1997 08 15
Downhole External Casing Measurements

This Request for Proposal (RFP) is a direct result of the April 15^th, 1997 PTAC Reservoir Recovery Problem and Opportunity Definition Workshop. The RFP is being sent to you for consideration of the proposed technology as a potential funder with other industry players. Should you be interested, please fill out the attached "Expression of Interest" form and return to Arlene Merling at PTAC no later than August 15, 1997. Provided there is sufficient producer interest, PTAC will issue this RFP to the industry at large, targeting potential suppliers and request specific proposals for consideration by those producers interested in the development of this technology.

Introduction
The industry is currently trying to address a number of issues that involve assessing near wellbore effects. These issues include, but are not limited to:

• formation damage assessment from drilling
• assessing causes and possible remedies for early water or gas breakthrough due to coning or cresting
• effectiveness of chemicals to remove near well bore damage
• effectiveness of near well bore blocking and diverting agents for flood conformance.

A core problem identified in addressing all these issues is the general lack of dynamic information on the near well bore during the drilling, completion and operation of wells. The purpose of this RFP is to encourage research and development of new or improved methods of measuring various properties of the near well bore area through use of external casing sensors which can be installed during well completion and monitor those properties throughout the wells producing life.

Requirements
PTAC would like to encourage the development of sensors, signal transmission methods and data processing/analysis methodologies which have the potential to provide more and various information on what happens in the near well bore area. Possible technologies might include:

1) Sensors - Useful sensors might detect:

a) fluid properties along a well bore to indicate what fluids are being produced from each zone;
b) reservoir properties such as temperature and pressure along the length of the well.
c) flow properties, perhaps use of acoustics to detect relative in flow velocities along the well.

2) Signal Transmission Methods - Might include:

a) wireline run external to the casing;
b) signal through casing with separate power source

3) Data Processing/Analysis Methodologies: To make use of the external signals there must be some method proposed for analyzing and interpreting the signals to determine what is physically happening in the near well bore. Issues to be addressed are:

a) Can the sensors be tested and calibrated before installation to show that readings will reflect reality;
b) How could the readings collected be used to learn about the near well bore response?
c) How would the readings provide an advantage over current in well methods?
d) How would readings potentially affect decisions on drilling, completion and operating practices?

Development Steps to be Addressed in Each Proposal
PTAC would like an early response from vendors who think they can contribute to addressing the problem of understanding near well bore issues, or from producers who can provide additional justification and support for near well bore studies by August 15, 1997. Representatives of the Reservoir Recovery Technical Subcommittee of PTAC will then work to ensure all interested parties are aware of the potential solutions and benefits. As specific proposals are prepared by vendors and submitted to PTAC, these will be reviewed and results provided to potential funders with feedback to the proponents over the summer. Specific development steps to be addressed in the proposals should include:

1) Define what can or could be detected external to the casing.
2) Define how the sensors could be installed in various completions.
3) Description of how readings might be interpreted, and advantage over existing methods.
4) Indicate what the potential costs might be to develop and prove out the tool and techniques
5) Describe what testing might be required to prove up and document the benefits of the technology.