High-Pressure Water Jetting: An Effective Method To Remove Drilling Damage

High-Pressure Water Jetting (HPWJ) has been used for decades for various industrial applications. The major uses of this technology have been to clean the various surfaces, as well as demolishing or cutting different materials. The process has been used in oil and gas wel s to clean tubulars from deposits of asphaltene, paraffin, and common inorganic scales e.g. calcium and magnesium compounds. These scales are usually very hard and difficult to remove by chemical methods. By utilizing abrasive materials such as sand and beads, the process has been used to cut steel pipes or make perforations. In recent times, drilling technology has revolutionized the shape of the wells. Most of the new wells are drilled in a horizontal direction across the reservoir thus exposing a relatively large reservoir area for drainage or injection. Majority of the new wells is completed `bare-foot i.e. without cementing a casing or a liner. As he horizontal wells have usually long open holes, the use of conventional acidization to remove drilling damage requires large volumes of acid. As a result acidization is very expensive. The acid utilization is very inefficient as most of the acid leaks into `thief zones. In an effort to reduce the cost of damage removal in long horizontal open holes, Qatar General Petroleum Corporation (QGPC) has utilized HPWJ technology to remove the drilling damage. The treatment has been applied to more than 10 horizontal wells to date and it has been found to be very successful. The process is simple to use because the only consumable is water. Service costs are minimal as the pumping equipment of the rig is utilized for the treatment. This paper covers theoretical aspects of the HPWJ technology, case histories and well performance data.