A Review of Leak Detection Systems for Natural Gas Pipelines and Facilities

Pipelines facilities, used for the transportation of natural gas in large quantities to homes and industries, remain the best economic, most reliable and safest mode of transport of energy. Despite these numerous advantages, gas pipelines have been enmeshed in various accidents and thefts, nonetheless this could be reduced if properly maintained and pipelines can last indefinitely without leaks. Pipelines are susceptible to leakages and rupture accidents as a result of age, corrosion, material defects, operational errors or other reasons. Pipeline failures may be caused intentionally (e.g. vandalism) or unintentionally (e.g. device/material failure and corrosion), which may result into irreversible damages such as financial losses, human casualties, ecological disaster and extreme environmental pollution. Leakages in natural gas facilities and installations require three vital aspects, namely: Gas Leakage Prevention, Gas Leakage Detection and Gas Leakage Mitigation. Many Gas Leak Detection methods are used for pipeline integrity management and especially for minimizing gas leakage. The performance of these methods depends on the approaches, operational conditions and pipeline networks. Also, there are some essential requirements and guidelines which must be met before we can consider any leak detection system suitable for production solutions, including sensitivity, reliability, accuracy and robustness. The attempt of this study is to carry out a critical review of these models, to ascertain the best model(s) applicable to natural gas leak detection. Keywords: Gas Leak Detection System, Leak Location, Leak Size DOI: 10.7176/JETP/13-2-02 Publication date: April 30th 202

Water Coning Prediction Review and Control: Developing an Integrated Approach

In petroleum industry, oil production strategy to circumvent water coning in reservoirs with strong water drive is quit challenging. To ameliorate this oil production related problem, several water coning prediction models and control approaches have been developed by researchers. The prediction approaches include analytical, empirical and numerical approach. The analytical and empirical prediction approaches are qualitative water coning prediction approach with limited field scale application. However, these approaches model predictions can gain field application if upscale. Numerical approach has provided the fulcrum to study the complexity of water coning phenomenon in bottom-water drive reservoirs, and its prediction and sensitivity results have found wide field application. In addition, the various developed water coning control methods: downhole oil-water separation (DOWS), downhole water sink (DWS), downhole water loop (DWL), among others have proved to be effective, as it reduces the water-cut, produced water and water handling problem at the surface during hydrocarbon production. However, the challenge of producing the bypassed oil in the reservoir remains unattended with these coning control methods. Also, even as effective as these water coning control methods may seems, they have their drawbacks that limit their application in certain reservoirs. Therefore, developing integrated approach that is adaptive to control water coning and produce bypassed oil in bottom-water drive reservoirs is important to the oil and gas industry

New Insights into CaO-swelling Cements

370-375Influence of CaO in improving slurry swelling is studied, using high pressure-high temperature (HP-HT) expansion cells, and compared with previous results. For varying temperatures and pressures the beginning and end of expansion and the duration, of expansion are observed. The expansion values are determined. The extent to which cement shrinks is found to be a balance between the chemical reaction of water and clinker mineral, and the physical reaction of gel dipole water attached to the electrically charged cement surfaces. An optimum water cement factor (WCF) of 0.45 ensures pumpability during oil well cementing, without causing increased hardened-paste porosity and permeability. Specially stable matrix is needed to use the swelling agent, and the smaller the CaO reactivity, the earlier the ‘‘Time-window’’ attains high temperature. Depending on the retarders used to suppress shrinkage, cement expands at an average value of 6 per cent for 19, 16, 15 and 6 min, at 60, 80, 90 and 105oC, respectively. Calcium oxide quantity between 12 and 14 per cent by weight of cement is recommended for good swelling. A second method of gradually mixing cement slurry components in stages represents an improvement of the CaO swelling ability over the old lump method which is quite useful

Aerated Wellbore Sandwash Experience in Binagadi Field

The application of light fluid system for hole cleaning in the past has been restricted to drilling and completion operations. This work describes a one year investigation of wellbore sand cleaning at Binagadi field in Azerbaijan. Aerated water was used in sand cleanout with emphasis on improved sand is to suspension and transport. A total of 56 sand plugs were cleaned with aerated fluid and 74 non-aerated in 56 wells. The objective of this work is to study the effect of aeration on sand cleanout operation in sand producing wells for a pressure depleted field. The effect of aeration on sand related workovers has also been studied. Well production data were reported on a daily basis through an automatic data-transfer system. As a result of this field, it was concluded that aeration helps to reduce lost circulation and greatly improve the success of sand cleaning. Aeration coefficient increases with the decline in reservoir pressure. Reservoir pressure decline is expressed as current reservoir pressure expressed as percentage of the hydrostatic pressure. Aeration coefficient from 18 to 40 m3/m3 corresponding to reservoir pressure decline of 20 to 5:1 are considered in this paper. Aerated sandwash can be applied in field produced by artificial lift methods when sprouting does not occur and in wells that have small standing fluid columns. Keywords: Sand, aeration, cleanout, workover-lif

Field Application of A Method for Waterflooding

314-317A field investigation, developed from laboratory test, conducted to identify and understand magnetic effects on oil recovery during waterflooding process at several oil fields in Azerbaijan. Results of the initial field testing of this improved oil recovery (IOR) method show, that magnetisation increases rock wettability, injectivity, as well as the flow capacity of porous media and favours degassing of water. The additional oil produced is attributed to the above factors and buoyant oil flow created by suction force of the magnetic type. Pressure stabilises easily during pressure buildup, scaling from formation water reduced by 80-97 per cent, downhole corrosion reduce by 35-40 per cent and clay swelling minimise by the constant transverse magnetic field. The results reavel that the method is novel are usel for studying magnetic fields

Investigation of the Effect of Eggshell Additive on Cement Sluryy Quality

<p>Cementing oil and gas well requires materials that ensures stability of the cased and cemented wellbore to isolate troubled zones. To achieve this job, the search for alternative material for cementing gas well has increased worldwide. Hence, it is necessary to make use of an appropriate cement programme designed with suitable additive that improves the cement bond strength, durability, resistance to abrasion on the wells life which improve quality of cement to provide zonal isolation. To protect the environment, investment, public trust and reputation, the cement plug sample porosity, permeability must be reduced, also an increase in compressive strength is needed to accomplish this technically. The research is aimed at evaluating the performance of eggshell as additive for gas well cementing operation at ambient condition. Laboratory test were conducted on a base cement sample or check plug mixed with different concentration from 30% to 70% to determine the effect on porosity, permeability and compressive strength of the cement sample. CT scan were conducted to study the composition and internal structure of the cement sample. The results showed that the 50% eggshell addition yielded the best casing integrity and should be used because it is nearly impermeable and non-porous in comparison to the base cement sample or check plug sample. An optimum concentration 50% eggshell/sandstone decreased the porosity and permeability to the barest which the aim of the study stands to achieve. The effect of eggshell and sandstone is prominent to a concentration 50%, this may be due to the equilibrium mixture present in the cement plug with the highest density of the samples obtained, and therefore increasing more than the optimum percentage of eggshell will increase cost of cementing without further improvement in performance. From the CT scan eggshell particle distribute non-uniformly in the mixture to clog the pores, helping to decrease the porosity and permeability only up to a specific quantity. At higher concentration, the result for permeability are found to be reversed whereas porosity keep decreasing. Eggshell does not have significant effect on permeability at higher concentration, while with less or mild concentration of eggshell the permeability reduced drastically. However, it is evident that addition of eggshell as additive resulted in better slurries with higher values of compressive strength greater than 500psi after 48hrs of curing which is the minimum strength before performing any perforation. After 48 hrs of curing the cement, cement sample with eggshell incorporated develop morestrength by 56% to 91% increase in the compressive strength, as the concentration increases compared to the base slurry. All of the prepared cement sample exhibited a sufficient strength required for oil and gas application. Therefore, the material showed potential in making short and long-term wellbore integrity requirement. Eggshell is thought to be responsible for reducing the porosity and permeability of the cement and improving its overall strength.</p><p>Keywords:- Cement Plug Sample, Eggshell Concentration, Porosity, Permeability, Compressive Strength, CT Scan, Zonal Isolation and Wellbore Integrity.</p&gt