New One-Trip Multi-Zone Frac Pack System with Positive Positioning

Abstract

Effective fracture stimulation of multiple pay zones usually requires multiple fracture treatments with multiple trips in and out of the wellbore for perforating and placing frac pack equipment. An additional concern is positive positioning of downhole equipment, particularly when performing high-pressure treatments in deviated wellbores or from a floating platform or drilling rig. A system is presented that allows stimulation of multiple pay intervals using several independent fracture treatments to be accomplished with a single trip into the wellbore to place packers, screens and gravel pack tools. The system also keeps the equipment in proper positioning for each treatment, thereby minimizing the risks associated with treating multiple zones. Treatment parameters are discussed to assist in designing the independent stimulations. We will also discuss several equipment issues important to eliminating risk associated with pumping these treatments. An example is presented to illustrate how this system can be used to treat a long production interval with high laminated sands. Introduction Hostorically, any well that encountered multiple pay zones and was a candidate for a frac pack treatment would be completed using a ‘stack pack’ procedure that included multiple trips into the well to perforate and complete each zone sequentially. This multiple trip operation is sometimes required by reservoir or operational considerations and may also be required from regulatory constraints. For water frac operations and circulating gravel pack treatments below fracture pressure, a one-trip multiple zone system has been successfully applied in a large number of offshore wells during the last few years1,2. These operations have been very successful and have resulted in excellent time savings and efficiencies. This paper discusses a new system that extends one-trip multi-zone fracturing technology to high-pressure gelled fracing applications, offering significant advantages in a variety of situations. The system described herein incorporates new designs and technologies that have been developed to meet growing requirements for robustness and ability to address the higher sand concentrations, fracturing rates, pressure differentials, and larger jobs that are being pumped today. Description of Equipment The complete gravel pack system described here was developed by extending and combining technologies already existing in a single zone frac pack system and a one-trip multi-zone gravel pack system. A drawing of a sample system is shown in Figure 1. The goal in designing this system was to meet the same pressure and rate requirements as a single trip frac pack equipment system. Thus all system packers used to isolate between zones should be capable of a 10,000 psi pressure differential during treatment. The system for 9–5/8 in. casing should be capable of fracturing rates as high as 40 BPM with sand concentrations of 12 ppa. The system for 7 in. casing should be capable of fracturing rates as high as 15 BPM with sand concentrations of 12 ppa. All pressure and sand concentration goals were met. The fracturing rate goal is somewhat dependent on the total length of the system because of the ‘snorkel tube’ that extends the crossover tool. This tube has a 2.441 in. ID in the 9–5/8 in. system and a 1.650 in. ID in the 7 in. system. When the overall system is very long, the increase in friction pressure through these small ID's becomes a consideration in the rate that can effectively be used.

Study, Forecast and Controlled Seismic Hazard Reduction in the Identified Segments of the Main Faults by Cyclic Injection of Fluid Through Deep Multi-Branch Directionally Inclined Wells

“…В частности, ранее было показано, что низкая скорость закачки также может снижать связанные с закачкой сейсмические риски за счет более равномерного распределения давления жидкости в трещине [Ji, Wu, 2020]. Не случайно гидравлические воздействия в природных условиях уже широко освоены в практических разработках мирового сообщества (гидроразрыв пласта) применительно к нефтенасыщенным осадочным породам с целью создания искусственного фильтрационного поля для добычи углеводородов (УВ) [Hubbert, Rubey, 1959;Migursky, Staroseltsev, 2000;Rylance, Mahadev, 2016;Vickery, Bayne, 2002;. Подобные мероприятия энергетически наиболее легко реализуемы и эффективны.…”

“…5), при котором формируется магистральный разрыв. Механический или гидравлический механизм воздействий [Rylance, Mahadev, 2016;Vickery, Bayne, 2002;Usachev, 1986; позволяет успешно достигать управляемой плавной разгрузки напряженного массива горных пород через последовательное волновое гидродинамическое воздействие, при котором поле напряжений изменяется под воздействием давления флюида на сегменты разломов.…”