DEVELOPMENT AND TESTING OF UNDERBALANCED DRILLING PRODUCTS. Final Report, Oct 1995 - July 2001
Underbalanced drilling is experiencing growth at a rate that rivals that of horizontal drilling in the mid-1980s and coiled-tubing drilling in the 1990s. Problems remain, however, for applying underbalanced drilling in a wider range of geological settings and drilling environments. This report addresses developments under this DOE project to develop products aimed at overcoming these problems. During Phase I of the DOE project, market analyses showed that up to 12,000 wells per year (i.e., 30% of all wells) will be drilled underbalanced in the U.S.A. within the next ten years. A user-friendly foam fluid hydraulics model (FOAM) was developed for a PC Windows environment during Phase I. FOAM predicts circulating pressures and flow characteristics of foam fluids used in underbalanced drilling operations. FOAM is based on the best available mathematical models, and was validated through comparison to existing models, laboratory test data and field data. This model does not handle two-phase flow or air and mist drilling where the foam quality is above 0.97. This FOAM model was greatly expanded during Phase II including adding an improved foam rheological model and a ''matching'' feature that allows the model to be field calibrated. During Phase I, a lightweight drilling fluid was developed that uses hollow glass spheres (HGS) to reduce the density of the mud to less than that of water. HGS fluids have several advantages over aerated fluids, including they are incompressible, they reduce corrosion and vibration problems, they allow the use of mud-pulse MWD tools, and they eliminate high compressor and nitrogen costs. Phase II tests showed that HGS significantly reduce formation damage with water-based drilling and completion fluids and thereby potentially can increase oil and gas production in wells drilled with water-based fluids. Extensive rheological testing was conducted with HGS drilling and completion fluids during Phase II. These tests showed that the HGS fluids act similarly to conventional fluids and that they have potential application in many areas, including underbalanced drilling, completions, and riserless drilling. Early field tests under this project are encouraging. These led to limited tests by industry (which are also described). Further field tests and cost analyses are needed to demonstrate the viability of HGS fluids in different applications. Once their effectiveness is demonstrated, they should find widespread application and should significantly reduce drilling costs and increase oil and gas production rates. A number of important oilfield applications for HGS outside of Underbalanced Drilling were identified. One of these--Dual Gradient Drilling (DGD) for deepwater exploration and development--is very promising. Investigative work on DGD under the project is reported, along with definition of a large joint-industry project resulting from the work. Other innovative products/applications are highlighted in the report including the use of HGS as a cement additive.
- Research Organization:
- Maurer Technology Inc. (US)
- Sponsoring Organization:
- (US)
- DOE Contract Number:
- AC21-94MC31197
- OSTI ID:
- 820613
- Resource Relation:
- Other Information: PBD: 1 Jul 2001
- Country of Publication:
- United States
- Language:
- English
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