Most sand-consolidating p!ast[cs require the sequential injection of at least four di#erent treating solutions to either catalyze the pfastic or to prepare the formation to receive the plastic. In addition, the jormation is consol!dated into a rigid, brittle mass of less strength than is fre-q~ently necessary to withstand down-ho[e stresses. A theoretical study and subsequent research to -remove these [imitations led to the development of a moisture-cured urethane elastomer which consolidates the sand in a tough, rubbery matrix that wilt undergo considerable movement without sloughing. This property allows the consolidated mas,r to deform arotind the casing so that the casing itself withstands the stresses. A typical treatment consists of the injection of {1) a small volume @ kerosene or diesel oii to establish an injection rate, (2) the polyurethane solution, and (3) a diesel oil overfiush to establish permeability. The polyurethane is catalyzed by the fortnation water and therefore exhibits relatively unlinthed placement time.To date, this technique has been used in six wells experiencing severe sand problemk in the Gulf Coast area. Three wells have been unqualified successes, one was abandoned prior to full evaluation and two failed to restrain the sand.

This paper presents results of analysis of the effect of fracturing on initial flow rates and on ultimate recoveries from low capacity oil formations. This analysis shows that even in formations of permeability as low as 0.1 md, large fracture treatments can yield oil recoveries and production rates approaching those of high permeability formations. Field production information is shown which supports the analytical work. Introduction Often hydrocarbon bearing formations are discovered which, while they are known to contain large quantities of oil, will not produce at commercially attractive rates without special well stimulation. Attempts to solve this problem led to the development of such techniques as underreaming, shooting, acidizing, and recently hydraulic fracturing. These methods of stimulation have been highly successful in many fields. All of these treatments, however, affect only the pay section near the well bore and therefore owe their success to circumventing and overcoming local permeability reduction about the well bore. It has been the belief that in treating wells to stimulate production in which there is no permeability reduction near the well, the maximum possible production rate increase would be of the order of two or fourfold. Hence, it has been concluded that fracture treatment of uniformly low capacity (permeability times thickness) formations could meet with but limited success. It is the purpose of this paper to show that the use of fracture treatments much larger than usually used can yield commercially attractive producing rates and high recoveries even in formations of permeability less than 0.1 of a md. Procedure In order to illustrate the effects of fracturing, an analytical study of some hypothetical systems was made in which one factor at a time was varied to show what is important in recovering oil from fractured wells.

This paper concerns the rupture or breakdown of rock formations as related to drilling, completing, and stimulating production of wells, and comprises data compiled from a study of literature and records of treatment of oil and gas wells, and from tests conducted in bores drilled into rock cores and outcrops of rock. Results of the investigation indicate that the internal pressure to rupture cylinders of rock and to breakdown rock formations surrounding a bore in the earth is dependent upon the extent of intrusion of fluids, the position of bedding planes, the ratio of internal to external diameter. the tensile strength of rock, and magnitude of confining pressure, and is independent of the size of bore, degree of fluid saturation, and temperature of rock within practical limits.It is concluded that the mathematical relationship of pressure in bores and stresses in the surrounding rock must not be limited by the simplifying assumptions of homogeneity, isotropy, and impermeability; that the incidence of lost circulation of drillin~ fluids to induced fractures may be reduced by preventing intrusion of fluids into the small intrinsic fractures along weak bedding planes; and that the magnitude of the breakdown pressure of wells to be treated may be lowered by removal of mud cake. PROCEDUREThe investigation was initiated with a study of the theories pertaining to the rupturing of thick-walled cylinders of homogeneous, isotropic, impermeable material and a study

Bearden, William G., SPE-AIME, Pan American Petroleum Corp. Pan American Petroleum Corp. Cocanower, R.D., SPE-AIME, The Western Co. Currans, Dan, SPE-AIME, Pan American Petroleum Corp. Pan American Petroleum Corp. Dillingham, Mat, SPE-AIME, The Western Co. The problem of measuring fluid flow in borehole sections with irregular diameters is identified, and corrective measures are developed for obtaining more exhaustive injectivity profile information. Introduction Since the first use of injection and production profiles using tracer-velocity logging techniques with the interpretation method based on hole-diameter information, there has been difficulty in obtaining reliable information in irregular boreholes. Most of the difficulties have arisen in those areas where the size, of the hole changes. A typical example of the errors of calculated velocity data is shown in Fig. 1. The velocity measurements recorded from 4,950 to 4,970 ft were in a section of nonuniform-diameter wellbore as shown by the caliper survey. The usual practice was to delete the erratic velocity data and construct an average profile through this section or to use the Self profile to determine the fluid losses. The primary purpose of our study was to investigate the influence of hole diameters and hole diameter-changes on the validity of tracer ejector readings. The secondary purpose was to investigate the accuracy of profiles in an irregular-shaped hole from which known profiles in an irregular-shaped hole from which known leak-off rates could be established by the tracer-velocity technique and Self Profile Method. Test Equipment and Methods The basis for this study was a series of large-scale tests performed at the Pan American Research Center, Tulsa, Okla. Four different apparatuses, as shown on Fig. 7, were used to simulate various wellbore configurations with diameters varying from approximately 4 3/4 to 23 1/2 in. Water was flowed through these apparatuses at various rates, and controlled leak-off points were installed at selected sections. A 1 3/8-in. points were installed at selected sections. A 1 3/8-in. standard tracer-ejector tool with dual gamma-ray detectors was used to make readings at various locations in the cells. These readings were then converted to flow rates and compared with the actual flow rates, which were simultaneously being metered. Two types of profiling techniques were investigated during this study. The first, using the tracer-velocity profile, involved ejecting a small volume of profile, involved ejecting a small volume of water-soluble radioactive-tracer material into the flow stream, then observing the length of time required for the material to pass two detectors spaced 5 ft apart. This time is an inverse function of the fluid velocity, which, if we know the hole diameter, may be converted to rate with Eq. 1. The second method investigated was the Self profile method. This method measures the radiation profile method. This method measures the radiation intensity of a moving slug of radioactive material in the borehole. As water is lost to the formation, a decrease in intensity provides information for constructing an injection profile independent of hole diameter. Test Procedures The first series of tests was performed on the apparatus as shown in Fig. 7a. Metered water entered at the top and exited at the bottom. The tracer-ejector tool was stationed at five different locations in the apparatus to record velocity readings at several different metered flow rates. In all, there were 43 readings. JPT P. 1089