oa Total and QP's joint acid stimulation research program to improve productivity from Qatar's oil and gas fields

In a first ever joint venture initiative, Qatar Petroleum has joined forces with Total in an effort to improve acid stimulation programs. Acid stimulation in carbonates can greatly increase well productivity. Near-wellbore impairment or formation damage is typically analysed by a term called skin factor. It is this 'skin' that is removed during an acidizing operation in a well. Typically, reducing the skin factor by a factor of 5 can increase a well's productivity by up to 50 percent (Furui et al. 2003). Acid stimulations performed in Qatar on 23 offshore wells in 2008-2009, increased oil production by 100 percent while at the same time reducing the water cut by 10 percent. In this joint venture project conducted by researchers and engineers from Total and Qatar Petroleum, the study is divided into three phases which also includes knowledge transfer and training. Phase 1 consists of core-flooding under reservoir conditions using standard acid recipes on outcrop and field cores. In Phase 2, improved or novel acidizing systems will be tested using a dual core setup, allowing the study of acid diversion from high permeability zones to low permeability zones. The objective here is not only to improve acidizing efficiency but also to mitigate the water production from heavily watered-out zones. Modeling activities will be undertaken to design acid stimulation treatments using results from the laboratory experiments. Phase 3 involves knowledge sharing and training on mud cake removal treatments. Mud cake is the damage caused to the near-wellbore, i.e., the interface between the reservoir matrix and the well, during the drilling of open hole wells. The knowledge gained will be implemented in both onshore and offshore fields as part of acid stimulation field trials.