We offer our services worldwide through our global network of offices. Services accounted for approximately 71%, 71% and 69% of  our revenue from operations for the years ended December 31, 2013, 2012 and 2011, respectively. We manufacture products primarily in four facilities for distribution on a global basis. Product sales accounted for approximately 29%,  29% and 31% of our revenue from operations for the years ended December 31, 2013, 2012 and 2011, respectively. Our product sales backlog at December 31, 2013 was approximately $36.8 million compared to $33.4 million at December 31, 2012.  Sources of raw materials for our products are readily available and we expect that our current sales backlog at December 31, 2013 will  be completed in 2014. Commercial oil and gas fields consist of porous and permeable reservoir rocks that contain natural gas, crude oil and water. Due to  the density differences of the fluids, natural gas typically caps the field and overlies an oil layer, which overlies the water. We provide  services that characterize the porous reservoir rock and all three reservoir fluids. Services relating to these fluids include determining  quality and measuring quantity of the fluids and their derived products. This includes determining the value of different crude oil and  natural gases by analyzing the individual components of complex hydrocarbons. These data sets are used by oil companies to deter- mine the most efficient method by which to recover, process and refine these hydrocarbons to produce the maximum value added to crude oil and natural gas. We analyze samples of reservoir rocks for their porosity, which determines reservoir storage capacity, and for their permeability,  which defines the ability of the fluids to flow through the rock. These measurements are used to determine how much oil and gas are  present in a reservoir and the rates at which the oil and gas can be produced. We also use our proprietary services and technologies  to correlate the reservoir description data to wireline logs and seismic data by determining the different acoustic velocities of reservoir  rocks containing water, oil and natural gas. These measurements are used in conjunction with our reservoir management services to  develop programs to produce more oil and gas from the reservoir. We provide diagnostic services and products to help optimize completion and reservoir operations and field developments strategies in order to increase recoverable reserves in the most efficient way. Two production enhancement methods commonly used are (i) hydraulic fracturing of the reservoir rock to improve flow and (ii) flooding a reservoir with water, carbon dioxide, nitrogen or  hydrocarbon gases to force more oil and gas to the wellbore. Many oilfields today are hydraulically fractured and/or flooded to  maximize oil and gas recovery. Although Core Laboratories is not a hydraulic fracturing company, we do provide services that are used by others to develop and perform hydraulic fracturing and field flood projects and to evaluate the success of those projects. Our services and technologies play a key role in the success of both methods. The hydraulic fracturing of a producing formation is achieved by pumping a proppant material in a fluid slurry into the reservoir zone  at extremely high pressures. This fractures the rock and the proppant materials “props” or holds the fractures open after the pressure  pumping is complete so that reservoir fluids can flow to the production wellbore. Our data on rock type and strength are critical for  determining the proper design of the hydraulic fracturing job. In addition, our testing indicates whether the fluid slurry is compatible  with the reservoir rock so that damage does not occur that would restrict production. We also provide testing of various propping  agents and software to help pick the best proppant based on net present value calculations of client investments. Our proprietary and patented ZERO WASH ®  tracer technology is used to determine that the proppant material was properly placed in the fracture to ensure effective flow and increased recovery. SPECTRACHEM ®  is another proprietary and patented technology developed for optimizing hydraulic fracture performance.  SPECTRACHEM ®  is used to aid operators in determining the efficiency of the fracture fluids used. SPECTRACHEM ®  tracers allow operators to evaluate the quantity of fracture fluid that returns to the wellbore during the clean-up period after a hydraulic fracturing  event. This technology also allows our clients to evaluate load recovery, gas breakthrough, fluid leak-off and breaker efficiency, all of  which are important factors for optimizing oil and/or natural gas production after the formation is hydraulically fractured. 2 Production Enhancement Reservoir Description