Abstract

Operating companies spend more money than necessary on tubular inspection due to the lack of a coordinated quality assurance program. A substantial percentage of previously inspected tubulars have rejectable defects that result in excessive expenditures due to failures. An inspection program is proposed to maximize efficiency and reduce costs. Supporting evidence is also presented indicating that operators should not be liable for a significant percentage of the damages marked on rental tubulars following use.

Introduction

Defects in drilling and production tubulars are directly attributable to the manufacturing process, transportation and handling, and in-well loading and environment. The high cost associated with tubular failures has increased the need to insure that only premium quality tubulars are used. The minimum specifications for allowable defects are defined In the various applicable API publications. Tubular inspections performed in accordance with these specifications are the most practical means available to assure product integrity.

Tubular inspection companies all claim to have the equipment, knowledge, and ability necessary to perform inspections in accordance with API specifications. Most of the equipment used has the capability of locating API defects if It is setup, calibrated, and operated properly.

Problems arise because of the following reasons:

  1. Lack of Inspection Quality - Data indicates that a significant percentage of previously inspected tubulars have rejectable defects.

  2. Conflict of Interest - An inspection company is often hired by parties who are motivated by different interests.

  3. Inefficient Record Keeping - As tubulars are transported and stockpiled, the inspection records are not maintained resulting in redundant inspections.

Results presented in this paper indicate that quality assurance super-vision minimizes rejectable defects and can be expected to reduce conflicts of interest and improve record keeping.

There are inherent problems with tubular inspection caused by the involvement of numerous parties with different purposes. This paper presents an inspection program designed to minimize these problems. Conoco's Oklahoma City Division North American Production (NAP) - is currently implementing a similar program. It is the premise of this paper that operators must take control of every aspect of tubular inspection and maintenance in order to bring about the necessary changes.

TYPICAL HISTORICAL INSPECTION SCENARIOS

When attempting to establish an inspection program, an understanding of the types of problems the system must overcome is essential. The following scenarios describe the experience of Conoco's Oklahoma City Production Division and illustrate the complex historical interrelationships at work during tubular inspection. It is believed that they also represent the typical experience of other Mid-Continent area operators.

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