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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.

Velocity strings are routinely installed to remediate liquid loading of gas wells. However, besides restoring stable production, velocity strings also reduce well capacity, easily by up to 50%. In PDO, a sliding side door (SSD) was introduced as part of the velocity string completion to reduce the loss of capacity by facilitating additional gas flow via the new annulus created between velocity string and original tubing. This paper documents different field cases that demonstrate how the SSD is manipulated to maximize well capacity, which in some cases was doubled for more than 1 year. The paper also presents modelling of gas production via velocity string, annulus or both (concurrent). Commercial software was not able to accurately predict the instability of concurrent gas production.

BackgroundColorectal cancer (CRC) screening was introduced in Aotearoa New Zealand at Waitematā District Health Board (WDHB) in late 2011. This study reviewed patterns of disease, treatment received, and survival of patients with national bowel screening program (NBSP)‐detected CRC versus non‐NBSP patients at WDHB 2012–2019.MethodsData collected retrospectively for all patients with adenocarcinoma of the colon or rectum at WDHB 2012–2019. Patient records were manually reviewed. Chi‐square, Fisher's exact test and the Mann Whitney U‐test used as appropriate. Kaplan–Meier and Cox proportional hazards regression modelling for survival analysis.Results1667 patients included (360 NBSP and 1307 non‐NBSP). 863 (51.8%) were male. Median age at diagnosis 73 years (range 21–100); NBSP patients were younger (median 68 vs. 76 years, P < 0.001). NBSP patients had significantly lower T, N, M and overall TNM stage than non‐BSP patients. Median survival estimate on Kaplan–Meier analysis was 94 months for all patients. Statistically significant (P < 0.05) predictors of mortality on multi‐variate regression analysis included increasing overall TNM stage compared with stage I (stage II HR 1.63 (95% CI 1.14–2.34), stage III HR 2.86 (95% CI 2.03–4.03), stage IV HR 7.73 (95% CI 5.59–10.68)), diagnosis within NBSP (HR 0.51 (95% CI 0.37–0.71)), increasing age in years (HR 1.03 (95% CI 1.02–1.03)), urgent/emergency surgery (HR 1.66 (95% CI 1.36–2.01)) and formal resection of primary tumour (HR 0.31 (95% CI 0.25–0.38)).ConclusionPatients diagnosed within the Aotearoa New Zealand NBSP were found to be younger and have earlier stage CRC. Diagnosis within the NBSP is an independent predictor of survival for patients with CRC.

Foam-assisted lift (FAL) is a well-established gas well deliquification technique to prolonge stable production from depleting, liquid loading gas wells. Field tests were carried out to delineate the operating envelope of FAL in PDO liquid loading gas wells. The field tests in five different wells consisted of step-down tests with and without continuous downhole injection of liquid foamer, to establish the associated reduction of the minimum stable gas rate. At the same time, the produced fluids were sampled and analyzed to diagnose potential impact on surface processing. The step-down tests were carried out using five different foamers that passed screening based on laboratory testing. FAL reduced the minimum stable rate by more than 40% independent of water cut i.e. for BS&W ranging between 14% and 96%. The step-down procedure required a surface choke which resulted in a significant reduction of the minimum stable gas rate, independent of the application of FAL.