Three kinds of fractures, i.e., regional, local and compound fractures, are present in the petroliferous Lower Jurassic Series in the western edge of the central segment of Huaying Mountain, Sichuan basin. The regional fractures ( joints ) include 4 sets which make up 2 sys tems, and are characterized by steady strikes, deep cut, long stretches and being vertical to the stratification plane. Each set of the joints has the same original strike, and the distribution of the joints is controlled by the nature of the rock and the thickness of the strata, and not by the structure.In comparison, the distribution of the local fractures is controlled not only by the nature of the rock and the thickness of the strata, by also by the structural feature. Local fractures are smaller in scale, shorter and typically wider than the regional ones. The compound fractures display the character of both regional and local fractures, with their distribution being only local, controlled by local structure features.
Many parameters extracted from mercury injection curves have been used to describe the character of reservoir pore structures. In this paper, a new pore-structure parameter, RApex, derived from mercury injection capillary pressure data is introduced. The physical meaning of RApex is the pore throat radium of a pore system with good internal connection and continuity formed when mercury is injected into the rock sample. The procedure to obtain RApex is described. Applications of RApex are illustrated with a gas-field case study in which the parameter was used for grading reservoirs and delineating stratigraphic positions favorable for hydrocarbon accumulation, and satisfactory results were obtained.
In this paper, the convolution model of synthetic seismic trace is replaced by the first Fredholm integrated equation, which is then solved by using Walsh equation. A variety of models have been tested on the computer and satisfactory results are obtained. Application of the method proposed in this paper is thus believed to be potentially prosperous.
The development and evolution of the Santanghu basin were controlled by the plate-tectonic background in different periods, leading to the formation of three types of proto-basins, namely, collision foreland basin, peripheral foreland basin and regenerated foreland basin. The superimposition and imprinting of the latter basin(s) on the former have given rise to the formation of a variety of petroleum systems. On the basis of the characteristics of tectonic evolution, source rocks, and reservoir and cap rocks of the basin, three types of petroleum systems have been recognized, and the principal characteristics and level of confidence of each of the systems are analyzed.
This paper analyzes the stress and deformation of casing string with casing stabilizers, deduces the calculation model of frictional drag of casing string in horizontal wells. The model takes into account the effect of stiffness of the string element and the effect of casing string stabilizers, and makes smoothing and interpolation to the measured well inclination data. The software based on the model is used to predict the frictional drag and hook load of running completion casing string in the experimental horizontal well (Well No. HW701) in Kelamayi oilfield, and the calculated results agree with the measured data.
A method of remote measurement of torque on drilling string (including suspending and drilling weight) while drilling is introduced in this paper .Two ”joints” are added to the top and bottom ends of the Kelly respectively. The torque and suspending weight transducers and signal processing circuits are installed in the joints. The signals of torque and drilling weight, therefore, may be transmitted and received through modulation frequencies. The advantage of this method is that the actual torque acting on the kelly can be measured while drilling.
This paper describes the experimental study of improved filtration reducer SPNH at high temperature. Experimental results show that the improved SPNH is capable of reducing filtration and viscosity, is anti-temperature and antisalt, and has high thermal stability and low cost. Its performances are remarkably better than other cognate sulphonated additives.
This paper presents a new method of performance prediction of oil and water production in oil-fields with water injection. The method is adaptive to various random factors in the process of oilfield exploitation. By using neural network models of nonlinear time series prediction, we constructed neural network predictors for the oil production and water production of oilfields. Prediction results show that the predictors have high accuracy and can be used for prediction of oil and water production in different production periods. This method improves the theory of the performance prediction of oil and water production. Two examples of performance prediction were given in this paper.
This paper considered the effect of formation damage and well completion methods and well completion parameters on the productivity of horizontal wells, and studied the mathematical models for the productivity prediction of the horizontal wells with open hole series of completion methods such as real open hole, slotted liner, wire wrapped screen, open hole down hole gravel pack, open hole prepacked gravel liner, perforated liner with open hole packer, perforated liner with open hole packer and external casing packer (ECP), and so on. Example calculations show that the mathematical models and their calculation methods are reasonable. They can be used to guide the optimum selection of well completion methods and the optimum design of well completion engineering.
In this paper, we get the general solution of generalized convection-diffusion (C-D) equation in Laplace space, and then get the solution under the condition of uniform pressure or non-permeable outer boundary, taking wellbore storage and skin effect into account. We calculate and discuss the effects on dimensionless bottom hole pressure (Pwd) of porosity spectral exponent, permeability spectral exponent, wellbore storage coefficient, and skin factor. After the effect of non-permeable boundary condition reaches the bottom hole ,a straight line on log-log plot yields with slope of 1.0.
The DL-1 device for lost circulation control simulates the extrusion and static pressure difference of the wellface by applying confined pressure, driving pressure and back pressure to the core, and simulates the state of the drilling fluid flowing in downhole annular space by using the model of parallel plate pore flow, which makes the shear stress of the drilling fluid to the core end plane the same as that to wellface, thus makes test conditions highly similar to downhole environment. This paper explains the thought, requirement and plan of the design of the device, and presents the main structural design. Test of the device conducted in Changqing oilfield for lost circulation control was successful.
In this paper, the high pressure fluid end of water injection pump was analyzed with three-dimensional finite element method, and the distribution law of stress at the fluid end was obtained. It can be used for the strength design of high pressure fluid end of water injection pump.
A set of practical soft wares about natural diamond bit design was developed by applying the techniques of Computer Aided Design (CAD). The use of these soft wares makes bit design more scientific and more effective. This paper describes the principle and content of these soft wares.
This paper discusses the working mechanism and the design and calculation methods of the transmission with magnetic couplers. This paper puts focus on some noticeable aspects in designing the magnetic coupler for high fluid pressure facilities. The authors have designed and built some magnetic couplers, which work at 15 MPa. These magnetic couplers have been performing very well for two years.
A cement slurry, whose density was 1.5 g/cm3, had been prepared using class-G oil-well cement with silica fume as a thermo stabilizer and microsphere as light-weight admixture. After curing at 45℃and atmospheric pressure for 48 hours, the cement slurry displayed a compressive strength of 15 MPa; the water loss ( at 7 MPa for 30 min. ) was less then 250 ml and no free water was observed. After curing at 350℃and 20 MPa for 3 days, the cement slurry had a compressive strength of more than 10 MPa. Such a temperature-resistant, lightweight cement slurry can be used for well cementing in low-pressure, viscous oil reservoirs planned for thermal recovery to considerably reduce the high temperature-induced strength decline of the cement and prolong the life span of the producing well.
Personal Digital Assistant (PDA) is a new kind of computer product. This paper discusses the historical development, characteristic and future of PDA and its position in the market. The paper also introduces the overall conception of designing the Petroleum Engineering Personal Digital Assistant (PEPDA)—one of the“National 863 Projects”.
A preliminary Approach on Specialized PDA Platform Design, JSWPI, 1997, 19(2):This paper discusses the importance of developing specialized PDA platforms and the different levels of a specialized PDA platform. Together with the presentation of developing a petroleum engineering PDA, the required functions and features of each of the platform levels are proposed .
GIS is widely used in recent years, it can improve applying environment of traditional DBMS. The paper describes the application of GIS in petroleum sector briefly. Production control in oil gas field is a basic event of gas field management. Applying GIS to oil gas field management can make decision more concrete and visual. Basic content of control system of oil gas field production is put forward in the paper. It also discuss the general method of constructing instruction system platform of oil gas field production based on GIS and key technique.
