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.

Introduction

With the increase in oil and gas prices, operators and service companies, alike, have an increased need to operate more efficiently. For many operators, increasing completion efficiency has a direct and very positive effect on profits, especially in a time of rising commodity prices. One means of maximizing the completion efficiency is to decrease the cycle time of a well or the time it takes to drill and complete a well. CTDFS is a means by which operators can decrease their cycle time while not sacrificing valuable production out of the well. By eliminating operations such as perforating with wireline and milling out bridge plugs, CTDFS has decreased the cycle time by as much as a factor of 10.

Equipment and personnel become less available when the demand for services increases. By applying CTDFS to the completions schedule of a well, operators and service companies can maximize the use of their assets. The efficiency of CTDFS allows wells to be perforated, fractured, and cleaned out in a few days as opposed to a typical length of several weeks with conventional methods. This allows operators to focus on one well at a time without having to distribute personnel across several simultaneous fracture treatments or completions.

The safety and environmental wellbeing of a wellsite is a driver behind successful and efficient operations. By using CTDFS, all parties involved have the opportunity to reduce the exposure time on location to activities that contribute most often to injury, such as rig-up/rig-down operations or mobilizing equipment. Making only one trip to the wellsite not only helps reduce the risk of injury present in day to day operations, but it also reduces the overall environmental footprint seen by the wellsite and the surrounding community.

When performing a CTDFS, it is important to ensure that the well selected for the service will benefit from the operation. Wells with multiple, laminated pay intervals that are typically approached using limited entry methods are prime candidates for CTDFS. The CTDFS process allows for pinpoint placement of fracture treatments, and the operator can be confident that effective fracture treatments are being delivered into each selected interval.

Wells A, B and C are located on the same pad in Willow Springs field in North East Texas. Wells A and B were completed using conventional "perf and plug" techniques and Well C with CTDFS. Prior to design, it was determined that CTDFS had potential to reduce water production, lower the completion cost, and decrease the overall completion time of the well. Each of the three completions will be discussed in depth, along with their respective results.

Well Properties

To better understand the completion operations performed on Well C, it was necessary to describe the surface configuration and well design.

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