Abstract

In the past, the operational and cost concerns of being able to treat and evaluate multilateral wells have left operators with limited economical options for remediation and evaluation. This paper describes a combination of fiber optic-enabled measurement system and a selective multilateral reentry tool.

The new system's bottomhole assembly design includes a multilateral reentry tool and real-time bottom hole feedback. The live feedback provides the operator with constant tool position in the wellbore which can serve as a key indicator of downhole tool function. With these specific measurements, downhole CT operations can be tracked and analyzed more quickly and clearly than ever before. Furthermore, this constant stream of critical data arms the onsite engineers and operators with information to make immediate decisions and thereby increase overall intervention efficiencies.

This paper demonstrates how this system has been effectively used during stimulation services for openhole multi lateral wells in Canada.

Introduction

The oil and gas fields of Western Canada are mature thus have many issues associated with mature fields. Mature fields by their very nature are usually depleted reservoirs. The depleted reservoirs make economics of well more challenging for the operator.

This challenge is being met by reducing surface cost for a given well through accessing the reservoir with more then one lateral per wellbore. The operator is able to have extensively greater reservoir surface contact area access. This is not however a perfect solution, as it greatly increases the complexity of the completion. This approach has been used in Canada primarily to date on carbonate reservoirs.

The carbonates targeted have enough hole stability in the formation to allow sidetracks to be used as openhole completions which simplifies this significantly. By using this technique, operators have been able to access greater reservoir surface contact area and compartmentalized parts of the reservoir using multi lateral completions with a minimal increase in the well construction complexity.

The intervention of these types of wells becomes more complex for two reasons. One reason is ensuring efficient intervention access to all laterals during the intervention. This poses a great challenge as the intervention now needs a method to orientate and more importantly recognize the lateral that has been entered. Another reason is the sub-hydrostatic condition of reservoir (cannot support a full column of fluid) due to their maturity which limits the use of pressure pulse telemetry.

The typical tool used for identification of laterals is pressure manipulated orientation. Defining the sub-hydrostatic condition of these reservoirs has been difficult to quantify before the intervention. Any method that makes this easier is needed. Accessing these laterals are critical to economical development of such oil and gas plays.

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