Titas Gas Research Articles

Evaluating the radioactivity and health risks in oil and gas production areas: insights from Titas Gas Field, Bangladesh

ABSTRACT Conducting comprehensive studies of radioactivity and associated risk assessments in the oil and gas industry is crucial due to the potential accumulation of Naturally Occurring Radioactive Materials in production operations. This pioneering study investigates radioactivity levels in surface soil from the Titas Gas Field area in Bangladesh by a High Purity Germanium (HPGe) detector, a crucial resource of the nation’s energy infrastructure. In surface soil, the activity of 226Ra, 232Th, and 40K varied from 18–41 Bq/kg, 28–62 Bq/kg, and 280–600 Bq/kg, respectively. Particularly, the levels of 232Th exceeded the global average value for soil. These elevated 232Th levels are likely attributed to a combination of natural geological processes of enriching thorium bearing minerals, geochemical processes favouring thorium retention and human activities selectively impacting these radionuclides. The estimated of radiological risk reveals that some indices exceed recommended limits, hence pose a concern for public health. The study recommends periodic monitoring, public awareness campaigns, remediation efforts, and long-term management strategies to protect environmental and public health. The findings of this research underscore the critical need to recognise and address radiological hazards associated with gas extraction activities to safeguard the health and safety of workers and nearby communities in Bangladesh.

Oil & Gas Data Acquisition, Monitoring and Reporting System Upgradation Proposal for Titas Gas Field

Oil & Gas Data Acquisition, Monitoring and Reporting System Upgradation Proposal for Titas Gas Field

Effects of Fire Hazards Due to Leakage in Gas Circulation Lines in Bangladesh: A Comprehensive Review

Fire hazards caused by leakages in gas circulation lines are dangerous and pose a threat that results in a significant loss of wealth, lives, and the environment. By adopting significant precautions, the risks of fire hazards can be reduced effectively through the use of new technologies and preventive measurements of the system. In addition, the effects of fire hazards due to leakage in gas circulation lines in the buildings as well as in the other systems can be assessed to create the context of preventive measures for a fire protection system in a way to overcome the fire hazards in gas circulation lines. The paper aims to review the effects of fire hazards due to leakage in gas circulation lines in Bangladesh. It is noted that in Bangladesh during 2018-2019, the total gas distribution line in the Titas gas system was measured as 13,138 km where the pressure-reducing system or gas riser was found as 1.2 million and the number of customers was found as 2.866 million. In the system, the number of fire accidents that occurred was 208 in the circulation system. Because of connecting the illegal gas lines and poor maintenance of the system, Bangladesh faces significant fire hazards every year. To avoid this kind of problem, proper maintenance along with the varieties of new technologies incorporating sensors and microcontrollers can be utilized.

Petrophysical evaluation of well log data for reservoir characterization in Titas gas field, Bangladesh: a case study

The petrophysical evaluation of the Titas gas field (Titas-15) has been carried out for its reservoir characterization and to quantify the reservoir hydrocarbon prospects and gas productivity. The Quick Log Analysis Tool (QLAT) of PE2 Essentials software has been utilized for the computer-processed interpretation inputting the various well log data such as gamma-ray (GR), density log (RHOB), density-porosity (DPHI), neutron porosity (NDHI), resistivity logs, etc. Among the three reservoir sand groups, three gas-bearing sub-zones have been identified in the upper sand group, which are primarily producing gas from the least net-pay of 9.5 m, 39.5 m and 28.5 m, respectively. The shale volume is calculated based on GR, caliper logs and neutron-density (N-D) cross-plot (minimum shale volume) methods whose average value is comprised between 26.3 and 33.9%. The range of effective porosity is 18.4–18.6% indicating a good reservoir quality; permeability is 14.11–25.95 mD; recognizing as the well-sorted nature of sands. Additionally, the hydrocarbon saturation in the respective zones varies from 48% to 60%, suggesting a good hydrocarbon reservoir, whereas the water saturation is 40–52%. Moreover, the range of measured ‘gas initially in place’ in upper, middle and lower gas sands are 2371.6–2579.1, 10330.7–11206.1 and 6373.1–7110.5 MMscf, respectively, implying an adequate gas reserve on commercial criteria. From the evaluation of petrophysical properties, the Titas reservoir has a higher ability to enhance hydrocarbon accumulation and production.

Factors Hold Key to Job Satisfaction of the Human Resources: A Study on Titas Gas Transmission & Distribution Company Limited

Titas Gas Transmission and Distribution Company Limited is the largest gas distribution company in Bangladesh. A total numbers of employees 2100 have been working in this sector. To measure factors hold key to job satisfaction of the human resources of the company, a sample of 115 employees were selected from head office, Dhaka, Gazipur, Mymensingh, Narayanganj offices on a random purposive sampling basis and data were collected through closed end questionnaire from field study on offices. To ascertain job satisfaction, 13 factors like job security, salary, promotion, job status, working condition, supervision, award, relation, communication, duration, participation and training were chosen. Different types of statistical tools like descriptive statistics, regression analysis, factor analysis, Mann-Whitney U- Test and Kruskal Wallis Test were used for analyzing and interpreting data. The study revealed that low level salary holders were more dissatisfied. It is shown that higher level of pay holders was highly satisfied on autonomy, participation, location, training etc. The study further indicated that the employees of Dhaka and Narayanganj revealed in foremost facilities than that of other located areas. The study also identified three factors are Factor-1: Developed monetary based human resources facilities; Factor-2: Technologically advanced facilities based on working conditions; Factor-3: Satisfactory level of practicing autonomy to be the most influential that in fact reflect as key factors of job satisfaction of human resources of TGTDCL in Bangladesh. Management of the company should provide adequate facilities and allocated to the employees maintaining equity to ensure legal rights disregarding manipulations of outwards intervention that damages the congenial environment of the organizational environments and lead to dissatisfactions of the human resources.

FACTORS AFFECTING PROFITS RELATING TO PURCHASE AND SALES: A STUDY ON TITAS GAS TRANSMISSION & DISTRIBUTION COMPANY LIMITED

The present study is an attempt to find out the factors affecting profits relating to purchase and sales of Titas Gas Transmission & Distribution Company Limited. The objectives of the study are to overview the affecting factors on profits, to determine the important factors that affect on profit relating to purchase and sales and to provide some suggestions and recommendations to enhance the profits. Correlation and regression have been applied to analyze the data. It is estimated that commercial, fertilizer and CNG are the most important factors to drive the profit both for the cases of purchase and sales. These three factors collectively explained the total variance of gross profit by 96.6 percent and 96.8 percent for the situation of purchase and sales respectively. The suggestions and recommendations are given to emphasize the purchase and sales on the identified factors to enhance the benefits of the company.

Environmental Impact Assessment Due to Gas Seepage of Titas Gas Field, Bangladesh

The biggest gas field of Bangladesh, Titas in Brahmanbaria continues to face a possible disaster due to the seepage of the huge amount of gas mixed with water and oil through thousands of holes and cracks on the surface environment in and around this gas field. Gas is leaking through more than 3,000 big holes, including some 30-ft diameter ones, spreading in paddy fields, water bodies, and the Titas river. Approximately 1000 acres of virgin land with varieties of flora and fauna have been affected through seepage. Soil condition in the villages has degraded and still degrading to such an extent that it becomes unpredictable to comment on how many years it needs to regain fertility. Yet the present alarming situation is rippled with confusion about the actual source of seepage till now. To help the situation, an assessment of the impact of gas seepage from the Titas gas field on the surrounding environment was needed to evaluate the overall environmental condition at present and to propose adequate control measures for the abatement of the adverse impact on the environment. Therefore, the main objective of this research work is to assess the environmental impact of this seepage from the Titas Gas field. To fulfill the object of this study, we have developed a questionnaire including 18 parameters. These parameters encompassed all the aspects of ecology, socio-economic and so on. We visited the study area and made the gathering with affected peoples. The answer to each parameter of the questionnaire has been taken from people. From this study, it is found that all the tube wells of the villages are automatically emitting a huge quantity of natural gas. It is observed that the emitting of gas from the tube well-produced enormous irritating noise. The air is found polluted in and around the site visited. The most severe and alarming finding the health-related disease (skin disease, asthma, hair fall, water-born diseases e.t.c). It is summarized that about six square km of the area of Bakail, Suhilpur, Shampur and Anandapur villages, the Titas River and Loiska swamp are at high risk due the seepage.

Geological and Geophysical Observations to Determine the Gas Seepage Source of Titas Gas Field Region, Bangladesh

Titas Gas Field, the largest gas field in Bangladesh, has been encountering gas seepages in numerous points at the surface in an area of about 7 sq. km. at the southeastern part of the field since 2006. Gas has been seeping through the water wells, small and large holes in the fields including agricultural lands, in the river and through the cracks in the ground. The present research attempts to point out the source of the gas seepages based on the field studies, wireline log analyses and other available borehole data. A reconnaissance resistivity survey has been carried out around the high seepages area to detect any evidence of shallow subsurface fault. No fault was detected by resistivity survey in the shallow depth in the seepage area and thus fault as a conduit for the seepage could not be confirmed. Primarily, all wells of Titas Well Location (TWL-C) (Titas-06, 08, 09 and 10) were suspected as possible source wells as the surface distribution of seepages generally clusters around TWL-C. Titas-06 and Titas-08 were taken out of suspect list as the gas seepage distributions do not follow well path and cement bonding against reservoir sands including ‘A’ sand in these two wells are also good. Gas seepages follow the well trajectories of Titas-09 and 10 wells but cement bonding against ‘A’ gas sand in Titas-09 also discarded the well as a probable source of the gas seepage. Also, the suggestion that Titas well-03 could be a source of gas seep is also ruled out because of the fact that it is located 3 km away from the seepage area, there is no evidence of any seepage in between the well 3 and the seepage area, and the gas sands are also well protected. The above evidences turned the whole focus onto Titas-10. Gamma ray, resistivity, density, sonic and neutron log signatures recorded initially in the Titas-10 well strongly indicated a major gas sand and has been designated ‘A1’ gas sand. On the basis of various logs including CBL/VDL log it is evident that about 23 meters (3157-3180-meter MD) gas sand at the top which is not protected by cement. It is most likely source of gas seeps in Titas gas field is the gap in the cement protection at the top of A sand in Titas-10 well.
 Asiat. Soc. Bangladesh, Sci. 45(1): 93-109, June 2019

Flowing gas material balance – a useful tool to revise subsurface maps

Subsurface geological maps are an interpretation based on limited data, yet they are the most important vehicles used to explore for undiscovered hydrocarbons and to develop proven hydrocarbon reserves. The flowing material balance (FMB) method uses flowing well head pressure, rather than shut in reservoir pressure, to estimate gas in place (GIP) and reserves at any stage of reservoir depletion. In addition, it can be applied to estimating permeability and skin of the reservoir and predicting production problems. However, application of the FMB for revising subsurface maps is not yet well understood and requires further study. The aim of this research was to develop a systematic approach to redraw subsurface maps using FMB with the aid of reservoir simulation and interpretive contouring methods. The Havlena and Odeh interpretation method was applied to identify a drive mechanism and the FMB was used to estimate GIP, which was checked against the volumetric GIP value. The pressure history match technique and interpretive contouring were applied to draw the revised maps. This step-wise technique was applied to the Titas gas field, operated by Petrobangla, and found that the Titas gas reservoir’s drive mechanism was volumetric drive. A review of the literature, including old reports and well drilling data, confirmed that there was no evidence of aquifer drive and gas water contact in the ‘A sand’ layers. Subsurface maps of sands A2, A3 and A4 were redrawn and validated using field data.

Suitability Analysis of the Potential Gas Fields of Bangladesh for Carbon Dioxide Sequestration and A Simulation Approach for Titas Gas Field

Global warming has become one of the major environmental issues all over the world. The temperature of the world is increasing day by day, and fortunately, everybody wants to mitigate this fearful condition from own perspective. Carbon dioxide sequestration is a worldwide recognized project for making huge amount of carbon inactive, which is the main component of greenhouse gases, by sequestrating it beneath the Earth. The paper aims to dictate the probable success of CO₂ sequestration in Bangladesh. As abandoned gas fields are the best options for sequestration, characteristics of the potential gas fields of Bangladesh have been analyzed according to Stefan Bachu's method of classification for CO₂ sequestration. Titas gas field shows the best suitability, and accordingly, an Eclipse simulation software basis approach has been taken for this field to determine possible outcomes from probable sequestration project. Simulation result predicts an amount of 2.92 Tcf carbon dioxide gas to be sequestrated after 50 years of simulation. Other criteria such as field pressure, gas saturation are also evaluated.

Seismo-Stratigraphic and Structural Interpretation of Seismic Data of Titas Gas Field, Bengal Basin, Bangladesh

ABSTRACT In the present study, seismic interpretation has been carried out over Titas structure of Bengal basin, Bangladesh to figure out its seismo-stratigraphic and structural behavior. Seven well marked reflecting horizons (R-01 to R-07) have been identified within the Neogene sedimentary sequences using 18 seismic sections and well log data. A new seismic stratigraphy of Neogene sequences has been proposed for the Titas structure ruling out the traditional lithostratigraphy. The studied structure has been divided into 3 megasequences (MS1, MS2 and MS3). Reflector R-01 and R-03 represent the tops of the megasequence 2 (MS2) and megasequence 1 (MS1) respectively. These well marked reflectors are correlated with the top of the traditional litho-groups called Tipam and Surma. Reflectors R-02 and R-04 represent acoustic impedance boundaries within MS2 and MS1 due to lithological gradation. However, R-02 and R-04 are not considered as sequence/ formation boundaries because geologically these are not well defined. Reflectors R-05, R-06 and R-07 represent top of the gas-bearing zones A, B and C that belongs to MS1. All these interfaces or reflectors are anti-form with a central long crestal zone. It forms a north-south trending semi-domal sub-surface anticlinal structure having a semi-dome shaped closure. The structure is asymmetric with steeper eastern flank and gentler western flank. The crestal region is essentially plain with discontinuous reflection. The semi-domal nature of the anticline is in contrast to the neighboring narrow anticlines. Structural pattern suggests its development in relation to the NE-SW trending stress field due to convergence of Indian plate with Burmese plate. Structures of the shallower and deeper reflectors are formed at different phases of structural development.

Localization of fugitive methane emission from natural gas distribution network of Titas Gas

Abstract The aim of this paper is to localize the fugitive leaks from the above ground facilities of the existing system of Titas Gas (TG) after developing mathematical model for fugitive emission. Soap screening techniques and Gasurveyor 500 series instrument were used in this study for detecting potential leaks. Leaked gas was quantified using either Hi-Flow gas sampler or bagging measurements system. The results show that the respective potential gas leaking point of City Gate Station (CGS), commercial Regulating and Metering Station (RMS), industrial RMS, residential RMS and Town Bordering Station (TBS)/ District Regulating Station (DRS) are scrubber dump valve (average leak rate 217.00 L/min), insulating point (average leak rate 4.04 L/min), tube fitting connector (average leak rate 8.00 L/min), connector (average leak rate 1.55 L/min) and pressure relief valve (average leak rate 437.92 L/min). Fugitive methane emission can be reduced by stopping leaks of fittings or components having high KLeak value.

Porosity Assessment of Gas Reservoir Using Wireline Log Data: A Case Study of Bokabil Formation, Bangladesh

Shale volume and porosity are the most important rock properties for petrophysical analysis, formation evaluation and estimation of hydrocarbon reserve in the oil and gas fields. This research shows how to shale volume and porosity estimation of Titas gas field (T-11) using wireline log data of Bokabil Formation in Bangladesh. Shale volume has been estimated from Gamma Ray, Self-Potential logs and True resistivity method. Porosity estimated from single log method as well as from Neutron-Density and sonic logs. Lithology is mainly sand and shale where sand is the dominant fraction. In A2 sand interval of T-11, sand and shaly sand appeared as alternating units. The shales are laminated. Shale volume percentage is ranges from 3.82 to 17.52 averaging 9.23 using Gamma Ray log which is optimistic and more reliable than other two methods. The total porosity (average) percentage is 25.09 based on sonic log which is over estimated but Neutron-density combination formula with clay corrected gives better results as averaging 18.17% which is more reliable for estimation of water saturation, formation evaluation and reserve estimation and similar as core porosity. The porosity quality is good of A2 gas sand which is potential hydrocarbon reservoir.

The Structure and Properties of Carburized and Hardened Vanadium Microalloyed Steels

Three 0.15% carbon steel samples containing small additions of vanadium and nitrogen singly or in combination have been carburized in a natural Titas gas atmosphere at a temperature of 9500C and a pressure of about 15 psia for time periods ranging from 1 to 5 hours and quenched in 10% brine from the carburizing temperature of 9500C after pre-cooling to 8600C in the furnace followed by tempering at a low temperature of 1600C. The structure and properties of the carburized and heat treated specimens were studied systematically by optical microscopy, surface hardness and microhardness measurements, X-ray diffractometry and impact tests. It was found that vanadium without nitrogen does not have any effect in the formation of retained austenite while vanadium with nitrogen is effective in promoting the formation of retained austenite in the case of carburized and hardened steels. It was also found that vanadium alone and vanadium with nitrogen refine the martensite platelets (needles) in the case of carburized and hardened steels, vanadium with nitrogen being more effective. Microhardness measurements have shown that vanadium improves the case hardness and the core hardness values; vanadium with nitrogen is more effective than vanadium alone in increasing the case hardness and the core hardness. The hardenability is found to increase with the increase of austenite grain size and with the extent of carbon penetration of the case of carburized steels. Vanadium as vanadium carbide, VC are detrimental to toughness and vanadium as vanadium carbonitride, V(C, N) are beneficial to toughness of the core of low carbon steels in carburized and hardened condition.

Diagenesis and reservoir quality of Bhuban sandstones (Neogene), Titas Gas Field, Bengal Basin, Bangladesh

This study deals with the diagenesis and reservoir quality of sandstones of the Bhuban Formation located at the Titas Gas Field of Bengal Basin. Petrographic study including XRD, CL, SEM and BSE image analysis and quantitative determination of reservoir properties were carried out for this study. The sandstones are fine to medium-grained, moderately well to well sorted subfeldspathic arenites with subordinate feldspathic and lithic arenites. The diagenetic processes include clay infiltration, compaction and cementation (quartz overgrowth, chlorite, kaolinite, calcite and minor amount of pyrite, dolomite and K-feldspar overgrowth). Quartz is the dominant pore occluding cement and generally occurred as small euhedral crystals, locally as large pyramidal crystals in the primary pores. Pressure solution derived from grain contact is the main contributor of quartz overgrowths. Chlorite occurs as pore-lining and pore filling cement. In some cases, chlorite helps to retain porosity by preventing quartz overgrowth. In some restricted depth interval, pore-occlusion by calcite cement is very much intense. Kaolinite locally developed as vermiform and accelerated the minor porosity loss due to pore-occlusion. Kaolinite/chlorite enhances ineffective microporosity. Kaolinite is a by-product of feldspar leaching in the presence of acidic fluid produced during the maturation of organic matter in the adjacent Miocene or deeper Oligocene source rocks. The relation between diagenesis and reservoir quality is as follows: the initial porosity was decreased by compaction and cementation and then increased by leaching of the metastable grains and dissolution of cement. Good quality reservoir rocks were deposited in fluvial environment and hence quality of reservoir rocks is also environment selective. Porosity and permeability data exhibit good inverse correlation with cement. However, some data points indicate multiple controls on permeability. Reservoir quality is thus controlled by pore occluding cement, textural parameters (grain size, pore size and sorting) and depositional environment. The reservoir finally resumed partly its pre-cementation quality after development of secondary porosity.

Dry sliding wear in case-hardened niobium microalloyed steels

Low-carbon steel samples containing a small addition of niobium singly or in combination with nitrogen have been carburized in a natural Titas gas atmosphere at 950 °C and 15 psi gas pressure for different time periods. At the end of the predetermined time period, the specimens were pre-cooled to 860 °C in the furnace and quenched in 10% brine. One set of the quenched specimens was tempered at a low temperature of 160 °C and the other set was sub-zero treated at −195 °C in liquid nitrogen, followed by tempering at the same tempering temperature. Surface hardness was measured by Rockwell hardness testing machine and optical microscopy was performed on etched samples. Using a pin-on-disc type apparatus, wear test was carried out under dry sliding condition to assess the beneficial effect of niobium and niobium with nitrogen on the wear properties of the carburized and hardened low-carbon steels in relation to the resulted surface hardness and microstructures. It has been found that niobium with or without nitrogen improves the wear resistance under both the heat treatment conditions. Niobium with nitrogen is more effective than niobium in improving the wear resistance. Whatever was the heat treatment condition, the wear rate of the specimens increases for all the steels as the carburizing time increases. It has also been found that samples with sub-zero treatment always have higher wear resistance than that of samples without sub-zero treatment. Niobium singly or in combination with nitrogen has been found as a modifier of the wear mechanism.

Effects of Molybdenum Additions on the Structure, Depth, and Austenite Grain Size of the Case of Carburized 0.13% Carbon Steels

Carbon (0.13%) steel samples containing about 0.48% molybdenum (Mo) singly and in combination with nickel (Ni) were carburized in a natural Titas gas atmosphere at a temperature of 1223 K (950 °C) and at a pressure of about 0.10 MPa (15 psia) for time periods ranging from 1–4 h followed by slow cooling in the furnace. Their microstructure was studied by optical microscopy. The austenite grain size of the case and the case depths were determined. It was found that Mo and Ni alone and in combination decrease the thickness of the cementite network near the surface of the carburized case of the steels. However, Ni is found to be more effective than Mo in decreasing the thickness of cementite network. Both Mo and Ni enhance the formation of Widmanstatten cementite plates at the grain boundary and within the grains near the surface of the carburized steels. However, Ni alone is more effective than Mo in the formation of Widmanstatten cementite plates. In the presence of Ni, Mo is much more effective in the formation of Widmanstatten cementite plates than Mo in absence of Ni. It was also revealed that both Mo and Ni increased the case depth. Ni is more effective than Mo in increasing the case depth. The combined effect of Mo and Ni is much greater than that of either Mo or Ni alone in increasing case depth. Mo as Mo carbide (Mo2C) particles refined the austenite grain size of the carburized case. Ni in solution was not found to have any effect in restricting grain growth of austenite, but the presence of Ni enhances the austenite grain size refining effect of Mo in the carburized case.

Structure and properties of carburized and hardened niobium micro-alloyed steels

Low-carbon steels containing a small addition of niobium singly or in combination with nitrogen have been carburized in a natural Titas gas atmosphere at 950°C for different time periods such as 1, 2, and 4 h. After a pre-determined time, the specimens were pre-cooled to 860°C in the furnace and quenched in 10% brine. One set of the quenched specimens was tempered at a low temperature of 160°C and the other set was sub-zero treated at −195°C in liquid nitrogen followed by tempering at the same temperature of 160°C. The relationship between the structure and the mechanical properties of the carburized and heat-treated specimens was investigated by means of optical microscopy, surface hardness and microhardness measurements, X-ray diffractometry and impact tests. It was found that niobium refines the martensite and reduces the formation of retained austenite in the case of the carburized and hardened low-carbon steels. Niobium with nitrogen was found to be more effective than niobium alone in refining the martensite and in decreasing the retained austenite content. Niobium improves the surface hardness, case hardness and core hardness. Niobium with nitrogen is more effective in improving the surface hardness and case hardness, but is less effective for core hardness than niobium. It was also found that both the NbC and Nb(C, N) particles are detrimental to the toughness of the core of low-carbon steels, but Nb(C, N) precipitates are less harmful than NbC precipitates.

Effects of niobium additions on the structure, depth, and austenite grain size of the case of carburized 0.07% C steels

Carbon (0.07%) steel samples containing about 0.04% Nb singly and in combination with nitrogen were carburized in a natural Titas gas atmosphere at a temperature of 1223 K (950 °C) and a pressure of about 0.10 MPa for 1/2 to 4 h, followed by slow cooling in the furnace. Their microstructures were studied by optical microscopy. The austenite grain size of the case and the case depths were determined on baseline samples of low-carbon steels and also on niobium and (Nb + N) microalloyed steel samples. It was found that, when compared to the baseline steel, niobium alone or in combination with nitrogen decreased the thickness of cementite network near the surface of the carburized case of the steels. However, niobium in combination with nitrogen was more effective than niobium in reducing the thickness of cementite network. Niobium with or without nitrogen inhibited the formation of Widmanstatten cementite plates at grain boundaries and within the grains near the surface in the hypereutectoid zone of the case.