracturing #hydraulicfracturing #leakoff #candidate

Leading Unconventional Completions in Egypt, I was lucky to be a part of such project in Khalda Petroleum Company led by Mohamed Salah and Mohamed ElSebaee, MBA You can consider this paper as a reference paper for the comparison between different multistage hydraulic fracturing completion technqiues Paper title:- Evaluation of Multistage Fracturing Stimulation Horizontal Well Completion Methods in Western Desert, Egypt 👨🔬 Authors: Mohamed Salah , Mohamed Gabry, Ph.D., Mohamed ElSebaee, MBA 📍 Presented at: SPE Middle East Oil & Gas Show and Conference, Manama, Kingdom of Bahrain, March 2017 🔢 Paper Number: SPE-183785-MS 🔗 DOI: https://lnkd.in/gGwhNYyK This paper presents a comprehensive evaluation of horizontal well completion and stimulation techniques used in Egypt’s Western Desert. It highlights the transition from traditional vertical wells to horizontal multistage fracturing to enhance reservoir contact and production efficiency in low-permeability, heterogeneous reservoirs. Completion methods such as plug-and-perforation, cemented sleeves with degradable balls, and coiled tubing-based abrasive jetting are assessed in terms of engineering design, post-frac performance, cleanup efficiency, and operational execution. The paper includes case studies, comparisons of technique performance, and practical field recommendations to optimize future stimulation programs.

🚨Deep-penetrating acid treatments in radially drilled channels as an alternative to hydraulic fracturing and matrix acidizing in carbonate reservoir 💡Deep-penetrating acid treatments in radially drilled channels are applied to provide stimulation in carbonate reservoirs. Maximum four 69 mm (2-3/4′′) diameter channels of up to 25m (82 ft.) are drilled along a pre-set trajectory. A special bottom-hole assembly on jointed pipes is deployed using a workover hoist. The technology allows re-entry of the drilled channels and acid treatment through the jet nozzle. The jetting nozzle has four 4.2 mm (11/64′′) perpendicular nozzles, and the acid outflow rate is approximately 100 m/s. In addition to rock dissolution, wormholes are washed into the formation at exactly the most effective location. 💡The first example of directional radially drilled channels with deep-penetrating acid treatment is through a jet nozzle on carbonate reservoirs. The technology proved its effectiveness and the planned significant oil increment targets were achieved. This method is very promising due to the very common occurrence of carbonate reservoirs in need of effective stimulation. The introduction of technology into the regular production program can now be considered and is supported by the results of the described project. 💡Efficiency of production stimulation technologies was compared at the analyzed fields (Fig. 10). It was found that the effect of radial drilling is 2 times higher than that of hydraulic fracturing and 4.5 times higher than that of reservoir stimulation by acidizing. Besides, the production decline rate is 25% lower than after hydraulic fracturing #petroleumengineering #hydraulicfracturing #stimulation #reservoirengineering #optimization #training #oilandgas #frac