Optimization of water consumption of hydraulic fracturing treatment by utilizing recycled flowback fluidse

摘要

As the hydraulic fracturing activities are dramatically increasing in Saudi Arabia, the demand of fresh water supply for stimulation jobs is also growing. Conventional acid/proppant fracturing stage normally acquires 80,000 to 100,000 gallons. In areas where water source is over a large scattered distance, delivering water to locations becomes logistically complex. Therefore, a solution to overcome the dilemma of fresh water scarcity is vital to preserve the resources and save the cost on the long-term. This paper analyzes the solutions implemented to preserve the fresh water utilization in fracturing applications in the kingdom and the other proposed solutions in the upcoming future. Two methods have been approved successfully into preserving fresh water consumption and alternate the utilization of fresh water resources: Sea-water Nano filtration, and CO2 fracturing fluid. Both applications have been implementing in Gauwar field into gas bearing zones as an acid or proppant treatments. However, delivering sea water from water injection plant, then filtrate it makes the process even more complex than utilizing a fresh water sources. Moreover, such a practice was not economically viable and requires an infrastructure for long term plan. In addition, remote areas and scattered gas fields won’t benefit much of this alternative. On the other hand, utilization of CO2 as a base fracturing fluid reduced the usage of fresh water as a current solution. Thus, it is still depending on the formation compatibility and the CO2 quantities in hand. As a result, a new solution is proposed to overcome the fresh water scarcity especially with the expansion of gas fracturing operations in the kingdom. The need to find a sustainable cost effective alternative is crucial, such as Recycling Flowback fluid to be reused as a base fluid for the next stages on the same well. The process will save fresh water resources, transportation of water from the source to the desired well in the front end and waive the need to treat the flowback fluid and dispose it into the waste disposal area on the back end. In the gas fields of the kingdom, most of onshore gas wells require fracturing operations to economically produce. More than 50 % of the new wells acquire 3-5 stages to be hydraulically fractured in order to produce commercially and sustain production. In the meantime, 40-60% of fracturing fluid returns back during the flowback operation after each stage where 10% of that fluid is mixed with gel and the rest is a gel-broken fluid. The concern is filtering the fluid after the gel is broken to simplify the process. In summary, this paper comprehensively reviews the benefit of using a robust fracturing fluid that can utilize 100% produced/flowback instead of freshwater for fracturing operations; that should become the norm as we move into a more environmental friendly paradigm.