Cleaning Oil Wells by Heated Oil

Abstract

There are over 200,000 oil wells in the United States that average less thana barrel of oil a day. Many of these wells are old - 25 years and over - yetthey penetrate and give access to unmined reserves of great potential value.The leading men in the industry in recent years have regarded as inevitable animprovement in producing methods by which a more satisfactory recovery could behad. Conditions in Settled Fields The rock pressure in settled fields has become practically nil, the "paysand" is fine-grained with porosities of capillary size, the rocktemperature is such that the oil is thick and viscous, the capillary resistancealmost equals the force of gravity and it is a wonder that any oil at allreaches the well. The average spacing of wells is about one well to eight acres. This is about 600 ft. apart. The sand immediately around the bore of the well, which hasacted as a strainer for all the oil produced from the eight acres, in thecourse of time becomes clogged up by the heavy compounds in the oil passingthrough it. If there is a flow or tendency of movement of the oil in thestratum, why should the oil flow through this small clogged area into the well? Still with the initial flush production and years of dribbling, an average of 20 per cent of the oil is recovered. Method of Cleaning Wells Most methods of cleaning oil wells have had for their objective thedeparaffining of the wells. The so-called paraffin base oils, as of Pennsylvania, leave a deposit of paraffin wax in the face of the sand andparaffin wax accumulates in the well itself and on the face of the pay sand, sensibly retarding the flow of oil. Almost no attempts have been made to cleanwells producing an asphalt base oil. All methods of cleaning, however, are beneficial and temporarily greatlyincrease the production, but they are all costly and of temporary value. The chief objection is that in every case the well must be shut down, the pumptubing and rods pulled and the treatment given. Then the well is restoredphysically to a producing condition and left to get dirty and plugged upagain.