FIRST SHOWING OF OIL

Taranaki Daily News, 23 August 1930, Page 11

FIRST SHOWING OF OIL

MOTUROA .OILFIELDS' WELL

WATER TO BE CEMENTED OFF.

DRILL NEARING CRITICAL DEPTH

Following upon a violent blow-out of gas at the Moturoa Oilfields, Ltd., well on Thursday, the first showing of oil since the company has been drilling appeared plentifully yesterday. It was a light oil that fairly easily evaporated, and had apparently filtered through the strata from a greater depth to the point reached by the drill, 2123 feet from the surface.

Within the 10-inch casing that lines the upper portion of the well a string of 8-inch casing has been lowered as the drilling progressed. A heavy flow of gas met at 1740 feet was augmented by the addition of further gas, and at a depth of 2123 feet a" violent blow-out of gas occurred on Thursday morning, coming up to the surface between , the 10-inch and 8-ineh casing. This occurrence was quite unexpected, and presented a very difficult problem for the drill superintendent and his crew, as the pressure of gas at times was in excess of 6001 b. to the square inch. It was almost impossible to get within the derrick owing to the continuous rush of gas out of the vent high into the air, but working under these exacting conditions, which made even breathing a very difficult matter, the men eventually secured control of the gas at 11 o’clock yesterday morning by fitting a collar and valve over the space between the two strings of casing.

LIQUID MUD PUMPED IN. Liquid mud was then poured into the. well by high pressure pumps, the method being to lead, the mud from the sump through a flexible hose and valve into the top of the eight-inch casing, utilise the pressure of the harnesssed gas, and drive the mud down 2123 feet to the bottom of the casing, allowing it thence to -circulate, up outside the 8-in. casing, where it effectively sealed, at any rate temporarily, the strata round the 8-in. easing through which the gas was making its way. At a higher level the mud entered the space between the 10inch and 8-inch casing through which the gas had previously beeen blowing out, and was finally led through a valve and flexible hose baek to the sump from which it came. Altogether about 15 tons of mud was pumped into the well yesterday. During the process of ■ this operation a good showing of oil was noticed flowing with the liquid mud out of the casing into the mud sump. This oil ultimately collected in a layer on top of the sump. The oil was very light, and the indications were that it had filtered through the strata from a greater depth. The showing of oil appeared rather earlier than was expected, and created considerable optimism amongst the authorities directing the drilling.

An inspection of the well last night showed that the escape of gas had entirely, stopped, thus indicating that the circulation of liquid mud had done its work effectively. The derrick was bespattered with mud, and a layer of oil was visible floating on top of the mud sump. The drilling superintendent (Mr. C. Taylor) stated, however, that owing to its lightness a certain amount of the oil had evaporated. CEMENTING-OFF THE WATER. Mr. Taylor stated that the intention now was to cement off all the water above the point where the present oil indications had occurred. This would be done by forcing about five tons of liquid cement round the outside of the 8-ineh casing in the same way in which the mud was circulated yesterday. The level at which oil was found in wells drilled many years ago on the Moturoa oilfield was at a depth of approximately 2300 feet. Allowing time for the cementing process, this depth, said Mr. Taylor, should be reached within the next five or six weeks at the Moturoa bore.

The operations of the three companies at present drilling near New Plymouth —Moturoa Oilfields, Ltd., Coal Oil (N.Z.), Ltd.j at Omata, and the. Blenheim Company—are now rapidly approaching the critical stage when the .drill wui tell whether oil exists in payable quantities or not. Drilling is temporarily suspended at the Blenheim bore owing to tools having been lost down the well, and the me J are fishing for the tools and a broken rope. The Omata bore is drilled to 1985 feet in hard shale, and drilling is more or less suspended while a new type of bit is being obtained.