Improved Depth Control For Slickline Increases Efficiency In Wireline Services

Abstract

The continuing quest for cost reduction in the oil field has required operators to take a closer look at all areas that might compromise efficiency. One area that has been identified is depth measurement accuracy. In addition to the critical part it, plays in service operations, depth measurement accuracy plays a significant role in the success of new completion concepts.

A new measurement system has been developed that increases the, efficiency of wireline operations by improving measurement inaccuracy experienced with traditional measurement systems.

Conventional methods for depth measurement have employed mechanical measurement devices without capability to make measurement adjustments for environmental or physical stress factors; therefore, these systems have not provided absolute accuracy. Through incorporation of a newly developed electronic counter that can provide continuous high-speed depth adjustment and data transmission, the new system can make the necessary adjustments for more accurate, depth control.

From testing and case histories, the practical benefits and enhanced capabilities of electronic depth measurement include:

1. Depth-measurement accuracy for ail commonly used Slick-lines and braided lines.


2. Measurement corrections for stretch resulting from line tension and temperature effects on counter heel.


3. Microprocessing compatible with slickline speeds.


4. Retrieval of depth, line speed, line tension, and, time data for downhole memory production surveys and wire management programs.


5. Use of the system for downhole, memory tool surveys as, a "cost-effective alternative to electric2line logging.


6. Use of the system to facilitate nippleless completions.

High speed resolution and data retrieval make this system inherently more efficient for support of slickline well servicing and other operations in which depth-control accuracy is critical to operational success.

Introduction

The volatility of oil prices has forced operators to focus more heavily on reduction of drilling and completion costs. Mechanical wireline or slickline services have provided a cost-effective means for routine well maintenance and workover for years. However, an increase in the scope of slickline services has recently been noted. One of the significant factors to this increase has been the development of a new measurement system that better supports industry needs for accurate depth control in servicing operations. Until economic constraints caused a resurgence of investigation

FIGURE 1: Wireline tools. Illustrations available in full paper.

into enhanced efficiency strategies, very little attention had been given to slickline depth measurement and the technical merit of surface measurement accuracy during normal operations. Slickline servicing provides an effective means for performing well maintenance by high speed mechanical manipulation of downhole service tools. Services such as setting packers and bridge plugs, perforating, and running downhole memory surveys can be accomplished with slickline at substantial savings over comparable electric line services. Accurate depth measurements are important to the efficiency of these operations and in some cases, are critical to the life of the well. For example, locating

FIGURE 2: Typical rig-up. Illustrations available in full paper.

holes in tubing for deploying tubing patches, running memory tool surveys where depth correlations are necessary to well performance evaluation, setting flow devices or bridge plugs, and locating depth of lost tools during "fishing" jo