In [1]:
%pylab inline

Welcome to pylab, a matplotlib-based Python environment [backend: module://IPython.kernel.zmq.pylab.backend_inline].
For more information, type 'help(pylab)'.

In [2]:
import numpy as np
from scipy.interpolate import splprep, splev
import matplotlib.pyplot as plt
import mayavi.mlab as mplt
from mpl_toolkits.mplot3d import Axes3D


Define a borehole path¶

We define the trajectory of a borehole, using a series of x,y,z tuples, and make each component of the borehole an array. If we had a real well, we load the numbers from the deviation survey just the same.

In [3]:
trajectory = np.array([[   0,   0,    0],
[   0,   0, -100],
[   0,   0, -200],
[   5,   0, -300],
[  10,  10, -400],
[  20,  20, -500],
[  40,  80, -650],
[ 160, 160, -700],
[ 600, 400, -800],
[1500, 960, -800]])
x = trajectory[:,0]
y = trajectory[:,1]
z = trajectory[:,2]


But, since we want the borehole to be continuous and smoothly shaped, we can up-sample the borehole by finding the B-Spline representation of the well path,

In [4]:
smoothness = 3.0
spline_order = 3
nest = -1 # estimate of number of knots needed (-1 = maximal)
knot_points, u = splprep([x,y,z], s=smoothness, k=spline_order, nest=-1)

# Evaluate spline, including interpolated points
x_int, y_int, z_int = splev(np.linspace(0, 1, 400), knot_points)

plt.gca(projection='3d')
plt.plot(x_int, y_int, z_int, color='grey', lw=3, alpha=0.75)
plt.show()


Define frac ports¶

Let's define a completion program so that our wellbore has 6 frac stages,

In [5]:
number_of_fracs = 6


and let's make it so that each one emanates from equally spaced frac ports spanning the bottom two-thirds of the well.

In [6]:
x_frac, y_frac, z_frac = splev(np.linspace(0.33, 1, number_of_fracs), knot_points)


Make a set of 3D axes, so we can plot the well path and the frac ports:

In [7]:
ax = plt.axes(projection='3d')
ax.plot(x_int, y_int, z_int, color='grey', lw=3, alpha=0.75)
ax.scatter(x_frac, y_frac, z_frac, s=100, c='grey')
plt.show()


Set a colour for each stage by cycling through red, green, and blue,

In [8]:
stage_color = []
for i in np.arange(number_of_fracs):
color = (1.0, 0.1, 0.1)
stage_color.append(np.roll(color, i))
stage_color = tuple(map(tuple, stage_color))


Define microseismic points¶

One approach is to create some dimensions for each frac stage and generate 100 points randomly within each zone. Each frac has an x half-length, y half-length, and z half-length. Let's also vary these randomly for each of the 6 stages. Define the dimensions for each stage:

In [9]:
frac_dims = []
half_extents = [500, 1000, 250]
for i in range(number_of_fracs):
for j in range(len(half_extents)):
dim = np.random.rand(3)[j] * half_extents[j]
frac_dims.append(dim)
frac_dims = np.reshape(frac_dims, (number_of_fracs, 3))


Plot microseismic point clouds with 100 points for each stage. The following code should launch a 3D viewer scene in its own window:

In [10]:
size_scalar = 100000
mplt.plot3d(x_int, y_int, z_int, tube_radius=10)
for i in range(number_of_fracs):
x_cloud = frac_dims[i,0] * (rand(100) - 0.5)
y_cloud = frac_dims[i,1] * (rand(100) - 0.5)
z_cloud = frac_dims[i,2] * (rand(100) - 0.5)

x_event = x_frac[i] + x_cloud
y_event = y_frac[i] + y_cloud
z_event = z_frac[i] + z_cloud

# Let's make the size of each point inversely proportional
# to the distance from the frac port
size = size_scalar / ((x_cloud**2 + y_cloud**2 + z_cloud**2)**0.002)

mplt.points3d(x_event, y_event, z_event, size, mode='sphere', colormap='jet')


You can swap out the last line in the code block above with mplt.points3d(x_event, y_event, z_event, size, mode='sphere', color = stage_color[i]) to colour each event by its corresponding stage.