Minimizing Environmental Impacts During Offshore Drilling and Production Using Innovative Waste Recycling and Reutilization Technology in China Bohai Oilfield

Abstract

In recent years, an oil company has intensified its drilling activities in China Bohai Oilfield to meet challenging production targets and has almost doubled its drilled wells. Aiming to minimize environmental impacts of drilling activities on China Bohai Bay which is an internal bay with weak self-cleaning ability, this oil company has always been exploring continuous improvement to minimize the impact of its drilling and production operations on the environment. With the intention of recycling and reutilizing drilling and production waste including cuttings, wasted drilling and production fluids, many efforts are done. In design, well profile is downsized, cement top is restricted and reusable drilling fluids are developed to reduce waste from the root; In the field, environment protection ships (EPS) equipped with solid modified control system, cuttings closed transfer system and cuttings treatment system are used to recycle the produced the waste while drilling platform work as backup when weather is bad; Moreover, offshore waste management online system (OWMOS) has been developed covering the whole life cycle data chain of waste generation, collection, transportation, storage, disposal (utilization). Statistics from OWMOS show that the amount of the waste produced from downsized wells has been reduced by 41~65% compared to similar wells drilled before. Moreover, environmentally friendly drilling fluids with low solid content are developed and liquid phase after solid-liquid separation treatment can be reused. Consequently, the usage amount of drilling fluids has been decreased by 55~75%, while the solid content are packed and transported to onshore for disposal. These wastes can be turned into raw materials of cement stabilized soil and ceramic, which can also provide economy benefit and reduce impact on the environment. Waste recycling and reutilization technology has been successfully applied in more than 40 wells and lay the foundation for the digital transformation acceleration of waste management of offshore drilling and production waste, which can provide more practical reference for waste management of other similar offshore oilfield.