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How to standardise well identification

Thursday, October 3, 2013

Developing a standard system for identifying wells continues to be a constant challenge in the E&P industry, writes Nalin Jena, Upstream Data Manager with Reliance Industries, Mumbai.

With over 500,000 wells drilled world-wide so far, and unconventional oil and gas staking to drill a million wells in this century, wells are going to be plenty.

Wells are the medium for the reservoirs providing the hydrocarbons. They are long-living, expensive and the business agents.

Loose well naming is quite common leading to (for example) a complete lack of traceability of 100,000 wells drilled in the state of Pennsylvania in 19th century.

The industry has learnt the hard way the importance and methods of proper well naming.

Evolution of digital oilfields, real-time subsurface data like cross-borehole seismic, and integration of technical data with business and commerce, is increasing the need to have a correct well name.

But independent and mutually discordant UWI (unique well identifier) can become a pain when acquiring or relinquishing blocks with wells.

Uniform naming standards

There is no uniform world-wide well naming standard.

Physically, a well is a fairly complex entity that can change in a number of ways overtime.

Due to its physical complexity, a well is also a very complex data modelling entity.

Within the PPDM Data Model, there are over 1700 tables and 43000 columns, and a significant number of field characters deal specifically with aspects (attributes) of a well through its entire life-cycle, from planning through licensing/permitting, drilling, completion, production and operations, abandonment and reclamation. It is therefore, impossible to embed all aspects of a well in its name.

The challenge for data managers is to be able to maintain the identity of the well, through all its various aspects and phases. The UWI (unique well identifier)is the thread of life to this important hydrocarbon asset.

Defining the well name

You need to define a unique name for the well for its computerized access and usage. You need a naming method that can be made consistent (algorithmic) across different creators. Establish methods of validating the name for it consistent interpretation and use.

There are 3 different types of name.

The ''common well name'' is the name popularly used and followed in the company. Ideally, this should be limited to early stages of well lifecycle and slowly replaced by a more robust name.

The ''short well name'' is an abbreviated identifier normally derived from the field-code, well number and the orientation.

The ''unique well identifier'' is a code which definitely identifies every borehole distinctly. No two wells in the database can have same UWI.

You need simple, consistent methods for identifying all wells -an identity that will not change through time and an identity that will not change with various well operations.

It is imperative that each well (i.e. hole-in-the ground)be uniquely identified in order for computer oriented data to be most reliable in storage, extraction and analysis.

All well activities are discriminated to identify changes in data. This assures correct data integration.

Issues

The basic problem is that the various standards were created about 50 years ago, and technology has moved forward in such a way that there are cases where the structure of the UWI simply can''t accommodate the way that the wells can now be drilled.

Accounting of every well-bore and its data is necessary for integration and proper access to large volumes of data.

Geoscientists and engineers unknowingly gamble on a routine basis. Every time they assume the datasets being used, like velocity, paleontology, logs, reservoir /core analyses, production and test information have been digitally integrated to the correct well/well bore. Seldom are these audited or checked in work processes.

Qualities of good name

A good well name has fixed fields of precise definition - Name has definite and clear parts.

It has clearly and completely identified the well, well bores and its interventions affecting data.

It doesn''t carry extra attribute information, which can be easily and surely looked-up.

It is scalable, expandable to different known conditions; amenable to sets of new conditions.

It can be explained and followed in a concise manner.

Impact to business

There are many problems which can arise from poorly labelled wells.

Well names can misappropriate expenses and revenues.

You can get litigation.

You can get incorrect and incomplete data assignment leading to erroneous analysis and interpretation.

UWI implementation and governance

This is the process for implementing a ''unique well identifier'' system.

Collect and define all existing well-bores with a UWI.

Build and verify the master. Update the fields of all attributes.

Maintain a data dictionary of the attributes to ensure consistent interpretation and use.

As all wells are drilled by the drilling department, the responsibility vests with them to get the UWI right.

The data management team will issue and maintain the UWI for all approved, ready-todrill wells.

Periodic audit and review of the UWI.

Publish the UWI and well data master.



Associated Companies
» Reliance Industries Ltd.

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