Hydraulic Fracturing In China
Authors: York D.J. , Meyer R.K. 
Published: March 2010

In 1988, Nowsco Well Service Ltd., Canada (Nowsco) entered into a contract with the People's Republic of China (PRC) from the Kelemayi Oilfield (Xinjiang Province) to provide expertise in hydraulic fracturing. The Kelemayi officials wishes to select, from existing producing wells, four candidates for hydraulic fracture stimulation. The Kelemayi representatives were to be provided with technical information on well selection, hydraulic fracture design field execution and post stimulation analysis. This paper summarizes the processes involved in implementing and executing a hydraulic fracturing contract in the People's Republic of China.

Introduction

In 1987, the People's Republic nf China (PRC), in an effort to acquire technical information and improve existing oil production, approached several service companies to bid on a stimulation contract for the Kelemayi Oilfield. Based on a similar successfully implemented contract in the Liaohe Oilfield of China, Nowsco Well Service Ltd. (Nowsco), was awarded part of the stimulation contract. The contract required that Nowsco select four wells from the existing producing oilfield and provide complete hydraulic fracture studies for each well. A delegation from China would visit Canadian operations and receive training in hydraulic fracture stimulation. Two Nowsco personnel would go to the People's Republic of China to train staff and implement hydraulic fracture designs in the field. The representatives from Nowsco included a chemist with a background in stimulation fluids and a fracture engineer with hydraulic fracture design and operations expertise.

Well Selection

The selection of the four candidate wells was carried out in Kelemayi, Xinjiang Province, PRC (Fig. l)(1). Twenty wells, five from each of four fields, were selected as possible fracture candidates by the Oilfield Technology Research Institute. One well from each field was chosen for a hydraulic fracture study. The well selection criteria are outlined below:Wells should not have been previously fractured, It was determined that all the candidate wells had been fractured previously. Examination of fracture treatment summaries revealed that all treatments had been overflushed.Wells should have good shale barriers for fracture containment above and below the zone(2). In two of the fields, the productive zones were bound by competent shale barriers. The other two fields contained large horizons with no shale barriers.Wells required good reservoir pressure.Wells with the most information on permeability, porosity, water saturation, and PVT data were chosen. Analysis of the logs gave good indication of the porosity, water saturation and net pay of the four candidate wells chosen. The reservoir pressure and PVT data were provided and assumed to be correct. The permeability was history matched based on reservoir simulation.An entire production history was required for a well to be considered suitable.Suitable wells would have little or no water cut.Successful study wells would have a minimum percentage of oil recovered. One well from field which best fit the above criteria was selected.