This paper was prepared for presentation at the 1999 SPE/ICoTA Coiled Tubing Roundtable held in Houston, Texas, 25–26 May 1999.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractZonal stimulation using hydraulic Fracturing, which typically was performed through jointed pipe, has recently been performed with Coiled Tubing. In the last two years, over one thousand fracturing treatments in North America have been executed using this method. Coiled Tubing allows a method of stimulating individual, bypassed or marginal zones, using positive zonal placement of proppant. Coiled tubing also gives the advantage of treating a well under pressure without introducing a kill fluid to the formation. In the Appalachians, where multiple small zones exist in one wellbore, this technology can provide significant cost savings by reducing trips to the well, equipment on location, and rig time to move downhole hardware. Coiled tubing fracturing eliminates the need for bridge plugs and allows stimulation of multiple zones in a single trip to the well. Ultimately the size of a stimulation treatment can be re-engineered because of the positive isolation for each specific zone in the wellbore. The overall effect to the producer is greater production at a lower total cost.

2 Energy and Power Engineering compared to the other technologies stems from significantly lower methane slip, and the high-power transfer efficiency resulting from directly connecting a turbine to a reciprocating pump, despite the comparatively lower thermal efficiency.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper describes the startup and application of coiled tubing-(CT-) conveyed fracturing for sand-control purposes in an oil field in Indonesia. Sand production becomes a major problem where well servicing is routinely performed to replace worn or stuck subsurface artificial lifting equipment. Some of the producer wells are slimhole, which prevents the use of conventional sand control using screen and gravel because it restricts the production flow severely. A recent field test was performed in four wells by fracturing through CT to provide screenless completion. The ultimate goal was to achieve an acceptable sand control in these weak formations while restoring production. We demonstrate that not only did the treatments achieve the objective but they also stimulated the well and improved well management.

Recently, the North America Oil and Gas industry has seen a rapid increase in the adoption of new hydraulic fracturing technologies such as dual-fuel diesel engine, electric system powered by gas turbine or engine on-site and turbine direct drive technology, to reduce emissions and operating costs. The objective of this paper is to provide a detailed analysis of economic, environmental, and technical considerations when selecting the next generation hydraulic fracturing equipment platform. It is believed that any next-generation technology must meet the following key requirements: 1. Reduction of GHG and EPA regulated emissions; 2. Reduced equipment footprint; 3. Capable of meeting the most stringent noise standard; 4. Improved reliability; 5. Improved pad-to-pad mobility; 6. Reduced maintenance and personnel costs; 7. Competitive capital cost. For the selection process, a methodology was developed to evaluate the energy density of fuel, thermal efficiency of prime movers, mechanical power transfer efficiency, and equipment operating environment and configuration against the above objectives. The methodology also considered the technical and commercial feasibility of key components. Natural gas is selected as the mobile primary energy source due to its higher energy density and lower emission profile than conventional diesel, and more economical and widely available on-site. Among all available natural gas-powered engines evaluated, which included dual-fuel diesel engine, gas reciprocating engine, single large turbine and direct drive turbine, the direct drive turbine scored the highest. The direct drive pumping unit is equipped with a 5,000 HHP continuous duty power end driven by a 5,000 HHP dual shaft turbine through a single speed reduction gearbox. This combination provides the most efficient mechanical power transfer efficiency resulting in significant fuel cost savings and reduction in greenhouse gas emissions. Because of its high-power density, the direct drive turbine system can potentially reduce the number of on-site equipment by 43% and personnel by 31%. Comparing to other next generation hydraulic fracturing system, the direct drive turbine technology has the lowest capital cost per HHP.