Abstract The recent increase in oil and gas prices has fueled the demand for operators to decrease completion times without jeopardizing production seen with current conventional completion methods. A recent application of coiled tubing deployed fracturing service (CTDFS) not only displayed an improved efficiency in completion time but created one of the most prolific wells in the Willow Springs field for ConocoPhillips. A total of 18 individually designed, hydraulically fractured stages in the Cotton Valley and Travis Peak formations were completed in 73 hr of continuous operations, including a round trip of tubing to switch methods of isolation. The increase in completion efficiency is largely contributed to hydra-jetting perforations in the casing and then immediately hydraulically stimulating the formation by way of the annulus. This paper will present the process by which the CTDFS was executed and the observed results.

Abstract The application of horizontal completions in lower-permeability formations is continuing to proliferate on a global scale. Caused either by formation damage issues or the very heterogeneous nature of many such reservoirs, actual wells will underperform when compared to original predictions from reservoir simulations. This will continue to result in a need for effective hydraulic-fracturing stimulations for many of these wells to reach economic production levels. Horizontal completions in moderate- to low-permeability reservoirs present the challenge of cost constraints that seldom allow the use of long-proven methods such as cemented completions and individual-fracturing of numerous zones with bridge plug isolation and multiple perforating runs. Some new methods being applied to overcome this problem require expensive downhole "jewelry" and some added risks that the liner and jewelry can be entirely run to the predetermined depth. In some methods, the operator must also accept reduced completion IDs that can later restrict production rates or hinder workover operations. These increased costs and risks must be accepted even before the actual fracturing treatments are attempted. This paper will discuss a new approach to controlled placement of multiple-stage fracturing treatments without the risks involved with packers or bridge plugs. By implementing a coiled tubing (CT) deployed hydrajet-perforating method, immediately followed by a fracturing treatment pumped down the annulus, the operator can use lower cost (and lower risk) liner completions, and delay the decision of selecting exactly where the perforated sections should be placed. In many cases, the final decisions on placement of the next perforated location can even be delayed until after the wellbore displacement of the preceding fracturing stage. By pumping the fracturing fluid slurry down the annulus of the CT and the casing the allowable frac rates can be higher than with tubing-deployed techniques. The total stimulation related costs are greatly reduced by being able to perforate/frac multiple times within the same day. Even where more than one day is required to complete the stimulation of all desired locations along the lateral, only one CT intervention and one pumping service company mobilization and rig-up will be needed, which will still improve the job economy over conventional methods. An additional benefit includes a reduction in the potential for excessive multiple fractures or near-wellbore tortuosity encountered with explosive charge perforating.

Abstract Application of a new coiled tubing assisted fracturing method (CTFM) has been implemented in the Elm Grove Field in Bossier Parish, Louisiana. The new method has allowed all potential pay intervals to be efficiently stimulated. As compared with traditional methods of stimulation, the new method has resulted in better sustained production.

Abstract In the winter of 2005, the first multistage completion in an openhole, ultratight sandstone reservoir of the Dot Three field, China, was successfully completed using hydrajet-fracturing technique. Six propped hydraulic fractures were placed individually at strategically selected locations along two horizontal wellbores. Many horizontal wells with openhole completions have been drilled in low-permeability sandstone formations. The Dot-Three reservoir is one such case. Many of these wells perform below predicted rates with uneconomical oil production. Until recently, no method existed to effectively fracture-stimulate this type of horizontal, openhole wellbore to optimize production. Successful proppant placement in the Dot Three field (this field has adopted early-c waterflood pattern) has proved to be extremely difficult in the past. Propped fracture treatments pumped within the past 10 years were not successful and their post-frac production only averaged 1 ton oil/day. Proppant placement problems occurred, and were believed to be caused by simultaneous propagation of very narrow multiple hydraulic fractures. Past propped fracture treatments were performed on vertical wells and a few multiple fracture treatments on horizontal wellbores. These were only possible inside a cased hole using conventional methods (i.e. perforate, frac, set mechanical/chemical zone isolation, repeat cycle). The resulting treatment efficiency was low and results were not satisfactory. Because successful development of this reservoir would significantly impact Chinese oil production, another method for fracturing cased, horizontal wellbores and a new method of propped fracture stimulation in horizontal, openhole wellbores was justified. This paper discusses a hydrajet-fracturing technique that uses dynamic fluid energy (instead of mechanical methods) to isolate treatment fluid flow to a specific fracture point along the wellbore. Final results compared to past fractures using conventional methods and post-fracture production responses of the two experiment wells are also discussed.