Positive DL test results are rare and occur more commonly in children than adults. There was poor agreement among experts on the interpretation of a positive DL test in adults. These observations highlight the difficulties in establishing the diagnosis of PCH in adults and calls for scrutiny of current laboratory practice.

No abstract

The conventional well stimulation treatments have been used in the oil and gas wells for long time to remove formation damage or skin in order to enhance the well production and be able to achieve economic rates. Wireline Applied Stimulation Pulsing (WASP®) is a prominent new technology that is gaining more grounds in the well stimulation for oil producer and water injector wells. WASP® is an electro-hydraulic technology that generates repeatable, high power hydraulic pressure pulses downhole over the entire desired interval. The repeated pulsing stimulates the near wellbore area, breaks up scale and causing tensile failures in formation rock, thus creating mini fractures/fissures for new flow paths and removing formation damage or skin caused by scale, fines etc. that were blocking perforations, slotted liners, sand screens or gravel packs, resulting in improved inflow. Petrogas Exploration and Development recently conducted a WASP® campaign trial that is the first application in the middle east in four vertical wells in the south of Oman oil fields. The wells were Well-A, Well-B, Well-C and Well-D. The vertical wells were completed on the Gharif and Al Khlata sandstone oil reservoirs, which contain relatively medium oil with a viscosity range of 44-239 cP. All the pay zones were perforated, except for Well-B which was completed with gravel pack. The wells were completed with artificial lift including PCP pumps and beam pumps with polish rod strings. It was understood that the poor/low production performance of the candidate wells was due to the high skin, caused by the damaged gravel pack and plugged perforations. The WASP® tool specifications that was run for the treatments of the wells were 2.750" in diameter, and the length was approximately 11.6 m. The conveyance was on electrical wireline cable by using a standard logging truck. The results of the WASP® treatments jobs have shown mixed results but generally Well-A/B, Well-C and Well-D showed improvement in well performance and consequently in the oil gains. In fact, in Well-C in Aseel field had the highest production rate increased by more than threefold - a remarkable improvement. The other wells are still in the monitoring stage. The operation performance of WASP® treatments went smoothly without any operational issues or lost time in all the jobs. WASP® technology demonstrated that it is an attractive alternative method to the conventional well stimulation methods that involve the use of hydraulic fracturing and injection of acid, solvents and deimulsifiers. These conventional well stimulation methods have limitations in the treatment of the pay zone and operationally intensive. WASP® technology is proven to be more effective, safe (HSE compliant), less time consuming and thus cost effective. Petrogas is now considering applying the WASP® technology to the water injectors.