IOSR-JAGG   Volume-2 ~ Issue-5 ~ SEP-OCT-2014

Abstract: Indravati "The lifeline of Bastar" is changing its course, in style and degree in a very short span of time which has invited attention of geo-scientists and policy makers to avoid any expected unpleasant circumstances .Here we have investigated the drainage rearrangement of Indravati river water, where , earlier, Jaura Nala( which used to flow northwards) connecting Kolab river and Indravati river acting as a feeder for Indravati, now flowing southward and draining the water of Indravati, has become a matter of serious concern for the sediment budgets and biotic distributions in the surroundings. Due to the stated changes, the likely hydro morphological impacts have also been discussed along with the possible measures to be adopted to avoid any disparity in future. A serious multidisciplinary probe into the possible causes ,the natural factors and human intervention, is warranted, taking in to account the considerations of changing surface topography including evidences derived from satellite and topographic data, understanding of geomorphological and sedimentological observations and impact due to man made structures like dams on the upstream side in Odisha.

Keywords: River capture, Indravati river, Chhattisgarh.

Abstract: The planned time to drill a geothermal well at Olkaria is sometimes exceeded by a big margin when down hole challenges are encountered whilst drilling. The geographical coordinates of Olkaria are 0o53'09"S and 36o16'12"E. The current drilling practice at the field is balanced pressure drilling. The common down hole problems encountered in the field are loss of circulation, well bore collapse, minimal Rate Of Penetration (ROP) and possible formation damage which consequently leads to reduced productivity of a well. It is evident that, the longer the drilling time, the higher the cost of the well. Underbalanced drilling is the application of drilling fluids to the bore at a pressure slightly lesser than the formation fluids pressure. If the process is well executed, it may lead to the reduction/elimination of most down hole challenges. This research was geared to establishing the effectiveness of Under Balanced Drilling (UBD) in solving the down hole problems experienced at the Olkaria geothermal field. In order to carry out this exercise, simulation of under balanced drilling conditions using the Hydraulic Underbalanced Simulator (HUBS) was done utilizing data from the field. Secondly, the economics of adopting under balanced drilling technology at the field was also done. Data from four geothermal wells namely OW 731A, OW915B, OW731 and OW804 was used in the simulation exercise. Analysis of loss of circulation to well productivity for a sample of 19 wells was also undertaken. Simulated annulus volume fraction profiles showed cuttings concentration of less than 5% and an optimum circulation flow rate of 0.03 m3/min. The costs associated with loss of circulation of drilling fluids on average amounts to USD 127,731.00. Most of the wells sampled had over 70% of the drilled depth experienced no loss of circulation during drilling. Wells which had a circulation regime of full returns, partial returns and no returns have shown that their productivity is higher compared to the other categories and had an average production capacity of 12.03 Mw

Keywords: Underbalanced drilling, Formation damage, Rate of penetration, Loss of circulation and down hole challenges.

Abstract: The friable quartzite zone near Barodia in Bundi district of Rajasthan has been met with almost continuously for a distance of about 1,400 yards in a general E-W direction. It is developed along the slopes of a chain of quartzite ridges, near the base of the lower Bhander quartzites. The width of this zone as measured on a horizontal plane varies from 50 to 300 feet. The depth of the friable zone is not known and could not be determined. The friable rock, however, has been met upto a depth of 25 feet in the existing workings and can be reasonably assumed to extend up to a depth of at least 50 feet. The good plantation indicates eco-friendly mining activity in the mine site of silica sand mining.

Key words: Silica-sand,Great Boundary Fault, Eco-friendly Mining etc.