It is of course impossible to devise a form for production records which will have a universal application. Factors in one field, which are locally important, may be unheard of elsewhere. Whatever form is used should be a condensed summary of essen tials, arranged in a manner that can be quickly comprehended.
The form suggested in Fig. 62 is elastic and includes factors which are regarded as having an importance in most areas.
The blank form can be drafted as a tracing, from which prints are taken and entries made on the latter under their respective heads. Some data will vary with time as the property is drilled. Such, notably, is Spacing.
A small graphic representation of the section or lease will give at a glance the locations and relative positions of wells. While the scale is necessarily small, it will show the well arrangement without referring to the larger lease or property maps. Where production is obtained from several sands, the average depth, thickness, porosity, and spacing should berecorded. The per cent of porosity may not be obtained from every well unless a special effort is made to do so at the time the well is drilled. Such determinations can be made from fragments of the sand which are drilled out or shot out while the well is being completed.
For the sake of comparison, the initial 24-hr. production of new wells is entered. While the determination of the future value of a well is erratic when judged from its initial production alone, it may sometimes be desired for that purpose. The extent to which initials maintain the level of production for the field, and the decline of initials as the property is drilled, may be of value also.
Where water is made with the oil, the amount of each should be entered as separate monthly production. Aside from the economic angle of the amount of water lifted by a certain well, it serves as a check to determine how rapidly one decreases as the other grows in volume. Steps may be taken to remedy defects in a single well before conditions have reached a critical stage. Where several wells begin to produce water with the oil, it is possible to determine the cause by noting the sequence of wells making water and the rate of increase for each. The measures necessary to preserve other wells from the casing leak of one of their number and the problem of encroaching bottom water are, clearly, widely different.
When a well is deepened to lower producing horizons it is ad visable to indicate that fact in the production records. Allow ance must be made in such instances for the sudden change in the rate of decline. The new sand, for all practical purposes, will per form like a new well, adding its high initial to the settled yield of the older sand. Where a well is deepened, some symbol, such as initial letters can be employed to indicate its deepening and the sand reached. This symbol can then be entered under the month when the deepening was completed.
Wells often show an abnormal decline until they are cleaned.
If the increased production following cleaning is entered without making note of the cause of the increase, it may lead to false conclusions later. Where neither deepening nor cleaning are recorded, any one following the production figures is at a loss. A sudden flare-up in production due to cleaning and a similar increase as a result of deepening may be due to either, but there should be no room for conjecture.
The production record, containing all essentials, can be kept on a form of convenient size. Sheets 10 by 12 in. are large enough for most purposes. Total production for each well and for the lease or section may be entered-as a summary. The leaves can then be bound to form a production record book.
Casing records will have a value to both auditor and engineer, while casing records fall in the prov ince of the latter only. The two have nothing in common, the casing records being confined entirely to the mechanical end of individual wells. The necessity for preserving such information is apparent. Almost any operator knows of instances where a change was undertaken on the mechanical equipment of a well when it was discovered too late that some important detail was not as anticipated.
The casing record can be made either as a graphic repre sentation or in the form of a table. For the purposes of record, it is felt that the latter is better since less time is consumed in filling in the desired information. In case of trouble with one of the wells, it is often advantageous then to make the graphic from the table. Remedial measures can be more easily planned when casing, tubing, shut-offs, and the like are visualized.
Where the drilling methods are standardized a form may be drawn up as a tracing, from which entry blanks are taken. Hori zontal spaces can be used for casing sizes—conductor at the ex treme left, followed by the largest casing used, that in turn by the next largest, and so on in succession until the smallest size is reached. Vertical spaces are reserved for wells, each of which is entered by name or number. Following the description of the well, the surface elevation is given as so many feet above the sea level. In the space under conductor, enter the depth in feet to which the latter was carried.
The same is done in succession for each of the casing strings, showing the depth in feet at which each size was landed. Points at which casing was cut or perforated, water shut-offs and type of same, liners, adapters, depth of working barrel and valves are additional items. Suitable space is reserved for the date of com pleting each well, whether shot or natural—with a shot record, if the former—and the dates of pulling and cleaning out.
Much of the bulk of such a record can be reduced by employ ing symbols to represent such details as shut-offs, perforations and the like. No set form can be followed, however, because methods and equipment are so variable. See form in Appendix, page 272.