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Abstract The method of stimulation employed at the Shell Groundbirch asset in the Montney tight gas play is the limited-entry slickwater hydraulic fracture. The original fracturing water specification was a simple filtering requirement and an allowable range of salinity. Considering the associated health, safety, security, and environment (HSSE) perspectives, costs, and perceptions with sourcing and disposing of water related to hydraulic fracturing, determining a fracturing water specification became critical. This paper will describe a concise and pragmatic approach for determining a new fracturing water specification and water handling system aimed at recycling flowback and produced water, while using as little fresh water as possible. This water specification case study is based on the industry considerations of hydraulic fracturing and water management, and their impacts on costs and the environment. This approach to determine a chemistry specification for slickwater hydraulic fracturing and handling considerations may be applied elsewhere to enable the optimization of sourcing and disposal, HSSE concerns, production impairment prevention, and cost reduction. The process of determining the water chemistry specification assessed bacteria, formation damage, scale, and friction reduction performance. After a year of consultation and experimentation, an improved, but still simple fracturing water specification was established. Chemical use includes a scale inhibitor in addition to the on-the-fly fracturing fluids of a friction reducer, a surfactant, and a biocide. Scale inhibitor usage depends on pH and iron content. Coupled with water chemistry considerations, an integrated team initiated an intrafield water handling system that first recycles flowback or produced water and uses fresh water only when brine volumes are insufficient. This paper will specifically address (1) a method to develop a water chemistry specification for slickwater fracturing, (2) a pragmatic means of forecasting water in tight gas developments, and (3) a means of integrating water chemistry and forecasting learning into application for pragmatic field development. Introduction Tight gas developments rely on hydraulic fracturing to produce gas at economically viable rates. One popular method of hydraulic fracturing is the limited-entry slickwater fracture treatment in which a number of perforation clusters are attempted to be simultaneously stimulated with a slickened water and proppant slurry in a number of stages throughout the wellbore. The implications of water in tight gas beyond hydraulic fracturing have been recognized at Shell Canada's Groundbirch development in the Montney play. Shell Canada's Groundbirch asset is located in Northeastern British Columbia, Canada, per Figure 1. The current land base consists of nearly 400 sections of Montney focused development of which about half are Shell's land held with Brion Energy, while the remainder are held jointly between Shell and other partners.

The gas plant for the proposed Niglintgak Anchor Field is expected to be assembled on a barge, towed to the Mackenzie River Delta and ballasted down onto the bottom of an excavation advanced into the side of a river channel. In order to place the barge onto the excavation, ballast tanks inside the barge will be filled with water pumped from the river. The gap between the barge and side slopes of the excavation will then be backfilled with excavated materials. The ballast water inside the unheated barge may convey thermal impact to the existing permafrost below the barge. During 2006 to 2008, field tests were initiated to investigate the water freezing progression and growth of hydrostatic pressure in the test tank as well as the dynamics of permafrost temperature under the tank. Based on results of the field tests, 3- dimensional geothermal analyses for the gas plant barge were carried out to predict the development and seasonal melt of ice within the ballast tanks and assess permafrost conditions under the barge over the operational life of the structure. Various scenarios of the ballast water freezing were considered.

Sandeep P. Kishore , Karen R. Siegel , Aria Ahmad , Amina A. Aitsi-Selmi k, Mohammed K. Ali , Phillip Baker , Sanjay Basu , Asaf Bitton , Gerald S. Bloomfield , Gene Bukhman , Eleanor Emery , Andrea B. Feigl , Karen Grepin , Mark D. Huffman , Kiti Kajana , Shweta Khandelwal , Kavitha Kolappa , Chenhui Liu , Naaznin Lokhandwala , Vishal Marwah kk, Modi Mwatsama , Nicole Novak , Shantanu Nundy , Paul H. Park , Cristina Parsons Perez , Matthew R. Price , Nikka Rapkin , Hester Rice , Ben Seligman , Sumit Shah , Joao da Silva , Devi Sridhar kkk, David Stuckler , Rajesh Vedanthan kk, Justin Zaman k,''', The Young Professionals’ Chronic Disease Network