Mitchell

 Executive Summary

Robert Mitchell, Halliburton Company

The Value of Research
I don’t believe I need to convince the readers of SPEDC of the value of research. Otherwise, you wouldn't be writing papers and reading this journal. However, I saw a poster that I think outlines the problem neatly.

We have all seen the inspirational posters with uplifting messages like "fly with the eagles, etc.," and some of you may have seen some of the mock-inspirational posters created in response. The poster I saw stated, "The simplest solutions are often the cleverest. They are also usually wrong."

Therefore, the subject of today's executive summary is the effective force. To account for the effects of fluid forces, the actual force in a pipe is replaced with the effective force in the equilibrium equations. Why must we do this? Consider a metal bar. I test the metal bar and find that it collapses under an axial load of 100 lbs. I then submerge the bar to a depth where the water pressure on the ends of the bar equal 100 lbs. Does the bar collapse? Most engineers would say no, but skeptics can easily perform the experiment to find out. The normal expectation is that the effective load on the bar would be zero in this case, and, indeed, the effective force is zero. Fluid pressures interact with the pipe in several distinct ways. A resultant load appears when we have a tapered pipe or a curved pipe. A resultant load appears when the pipe inclination changes or when the pressure changes with position. If we pose a simple problem where these effects are zero, then we might be persuaded that the effective force is an invalid concept. We would be wrong.

What should we do? The simple answer is to read what others have done to invent the concept. The original papers by Klinkenberg and Lubinski, for instance, go to great lengths to understand and explain the effects of fluid pressure. Studying the history of a subject is often a useful way to learn about a subject and to add depth to your understanding. This simple concept is not wrong--it's called research.

In this issue, we have a variety of Drilling and Completion topics. Included in the completion topics are: Guidelines For Shale Inhibition During Openhole Gravel Packing With Water-Based Fluids. The drilling community is well aware of problems with shale swelling and sloughing caused by water-based drilling muds. The problems with shale reactivity during gravel packing remain largely unexplored. This paper provides guidelines on selection methodology of shale inhibitors for gravel-packing applications. Standard hot roll dispersion tests were found useful, but the authors have determined that a dynamic flow through test should be used for assurance of a successful water packing treatment. Improved Prediction of Shallow Sediment Fracturing For Offshore Applications. Shallow sediments in deep-water wells have proven troublesome. Among problems associated with these formations are low fracture strength, borehole collapse, water influx, poor cement jobs, and shallow gas flows. In this paper, a generalized fracture model is developed for shallow sediments in relaxed depositional environments. The model was tested for five deepwater cases and one shallow-water well, and the correlations to measured frac gradients were found to be excellent. First Laboratory Perforating Tests in Coal Show Lower-Than-Expected Penetration. In an era of increasing energy costs, the huge coal bed methane resources begin to look more attractive. Because of the low production rate, however, completion fundamentals are critical and have received little attention. This paper represents the first testing program to investigate the perforating characteristics of coal. Both penetration and tunnel diameter were found to be significantly less for coal than would be predicted by current weak rock models. This means impaired flow and communication to the wellbore. Clearly, further research in perforating coal, perhaps providing improved gas flow, could yield large dividends. Rapid Planning and Execution of the First Multilateral Well in the Gulf of Thailand: Results and Lessons Learned. Routine drilling in the Kaphong field discovered unexpectedly two new production horizons. This paper chronicles the rapid process that planned and executed the multilateral well needed to tap this reservoir. The authors share the lessons learned and the unintended consequences of executing this project so quickly. Tubing Buckling--The Rest of the Story. The first study of tubing buckling characterized the buckling as independent of boundary effects, and examination of the formulation clearly shows that the solution is not consistent with typical packers. The conventional wisdom is that the buckling solution applies "far from the packer." In this paper, the effect of the packer on the buckling solution is explicitly determined, so that the completion engineer can now determine the "near packer" tubing stresses and bending moments for his tubing design.

For drilling topics this issue includes: Universal Process For Benchmarking Drilling Fluid Performance. Benchmarking drilling performance is not easy. Most commonly, drilling costs have been correlated to key performance indicators and individual drilling metrics, with varying degrees of success. The benchmarking of drilling fluid costs is even more problematic. In this paper, the approach is to compare mud cost to a corresponding technical limit. The authors have offered to share their techniques with the industry, and have supplied full implementation details. Correlations and Analysis of Cuttings Transport With Aerated Fluids in Deviated Wells. The use of underbalanced drilling techniques has been successful in improving recovery in mature fields and in developing low-pressure, low-permeability reservoirs. Cuttings transport is a major factor in the cost of wells, but the understanding of cuttings transport with multiphase fluids is very limited. This paper helps fill this void with data and empirical correlations for hole cleaning with aerated fluids at intermediate inclinations with pipe rotation. Measuring and Predicting Dynamic Sag. Sag is the variation in density of a drilling fluid as a result of the settling of suspended particles or weighting material in a wellbore. Sag is a concern, because it can cause costly and hazardous situations while drilling or cementing. This paper presents a new testing apparatus for static and dynamic settling rate measurements. The discovery that there is a lack of correlation between sag and traditional viscometer measurements is significant. The new testing device provides not only better understanding of the sag phenomena, but also provides a better means to characterize fluid performance. Factors Controlling The Membrane Efficiency of Shales When Interacting With Water-Based and Oil-Based Muds. At first glance, this paper seems to be too esoteric for a drilling and completions journal. However, this paper has direct impact on the formulation of drilling fluids to prevent shale swelling and subsequent wellbore collapse. Applications such as design of water-based muds and the importance of stable emulsions of oil-based muds make this paper must reading for drilling fluid researchers. Underbalanced Drilling of a Horizontal Well in Depleted Reservoir: A Wellbore-Stability Perspective. Underbalanced drilling has been shown to reduce formation damage and differential sticking. Highly depleted reservoirs have extremely low pore pressures, thus requiring a very low ECD to achieve underbalanced conditions. The result is that the wellbore has limited support from the mud pressure, increasing the risk of wellbore instability. This paper presents a practical wellbore stability technique for evaluating underbalanced drilling for a horizontal well. Best Practice in Understanding and Managing Lost Circulation Challenges. Lost circulation is defined as the loss of whole mud into the formation, as opposed to simple fluid loss. Natural lost circulation occurs when drilling operations penetrate a formation with large pores and leaky faults and fractures. Artificial lost circulation occurs when hydraulic fractures are created. This paper provides a comprehensive review of the emerging technologies for controlling lost circulation, and evaluates where they are most applicable. Cementing Under Pressure in Well-Kill Operations: A Case History From the Eastern Mediterranean Sea. Cementing in an unbalanced wellbore in an active gas flow has its difficulties. The gas flow can cause channels that compromise the integrity of the cement plug. These problems were dealt with by careful contingency planning, special cement formulation, and the use of a hydraulic simulator to plan the operation. Connection Performance Evaluation For Casing-Drilling Application. Casing drilling technology combines drilling problems with casing concerns. As a result, the performance of connectors under these conditions is receiving increased scrutiny. This paper describes a testing program to simulate actual working conditions for a casing drilling connection. The test program has four phases: design selection, fatigue to failure, static capacity, and post fatigue testing. The results of testing 9 5/8, 53.3 lb P-110 drilling with casing connectors are presented in detail. Ultradeep Drilling Pushes Drillstring Technology Innovations. This paper presents a comprehensive review of the technical challenges posed by ultradeep drilling, 25,000 ft TVD or greater. Tensile load limits require high strength drillpipe and nonsteel alternatives, double-shoulder connectors, and new pipe handling technologies. BOP shearing capacity and pressure integrity upon drill pipe collapse may need increases in performance limits. Finally, improved BHA connection technology is needed to minimize downhole failures.

Progress on the Big Backlog
There are several good things to report. John Thorogood has completed the review process for all the papers over 2 years old. John deserves a big thank you. If you see him, buy him a drink. He probably needs it. Please notice that this issue of SPEDC has 15 papers, which is an increase over the 9 papers in the last issue. Therefore, we are making progress.

Conflict of Interest
You may have noticed that one of my papers is in the current issue of SPEDC. Because most SPE journal editors also write papers, SPE provides for this case. Curtis Cheatham acts as the executive editor for all of my papers, and I don't get to say a thing about it.