How Halliburton set a Latin American TCP record

Overview 

Perforating longer production intervals saves trips and rig time. However, if jobs are not properly planned, the explosive force can also damage wellbore components and ultimately increase operators’ costs, wiping out savings. So it is critical to accurately predict explosive forces and how the wellbore will react. An operator in Brazil and Halliburton set a perforating record for Latin America by perforating a deepwater well with 303 meters of 7-inch guns loaded at 12 shots per foot. This virtually doubled Halliburton’s previous record in Brazil (153 meters). ShockPro™ simulation software and meticulous preparation resulted in saving an additional five to six days of deepwater rig time. Had simulations shown detonation was too risky, the operator would have had to perforate in two trips. But instead, simulations revealed some easily made plan modifications that gave the operator the confidence it needed to move forward.

Challenge: 

Longer strings of perforating guns can mean fewer perforating runs. However, longer strings also increase risk. Perforating long producing intervals using large, high-shot-density guns can cause material failure of wellbore components. The pressure inside the guns is atmospheric, but the pressure outside may be 8,000 to 10,000 psi. This causes a dynamic under-balance when gun chambers open, creating a great amount of turbulence in the wellbore. This turbulence can bend, compress, twist and sever tubulars in a matter of seconds. When severed, they fall into wellbores and must be fished out. But because tubulars usually sever in the middle of pipe and rarely at joints, fishing is extremely difficult. Sometimes milling is the only answer. Fishing for severed tubulars in deepwater wells like this one could easily exceed $10 million USD of rig time – a cost that would exceed savings from eliminating a perforating run. The shaped charges used in perforating generate a focused jet of energy that goes straight out. But the detonations also generate “remnant” energy in the form of pressure pulses that move up and down the wellbore. If formation permeability is high enough, this energy will be absorbed into the reservoir. If not, it will stay inside the wellbore and cause tubulars to twist and corkscrew.

Solution: 

Halliburton listened and responded to the operator’s requirements to maximize asset value. To gain better subsurface insight, a recommendation was made to deploy the CoreVault^® RFP system, which integrates wireline rock coring with fluid sampling and measurement of pressures and temperature downhole, while preventing fluids from escaping during the acquisition of high-quality rotary sidewall cores. This unique solution provides an analysis of the complete reservoir. It captures and retains reservoir fluids, and delivers pressure-temperature measurements with the rock samples to the surface, enabling volumetric measurement of hydrocarbon properties. Additionally, the CoreVault RFP system yields immediate data at surface prior to full laboratory analysis, providing answers directly at the wellsite. With the CoreVault RFP system, operators are better able to predict production, manage their assets, and understand the economics of their reservoir, particularly in unconventional reservoirs. The data obtained can significantly enhance economic value and reduce exploration/development risk. 

Result:  

Halliburton ShockPro simulation software provides the industry’s only tool that can accurately and mathematically model pressure waves as they build inside the wellbore at the instant of detonation. Computational fluid dynamics helped the operator in Brazil and Halliburton understand forces that could exceed tensile ratings of wellbore components. It also helped both companies understand what they needed to do to enable the reservoir to absorb these forces. All this planning and collaboration paid handsome dividends. The operator and Halliburton safely perforated the entire reservoir in one run. The length of the perforating string set a record for all of Latin America. This saved the operator the cost of what would normally have been a second run. The cost of that run could easily have exceeded $5 million USD.