Efficient Multifractured Horizontal Completions Change the Economic Equation in Latin America through Improved Reservoir Contact and Well Productivity

Abstract

Latin America hasn't escaped the general industry trend of finding reserves in ever challenging environments. Complex geology and low permeability are the common denominator in today's environment. Developing reserves under these conditions with conventional vertical wells is in most cases uneconomical. In this setting, horizontal wells have come to mitigate the problem, however in most unfavorable conditions where oil and gas are found in tight formations fracture stimulation needs to be added to the equation. Conventional multistage fracturing techniques including perforating, fracture stimulating and isolating stages with a composite bridge plug have been applied in some cases with limited success. The time consumed in the completion operations extends over weeks making wells uneconomical. In addition, the prolonged time over which the frac fluid remains in the formation before being flowed back often affects well productivity. This paper describes the experience of three operators in Latin America that have implemented a new completion system to overcome the time consuming and productivity limitations of conventional completions described above. The new completion system is run as part of the production liner, does not require cementing and provides positive mechanical diversion at specified intervals, so fracturing and stimulations can be pumped effectively to their targeted zone. The system has also been designed, so all of the fracturing or stimulation treatments along the horizontal wellbore can be pumped in one continuous operation, thus minimizing the associated risks and optimizing the efficiencies of both the personnel and equipment needed to perform the work. The conclusions will show the operational efficiencies and reliability of this novel completion system, as well as analyze the cost benefits and production increases that have been observed. Introduction Operating companies are continuously pushing to improve hydrocarbon recovery, a task that is becoming more and more difficult as they are pushed to develop fields in more complex settings and with poorer reservoirs properties. Horizontal wells have been a tool widely used to improve both production rates and recovered reserves per wellbore in order to improve the economics of particular projects or make them commercially viable in extreme cases. Over the last two decades many developments have enabled accelerated growth in horizontal well applications. Drilling has led the way, with current technology capable of drilling thousands of feet laterally through a hydrocarbon reservoir. Drilling technology has evolved to a point where horizontal wells can be constructed at comparable costs to vertical wells while offering the advantage of higher production rates and better access to reserves. Often times fewer horizontals are required to develop a field given its larger drainage area. However horizontal well completion has lagged behind, in particular when a stimulation treatment is part of the completion or has to be applied as a remedial treatment in wells performing below expectations1.

Well Completion Strategy and Optimization in a North Dakota Bakken Oilfield

“…As of September 2010, over 5,200 OHMS have been run worldwide in hundreds of formations, both on and offshore, proving the versatility of these systems (Al-Naimi et al, 2008;Saldungaray et al, 2008;Samuelson et al, 2008;Solares et al, 2008;Achi et al, 2009;Bukovac et al, 2009;Casero et al, 2009;Desai et al, 2009;Lee et al, 2009). Figure 11.…”

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“…As of March 2010, over 4,500 OHMS have been run worldwide in a variety of formations, both on and offshore, proving the versatility of these systems (Al-Naimi et al, 2008;Saldungaray et al, 2008;Samuelson et al, 2008;Solares et al, 2008;Achi et al, 2009;Bukovac et al, 2009;Casero et al, 2009;Desai et al, 2009;Lee et al, 2009). Figure 6.…”

Optimization of Completions in Unconventional Reservoirs for Improved Efficiency and Ultimate Recovery

“…This trend is still increasing in a direction which would indicate that optimization of multi-stage completions has yet to be fully realized. As of September 2010, over 5,200 OHMS have been run worldwide in a variety of formations, both on and offshore, proving the versatility of these systems (Al-Naimi et al, 2008;Saldungaray et al, 2008;Samuelson et al, 2008;Solares et al, 2008;Achi et al, 2009;Bukovac et al, 2009;Casero et al, 2009;Desai et al, 2009;Lee et al, 2009 Figure 1. Resource triangle (modified from Masters, 1979 andMiskimins, 2008).…”